WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Ecology And Ecological Organization

Chapter 5 Environment And Its Resources Summary

  1. Ecology is the study of interactions between organisms and their environment including other organisms.
  2. Levels of organization in ecology include organism the population, community, ecosystem and biosphere.
  3. An ecosystem is all the living things in an area interacting with all of the abiotic parts of the environment.
  4. Adaptations allow organisms to live in different types of habitats.
  5. Sun loving plant is called heliophytes and shade tolerant plant is called sciophytes.
  6. Plants of dry areas are called xerophytes.
  7. Some animals resist the effect of cold called freeze tolerant animals, some are drought resistants or drought evaders.
  8. Places with high humidity have greater biodiversity.
  9. Megatherms are the plants adapted to high temperature and microtherms are the plants adapted to cold climate.
  10. Animales undego hibernaion to avoid cold climate and to avoid. high temperature they undergo aestivation.
  11. Members of a species, inhibiting same place, collectively called population. Natality, mortality, migration are some factors that affect population growth.
  12. Interactions amongst different species in a biotic community are-cooperation, competition, predation and parasitism.
  13. Cooperation may be of different types:
    1. Symbiosis
    2. Mutualism
    3. Commensalism.
  14. Functional interrelation between biotic community and their habitat constitutes an ecosystem.
  15. An ecosystem constitutes two types of components or factors:
    1. Abiotic
    2. Biotic.
  16. The functioning of ecosystem depends on the food chain, food web, energy flow, and nutrient cycle.

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WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Ecology And Ecological Organization

WBBSE Class 9 Ecology Solutions

Chapter 5 Environment And Its Resources Ecology And Ecological Organization Short Answer Type Questions

Question 1. What is meant by environment?

Answer:

Environment:-

All physical, living and non-living components surrounding the living organisms, which show direct or indirect impact on their behaviour, reproduction and lifestyle, are collectively known as environment.

WBBSE Class 9 Life Science Solutions

Question 2. What is ecology?

Answer:

Ecology:-

Ecology is the branch of science, dealing with blooming and leaf abscission in plants and breeding and migration in animals, depend upon the relative length of light and dark periods.

Question 3. What is an ecosystem?

Answer:

Ecosystem:-

An ecosystem is a functional unit of nature, where various living components interact with each other and with the non-living components, in a specific environment.

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Question 4. What is autecology?

Answer:

Autecology:-

The branch of ecology dealing with the study of interrelation amongst different members of a single species (population) with each other and with the environment, is called autecology. Ecology of termites is an example of autecology.

Key Questions on Ecology for Class 9

Question 5. What is synecology?

Answer:

Synecology:-

The branch of ecology dealing with the study of interrelation amongst members of different species (community), residing in diverse environment, with each other and with the environment is called synecology. Ecology of a forest is an example of synecology.

WBBSE Class 9 Life Science Question And Answer Question 6

Mention three environmental factors, which have direct impact on organisms at individual level.

Answer:

Environmental Factors, Which Have Direct Impact On Organisms At Individual Level:-

Light, relative humidity and temperature are three main environmental factors, which have direct impact on organisms at individual level.

Question 7. What is photoperiodism?

Answer:

Photoperiodism:-

The physiological activity of various organisms depending upon the length of day or night is known as photoperiodism. For example, light for blooming, are called short-day plants. Example-Rice, cotton, sugarcane, dahlia, etc.

Question 8. What is meant by long day plant?

Answer:

Long Day Plant:-

The plants, that require a longer span of daylight for blooming, are called long-day plants. Example-Mustard, radish, etc.

Practice Questions for Chapter 5 Ecology

Question 9 What is meant by the short-day plant?

Answer:

Short-Day Plant:-

The plants require a shorter span of the day living and living components of an environment.

Question 10 Which physiological activities of plants are affected mainly by relative humidity?

Answer:

The rate of transpiration, water absorption and germination of seeds are some physiological activities of plants, which are directly affected by relative humidity.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization short day plant dahlia

Important Concepts in Ecological Organization for Class 9

Question 11 How does environmental temperature affect the biological activities of plants?

Answer:

Environmental Temperature Affect The Biological Activities Of Plants As Follows:-

Distribution of vegetation, rate of metabolism, blooming of flowers, transpiration, etc. are various biological activities of plants, which are directly affected by environmental temperature.

WBBSE Class 9 Life Science Question And Answer

Question 12. Mention a few examples of the impact of environmental temperature on animals.

Answer:

Few Examples Of The Impact Of Environmental Temperature On Animals:-

1. The sex ratio of rat fleas and Daphnia are affected by temperature.
2. Hyla, the tree frog becomes darker in colour in higher temperatures.
3. The body size of birds and Daphnia mammals of the cooler regions becomes larger.
4. At higher temperatures, the metabolic rate becomes higher.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization daphnia

Question 13 What is natality? Express natality by an equation.

Answer:

Natality And Equation For Natality:-

Natality: Natality or birth rate can be defined as, the ratio of total live births to total population in a specified community or area, over a specific period of time.

