Ecology

The study of organisms and their environment

ECOSYSTEMS All of the biotic parts (bacteria, fungi, animals, etc.) and the abiotic parts

(temperature, wind, water, etc.) together make up an ecosystem

A Stable Ecosystem: Population numbers fluctuate at a

predictable rate Supply of resources fluctuate at a

predictable rate Energy flows through the ecosystem at a

fairly constant rate over time

There are limiting factors in an ecosystem that control the number of individuals that can live there Limiting factors are space, food, water,

mates, etc. Limiting factors limit the number of

individuals that can inhabit an ecosystem

Limiting factors cause competition among organisms

Determine the carrying capacity – maximum number of individuals that can live in an ecosystem

Density Dependent Factors Limiting factor that acts more

strongly on large populations than small ones

Ex: disease, predators (usually biotic)

Can be triggered by increases in a population

Density Independent Factors A limiting factor that occurs

regardless of how large the population is

Mostly abiotic Ex: volcanic eruption,

flooding, and fire

Niche The combination of where an

organism fits into the food web, the specific habitat in which it lives, how it obtains food, their behavior, etc.

Human Population Growth Has Placed Tremendous

Strains on the Environment for Resources

HUMAN POPULATION GROWTH HAS AN EFFECT ON: Food shortages Large amounts of waste produced Lowers the amount of available fertile

soil Demand for land has led to deforestation

which can increase erosion rates

Increases acids produced in the atmosphere due to burning of fuels from cars, factories, etc.

Higher production of chemicals that can damage the environment (CFCs for example)

Decreases the availability of renewable and nonrenewable resources

Contribute to poorer air quality Decreases the amount of clean water Larger amounts of waste products Some waste products are not biodegradable

or are toxic to the environment (Freon for example)

Use of chlorofluorohydrocarbons (CFCs) contributes to the depletion of the ozone layer that protects the earth from UV rays from the sun

Burning of fossil fuels for energy and transportation increases greenhouse gases released into the atmosphere (mostly CO2), which increases global temperatures that affect sea levels, climate and atmospheric composition

GEOCHEMICAL CYCLES Movement of a particular form of

matter through the living and nonliving parts of an ecosystem

Earth is a closed system, because matter changes form but is neither created nor destroyed; it is used over and over again

CARBON CYCLE

NITROGEN CYCLE

WATER CYCLE