Lecture 8 Flashcards
What is an ecosystem based on A.G tansley in 1935?
An ecosystem is a functional unit of nature encompassing complex interaction between its biotic (living) and abiotic (non-living) components.
What does an ecosystem include?
1) abiotic components (non living )
2)biotic components(living)
What are the three categories of the abiotic components ?
1)physical factors
2)inorganic substances
3)organic compounds
What are the physical factors ?
Sun light, temperature, rainfall, humidity and pressure.
What are the inorganic substances ?
Carbon dioxide, nitrogen, oxygen, phosphorus, sulphur, water, rock, soil and other minerals.
What are the organic components ?
Carbohydrates, proteins and lipids.
What are the categories of biotic components ?
1)producers
2)consumers
3)decomposers
Define the producers ?
The green plants manufacture food for the entire ecosystem through the process of photosynthesis. Green plants are called autotrophs, as they absorb water and nutrients from the soil, carbon dioxide from the air, and capture solar energy for this process.
Who are the consumers ?
They are called heterotrophs and they consume food synthesized by the autotrophs.
What are the three categories of consumers ?
1)herbivores
2)carnivores
3)omnivores
Who are the Herbivores?
e.g. cow, deer and rabbit etc.) feed directly on plants,
Who are the carnivores?
carnivores are animals which eat other animals (eg. lion, cat, dog etc.)
Who are the omnivores ?
omnivores organisms feeding upon both plants and animals e.g. human, pigs and sparrow.
What othr name for decomposers?
Saprotrophs
Who are the decomposers ?
These are mostly bacteria and fungi that feed on dead decomposed and the dead organic matter of plants and animals by secreting enzymes outside their body on the decaying matter. They play a very important role in recycling of nutrients.
