E C O L O G Y

FANTASY LIFE.

Sunday, January 4, 2009

11)Why is there a need for conservation?

Conservation is necessary for the maintenance of the Earth's biodiversity. Conservation is the protection and preservation of natural resources in the environment.

Conservation is necessary for the following reasons:
~To prevent extinction of plants and animal species
~To maintain a stable and balanced ecosystem
~To maintain a large gene pool
~To ensure the conservation of marine life
~To maintain biodiversity
~Conservation is of scientific value
~Conservation preserves natural scenery and wildlife for people to appreciate

We can help in conservation by:
~Keeping the environment clean
~Managing the use of Earth's resources
~Protecting wildlife

Labels: Conservation

-------------------final fantasy--------------- ; {6:45 AM}
_________________________________________________________

Saturday, January 3, 2009

10)Discuss the impact of human activites on our ecosystem, highlighting issues on deforestation, over-fishing, eutrophication and biomagnification.

Human beings are continually using and depleting or reducing the Earth's natural resources and upsetting the balance of nature in many areas by certain activities. The uncontrolled use of the Earth's natural resources, like forests and wildlife, has caused lasting damage to the environment. Such activities are
~Deforestation
~Over-fishing
~Eutrophication
~Biomagnification

Deforestation
With modern technology, forests are being cleared at much faster rate than they can be replace. This leads to loss of habitats which leads to extinction of animals. As trees are removed, topsoil gets washed away or eroded during heavy rain, causing soil erosion. Without the topsoil, the land becomes barren and plants cannot grow in the soil. This causes desertification and leads to habitat loss. Eroded soil may be deposited in rivers or streams. This causes flooding as it blocks the flow of water.

Over-finshing
As human population increases, so does the demand for fish. Some species of fish will have their populations decreased. Some fishing method will destroy marine habitat such as cyanide fishing, cyanide or dynamite is used to stun and catch reef fish, however corals and many other reef organisms are killed in the process.

Eutrophication
Eutrophication is an increase in chemical nutrients in an ecosystem and mean the resultant increase in the ecosystem's primary. As fertilisers are being washed into nearby rivers or lake, it will lead to profuse growth and multiplication of algae and water plants in the lake or river. Submerged algae and plants will die due to lack of sunlight andwill be decomposed by bacteria. Other organisms will die as well as the bacteria rapidly uses the oxygen to decomposes those death plants.

Biomagnification
Also known as bioamplification which is the increase in concentration of a substance sush as pesticide DDT (dichloro-diphenyl-trichloroetheane...so long). DDT is insoluble in water and organisms cannot break down DDT, hence, DDT accumulates in the bodies of consumers. This results in the insecticide being passed along food chains, increasing in concentration in the bodies of organisms along the trophic levels.

Picture of DDT

For e.g. Mercury is only present in small amounts in seawater and is absorbed by algae. Biomagnification result in the buildupin the adipose tissue of successive trophic levels: zooplankton, small fish, larger fish etc. Anything which eats these fish also consumes the higher level of mercury the fish have accumulated.

Picture shows a thousand words!!

-------------------final fantasy--------------- ; {4:27 AM}
_________________________________________________________

9)Describe the carbon cycle.

The carbon cycle is made up of various processes by which carbon, in form of carbon dioxide, is removed from and released into the environment.The cycle is usually thought of as four major reservoirs of carbon interconnected by pathways of exchange. These reservoirs are the atmosphere, terrestrial biosphere, the ocean, sediments like fossil fuels.

Removal of carbon dioxide from the environment

Carbon dioxide is being absorbed by green plants during photosynthesis. Carbonhydrates like glucose are then produced. Glucose may change to other organic compounds, carbon compounds become part of the animals when they feed on the green plants. The carbon compounds may also be preserved in fossil fuels such as cool.

Release of carbon dioxide into the environment

Respiration: Carbon dioxide is release from living organisms when they respire.

Combustion: When coal and natural gas are burnt or undergo combustion, carbon compounds are broken down and carbon dioxide is released into the environment.

Decay: When organisms die, their bodies are broken down to simple substances by decomposers. Carbon dioxide is then released into the environment. Some simple substances are used by the decomposers and when they respire, carbon dioxide is also released into the environment.