Expression: Natality is expressed as the number of live births per 1000 of the population per year. It is represented by the following nb equation

B = \(\frac{nb}{N}\) x 1000, where, B = birth rate or natality, N = total number of individuals in a population, nb = number of live births.

Question 14 What is mortality? Express mortality by an equation.

Answer:

Mortality And Equation For Mortality:-

Mortality: Mortality or death rate can be defined as, the ratio of total deaths to total population in a specified community or area, over a specific period of time.

Expression: Mortality is expressed as the number of deaths per 1000 of the population per year. It is represented as the following equation-

D = \(\frac{nd}{N}\) × 1000,

where, D= Death rate or mortality, N = Total number of individuals in a population, nd Number of deaths.

Question 15 What is meant by absolute natality?

Answer:

Absolute Natality:-

The theoretical rate of increase of a population size in presence of all favourable factors and complete absence of any negative factor related to birth, is known as absolute natality.

Question 16 What is meant by realized or ecological natality

Answer:

Realized Or Ecological Natality:-

The true rate of increase of a population size, in presence of all controlling factors (environ- mental pressure) acting on the birth of new members, is called realised or ecological natality.

Question 17 Why is absolute natality higher than realized natality?

Answer:

Absolute Natality Higher Than Realized Natality:-

In nature, different controlling factors restrict the reproductive process and increase foetal death. Therefore, the natality value never reaches that level as expected in an ideal setup. That is why, absolute natality becomes higher than realized natality.

Question 18 What is migration?

Answer:

Migration:-

Migration is the movement of animals or human beings, individually or in large group, from one place to another, temporarily or permanently, due to environmental or biological factors.

Question 19 Why do animals migrate from one place to another?

Answer:

Animals Migrate From One Place To Another:-

Animals migrate from one place to another due to seasonal food and water scarcity, temperature change, natural calamities like excessive rainfall or snowfall, population pressure and in search of good breeding place, etc.

Question 20 What is immigration? What is its impact on a population?

Answer:

Immigration And Impact Of Immigration On Population:-

Immigration: Immigration is the permanent inflow of a bulk of animals or human beings, from any other locality into a population.
Impact: Immigration increases the size of a population.

Question 21 What is emigration? What is the impact of emigration on a population?

Answer:

Emigration And Impact Of Emigration On Population:-

Emigration: Emigration is the permanent exit of the bulk of animals or human beings of a population from their habitat to some other place. Impact: Emigration reduces the size of a population.

Question 22 What is meant by population density?

Answer:

Population Density:-

Population density is the number of individuals of a population, residing in a unit area of their natural habitat. It can be expressed by the following equation-

D = \(\frac{N}{A}\)

where, D = Population density, N = Number of individuals of a population, A = Area of the natural habitat.

Question 23 What is the population? What is the population size?

Answer:

Population And The Population Size:-

Population: Population is an aggregate of naturally interbreeding individuals inhabiting in the same geographical area at a certain period of time.

Population size: Population size (usually denoted by N) is the number of individual organisms in a population.

Question 24 What is carrying capacity?

Answer:

Carrying Capacity:-

Carrying capacity of an ecosystem is the maximum population size of a given species that the environment can sustain indefinitely, by providing the necessary resources (food, water, habitat) available in the environment.

Question 25 What is overpopulation?

Answer:

Overpopulation:-

If the population size of a species exceeds the carrying capacity of the environment for that particular kind of species, then this unsustainable condition is known as overpopulation. Various factors like, increased natality, reduced mortality, increased rate of immigration or depletion of resources are responsible for overpopulation.

Question 26 What is biotic community?

Answer:

Biotic Community:-

A biotic community is a natural assemblage of a number of interacting populations that occupy the same geographical area, in a particular time.

Question 27 Which types of interactions are commonly seen in a biotic community?

Answer:

Types Of Interactions Are Commonly Seen In A Biotic Community:-

Members of a biotic community are involved in various interactions. These are competition, predation, parasitism, cooperation, etc.

Question 28 What is meant by competition? Give example.

Answer:

Competition And Example Of Competition:-

Competition: Competition is a negative interaction amongst the members of same or different species in a population to obtain more of the limited natural resources (food, water, shelter) for survival.

Example: Lions compete for food with cheetah and hyena.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization compitition
Question 29 What is meant by predal What is meant by predation? Give example.

Answer:

Predation: Predation is an interspecific positive-negative interaction between prey and predators, where the predator survives by feeding on the prey.

Example:
Birds feed on insects, snakes feed on rats and frogs, and lions feed on zebras.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization predation

Question 30 What is meant by parasitism? Give example.

Answer:

Parasitism: Parasitism is a non-mutual, symbiotic, positive-negative interaction, where one organism is benefited at the expense of the other.

Example: Tapeworms (Taenia) draw nutrition (Cuscuta). suck nutrients from the phloem of the host from the human (host) intestine. Dodder plants

Question 31 What is meant by cooperation? Mention the types of cooperation.

Answer:

Cooperation: Cooperation is a positive either both are benefited or one is benefited and interaction between two different species, where the other remains unaffected.

