While studying vegetation of an area, terms like 'population' and 'community' are often used. Which one of the following statements best describes a population?
- A.A group of organisms of one species, living in the same area at the same time.
- B.A group of organisms of one species living in different areas during different seasons.
- C.A unit consisting of biotic and abiotic components.
- D.A group of organisms of more than one species, living in the same area at the same time.
Correct answer
Explanation
The correct answer is A, a group of organisms of one species, living in the same area at the same time. In ecology, a population is defined by three things together: one species, one place and one time.
Ecology studies life in levels. An individual organism is the smallest unit. All individuals of one species living in a given area at a given time form a population, for example all the teak trees in a forest this year. All the populations of different species living together and interacting in that area form a community. A community together with the non-living surroundings, such as soil, water, light and air, makes an ecosystem, and all the ecosystems of the Earth form the biosphere.
B is wrong: members spread over different areas and seasons do not form one population.
C is wrong: a unit of biotic and abiotic components is an ecosystem.
D is wrong: several species living together in one area form a community.
Exam tip: organism → population (one species) → community (many species) → ecosystem (plus abiotic) → biosphere.
Practice Questions
View allConsider the following :
1. Battery storage
2. Biomass generators
3. Fuel cells
4. Rooftop solar photovoltaic units
How many of the above are considered "Distributed Energy Resources"?
- A.Only one
- B.Only two
- C.Only three
- D.All four
Show answer
Battery storage, biomass generators, fuel cells and rooftop solar units are all small, local sources that generate or store power close to where it is used, which is what Distributed Energy Resources are.
Read the full explanation →Due to some reasons, if there is a huge fall in the population of species of butterflies, what could be its likely consequence/consequences ?
1. Pollination of some plants could be adversely affected.
2. There could be a drastic increase in the fungal infections of some cultivated plants.
3. It could lead to a fall in the population of some species of wasps, spiders and birds.
Select the correct answer using the code given below :
- A.1 only
- B.2 and 3 only
- C.1 and 3 only
- D.1, 2 and 3
Show answer
Butterflies are pollinators and also food for many animals, so their decline would hurt pollination and their predators; it has no direct link with fungal diseases of crops.
Read the full explanation →Consider the following statements :
1. Lions do not have a particular breeding season.
2. Unlike most other big cats, cheetahs do not roar.
3. Unlike male lions, male leopards do not proclaim their territory by scent marking.
Which of the statements given above are correct ?
- A.1 and 2 only
- B.2 and 3 only
- C.1 and 3 only
- D.1, 2 and 3
Show answer
Lions breed at any time of year and cheetahs cannot roar, but male leopards do mark their territory with scent.
Read the full explanation →Which one of the following National Parks lies completely in the temperate alpine zone?
- A.Manas National Park
- B.Namdapha National Park
- C.Neora Valley National Park
- D.Valley of Flowers National Park
Show answer
Set high in the Garhwal Himalaya of Uttarakhand, roughly between 3,200 and 6,600 metres, it lies wholly in the temperate alpine zone.
Read the full explanation →Consider the following kinds of organisms:
1. Copepods
2. Cyanobacteria
3. Diatoms
4. Foraminifera
Which of the above are primary producers in the food chains of oceans?
- A.1 and 2
- B.2 and 3
- C.3 and 4
- D.1 and 4
Show answer
Cyanobacteria and diatoms carry out photosynthesis, so they are phytoplankton, the primary producers at the base of ocean food chains.
Read the full explanation →