SL Option G Flashcards
(22 cards)
Main abiotic factors
- temperature
- water
- light
- soil pH
- salinity
- mineral nutrients
Distribution of animal species affected by… (5)
- temperature: external temperatures affect all animals
- water: uh
- breeding sites: example; mosquitos need stagnant water for egg laying
- food supply: can only live where specific dietary needs met
- territory: some species establish/defend territories for feeding/breeding
Random sample
each individual in a population has an equal chance of being selected
Quadrats
square frames to mark sample areas in random sampling of plant populations
Transect
alternative to random sampling; investigate plant/animal distributions along a line marked out across a site
useful if gradient
Population equation using quadrat
mean number per quadrat x total area/area of each quadrat
Niche concept
mode of existence of a species in an ecosystem:
- habitat: where they live
- nutrition: how to obtain food
- relationships: how to interact with other species
competitive exclusion principle
one species can occupy a niche in an ecosystem
Fundamental niche
a species potential mode of existence, given the adaptations of the species
Realized niche
a species actual mode of existence, which results from its adaptations and competition from other species
5 Examples of Interactions between species
HERBIVORY: a primary consumer feeding on a plant or other producer - producers growth affects food availability for the herbivore
PREDATION: a consumer feeding on another consumer. Numbers and behavior of the prey affect the predator
PARASITISM: a parasite is an organism that lives on or in a host and obtains food from it - the host is always harmed by the parasite
COMPETITION: two species using the same resource compete f the amount of the resource used by teh species reduces he amount available to the other species
MUTUALISM: mutualists are members of different species that live together in a close relationship, from which both benefit
Biomass
total dry mass of organic matter in organisms or ecosystems
Gross production
Total amount of organic matter produced by plants in an ecosystem
Net production
amount of gross production in an ecosystem remaining after subtracting the amount used by plants in respiration
gross production = plant respiration + net production
Primary succession
starts in an environment where living organisms may not have previously existed (for example, a new volcano island)
Secondary succession
occurs in areas where an ecosystem is present, but is replaced by other ecosystems because of change in conditions (for example, abandoned farm turning to a forest)
Biome
type of ecosystem
Major biomes of the world
- desert: rainfall low/ hot days, cold nights/ few plants
- grassland: raindfall low, dominated by grasses/herbs
- shrubland: cool wet winders/dry sommers, drought resistant shrubs
- temperate decideuous forest: moderate rainfall, trees that shed their leaves
- tropical rainforest: rainfall high, huge diversity of plants
- tundra: low temperatures, very small trees
In situ conservation
conserving a species in its own habitat
-species remain adapted to environment
greater genetic diversity
Three ways of ex-situ conservation methods
- Captive breeding in zoos
- Botanic garden
- seed banks
Lincoln index population size equation
population size = n1 x n2 / n3
n1 = number caught and marked initially n2 = total number caught on the second occasion n3 = number of marked individuals recaptured
maximum sustainable yield
largest amount that can be harvested without a decline in stocks