Types:

Cooperation is of three types:

1. Commensalism
2. Mutualism
3. Protocooperation.

Question 32 What is symbiosis? Give example.

Answer:

Symbiosis:

Symbiosis is an interspecific cooperation in which two species live in a close physical association and both are benefited in some way or the other. This is also known as obligatory mutualism.

Example:

Trichonympha receives shelter and nutrients in the intestine of termites and in return help in the digestion of cellulose of the wood fragments taken by the termites as food. Rhizobium bacteria trap atmospheric nitrogen and supply it to leguminous plants, and in return, they get shelter in the root nodules of those plants.

Question 33 What is meant by commensalism? Give example.

Answer:

Commensalism:

Commensalism is a positive neutral interspecific interaction, where one member is benefited but the other remains unaffected.

Example:

Orchids (epiphytes) grow on branches of mango trees, thereby getting safe shelter but the mango tree remains unaffected. Sucker fishes fix on the body of sharks and get food from the discards of sharks’ meal, but the shark remains unharmed.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization commensalism orchid on mango tree

Question 34 What is meant by mutualism? Give example.

Answer:

Mutualism:

Mutualism is a positive-positive interspecific interaction, where both members are benefited from one another, but close physical association is not evident.

Example:

Insects collect nectar and pollens from flowers. In exchange, they help in spreading pollen grains from one flower to another, thereby helping in reproduction.

Question 35 What is meant by protocooperation? Give example.

Answer:

Protocooperation:

Protocooperation is a positive-positive interspecific interaction, where both members are benefited but obligatory interdependence is not evident.

Example:

Sea-anemone often rides on the shell of a hermit crab. Here, sea anemone intakes discarded food of hermit crab and in return protects it from predators by its stinging cells. This relation is not obligatory because both can survive independently.

Question 36 How do different organisms remain organised in nature?

Answer:

In nature, all living organisms maintain a close interrelation among themselves and with the non-living components of the environment. This interrelationship helps to organize all the biotic components of nature.

Understanding Food Chains and Food Webs for Solutions

Question 37 How many types of ecosystems are there?

Answer:

The ecosystem is normally of two types:

1. Natural ecosystem: The ecosystem that develops naturally in an environment. Example-Pond ecosystem.

2. Artificial ecosystem: The ecosystem which is artificially created by human beings. Example- Ecosystem in a crop field.

Question 38 What is a biome? What is biomass?

Answer:

Biome:

A biome refers to a living community characterized by distinctive plant and animal species and maintained under the climatic conditions of the largest geographical region.

Biomass:

Biomass refers to the mass of various living organisms in a particular area or ecosystem, at a given time.

Question 39 What is an ecological niche? What do you mean by planktons?

Answer:

Ecological niche:

The ecological niche is defined as the role and position of a particular species in its environment.

Planktons:

Planktons are a diverse group of microscopic organisms which can float freely with oceanic currents and in other water bodies. There are two types of planktons- phytoplanktons and zooplanktons.

Question 40 What are phytoplanktons and zooplanktons?

Answer:

Phytoplanktons:

The photosynthesising microscopic organisms drifting on the upper surface of water bodies are known as phytoplanktons.

Example:

Cyanobacteria, Dinoflagellates, etc.

Zooplankton: The heterotrophic, microscopic organisms belonging to the animal community, that drift on the surface of the water body, are called zooplankton.

Examples: Cyclops, Daphnia, etc.

Question 41 Who are called producers of an ecosystem? What are their functions?

Answer:

Producers:

In an ecosystem, those organisms, which are capable of synthesizing their own food, are called producers. Green plants (autotrophs) play the role of producers in an ecosystem.

Function:

Producers utilize solar energy to synthesize their own food. They trap the energy from the sunlight and convert it into chemical energy within their body. The food, so produced, is utilized by other members of the ecosystem.

Question 42 Who are called consumers of an ecosystem? Discuss their types.

Answer:

Consumers:

In an ecosystem, the living organisms, who cannot prepare their own food and depend upon plants or other animals for their nutrition, are called consumers. Animals and human beings (heterotrophs) play the role of consumers in an ecosystem.

Types:

Depending upon their food habits, consumers may be of various types:

1. Primary consumers: Directly depend on plants (producers) for food.
2. Secondary consumers: Feed on primary consumers.
3. Tertiary consumers: Feed on secondary consumers.

Question 43 Who are the decomposers in an ecosystem? What is their role in the ecosystem?

Answer:

Decomposers:

In an ecosystem, the organisms which degrade the complex organic substances of dead bodies of producers and consumers and their organic wastes into simpler substances and obtain food from them are known as decomposers. Microorganisms, such as bacteria, fungi, etc. play the role of decomposers in an ecosystem.

Role:

1. They help in the decomposition of dead plant and animal remains and organic wastes, thereby preventing environmental pollution.
2. They convert large and complex organic matter into small and simple organic matter. As a result, a continuous supply of organic elements on Earth is maintained.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization decomposer bacteria

Question 44 Who are the transformers of an ecosystem?

Answer:

Transformers Of An Ecosystem:-

The microorganisms, break simple. organic compounds and release inorganic elements from them are known as transformers. Different denitrifying bacteria, sulphur bacteria, phosphobacteria belong to this group.

