Populations

Question 1

Define Ecology

Answer 1

The study of inter-relationships between organisms and their environment.

Question 2

Distinguish biotic from abiotic factors

Answer 2

Biotic- Living components of an environment. Abiotic- Non-living components of an environment.

Question 3

Define Biosphere

Answer 3

Life supporting land, air and water that surrounds the Earth.

Question 4

Define Ecosystem

Answer 4

All biotic and abiotic features in a specific area e.g. a lake

Question 5

What are the two major processes in an ecosystem?

Answer 5

The flow of energy through the system. The cycling of elements in the system.

Question 6

Define Population

Answer 6

A group of interbreeding organisms that can produce fertile offspring (a species) in a habitat.

Question 7

Define a Community

Answer 7

Populations of different species living and interacting in the same place at the same time.

Question 8

Define Habitat and Microhabitat

Answer 8

Habitat- The place a community lives. E.g. leaf canopy. Microhabitat- A smaller unit with a microclimate e.g. crevice on an oak tree.

Question 9

What is an Ecological Niche?

Answer 9

How an organism fits into its environment. Where the organism lives and what its purpose is.

Question 10

What tool would you use to randomly sample a field?

Answer 10

A frame quadrat or point quadrat

Question 11

What tool would you use to measure transition in communities?

Answer 11

Systematic sampling along transects.

Question 12

Give the three factors to consider when using quadrats and explain how you would vary them

Answer 12

Size of quadrat- Size of animals/ plants being counted how they are distribute. Larger species = larger quadrats. Species appearing in groups will be better represented with many small quadrats. Number of quadrats to record within the study- Larger number = more reliable results. Reliability vs practicality. The greater the no. of diff. species the greater no. quadrats required for valid results. Position of quadrat in the area- Random sampling to produce statistically significant results.

Question 13

How would you undergo random sampling?

Answer 13

• Lay out 2 tape measures at right angles creating an x and y axis. -Generate coordinates with a random number generator. -Place a quadrat at the intersection of each pair of coordinates and record the species within it.

Question 14

How would you complete systematic sampling along transects?

Answer 14

Pladce a string across the ground in a straight line. Any organism that touches the string is recorded. A belt transect uses a strip normally around 1 metre in length.

Question 15

Define abundance

Answer 15

Number of individuals of a species in a given space.

Question 16

Give 2 measures of abundance

Answer 16

Frequency Percentage cover

Question 17

What is frequency and what does measure?

Answer 17

Likelihood of a species occurring in a quadrat. A simple Y/N for each quadrat. Useful for grass or vegetation. No information on density and detailed distribution of the species

Question 18

What is percentage cover and what does it measure?

Answer 18

Estimate of area covered by a species in a quadrat. Useful for hard to count species e.g. grass. Less useful where organisms occur in overlapping layers.

Question 19

What is the equation for the mark release-recapture technique?

Answer 19