Ecosystem Change

Seite 1

change over time

within species - evolution

within ecosystem (biotic) - succession

within ecosystem (abiotic) - weathering, erosion, geological uplift, climate change

Succession

change to mixture of species within community (all living organisms in particular area at particular time)

primary or secondary

primary succession

start from bare rock

producers: pioneers/soil builders - lichen (fungi break up rock, algae photosynthesise), moss, cryptogamics

soil = weeds and and grasses = consumers: herbivores

more established plants (shrubs, etc.) = consumers: larger herbivores + small carnivores (2nd order)

early trees = consumers: largest herbivores and carnivores

climax forest

can't start with consumers - must be producers

slowly becomes more diverse and established

climax forest = stable and complex ecosystem

pioneer species, intermediate species, climax community

Seite 2

Human Impact on Ecosystem Change

CHHIMP

Climate Change (greenhouse effect = global warming = climate change)

alter biotic and abiotic components of all ecosystems

change in species and population sizes

ecosystem breakdown/collapse = mass extinctions

size and continued survival of human population threatened

greenhouse effect - carbon dioxide, ash, etc. create "blanket" over atmosphere

Infra-Red radiation unable to escape = warming

Harvesting/Agriculture

Resources produced - food, materials

Jobs

requires land - cleared

use of fertilisers and pesticides - excess nutrients - eutrophication

alter natural state of ecosystem - introduce animals/plants, clear animals/plants, use water

Habitat Destruction

more land for agriculture

develop urban and rural areas

access land for mining

native vegetation cleared

habitats removed or destroyed/altered

ecosystems broken into fragments

not large enough to sustain energy flow or matter cycling

introduced species able to invade and establish

Introduced Species

reduce survival of native populations - competition = extinction, endangered

weeds compete with natives for nutrients, water and light

animals alter food web and energy flow

Mining (many types - oil, logging, fossil fuels...)

provides resources, finances and jobs

requires clearing of land = habitat destruction = ecosystem change

carbon emissions = greenhouse effect

oil spills, etc.

Pollution (air, solid waste, water...)

fertilisers = change in freshwater ecosystems - eutrophication

fertiliser run-off = excess nutrients = algal blooms on surface

algal blooms alter abiotic - limit light entry, use up oxygen and encourage decomposers - use oxygen

biotic components alter due to change to abiotic - plants die (no light), animals die (no oxygen, no producers)

solid waste - alter abiotic, impact plants, endanger animals

air pollution - greenhouse effect, alter abiotic, impact plants