Question 45 What is meant by flora and fauna?

Answer:

Flora And Fauna:-

Flora: In an ecosystem, the entire plant community of a particular region is referred to as flora.

Fauna: In an ecosystem, the entire animal community of a particular region is referred to as fauna.

Question 46 What is meant by the nutrient cycle? What is its significance?

Answer:

Nutrient cycle:

The cyclic process by which organic and inorganic matters of the environment are utilized by living organisms and are again returned to the environment, thereby maintaining their balance, is known as the nutrient cycle.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization nutrient cycle

Significance:

1. The constancy of nutrient elements within the environment is maintained.
2. In this cycle, producers collect nutrients from the environment and these are returned by decomposers and transformers.

WBBSE Class Nine Life Science Question 47

Nutrient cycle is a type of biogeochemical cycle explained.

Answer:

Nutrient Cycle Is A Type Of Biogeochemical Cycle:-

1. Different living organisms (plants, animals, microbes) participate in the nutrient cycle. Therefore, it is a bicycle.
2. Soil, rock, water, etc. are various geographic elements that are included in the nutrient cycle. Hence, it is a cycle.
3. The nutrient elements participate in various chemical reactions occurring within the body of living organisms. Hence, it is a chemical cycle.
Combining the above three conditions, it can be rightly said that the nutrient cycle is a type of biogeochemical cycle.

Question 48 What is energy flow in an ecosystem? Why it is unidirectional?

Answer:

Energy flow:

In an ecosystem, the flow of energy along a food chain, starting from the producer and gradually reaching the top level consumer through different trophic levels, is known as energy flow in an ecosystem.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization energy flow
Unidirectional flow: In any ecosystem, energy flow occurs through different trophic levels, starting from producer decomposer. But this energy never comes back to the producer again. Due to this reason, energy flow in an ecosystem is unidirectional.

Sample Solutions from WBBSE Class 9 Life Science Chapter 5

Question 49 What is meant by trophic level? What is 10% law of energy flow?

Answer:

Trophic level:

The trophic level refers to the position of a particular species in the ecological food chain. On the basis of their feeding habits, the organisms are classified into four types

1. Producer
2. Primary consumer
3. Secondary consumer
4. Tertiary consumer.

10% law of energy flow:

According to this law, each and every trophic level of a food chain in an ecosystem receives 10% energy from its previous trophic level. This law was proposed by
Lindeman.

WBBSE Class Nine Life Science Question 50

What is the food pyramid? What is an energy pyramid?

Answer:

Food pyramid:

The food pyramid is the graphical representation of different trophic levels in a food chain, starting from the producer at the base to the top-level consumer at the peak.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization food pyramid

Energy pyramid:

The energy pyramid is the graphical representation of different trophic levels in a food chain, based on the total content of energy trapped in different levels from a producer at the base to the consumers at the peak.

Question 51 What is adaptation? Write two features of the food chain.

Answer:

Adaptation:

Adaptation is an evolutionary process by which an organism undergoes permanent anatomical or physiological or behavioural changes, in order to cope with the changing environment.

Features of the food chain:

1. Energy flow occurs according to the sequential arrangement of various trophic levels in a food chain, i.e., producer primary consumer → secondary consumer→ tertiary consumer.
2. Different food chains in an ecosystem connect together to form a food web.

Question 52 What is the food chain? What is the food web?

Answer:

Food chain: The food chain is a feeding hierarchy of different organisms in an ecological community in which organisms are linked to each other through the transfer of energy via food, starting from producers or detritus and finishing at the topmost level of consumers.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization food chain

Food web: Food web is the network of several food chains, interconnected at different trophic levels, so as to develop a distribution system of energy via food amongst every member of the biotic community.

WB Class 9 Life Science Question Answer

Question 53. What is a grazing food chain?

Answer:

Grazing Food Chain:-

The food chain that starts from producers and proceeds through different consumers from lower to higher level, is known as grazing food chain.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization grazing food chain

WBBSE Class Nine Life Science

Question 54. What is parasitic food chain?

Answer:

parasitic Food Chain:-

The food chain that starts from producers (such as plants) and ends to any parasite, is called a parasitic food chain.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization parasitic food chain

Question 55. What is the detritus food chain?

Answer:

Detritus Food Chain:-

The food chain that starts from dead and decaying organic matter and ends to any large consumer, is called a detritus food chain.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization detritus food chain

Question 56. What is diurnal thermoperiodicity?

Answer:

Diurnal Thermoperiodicity:-

Diurnal thermoperiodicity is the response of organisms to daily changes of temperature. Example-Day time temperature is favourable for photosynthesis, transpiration, etc. and low temperature at night is suitable for storage of food, growth, etc. Seed germination is influenced by diurnal changes of temperature.

WB Class 9 Life Science Question Answer

Question 57. What is seasonal thermodynamics?

