Populations

Question 1

How does biotic factors cause variation in populations?

Answer 1

• predation
• intraspecific or interspecific competition
• parasites and disease

Question 2

What abiotic factors cause variation in populations?

Answer 2

• temperature
• soil pH
• light intensity
• humidity
• soil salinity

Question 3

Process of predation causing variation in a population?

Answer 3

• predators consume prey
• prey number declines
• lack of food for predators
• predator numbers decline
• lack of predators
• number of prey increase
• more prey
• number of predators increase

Question 4

What is interspecific competition?

Answer 4

• between organisms of different species

- if occupy similar niches they compete for resources

Question 5

What is the competitive exclusion principle?

Answer 5

Size of population of organism with advantage will increase until other organism is removed

Question 6

What is intraspecific competition?

Answer 6

Between individuals of the same species. The availability of resources will determine the size of the population

Question 7

Equation for population size?

Answer 7

= (average number in sample divided by area used in sample) x total area

Question 8

Equation for mark release recapture

Answer 8

(Number in first sample x number in second sample) divided by number marked in second sample

Question 9

Stage 1 of demographic transition model ?

Answer 9

• total pop is small and stable
• increasing birth rate - no contraception, children work
• high death rate- lack of food, poor sanitation
• Low population

Question 10

Stage 2 of demographic transition model?

Answer 10

-Expanding total population
-increasing birth rate, decreasing death rate- better sanitation
Pop is increasing

Question 11

Stage 3 of demographic transition model?

Answer 11

• Expanding population
• birth rate decreasing- birth control, family planning, urbanisation
• death rate decreasing- improved medical care and food supplies

Question 12

Stage 4 of demographic transition model

.

Answer 12

-Population constant
-birth and death rate fluctuate at low level
Population high

Question 13

Stage 5 of demographic transition model?

Answer 13

Declining population

• decreasing birth rate- increased expense of children
• decreasing death rate- better health care
• well developed countries

Question 14

What is a niche ?

Answer 14

Roles of species within their habitat with abiotic and biotic factors