The picture above shows a carbon cycle.

Importance of carbon cycle
~Ensures that there is a continuous supply of carbon dioxide for plants in order to produce food for non-photosynthetic organisms.
~Enables energy to flow through the ecosystem.

Labels: Carbon cycle

-------------------final fantasy--------------- ; {2:49 AM}
_________________________________________________________

Tuesday, December 30, 2008

8)What happens to most of the energy in the ecosystem?

Energy flow in an ecosystem is non-cyclic. Energy is lost to the environment as heat, which cannot be recycled in the ecosystem. Hence, energy must be constantly supplied to the ecosystem. In any ecosystem, the ultimate source of energy is the sun. Light energy is then absorbed by chlorophyll in producers and then converted to chemical energy during photosynthesis. Energy is then passed from one trophic level to another through feeding. Dead organisms and egested and excreted materials contain trapped chemical energy. The energy is then released by activity of decomposers, some energy is used by the decomposers while the rest of the energy is lost as heat. Eventually, all the energy that enters the biotic part of the ecosystem is lost as heat energy and living organisms are unable to use heat energy to do work.

Labels: Energy

-------------------final fantasy--------------- ; {11:58 PM}
_________________________________________________________

7)Why are short food chains better??

Since about 90% of the energy is lost when it is transferred to the next trophic level, a shorter food chain means more energy is avaliable to the final consumer as less energy is lost to the environment.For e.g, we will recieve more energy if we feeds directly on crop plants rather than eating a cattle that feed on crop plants. Therefore, a shorter food chain is more efficient than long food chain.

Labels: Food chains

-------------------final fantasy--------------- ; {11:41 PM}
_________________________________________________________

6)What are ecological pyramids? Describe the different types of ecological pyramids.

An ecological pyramid is a graphical representation designed to show the biomass or productivity at each trophic level in a ecosystem.
*Each stage in a food chain is known as a trophic level.

The picture above shows an ecological pyramid

There are two types of ecological pyramid, the Pyramid of biomass and the Pyramid of energy(pyramid of productivity).

Pyramid of biomass
An ecological pyramid of biomass shows the relationship between biomass and trophic level. It is constructed based on the dry mass of organisms in each trophic level at any one time. Lets take this food chain as an example.
Grass-->Rabbit-->Snake-->Hawk
All the grass together have a larger biomass than the rabbits, all the rabbits together have a larger biomass than the snake, all the snakes together have a larger biomass than the hawks. Hence, the pyramid of biomass for this food chain will be broad at base and narrow towards the top.

Pyramid of energy
An ecological pyramid of energy shows the production or turnover of biomass at each trophic level. It is constructed base on the total energy level in each trophic level over a certain period of time,for e.g, 1 year.
More and more energy is lost as it goes down a food chain.Almost 90% of the energy is lost when it is transferred from one trophic level to another. The total energy level is the highest at the first trophic level and lowest at the last trophic level. Hence, the pyramid of energy is always broad at base and narrow towards the top.

Labels: Ecological pyramids

-------------------final fantasy--------------- ; {10:47 PM}
_________________________________________________________

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

A predator is an organisms that feeds on other organisms which is the prey

In the picture above, the spider is the predator while the fly is the prey.

An increase in population of prey would means more food for the predator, thus causing the population of predator to increase. However, this causes the population of prey to decrease, which in turn results in a decrease in the predator population due to the lack of food. As the population of predatore decreases, the population of prey would increase again and so on..

A prey-predator graph

If they are two predators feeding on the same prey. Both predators will be competing against each other for food. This causes the population of prey to decrease. Overtime both population of predator would decrease if they do not look for other scoure of food and the population of prey would increase when there are lesser predators.

Labels: Predator-prey relationship

-------------------final fantasy--------------- ; {10:19 PM}
_________________________________________________________

Jin Hao
Queenstown

;

Biology Assignment
soulesspuppy@hotmail.com
4A

LINKS

Keng Kiat | Valerie |

Credits

Info and images are taken from wikipedia. Please do not remove credits.view my other blogskins. This blogskin is made by Devil regina

Past fantasy

December 2008
January 2009

Forum

TAGBAORD CODE GOES HERE