Why is there a need for conservation?

Conservation is necessary for the maintenance of the Earth's biodiversity.

It is necessary for the following reasons:

• to prevent extinction of plant species
• to maintain a stable and balanced ecosystem
• to mailtain a large gene pool
• to ensure the conservation of marine life
• provide useful infomation to humans
• preserves natural scenery and wildlife for people to appreciate
• to maintain biodiversity

Discuss the impact of human activities on our ecosystem.

Impact of human activities on our environment

Impacts of deforestation
1)When the trees are removed,the topsoil is exposed to directly to the force of the rain. Without the roots to hold soil together,the topsoil which is the most fertile layer gets washed away or eroded during heavy rain, especilly when the rain falls on steep slopes.
2)Eroded soil may be deposited in rivers and streams, blocking the flow of water causing floods.
3)Sunlight now falls directly onto the soil.Water evaporate rapidly from the soil, which then hardens and barren.Plants can no longer grow and organisms that feed on these plants will go die off without food.This is called desertification
4)It also causes climate change.When the trees are cleared, the area becomes dry and warm and annual rainfall decreases
www.mcgarrigles.com

Impacts of over-fishing
If fishing practices are not controlled, some species of fish will be caught faster than they can be replaced. Young fish that are caught will not have a chance to grow and reproduce. Hence, fish populations will decrease.

www.greenpeace.org

Impacts of eutrophication
Chemical fertilisers containing nitrates and phosphates are used to increase the yield of crops. However, the overuse of these fertilisers may cause water pollution. Nitrates and phosphates in the fertilisers leads to the profuse growth and multiplication of algae and water plants in the river or lake. Submerged algae and plants die due to lack of sunlight. The dead bodies of the algae and water plants are decomposed by bacteria. Bacteria grow and multiply rapidly, using up the oxygen in the water. Other organisms such as fish die due to lack of oxygen.

Impacts of biomagnification/bioaccumulation
Insecticides are substances used to kill insects. However, insecticides may end up affecting other organisms as well. For example, insecticides such as DDT (dichlorodiphenyltrichloroethane) are non-biodegradable. This means that they cannot be broken down by microorganisms like bacteria. They can remain in the soil or water for many years. Insecticides may be carried by rainwater into streams, rivers and lakes. In high concentrations, they may poison fish or animals that take in the polluted water or feed on the contaminated fish.

Describe the carbon cycle.

The Carbon Cycle

The Carbon Cycle is a biogeochemical process where carbon is recycled through the ecosystem. The concentration of carbon in living matter(18%) is almost 100 times greater than its concentration in the earth (0.19%). So living things extract carbon from their nonliving environment. For life to continue, this carbon must be recycled. See the diagram for a detailed look at the carbon cycle. An example of a route carbon takes in this cycle is carbon dioxide in the atmosphere is absorbed by plants and used in photosynthesis to produce sugars which the plant uses for energy. When the plant dies, it decomposers and the carbon stored in the plant will, over millions of years, form into coal (a fossil fuel). The coal is burnt and gives off carbon dioxide which goes into the atmosphere.

http://en.wikipedia.org/wiki/Carbon_cycle

What happens to most of the energy in the ecosystem?

Most of the energy in the ecosystem is lost as heat.Heat lost through respiration of organism to the environment.

Why are short food chains better?

Since energy is lost at each trophic level,less and less energy is availablefor the organism at the next level as we go down the food chain. Hence, food chains are generally short. A shorter food chain means more energy is available to the final consumer because less energy is lost to the environment. www.ngfl-cymru.org.uk

What are ecological pyramids? Describe the different types of ecological pyramids

Ecological pyramids
We can compare the trophic levels in a food chain using ecological pyramids.

Pyramid of numbers
A pyramid of numbers allows to compare the number of organisms present in each trophic level at a particular time.

Pyramid of biomass
A pyramid of biomass allows us to compare the mass of organisms present in each trophic level at a particular time.

Variations in ecological pyramids
Most ecological pyramids are pyramid-shaped, but there are important exceptions.

A pyramid of numbers may be upside down or inverted if organisms of one trophic level or many small organisms of another trophic level feed on large organism of another trophic level. In this case, the pyramid of numbers is inverted.

Pyramids of biomass for rapidly reproducing organisms are also not pyramid-shaped. Since the pyramid of biomass is based on standing mass, it does not take into account the rate of reproduction of organisms.

Pyramid of energy
The total energy in the various trophic levels of a food chain can be represent in the form of a pyramid. This is called the pyramid of energy.

What is the relationship between a predator and a prey? Two predators with the same prey?

What is the relationship between a predator and a prey?
A predator is an organism that kills and feed on other organisms. The organisms that are eaten are called the prey.



Two predators with the same prey.
However,this cycle changes when another predator of the same prey is introduced into the same biotic environment.Prey will be hunted and fed on continuously until the number falls until it is almost extinct.Food is now scarce for both predators.Therefore the population of both predators will drop as there is hardly any prey.This fragile cycle might break as time passes and both prey and predator goes extinct unless predators hunt for a different prey and the prey evolves to be able to evade the predator.