TS Inter 1st Year Zoology Study Material Chapter 8 Ecology and Environment (Page 1)

Very Short Answer Type Questions

Question 1.

Define the term ecology. (T.Q.)

Answer:

Ecology was defined as “the study of the relationship of organisms with their environment”.

Question 2.

What is autecology?

Answer:

Autecology is the ecology of a single species/population in relation to its environment. It is also known as species (population) ecology.

Question 3.

What do you call the study of interactions of organisms of a community?

Answer:

Synecology is a branch of ecology that deals with the structure, development and distribution of ecological communities.

Question 4.

What is an ecological population? (T.Q.)

Answer:

Population is a group of organisms of the same species, living in a specific area at a specific time.

Question 5.

Define a community. (T.Q.)

Answer:

Community is an association of the interacting members of populations of different autotrophic and heterotrophic species in a particular area.

Question 6.

What is an ecosystem? (T.Q.)

Answer:

Ecosystem is the next level of organisation above the level of biological community. An ecosystem is a functional unit of the biosphere in which members of the community interact among themselves and with surrounding environment.

Question 7.

Distinguish between ecosystem and biome.

Answer:

1.Ecosystem is a functional unit of biosphere in which members of the community interact among themselves and with surrounding environment.
2.A biome is a large community of plants and animals that occupies a vast region.

Question 8.

What is a biome? Name any two biomes you studied. (T.Q.)

Answer:

A biome is a large community of plants and animals that occupies a vast region.
eg : Tropical rain forest, desert, coniferous forest, tundra etc.

Question 9.

What is meant by ecosphere? (T.Q.)

Answer:

All the habitable zones on the Earth constitute the ecosphere or biosphere. It is the part of the Earth that supports life.

Question 10.

Define the term habitat.

Answer:

Habitat is the place in which an organism lives. It is comparable to the address of an organism.

Question 11.

Explain the difference between the ‘niche* of an organism and its ‘habitat’. (T.Q.)

Answer:

1.Niche : With in a community, each organism occupies a particular biological role or Niche. Niche is the functional role of an organism in an ecosystem.
2.Habitat is the place in which an organism lives.

Question 12.

A population has more genetically similar organisms than those on biotic community. Justify the statement. (T.Q.)

Answer:

1.Population is a group of organisms of the same species, living in a specific area at a specific time.
2.Community is an association of the interacting members of populations of different autotrophic and heterotrophic species in a particular area.

Question 13.

Among the red, green and brown algae that inhabit the sea, which is likely to be found in the deepest waters? Why?

Answer:

There are microbes like archaebacteria that flourish in hotsprings and in some parts of deep seas, where temperatures far exceed 100°C. Brown algae is likely to be found in the deepest waters as it is an alchea bacterium.

Question 14.

What is the source of energy for deep sea inhabitants?

Answer:

The source of energy for deep sea inhabitants is by the action of brown algae releasing energy during synthesis of their food. The spectral quality of solar radiation is also important in life. Also detritus food of sea bottom.

Question 15.

How do the fish living in Antarctic waters manage to keep their body fluids from freezing? (T.Q.)

Answer:

Many fish thrive in Antarctic waters where the temperature is always below zero. Many species have evolved a relatively constant internal environment. It permits all biochemical reactions and physiological functions to proceed with maximal efficiency and thus, enhance the overall fitness of the species.

Question 16.

How does your body solve the problem of altitude sickness, when you ascend tall mountains? (T.Q.)

Answer:

Altitude also causes variations in temperature. For instance, the temperature decreases gradually as we move to the top of the mountains we experience altitude sickness if we ever been to any high altitude place. Its symptoms include nausea, fatigue and heart palpitations. We can solve the problem because the body compensates low oxygen availability by increasing red blood cell production and increasing the rate of breathing.

Question 17.

Name the structural components of an ecosystem.

Answer:

The structural components of ecosystem are of two types: Abiotic and biotic factors. Abiotic factors are two types : physical and chemical.
Physical are light, temperature, soil, pressure etc.
Chemical are oxygen, carbondioxide, minerals of soil / water.

Question 18.

What is the effect of light on body pigmentation? (T.Q.)

Answer:

Light influences the colour of the skin. The animals which live in regions of low intensity of light have less pigmentation than that of the animals exposed to light.

Question 19.

Distinguish the terms phototaxis and photokinesis. (T.Q.)

