ecosystems Flashcards
what is ecology
the study of interactions between organisms and their environment
list some physical factors that have an effect on ecology
temperature, water, sunlight, wind, soil chemistry, disturbance etc
list some biotic factors that have an effect on ecology
predator/prey, parasites, symbionts, competitors etc
what are the different levels of ecological organisation
biosphere biome ecosystem community population individual
what is the biosphere
the parts of the earth inhabited by organisms
what is the biome
a climatic region e.g. tundra, deep sea, savannah, tropical rainforest
what is an ecosystem
the functional unit of ecology: the organisms in a habitat type that interact to create its structure e.g. rainforest in the amazon catchment
what is a community
a subset of the ecosystem that is found in one location e.g. amazon rainforest birds, their prey and predators
what is a population
the members of one species that interact together e.g. macaws
give some global patterns in biodiversity
- species are not evenly distributed over the earth’s surface
- different taxonomic groups often show parallel patterns of biodiversity e.g. rainforest is a favourable environment for amphibians, mammals and birds
- distribution of threatened species is not similar for different taxonomic groups e.g. rare birds - Pakistan, rare mammals - south east Africa
- there are more species near the equator than the poles
what are the most likely explanations for the greater number of species near the equators
there is greater climatic stability and productivity at the equator, leading to greater speciation/smaller niches.
at the equator there is the same amount of daylight all year round and the climate is warmer
what happens to the mammal biodiversity when forest size is increased and why
mammal biodiversity increases - some species need a larger range than others so the increase in range allows more species to inhabit the forest
what is an island
can be an island of one habitat e.g. woodland, water
what do immigration and extinction rates depend on
island size
what does the equilibrium number of species depend on
the equilibrium number of species depends on the size of the island and the rate of immigration and extinction
compare a small island to a large island in terms of their immigration and extinction rates
immigration rate is greater in large islands compared to small islands
extinction rate is greater in small islands compared to large islands
what does McArthur and Wilson’s model of habitat locations suggest about species diversity
greater barriers to colonisation will result in lower diversity
i.e. the further away an island the less species inhabit it
what are the global patterns in body size
Bergmann’s rule - find larger bodies at higher altitudes because temperature decreases at higher altitudes - larger mammals experience less heat loss
body size is larger in regions of low biodiversity
members of a tropical species of bird are more consistent in size than members of temperate species
do all organisms need energy
yes - either form the sun, chemicals or each other
in most ecosystems how is energy form the sun converted into organic molecules
by primary producers - by photosynthesis
what is gross primary production (GPP)
the total amount of energy generated by autotrophs in an ecosystem
what is an autotroph
an organism that is able to form nutritional organic substances from simple inorganic substances such as carbon dioxide.
what is net primary productivity (NPP)
how much of the GPP is available to other organisms (autotrophs use some of the energy)
NPP = GPP - respiration by autotrophs
what fraction of GPP is usually NPP
half
