Biology yr 11

Abiotic

the non living factors in a set area

Community

species within a set area which depend on other species’ to live

Biotic

the living factors in a set area

Stable community

when all the species and environmental factors are in balance so population stays fairly constant

Ecosystem

All of the interacting living and non living factors in a set area

Population

All of the individuals of a species in a set area at a particular time

Interdependence

All the different populations of organisms living and interacting in a set area

What are the main 4 things animals compete for?

food, water, territory and mates

Interspecific competition

competition between individuals of different species

Intraspecific competition

between individuals of the same species (only the best genes are past on go the next generation)

What do plants compete for?

space

light

mineral ion

water

Abiotic factors affecting the distribution of organisms

Temperature

Rainfall/moisture

Light intensity

pH and mineral content of soil

wind speed and direction

oxygen levels in water

CO2 levels in air

Biotic factors affecting the distribution of organisms

Availability of food

New pathogens (or parasites)

New predators arriving

Interspecific competition

Adaptations definition

Features that allow organisms to survive in the environments in which they normally live

What are the different types of adaptations?

Physical - eg coloured fur for camouflage

Behavioural - eg rabbits digging burrows

Functional - eg snakes producing venom

Extremophiles definition

Organisms with adaptations that enable them to live in conditions that are far outside normal ranges

What are some types of extremophiles?

some can survive high temperatures/ pressures/ salt concentration

How do you use quadrats?

1. produce a grid of the area

2. randomly choose coordinates to place the quadrats using a random number generator

3. count the number or % cover of organisms in each quadrant

4. calculate the mean of each quadrat

5. calculate field area /quadrat area x mean number per quadrat to find the population size of the species in the area

How do you use transects?

1. place a line perpendicular to/across the area to be studied

2. At regular intervals place a transect on the line and count the number of organisms in the quadrat

3. repeat several times choosing places for the transect and work out the averages of the organisms you find at the different places along the transect line