Answer:

1.Phototaxis is oriented locomotor movement of an organism towards or away from the direction of light.
2.Photokinesis is the influence of light on non-directional movement of organisms as seen in the larvae of Pinnotheres macculatus-the mussel crab. Intensity of light influences the velocity of the movement of organism.

Question 20.

What is the primardial source of energy for all living organisms?

Answer:

The primardial source of energy for all living organisms is Sunlight.

Question 21.

What are biological rhythms?

Answer:

In the bodies of organisms, many behavioural activities are repeated at regular intervals and these are called biological rhythms.

Question 22.

What are circadian rhythms?

Answer:

Biological rhythms that occur in a time period of 24 hours are circadian rhythms.

Question 23.

What is photoperiodism? (T.Q.)

Answer:

The duration of the light hours / exposure to light in a day is known as photoperiod. The response of organisms for the photoperiod is called Photoperiodism.

Question 24.

Distinguish between photoperiod and critical photoperiod. (T.Q.)

Answer:

The duration of the light hours / exposure to light in a day is known as Photoperiod. The specific day length which is essential for the initiation of seasonal events is called ‘Critical Photoperiod’.

Question 25.

Explain Bioluminescence.

Answer:

Production of light by certain living organisms is called Bioluminestence. The light emitted by living organisms is devoid of infrared rays and so it is called cold light.

Question 26.

Mention the advantages of some UV rays to us. March 2014

Answer:

UV radiation helps in the conversion of sterols present in the skin into vitamin D in mammals.

Question 27.

Distinguish between the terms heat and temperature.

Answer:

Temperature is a measure of the intensity of heat.

Question 28.

Distinguish between minimum effective temperature and maximum effective temperature.

Answer:

1.The lowest temperature at which an organism can live indefinitely is called minimum effective temperature.
2.The maximum temperature at which a species can live indefinitely in an active state is called maximum effective temperature.

Question 29.

What is optimum temperature?

Answer:

The temperature at which the metabolic activities occur at the climax level is called “optimum temperature”.

Question 30.

What is cyclomorphosis? Explain its importance in Daphnia. March 2019

Answer:

The cyclic seasonal morphological variations among certain organisms is called cyclomorphosis. In Daphnia (water flea) the body may become elongated with hood or short with out hood depending upon seasons. Cyclomorphosis is a seasonal adaptation to changing densities of water in lakes based on seasons.

Question 31.

What are “regulators”? (T.Q.)

Answer:

Some organisms are able to maintain homeostasis by physiological (sometimes behavioural) means which ensures constant body temperature constant osmotic concentration. These are called regulators.
There are no perfect regulators. (Eg : Birds and Mammals)

Question 32.

What are ‘conformers’? (T.Q.)

Answer:

In aquatic animals, the osmotic concentration of the body fluids changes along with that of the surrounding water. Such animals are described as conformers. There are no perfect conformers.

Question 33.

Define commensalism. Give one example. [May 2017 – A.P.] (T. Q.)

Answer:

The interaction where one species is benefited and the other is neither benefited nor harmed is called “commensalism”.
Example : Barnacles growing on the back of a whale benefit while the whale derives no noticeable benefit.

Question 34.

Define mutualism. Give one example. [March 2015 – A.P.] (T. Q.)

Answer:

This type of interaction benefits both the interacting species.
Example: Lichens represent an intimate mutualistic relationship between a fungus and photosynthetic algae.

Question 35.

Define parasitism. Give one example.

Answer:

In parasitism only one species benefits and the interaction is detrimental to the other species. Parasite generally harms ho’st. Malarial parasite causes harm to the host man by causing malaria.

Question 36.

Define amensalism. Give one example. (T.Q.)

Answer:

In amensalism one species is harmed whereas the other is unaffected.

Question 37.

What is predation? Give one example.

Answer:

Predation :
Only one species benefits and the interaction is detrimental to the other species. Tiger predates upon a deer.

Question 38.

What is meant by interspecific competition? Give one example. (T.Q.)

Answer:

Interspecific competition is a potent force in the process of organic evolution, involving natural selection.
Example : In intertidal communities of the American Pacific Coast, the Starfish Pisaster is an important predator. In a field experiment, when all the starfish were removed from an enclosed intertidal area, more than 10 species of invertebrates became extinct within a year, because of increased inter-specific competition.

Question 39.

Distinguish between predation and parasitism.

