(4.1-4.5) Organisms in the environment

keywords, experiments, biotic + abiotic factors

Define population.

A group of organisms of the same species living in the same place at the same time

Define community

All of the populations living in the same area at the same time

Define interdependence

The reliance of different species in a community on one another

Define habitat

The place an organism lives in

Define ecosystem

All the biotic and abiotic factors that interact within an area at any given time

What is a quadrat?

A metre by metre, gridded square

used to estimate abundance of a species

How can you investigate the population size of a species in 2 areas with quadrats?

1. Use 2 tape measures + lay out a survey area

2. Randomly generate coordinates to lay a quadrat

3. Count the number of the organism in the quadrat

4. Repeat 10 times

5. Estimate the total by doing

   • total area/samples area*total dandelions counted

6. Do the same for the other area.

7. Compare.

Define biodiversity

the range and variety of different species of organisms on Earth/within an ecosystem

How can you investigate the biodiversity of an area with quadrats?

1. Tape measure an area

2. Randomly generate coordinates

3. Record the different species within the quadrat

4. Repeat 10 times

Why use a random number generator?

ecological studies must be random and representative of the area

What is a biotic factor?

A living factor within an environment

What is an abiotic factor?

A non-living factor within an environment

Give examples of biotic factors.

New pathogens

New predators

Availability of food

Competition

Give examples of abiotic factors.

Light intensity

Temperature

Soil pH

Moisture levels

Oxygen levels (aquatic animals)

Wind intensity

CO2 levels (plants)