Answer:

Seasonal Thermodynamics:-

Seasonal thermodynamics is the response of organisms to seasonal changes in temperature along with photoperiodicity. It controls flowering, fruiting, leaf fall, growing of new leaves, etc. Example-Apple tree needs exposure to 7°C for more than 800 hours to set fruit. Wheat needs 10-25°C temperature in early winter for seed germination.

WBBSE Class 9 Life Science Question And Answer

Question 58. What do you mean by vital index?

Answer:

Vital Index:-

The percentage ratio of natality over mortality within a population in a given time, is known as vital index. Vital index determines the normal growth of a population.

Vital index (V) = \(\frac{Natality}{Mortality}\) × 100

In the case of a growing population, V > 100

In case of negative growth, V < 100

In case of zero growth or stable population, V = 100.

Question 59. Distinguish between producers and consumers.

Answer:

Distinguishing features between producers and consumers are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization features between products and consumers

Question 60. Distinguish between producers and decomposes.

Answer:

Distinguishing features between producers and decomposes are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization features between producers and decomposers

WB Class 9 Life Science Question Answer

Question 61. Distinguish between consumers and decomposers.

Answer:

Distinguishing features between consumers and decomposers are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization features between consumers and decomposers

WBBSE Class 9 Life Science Question And Answer

Question 62. Distinguish between macro consumers and micro consumers.

Answer:

Distinguishing features between macro consumers and micro consumers are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization features between macroconsumers and microconsumers

Question 63. Distinguish between mutualism and commensalism.

Answer:

Distinguishing features between mutualism and commensalism are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization features between mutualism and commensalism

Question 64. Distinguish between intraspecific competition and interspecific competition.

Answer:

Distinguishing features between intraspecific competition and interspecific competition are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization features between insraspecific and interspecific

Concepts Related to Biotic and Abiotic Factors for Class 9 Solutions

Question 65. Distinguish between the food chain and the food web.

Answer:

Distinguishing features between the food chain and the food web are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization features between food chain and food web

Question 66. Distinguish between the grazing food chain and the detritus food chain.

Answer:

Distinguishing features between the grazing food chain and the detritus food chain are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization features between grazing food chain and detritus food chain

WB Class 9 Life Science Question Answer

Question 67. Distinguish between population and community.

Answer:

Distinguishing features between population and community are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization features between population and community

Question 68. Distinguish between population and community.

Answer:

Distinguishing features between population and community are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization features between population and mortality

Question 69. Write the difference between habitat and niche.

Answer:

Distinguishing features between habitat and niche are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization features between habitat and niche

WB Class 9 Life Science Question Answer

Question 70 Mention Gause’s hypothesis.

Answer:

Gause’s Hypothesis:-

A population of each species within a community has a separate ecological niche. No two species within a given community can have exactly the same niche and live permanently together.

If two species happen to have the same niche in a community, a direct competition between the two, will eliminate one of them. It is due to competitive exclusion. This is Gause’s hypothesis.

Question 71 What do you mean by ecological equivalents?

Answer:

Ecological Equivalents:-

The organisms which are found in different geographical regions of the world but occupy the same or similar niches are called ecological eBison of Asia, kangaroo of Australia and zebra of Africa are ecological equivalents since all are

Question 72 What are eurythermal and stenothermal organisms?

Answer:

Eurythermal And Stenothermal Organisms:-

Eurythermal organisms: Some organisms can tolerate and thrive in a wide range of temperatures. Such organisms are called eurythermal.

Stenothermal organisms: A vast majority of organisms are restricted to a narrow range of temperatures. Such organisms are called stenothermal.

Question 73 Write Allen’s rule and Bergmann’s rule.

Answer:

Allen’s rule And Bergmann’s rule:-

Temperature affects a number of morphological features in animals. These effects follow two rules. Allen’s rule: The tail, snout, ears and legs of mammals are relatively shorter in colder regions than in warmer regions.

Bergmann’s rule: The birds and mammals of cold regions are large sized than those of warmer region.

WB Class 9 Life Science Question Answer

Question 74 Write Jordan’s rule and Gloger’s rule.

Answer:

Jordan’s rule And Gloger’s rule:-

Jordan’s rule: Fish occurring in cold water tends to have more vertebrae than those found in warmer water.

Gloger’s rule: The mammals, birds and insects of the tropical region (warmer region) are more darker in colour and heavily pigmented than those of arctic regions.

Question 75. Write short notes on adaptations of desert plants and animals. Or, a Short note on adaptations of plants to water scarcity.

Answer:

Adaptations of desert plants:

Desert plants have thick cuticles on their leaf surfaces, sunken stomata present and CAM pathway of photosynthesis. In some desert plants, leaves are reduced to spines and the photosynthetic function is taken over by the flattened stems.

Adaptations of desert animals:

The desert animal like the kangaroo rat, is capable of meeting all its water requirements through its internal fat oxidation. It has the ability to concentrate its urine to minimise the volume of water used to excrete the wastes.

Question 76. Write adaptive features of xerophytes.

Answer:

Features Of Xerophytes:-

The plants of hot deserts are adapted to survive in dry conditions of soil and high temperature. Such plants are called xerophytes. The adaptive features of xerophytes are mentioned here.

