Topic 19 - Populations

Question 1

Populations

Answer 1

A group of organisms in the same species living in the same habitat

Question 2

Habitat

Answer 2

Part of an ecosystem in which particular organisms live

Question 3

Community

Answer 3

All the populations of different species in the same area at the same time

Question 4

Ecosystem

Answer 4

A community and the non-living components of an environment (the biotic and abiotic factors). Ecosystems can range in size from very small to very large.

Question 5

Niche

Answer 5

An organisms role within an ecosystem, including their position in the food web and habitat. Each species occupies their own niche government by adaptation to both abiotic and biotic conditions.

Question 6

Carrying capacity

Answer 6

The maximum population size an ecosystem can support

Question 7

Abiotic factors

Answer 7

Non-living conditions of an ecosystem

Question 8

Biotic factors

Answer 8

Impact of the interactions between organisms

Question 9

Examples of abiotic factors

Answer 9

Temperature, oxygen and carbon dioxide concentration, light intensity, pH and soil conditions

Question 10

Examples of biotic factors

Answer 10

Interspecific and intraspecific competition and predation which affects population size.

Question 11

Interspecific competition

Answer 11

Members of different species are are in competition for the same resource that is in limited supply e.g food, water, habitat. Individuals more adapted to the environment are more likely to succeed.

Question 12

Intraspecific competition

Answer 12

When members of the same species are in competition for resources and a mate. Completion for a mate links to courtship rituals. Individuals that are fitter, will have more energy to preform a more impressive courtship ritual or may have fur or feathers on a better condition to attract a mate.

Question 13

Predator prey relationship pattern

Answer 13

• size of predator and prey population fluctuate
• there will be more prey than predators
• the size of the population will always change in the prey and then the predators (lag time)

Question 14

Why do we sample?

Answer 14

More time efficient, and if implemented correctly, can be more accurate

Question 15

How do you let your sample accurately represent the population?

Answer 15

• random sampling to eliminate bias
• large sample, at least 30

Question 16

What sampling method do you use for slow moving or non-motile organisms

Answer 16

Quadrat

Question 17

When using quadrat, what method of sampling do you use when there is an uneven distribution?

Answer 17

Line transect

Question 18

When using quadrat, what method of sampling do you use when there is an uniform distribution?

Answer 18

Random sampling

Question 19

What sampling method do you use for motile organisms?

Answer 19

Mark-release-recapture method

Question 20

What is the equation for mark release recapture

Answer 20

Estimated population size = number of organisms initially caught x number of organisms in second sample / number of organisms recaptured

Question 21

Succession

Answer 21

The change in an ecological community over time

Question 22

What are pioneer species

Answer 22

E.g. lichen, bryophytes and annual plants are adapted to survive in harsh abiotic factors, and through their death and decomposition, change the abiotic factors to become less harsh and form a thin layer of soil, humus.

Question 23

What comes after pioneer species in primary succession?

Answer 23

Mosses and smaller plants further increase the depth and nutrient content of the soil, followed by grasses, perennials, small trees and shrub and the larger trees until climax community e.g. woodland or forest that stabilises the land.

Question 24

Final stage of succession

Answer 24

Climax community - trees