Course: Basic Concepts of Ecology | Semester: 2nd Semester (FYUG)
Time: 3 Hours | Full Marks: 70 | Pass Marks: 28
Define biome.
"A biome is a large geographical area characterized by specific climate conditions, plant communities, and animal life that have adapted to that particular environment."
Define habitat with example.
A habitat is the specific physical place or environment where a particular species lives and finds the necessary resources (food, water, shelter) to survive.
What is the difference between autecology and synecology?
| Feature | Autecology | Synecology |
|---|---|---|
| Definition | Study of an individual species in relation to its environment. | Study of groups of organisms (communities) in relation to their environment. |
| Focus | Single species or individual organism. | Multiple species and their interactions. |
Write short notes on: (i) Ecological niche, (ii) Ecological amplitude.
(i) Ecological Niche:
The ecological niche refers to the functional role and position of a species within its ecosystem. It encompasses not just where the organism lives (habitat), but what it does, what it eats, and how it interacts with other biotic and abiotic factors. It includes the organism's "profession" or "job" in the environment.
(ii) Ecological Amplitude:
Ecological amplitude describes the range of environmental conditions (such as temperature, pH, or salinity) within which a specific species can survive and function. Species with a wide amplitude are called euryoecious (adaptable), while those with a narrow amplitude are stenoecious (specialized).
Write short notes on: (i) Ecozone, (ii) Liebig's law of the minimum.
(i) Ecozone:
An ecozone (also known as a biogeographic realm) is the largest scale biogeographic division of the Earth's surface. It is based on the distribution patterns of terrestrial organisms. Each ecozone contains regions that have evolved in relative isolation over long periods of time, separated by geographic barriers like oceans or mountain ranges.
(ii) Liebig's Law of the Minimum:
"Growth is controlled not by the total amount of resources available, but by the scarcest resource (limiting factor)."
Originally developed for agriculture, this law states that if one of the essential plant nutrients is deficient, plant growth will be poor even when all other nutrients are abundant. In ecology, this applies to any environmental factor (light, water, nutrients) that limits the population growth of a species.
Define population.
A population is a group of individuals belonging to the same species living in a specific geographical area at a given time and capable of interbreeding.
What is density independent population growth?
This refers to population growth that is influenced by environmental factors (like natural disasters, weather, or forest fires) that affect the population regardless of its size or density.
What are absolute natality and realized natality?
Write about any five characteristics of a population.
Give a detailed account on the different types of population growth curve.
There are two primary types of population growth curves:
What is the role of keystone species in an ecosystem?
A keystone species has a disproportionately large effect on its natural environment relative to its abundance. They play a critical role in maintaining the structure and biodiversity of an ecological community.
Write the difference between primary and secondary succession.
| Feature | Primary Succession | Secondary Succession |
|---|---|---|
| Starting Point | Starts on barren land (no soil), like bare rock. | Starts in an area where soil already exists but vegetation was destroyed. |
| Speed | Very slow (takes hundreds of years). | Faster (takes decades). |
Define commensalism. Give example.
Commensalism is a type of biological interaction where one species benefits while the other species is neither helped nor harmed (+/0).
Give a brief account about the structure of a community.
The structure of a community involves the physical and biological organization of different species living together:
Write about the different stages of succession.
The process of ecological succession typically follows these stages:
Mention different types of food chain with examples.
Define trophic level. Give example.
A trophic level is the specific position an organism occupies in a food chain.
What is an estuarine ecosystem?
An estuarine ecosystem is a coastal area where freshwater from rivers mixes with saltwater from the ocean, creating a unique, highly productive brackish water environment.
Write a note on different types of terrestrial ecosystem.
Terrestrial ecosystems are land-based and include:
Write short notes on: (i) Abiotic components, (ii) Functions of an ecosystem.
(i) Abiotic Components: Non-living factors like sunlight, temperature, water, soil, and atmospheric gases that sustain life.
(ii) Functions: Energy flow, nutrient cycling (biogeochemical cycles), and ecological regulation.
Give two examples of nitrogen-fixing bacteria.
Define ammonification.
Ammonification is the process by which decomposers (bacteria and fungi) convert organic nitrogen from dead organisms and waste into inorganic ammonia (NH3) or ammonium ions (NH4+).
Mention types of biogeochemical cycle.
Describe sulphur cycle with suitable diagram.
The sulphur cycle is a sedimentary cycle where sulphur moves through the lithosphere, hydrosphere, and atmosphere. Key steps include mineralization of organic sulphur, oxidation to sulfate, and reduction back to sulfide.
Describe phosphorus cycle with suitable diagram.
Phosphorus is primarily found in rocks. Weathering releases phosphate into soil and water, which plants absorb. It moves through food chains and returns to soil via decomposition. Unlike nitrogen, it has no significant gas phase.