Root: Well developed, long and stout taproot without branches, presence of root hairs, roots go deep into the soil in search of water.

Shoot: Hard, woody, covered with hairs, wax and silica. Some of the plants show modified stems in Opuntia, the stem forms a leaf-like structure termed as phylloclade. In some plants, the stem is modified into the leaf-like structure, called a phyllode.

Example: Acacea catechu, Parkinsonia aculeata.

Leaves: They are modified in such a way that water loss due to transpiration reduces to a minimum. Leaf surfaces are shining, stomata are present on the lower surface of the leaf and are sunken. In some plants, like Asparagus racemosus, and Ruscus aculeatus axillary branches are modified into leaf-like structures, called cladode.

Study Guide for Class 9 Life Science Ecology Questions

Question 77. Mention the adaptive features of heliophytes.

Answer:

Heliophytes:-

Plants growing in bright light are called heliophytes or sunplants. Heliophytes are adapted to higher temperatures for photosynthesis.

The important features are:

1. Shorter and thicker internodes.
2. Smaller and thicker leaves.
3. Thick cuticle, often sunken stomata.
4. Leaves are pale green in colour with a shining surface.
5. Palisade parenchyma is well developed.

Question 78 Write some adaptive features as found in camels in the desert to withstand water loss.

Answer:

Some Adaptive Features As Found In Camels In The Desert To Withstand Water Loss:-

1. Synthesis of metabolic water by oxidation of fat present in the hump.
2. Water sacs are present in the stomach.
3. Control of water loss by the kidneys; either by secreting concentrated urine or by reducing the flow of urine.
4. Reduction of glomerular filtration rate.

Question 79. What do you mean by pneumatophores?

Answer:

Pneumatophores:-

The pneumatophores are the respiratory or breathing roots of halophytes which help to take up oxygen from the atmosphere and transport it to the main root.

WB Class 9 Life Science Question Answer

Question 80. Write the difference between hibernation and aestivation.

Answer:

Differences between hibernation and aestivation are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization differences between hibernation and aestivation

Question 81. Differentiate between ectotherms and endotherms.

Answer:

Differences between ectotherms and endotherms are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization differences between ecotherms and endotherms

Question 82. Differentiate between ectoparasites and endoparasites.

Answer:

Differences between ectoparasites and endoparasites are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization differences between ectoparastes and endoparasites

Question 83 Differentiate between primary productivity and secondary productivity.

Answer:

Differences between primary productivity and secondary productivity are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization differences between primary and secondary productivity

Question 84. Differentiate between Net primary productivity (NPP) and Gross primary productivity (GPP).

Answer:

Differences between NPP and GPP are:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization differences between NPP and GPP

Question 85. Define trophic levels.

Answer:

Trophic Levels:-

The specific place occupied by different organisms in the food chain in an ecosystem constitutes trophic levels.

Trophic levels in an ecosystem are described below:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources Ecology and Ecological Organization differences between levels in an ecosystem

Question 86. Define standing crop, standing state and detritus.

Answer:

Standing crop:

The amount of living material present in different trophic levels at a given time is called a standing crop.

Standing state:

The amount of nutrients present in the soil at a given time is called a standing state.

Detritus:

Dead plant parts and animal remains constitute detritus.

 

Chapter 5 Environment And Its Resources Ecology And Ecological Organization Answer in a single word or sentence

Question 1. Who first coined the term ‘ecology’?
Answer: Ernst Haeckel (1869)

Question 2. Which level of ecology deals with the interaction of a species with the environment?
Answer: Population

Question 3. Which level of ecology deals with the interaction of two or more species?
Answer: Community

Question 4. Give an example of effect of light on plants.
Answer: Long day plants (such as mustard, radish, etc.) require light for more than 12 hours for flowering.

Question 5. Which type of plants are adapted to survive in bright sunlight?
Answer: Heliophytes

Question 6. Which type of plants are adapted to survive in low sunlight?
Answer: Sciophytes

Question 7. In which physiological event, does the flowering of plants depend upon the span of daylight?
Answer: Photoperiodism

Question 8. Name some long day plants.
Answer: Mustard, radish, tobacco, etc. are long day plants.

Question 9. Name some short day plants.
Answer: Dahlia, cosmos, sugarcane, strawberry, etc. are common short day plants.

Question 10. Name some day neutral plants.
Answer: Cucumber, tomato, cotton, etc. are some day neutral plants.

Question 11. Give an example of effect of humidity on plants.
Answer: Increase in humidity reduces the rate of transpiration in plants.

Question 12. Give an example of effect of temperature on plants.
Answer: Reduction of temperature reduces the rate of flowering in certain plants such as tulip.

Question 13. Give an example of effect of light on animals.
Answer: Zooplanktons move towards the upper surface of the water bodies in presence of sunlight.

Question 14. Give an example of effect of humidity on animals.
Answer: In certain desert animals, like Moloch horridus, the skin possesses numerous hygroscopic spines to keep the body moist as much as possible.

Question 15. Give an example of effect of temperature on animals.
Answer: Due to extremely low temperature in polar regions, the size of polar bears are bigger compared to the bears of warmer region.

