Monday, December 22, 2008

How do the physical features of the surroundings affect organisms? What are these physical factors?


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Okay, let's start with the a term called the abiotic environment. (The abiotic factors of the environment include light, temperature, and atmospheric gases.)



Abiotic factors









  1. Climate










  • Light intensity




  • Temperature




  • Amount of water available






2. Oxygen content







3. Salinity (salt concentration) of soil or water







4. pH of soil or water

























How does all of the physical surroundings mentioned above affect the environment?







Firstly, the physical features of the surroundings and the nature of the soil determine the types of plants found in a region. (eg. plants that need more water, plants that need less water)







Since animals rely directly or indirectly on plants for food, the diversity of the animals in a region is thus first determined by the plant source. Organisms in a region are usually adapted to their environment.













How does light intensity affect organisms?







Light intensity affects the distribution and growth of both plants and animals. Plants that carry out photosynthesis naturally exist where there is an adequate amount of sunlight.


eg. Plants that photosynthesis only exist at areas where their is sufficient sunlight. However, too much sunlight will cause the plant to grow slowly, which shows why plants that grow under the sun end up much shorter than those which grow in the shade.








Temperature






Temperature affects the rate of enzymes, which control the metabolic or physiological activities of plants and animals. Since most organisms cannot tolerate extremes of temperatures, temperatures that are too high or too low would kill them.


eg. Migrating birds migrate twice a year. When winter arrives, they fly in a group to an area which has a warmer climate, and they return when winter has passed.








Amount of available water






Water is essential for living. Thus, the amount of available water greatly affects the number and location of various species in the region. The amount of available water also depends on the amount of precipitation throughout the year.


eg. Aquatic animals have gills for absorbing oxygen or special structures for swimming.





Oxygen content






Most organisms are aerobic, which means that they require oxygen for respiration, thus they are unable to survive in an environment with low oxygen content.


eg. Carp, an air-breathing fish, can gulp air at the surface of the water.



Salinity






Salinity (salt concentration) of water is an important factor affecting aquatic organisms, as animals that live in seawater tend to lose water by osmosis.


eg. The cytoplasm of the cells of freshwater organisms usually has a higher salt concentration than the surrounding water. The cell walls of freshwater plants have rigid cell walls that prevents the cell from bursting.



pHBold






pH refers to the acidity or alkalinity of a solution. Aquatic organisms are very sensitive to the pH of water that they live in.



eg. In strong daylight, photosynthesis in plants makes water more alkalie by using up the carbon dioxide. At night, photosynthesis stops, and thus the carbon dioxide produced in respiration makes the water more acidic.








Common terms in ecology;

Here are some common terms that you might encounter while learning about ecology.


Organism - An individual living thing

Population - A group of individuals of a single species that inhabits the same area

Community - All the different populations wihtin a given area. Within the community, each type of organism (species) fills a certain position

Habitat - The particular part of the environment in which an organism lives

Niche - The role or function of an organism in the ecosystem in which it lives

Ecosystem - A community and its physical environment. An ecosystem must have three components: (a) A source of energy.
(b) Autotrophs to convert this energy to organic compounds
(c) The ability to recycle materials between the physical environment and the individual organism

Biosphere - The portion of the earth on which life exists. It consists of all the ecosystems on the earth

Introduction


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Do you know that in nature, organisms living in the same area pften form relationshipds with one another in order to survive?

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In this case, let's imagine;

In a simple scenario...

There are lions, deers and grass in a jungle.

Their food chain are as followed:

Grass (consumed by) --> Deer (preyed upon by) --> Lions

Life was going very peacefully for all the animals and plants. There was always just enough food to go around.

However, one fine day, a group of hunters arrived, and they started hunting deer. And soon enough, the deer population has decreased such that there isn't enough prey for the lions.

Lions cannot eat grass, and thus, many of the lions either have to move away, or die of starvation. Now, since there are not that many deers to consume the grass anymore, there is an overcrowding of grass.

Unknowingly, the group of hunters had upsetted the natural food chain.

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I hope that after reading this, you can grasp a little bit of concept about the ecosystem, which will be what this blog consists of. Now, you know that nature is so fragile, and that an inconsiderate action might cause ultimate pandemonium in the wonderful world of nature. (: