Ecosystem_terminals

EVS_CH5_terminals

Define  Autotrophs

The plants that manufacture their own food for the entire ecosystem.

They are also known as producers.

Define: Heterotrophs

They consume food synthesized by the autotrophs, dependent on other.

Define: Primary carnivores

Consumers that depend on producers or other organisms for food.

Define: Saprotophs

Saprotroph, also called saprophyte or saprobe, organism that feeds on nonliving organic matter known as detritus at a microscopic level.

OR

saprotrophs are orgnisms that obtain nutrition from dead and decaying organic matter.

Define: Omnivores

An omnivore is an animal that eats both plants and animals for their main food.  Eg. crow

Give reasons whether the following statements are true or false.

(i) Food chains are more stable than food webs.

FALSE

A food web is actually several food chain jointed together.

Because most organism depend on more than one species for their food requirement food web is more accurate modal than food chain.

Give reasons whether the following statements are true or false.

(ii) Pyramids of energy are never inverted where as pyramid of biomass may be inverted.

TRUE

These can never be inverted because energy is always lost as you go up a trophic level. They show the amount of energy put into each trophic level in a given time.

Give reasons whether the following statements are true or false.

(iii) A detritus food chain begins with autotrophs.

FALSE

The detritus food chain begins with the dead organic matter and not producers or autotrophs

Give reasons whether the following statements are true or false.

(iv) Phytoplankton is the term applied to floating organisms in a pond.

FALSE

phytoplankton are micro plants.

Give reasons whether the following statements are true or false.

(v) Aphotic is the upper zone of a pond.

FALSE

It is the bottomost zone.

Give Reasons

We see more wall lizards near the tube light during summer

Lizarda are warm blooded animals which are active in high temperature and their rate of activity increases in hot environment.

Energy pyramids are never inverted.

Pyramid of energy is the only pyramid that can never be inverted and is always upright. This is because some amount of energy in the form of heat is always lost to the environment at every trophic level of the food chain.

We can not directly use atmospheric nitrogen

A plant can not use atmospheric nitrogen directly because it is present in free gaseous form in the atmosphere whereas plants are capable of absorbing N2 in the form of Nitrogen compounds like Nitrites and nitrates only from the soil, which is converted by the microorganisms in the soil.

There is higher concentration of cabon dioxide in the aphotic zone

In the aphotic zone, there virtually no light from the sun , so photosynthesis can not take place. Consequently there are no plants or other photosynthetic organisms in this zone.

So concentration of CO₂ increases.

Food chains have a limited number of steps

A food chain's length is restricted to just 3 or 4 steps due to energy loss.

What is an ecosystem?

The simplest definition of an ecosystem is that it is a community or group of living organisms that live in and interact with each other in a specific environment

Explain structural components of an ecosystem.

Abiotic

Biotic

Define decomposers and give their role in sustaining an ecosystem.

Decomposers are organisms that break down the dead organic matter into simpler substances to release energy and nutrients.

Without them, waste would pile up in the environment making it unavailable for plants and producers.

Why are ecosystems dynamic in nature? Give the various functional components of an ecosystem.

Ecosystems are dynamic entities controlled both by external and internal factors

 External factors, such as climate and the parent material that forms the soil

The ecosystem is largely divided into two functional components; the Abiotic and Biotic.

What is an ecological pyramid?

Ecological pyramid is a graphical representation in the form of a pyramid showing the feeding relationship of groups of organisms.

 Define and differentiate between different pyramid of energy and pyramid of numbers.

pyramid of energy shows the rate of energy flow and/or productivity at successive trophic levels

the pyramid of numbers shows the relationship between producers and consumers at successive trophic levels in terms of their number

List the various steps of nitrogen cycle in a sequence

Nitrogen fixation

Nitrification

Assimilation

Ammonification

Denitrification