Question 16. In which type of animals, very few sweat glands are found?
Answer: Desert animals

Question 17 In which geographical region, plants have less leaves and more spines?
Answer: Desert

Question 18 In which region tall trees with needle-like leaves are found?
Answer: Tall trees with needle-like leaves are seen in regions, where occasional snowfall occurs.

Question 19 Name one component of population.
Answer: Species

Question 20 Name two factors that regulate population size.
Answer: Natality and mortality

Question 21 Name two factors that increase population size.
Answer: High natality and immigration

Question 22 Name two factors that decrease population size.
Answer: High mortality and emigration

Question 23 Members of which age group are predominant in a growing population?
Answer: Lower age group

Question 24 In a community, size of which trophic level increases with decrease in number of predators?
Answer: Primary consumer

Question 25 Name one positive and one negative interspecific interaction.
Answer: Commensalism is a positive and predation is a negative interspecific interaction.

Question 26 Give an example of symbiosis.
Answer: Lichen

Question 27 Name the interspecific relation between orchid and mango tree.
Answer: Commensalism

Question 28 Which type of symbiosis is noticed between Trychonympha and termites?
Answer: Obligatory symbiosis

Question 29 Which type of relation is prevalent amongst various predators in a community?
Answer: Competition

Question 30 What is hyperparasite?
Answer: A parasite, that draws nutrition from another parasite, is called a hyperparasite.

Question 31 What kind of interaction is competition?
Answer: Negative-negative (- -) interaction

Question 32 What kind of interaction is predation?
Answer: Positive-negative interaction

Question 33 Give two examples of positive-positive interaction.
Answer: Mutualism and protocooperation

Question 34 What happens in commensalism?
Answer: In commensalism, one individual is benefited and the other individual is neither benefited nor harmed.

Question 35 Which is the ultimate source of energy in every ecosystem?
Answer: Sun

Question 36 Who acts as producer in any ecosystem?
Answer: Green plants

Question 37 Who acts as consumer in any ecosystem?
Answer: All animals

Question 38 Who acts as decomposer in any ecosystem?
Answer: Microorganisms, such as bacteria, fungi, etc.

Question 39 Give two examples of phytoplanktons.
Answer: Chlamydomonas and Volvox

Question 40 Give two examples of zooplanktons.
Answer: Cyclops and Daphnia

Question 41 Name two pelagic animals.
Answer: Mosquito larvae and jellyfish

Question 42 Give two examples of necton.
Answer: Fishes and whales

Question 43 Give two examples of benthos.
Answer: Corals and sea-anemones

Question 44 What will happen if all the producers of any ecosystem are completely destroyed?
Answer: If all the producers of an ecosystem are completely destroyed, the entire animal population of that ecosystem will be destroyed.

Question 45 Name two plants that act as consumers.
Answer: Dionaea sp. (venus flytrap) and Nepenthes sp. (pitcher plant) are two insectivorous plants that act as consumers.

Question 46 How much energy is transferred from one trophic level to the next in an ecosystem?
Answer: 10%

Question 47 Who proposed the 10% law of energy flow in an ecosystem?
Answer: Raymond Lindeman

Question 48 Give an example of detritus food chain.
Answer: Decaying leaves → Earthworm → Sparrow → Hawk.

Question 49 Who are microconsumers in any ecosystem?
Answer: All fungi and bacteria

Question 50 Give an example of grazing food chain.
Answer: Grass → Grasshopper → Frog → Snake → Hawk.

Question 51 Who are macroconsumers in any ecosystem?
Answer: All herbivores (cow, goat, etc.) and all carnivores (cat, dog, tiger, lion, etc.).

Question 52 Give examples of terrestrial and aquatic ecosystems.
Answer: Example of a terrestrial ecosystem is a forest ecosystem and an example of aquatic ecosystem is pond ecosystem.

Question 53 Name two nutrient cycle.
Answer: Carbon cycle and oxygen cycle

Chapter 5 Environment And Its Resources Ecology And Ecological Organization Fill In The Blanks

