Chapter 17: Ecosystems

Population: all the individuals of the same species (ducks)
Community: all the different species in an area (ducks + maple trees + dragonflies)
Ecosystem: the community plus the physical factors in an area (ducks + maple trees + dragonflies + temperature + soil + rainfall)

Biotic Factors: living elements in an ecosystem (plants & animals)
Abiotic Factors: non living elements in an ecosystem (soil, temp, water, noise)

Habitat: the physical space where an organism lives

BIODIVERSITY: a measure of the number of species in an ecosystem. Some ecosystems are more diverse than others.

Succession: process where organisms arrive and inhabit a new ecosystem:
Pioneer species: the first to inhabit a new area *See text on Glacier Bay

Energy Flow in Ecosystems

Primary Productivity: the rate which protosynthesis produces organic materials

Producers: capture energy from the sun, convert to organic material -- plants
Consumers: organisms that gain their energy from eating other things -- animals

Food Web

Herbivores Carnivores Omnivores   Producers Primary Consumers Secondary Consumers Tertiary Consumers

Decomposers - cause decay
Detritivore - an organism that feeds on dead or waste (bacteria, fungi)

Energy Transfer - as you go up trophic levels, organisms lose energy.
An ecosystem can support more primary consumers, than tertiary consumers

Ecosystems Cycle Materials

Biogeochemical cycles

Water Cycle

ground water
transpiration (from plants)
evaporation (from bodies of water)
precipitation (from clouds)

Carbon Cycle

Respiration (breathing of animals)
Combustion (burning)
Photosynthesis (uses CO2 and converts to oxygen)

Nitrogen Cycle

Nitrogen is a fertilizer for plants
79% of the air is made of nitrogen

Human Effects on Atmosphere

1. Pollution
2. Acid Rain
3. Ozone Depletion
4. Global Warming (greenhouse effect)