2.4 biomes, zonation, and succession Flashcards
1
Q
biomes
A
- deserts: hot and cold
- forests: tropical, temperate, boreal
- grassland: savanna, temperate
- tundra: arctic
2
Q
abiotic factors that define biomes
A
- precipitation
- temp
3
Q
zonation
A
different communities found along an abiotic gradient (e.g. altitude around mean tide level on shoreline)
4
Q
abiotic factors that drive zonation
A
- temperature
- salinity
- desiccation (drying out)
5
Q
biotic factors that influence distribution of species
A
- competition
- predation
6
Q
succession
A
- change in species composition in an ecosystem over time
- bare rock surface → pioneer species (colonisation) → establishment (invertebrates + soil) → competition → stabilisation → climax community (stable dynamic equilibrium)
7
Q
changes during succession
A
- productivity starts very low
–> initial stages: poor conditions, few producers and consumers
–> later stages: good conditions, many producers and consumers - complexity of food web increases (more trophic levels, more biotic interactions) –> increases stability
- greater numbers of species = greater genetic diversity
8
Q
secondary succession
A
- occurs when existing ecosystem is destroyed, but some components of original community remain intact (soil, seeds, roots, surviving organisms)
- occurs at a faster rate compared to primary succession because soil and other resources are already present
9
Q
r strategist species
A
- unstable environment, density independent
- oganism size: small
- energy used to make each individual: low
- # of offspring produced: many
- survivorship curve: type III
10
Q
k strategist species
A
- stable environment, density dependent
- organism size: large
- energy used to make each individual: high
- # of offspring produced: few
- survivorship curve: type I or II
11
Q
primary succession
A
Primary succession occurs in areas with no previous life or soil, such as after a volcanic eruption or glacier retreat, and begins with pioneer species like lichens and mosses.
