Notes

Ecology

-Every 20 minutes, on average, one species of plant or animal becomes extinct
-The scientific study of the interactions between organism and their environment is called ecology
- All organisms including humans, interact continuously with their environments
-The outside world can be divided up into two major components
--Abiotic component
--Biotic component
-Humans have always had an interest in other organisms and their environments
-When we study the interactions between organisms and their environments, it is convenient to divide ecology into four increasingly comprehensive levels
--organismal ecology
--population ecology
--community ecology
--ecosystem ecology
-The science of ecology should be distinguished from the informal use of the word ecology to refer environmental concerns
-Chemical fertilizers and pesticides, for example, showed great promise for increasing agricultural productivity and eliminate insect borne diseases.
-The biosphere is patchy
-We can see this environmental patchwork on several levels.
-Its clear that no part of the biosphere is untouched by the abusive impact of human populations and their technology
-Solar energy powers nearly all ecosystems
-Aquatic organisms have a seemingly unlimited supply of water, but they face problems of water balance if their own solute concentration does not match of their surroundings
-Environmental temperature is an important abiotic factor because of its affect on metabolism
-Some organisms(bacteria, protists, insects) depend on nutrients blown to them by winds
-The physical structure and chemical composition of rocks and soil limit the distribution of plants
-Catastrophic disturbances, such as fires, hurricanes, tornadoes, and volcanic eruptions, devastate biological communities
-Some disturbances, such as volcanic eruptions, are so infrequent and irregular over space and time that organisms have not acquired evolutionary adaptations to them
-The consequent increase in evaporative cooling can be advantageous on a hot summer day, but can cause dangerous wind chill in the winter
-Surveying the abiotic factors of the biosphere
-The fields of ecology and evolutionary biology are tightly linked
-Many organisms respond to environmental challenge with some type of change in body shape or anatomy(structure)
-Other anatomical changes are irreversible over the lifetime of an individual
-Population density is the number of individuals of a species per unit area or volume
-In contrast to plants, most animals can respond to an unfavorable change in the environment by moving to a new location
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