1. Group of organisms of same species is known as Population

2. Circadian rhythm is the daily rhythm of activities which is controlled by light.

3 Animals living in desert regions have few Sweat glands.

4 Decomposes show Saprophytic nutrition.

5 Inflow of bulk of animals into a population is called Immigration

6 Interaction between flowers and insects is known as Mutualism

7 In predation, the animal which kills other animal to consume it, is called Predator.

8 The step of food chain is called Trophic levels

9. Birds of temperate region Narrower wings have than that of tropical regions.

10 Organisms that break down organic molecules and return elementary components to nature, are called Transformers

11 There are Three types of food chain in an ecosystem.

12 The sum total of the solar energy trapped by all producers is called primary Gross production.

13 Cyclical pool of carbon cycle involves the atmosphere and the Seawater

14 Immigration/Natality increases the size of the population.

15 The size of the population reduces due to Emigration/Mortality

16 The density of population Increases due to natality.

17 Plasmodium is a Obligatory parasite.

18 The interaction between the parasite and the host is called Parasitism

19 The interaction between sea-anaemone and hermit crab is called Protocooperation

20 Ecosystem in a crop field is an example of Artificial ecosystem.

21 Grasshopper plays an important role in ecosystem as Primary consumer.

22 The organisms which are restricted to a narrow range of salinity is called Stenohaline.

23 In desert plants, stomatas are arranged in Deep pits to minimize water loss.

24 Some frogs are cryptically coloured to avoid Predation

25 Sunken stomata are found in Xerophytes

26 Individuals of the same species inhabiting a particular locality form Population.

27 Carrying capacity of environment is determined by Limiting resources

28 The association between Rhizobium and roots of leguminous plants is Symbiosis

29 Association of animals in which both the partners are benefited is called Mutualism.

30 A tiny free floating animals in surface water constitute Zooplankton

31 Mycorrhiza is an example of Symbiotic relationship.

32 Halophytes are Salt resistant.

33 Human population exhibits S shaped growth.

34 The basic unit of study in ecology is Organism

35 Cuscuta is an example of Ectoparasitism

36 Herbivores are Primary consumers.

37 Every food chain start with a Producer

38 Autotrophic planktons are called Phytoplankton

39 The transitional zones between adjacent biomes are called Ecotones

40 Phosphorus has Sedimentary types of cycle.

41 The pyramid of Energy is always upright.

42 Inverted pyramid is generally found in Tree dominated ecosystem.

43 Elton proposed the concept of ecological pyramid.

44. In aquatic ecosystem, the limiting factor for the productivity is Light.

Chapter 5 Environment And Its Resources Ecology And Ecological Organization State True Or False

Question 1. Population is a bigger unit than community.

Answer: False

Question 2. Light enhances the pigmentation of skin.

Answer: True

Question 3. Poikilotherms can maintain constant body temperature.

Answer: False

Question 4. Population size remains constant if birth rate is lower than death rate.

Answer: True

Question 5. Migration is of two types.

Answer: True

Question 6. Lichen is a type of obligatory mutualism.

Answer: True

Question 7. Predation normally is an intraspecific interaction.

Answer: False

Question 8. Parasitism is a negative-positive association.

Answer: True

Question 9. Tapeworm is an ectoparasite.

Answer: False

Question 10. Organic matters like protein, fat are biotic factors of an ecosystem.

Answer: False

Question 11. Tertiary consumers are considered as decomposers.

Answer: False

Question 12. Different food chains interconnect to form food web.

Answer: True

Question 13. Only 0.02% of the total energy, that comes to the earth from the sun, can be trapped.

Answer: True

Question 14. Carbon bed of the lithosphere acts as a reservoir pool for carbon.

Answer: True

Question 15. Chemo synthetic microorganisms are tropospheres.

Answer: False

Chapter 5 Environment And Its Resources Ecology And Ecological Organization Match The Columns

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Ecology And Ecological Organization Environment And Its Resources match the columns 1

Answer: 1-F; 2-A; 3-C; 4-B; 5-D; 6-E

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Ecology And Ecological Organization Environment And Its Resources match the columns 2

Answer: 1-B; 2-A; 3-D; 4-C

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Ecology And Ecological Organization Environment And Its Resources match the columns 3

Answer: 1-D; 2-C; 3-A; 4-E

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Ecology And Ecological Organization Environment And Its Resources match the columns 4

Answer: 1-D; 2-C: 3-B: 4-A; 5-E; 6 -G

Chapter 5 Environment And Its Resources Ecology And Ecological Organization Find The Odd One Out

Question 1. Community, Population, Food web, Species

Answer: Food web

Question 2. Circadian rhythm, Natality, Mortality, Immigration

Answer: Circadian rhythm

Question 3. J-shaped growth curve, Ant, Insect pest, Man

Answer: Man

Question 4. Decomposer, Human, Reducer, Transformer

Answer: Human

Question 5. Transducer, Phytoplankton, Autotroph, Heterotroph

Answer: Heterotroph

Chapter 5 Environment And Its Resources Ecology And Ecological Organization Fill In The Blanks By Looking At The First Pair

1. Producer: Transducer :: Decomposer: Producer

2. Bacteria: Microconsumer:: Tiger: Macroconsumer

3 Floating water ecosystem: Lotic : Stable water ecosystem: Lentic

4. Fish: Necton:: Coral: Benthos

5 Phosphorus cycle: Sedimentary cycle :: O2cycle: Gaseous cycle

Chapter 5 Environment And Its Resources Ecology And Ecological Organization Among The Four Concepts Given, Three Of Them Belong To One. Find That

Question 1. Functional characteristics of ecosystem, Food chain, Food web, Energy flow
Answer: Functional characteristics of ecosystem

Question 2. O2 cycle, Nutritional cycle, Phosphorus cycle, N2 cycle
Answer: Nutritional cycle

Question 3. Commensalism, Mutualism,Protocooperation, Cooperation
Answer: Cooperation

Question 4. Competition, Predation, Parasitism, Interaction in community level
Answer: Interaction in community level

Question 5. Age related structure, Features of population, Size of population, S-shaped growth curve
Answer: Features of population

 

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