Population Size 24.1

Question 1

Why can the population not grow indefinitely?

Answer 1

Because of limiting factors that would prevent the population from rising above a certain level like lack of space and also lack of food and other resources

Question 2

If you put the population growth on a graph what would it look like?

Answer 2

It would be a curve shape, it would start increasing gradually, then increase constantly and finally level off at a certain point.

Question 3

What are the 3 phases of the population growth curve?

Answer 3

• Slow growth phase
• Rapid growth phase
• Stable state

Question 4

Describe the first state of the population growth curve

Answer 4

The slow growth phase is where the small numbers of the initial population will reproduce slowly and increase the size of the population as there are more births than deaths.

Question 5

Describe the second state of the population growth curve

Answer 5

The rapid growth phase is where the number of individuals is increasing, so breeding is also increasing exponentially and no factors are limiting the growth.

Question 6

Describe the third state of the population growth curve

Answer 6

The stable state is where the population is prevented from growing because of external limiting factors. This means the growth curve will level off and remain relatively stable because of birth rates and death rates being equal. Sometimes there will be small fluctuations because of the limiting factors and their presence

Question 7

What is a limiting factor?

Answer 7

This is a factor that prevents the population size from growing further

Question 8

What are limiting abiotic factors?

Answer 8

Temperature, Light, Water and oxygen availabilty, humidity, pH etc…

Question 9

What are limiting biotic factors?

Answer 9

Competition for resources, disease, predators

Question 10

What is the carrying capacity?

Answer 10

The carrying capacity is the maximum population size that an environment can support

Question 11

What is another variable that can affect population size?

Answer 11

Migration

Question 12

What is immigration?

Answer 12

This is when organisms move into a particular area which increases population size

Question 13

What is emigration?

Answer 13

This is when organisms move out of an area which decreases population size

Question 14

What are density independence factors?

Answer 14

These are factors that can drastically affect population size regardless of how big it is.

Question 15

Give some examples of density independence factors?

Answer 15

Volcanoes, earthquakes, tsunamis, fires, storms etc…