Answer:

In both parasitism and predation only one species benefits (parasite and predator, respectively) and the interaction is detrimental to the other species (Host and Prey respectively). Sometimes predator controls over population of prey. Majority of parasites harm the host.

Question 40.

Distinguish between the interactions commensalism and amensalism.

Answer:

The interaction where one species is benefited and the other is neither benefited nor harmed is called “commensalism”.
Example: Barnacles growing on the back of a whale benefit while the whale derives no noticeable benefit.
In amensalism on the other hand one species is harmed whereas the other is unaffected.

Question 41.

In an ecological food chain, what types of interactions exist between trophic levels?

Answer:

Types of interactions exist between trophic levels are mutualism, commensalism, parasitism, amensalism, parasitism and predation.

Question 42.

What is camouflage? Give its significance. (T.Q.)

Answer:

Some species of insects and frogs are cryptically coloured (camouflaged) to avoid being detected easily by the predator.
Example : Stick insect.

Question 43.

What is Gause’s principle ? When is it applicable? (T.O.)

Answer:

Gause’s principle of competitive exclusion states that two closely related species competing for the same resources cannot co-exist indefinitely and the competitively inferior one will be eliminated in due course of time.

Question 44.

Name the association that exist in micorrhiza. (T.O.)

Answer:

Mycorrhizae are associations between fungi and the roots of higher plants. The fungi help the plant in the absorption of essential nutrients from the soil while the plant in turn provides the fungi with energy yielding carbohydrates. It is mutualism.

Question 45.

What are lichens?

Answer:

Lichens represent an intimate mutualistic relationship between a fungus and photosynthesising algae or cyanobacteria.

Question 46.

Name the major types of ecosystems.

Answer:

Major types of ecosystems are basically two types : Natural and Artificial. Natural ecosystems are aquatic and terrestrial ecosystems. Artificial ecosystems are agro-ecosystems like cropland ecosystems, aquaculture ponds and aquaria.

Question 47.

Distinguish between natural ecosystem and an artificial ecosystem.

Answer:

Natural Ecosystems :
These are naturally occurring ecosystems and these is no role of humans in the formation of such types of ecosystems.
Artificial ecosystems :
These are man made ecosystems such as agricultural or agro ecosystems. They include cropland ecosystems, aquaculture ponds and aquaria.

Question 48.

What is an estuary?

Answer:

Estuary is the zone where river joins the sea. Sea water ascends up into the river twice a day.

Question 49.

How does an estuarine ecosysterri differ from freshwater ecosystem?

Answer:

The Freshwater Ecosystem :
Is the smallest aquatic ecosystem. It includes rivers, lakes, ponds etc. Fresh water ecosystem is studied under Limnology.
Estuarine Ecosystem :
Estuary is the zone where river joins the sea. Sea water ascends up into the river twice a day. Estuarine organisms are capable of with standing the fluctuations in salinity.

Question 50.

Distinguish between lotic and lentic habitats. March 2018 – A.P.

Answer:

1.The still water bodies like ponds, lakes, reservoirs, etc., fall under the category of lentic ecosystems.
2.Streams, rivers and flowing water bodies are called lotic ecosystems.

Question 51.

What is limnology?

Answer:

The study of freshwater ecosystem is called as Limnology.

Question 52.

What is euphotic zone?

Answer:

It is the shallow part of the lake closer to the shore. Light penetrates up to the bottom. It is Euphotic zone. It has rich vegetation and higher rate of photosynthesis, hence rich in oxygen.

Question 53.

What is zone of compensation in an aquatic ecosystem? (T.Q.)

Answer:

The imaginary line that separates the limnetic zone from the profundal zone is known as zone of compensation / compensation point / light compensation level.

Question 54.

Distinguish between phytoplankton and zooplankton. (T.Q.)

Answer:

1.Chlorophyll bearing floating micro organisms present in the water form the phytoplankton, eg : diatoms, volvox.
2.Small microscopic floating animals present in the surface waters form the zooplankton, eg: rotifers, copepods, Daphnia.

Question 55.

Distinguish between neuston and nekton. (T.Q.)

Answer:

1.The animals living at the air – water interface constitute the neuston.
2.The animals such as fishes, amphibians, water snakes which are capable of swimming constitute the nekton.

Question 56.

What is periphyton? (T.Q.)

Answer:

The animals that are attached to / creeping on the aquatic plants, such as the water snails, nymphs of insects, bryozoans, hydras constitute the periphyton.