Our Environment Flashcards
Ecosystem
The ecosystem comprises all the biotic and abiotic factors interacting with one another in a given area.
Biotic components include all living organisms such as plants, animals, microorganisms and humans,
etc. and abiotic components include sunlight, temperature, air, wind, rainfall, soil and minerals, etc. E.g.
pond ecosystem, grassland ecosystem, etc.
Mode of nutrition in animals and plants
Autotrophic and Heterotrophic are the two modes of nutrition in living organisms. Plants and some
bacteria are autotrophic as they make their own food. Animals, fungi and some bacteria are
heterotrophic as they derive their food from other organisms.
Saprophytes and decomposers
Saprophytes feed on dead and decaying material, e.g. fungi and microorganisms. They absorb nutrients
from dead and decaying plants and animal parts. Decomposers break down the organic matter or waste
material and release nutrients into the soil. For example, bacteria, worms, slugs, and snails. They are
considered extremely important in soil biology. They break down the complex organic matter into
simpler substances that are taken up by the plants for various metabolic activities.
Abiotic components
Non-living chemical and physical components of the environment like the soil, air, water, temperature,
etc.
Biotic components
Living organisms of the environment like plants, animals, microbes and fungi.
Trophic levels
It refers to the various levels in a food web as per the flow of energy. The different trophic levels are -
* Producers (T1)
* Primary consumers (herbivores-T2)
* Secondary consumers (primary carnivores -T2)
* Tertiary consumers(Sec carnivores -T3)
* Quaternary consumers (Ter. carnivores T4)
* Decomposers
Pyramid of trophic levels
- Is a graphical representation.
- Can be the pyramid of numbers, the pyramid of biomass or the pyramid of energy.
- All the pyramids start with producers.
a) Pyramid of numbers: gives the number of organisms present at each trophic level.
It can be upright or inverted.
b) Pyramid of biomass: gives the biomass of each trophic level and could be upright or inverted.
c) Pyramid of energy: is always upright as it shows the flow of energy from one trophic level to the
next trophic level.
Law of conservation of energy
- Energy can neither be created nor destroyed; rather, it transforms from one form to another.
- In biological systems, it gets passed from one organism to another across trophic levels.
Energy flow
- Transfer of energy from one trophic level to another depicting its direction and amount.
- Can be represented by the pyramid of energy.
- In any food chain, only 10% of the energy is transferred from one trophic level to another.
Food chain
A series of organisms each dependent on the next as a source of food
Food web
- Is formed by interconnections of different food chains.
- Is a graphical representation of ‘Who eats Whom’ in an ecosystem
Characteristics of ecosystem
- Includes the summary of trophic levels.
- Their energy flow and pyramids.
Environment
- Includes all living and nonliving things.
- Unlike ecosystems, there need not be any necessary interaction between them.
Pollution
Pollution is the introduction of harmful materials (pollutants) into the environment. Pollution can be due
to natural causes such as volcanic eruptions, forest fires, etc. or due to human activities, such as carbon
emission, industrial runoff, etc.
Biodegradable waste
- Waste is derived from plants or animals.
- Decomposed into the soil by a natural agent such as weather, water, air, heat, micro-organisms,
etc.
