G&E: Variation in Population Size

Question 1

How can abiotic conditions affect population size?

Answer 1

If conditions are not ideal, then an organism cannot grow fast or reproduce successfully.

Question 2

What are the 3 ways that biotic factors affect population size?

Answer 2

Interspecific competition

Intraspecific competition

Predation

Question 3

Interspecific competition

Answer 3

Organisms of different species compete with each other for the same resources

Question 4

What can interspecific competition do to the resources available to populations?

Answer 4

Reduce the available resources, meaning both populations will be limited by lower amounts of food.

Have less energy for growth and reproduction, so populations sizes will be lower.

Question 5

Intraspecific competition

Answer 5

When organisms of the same species compete with each other for the same resources.

Question 6

Describe intraspecific competition in a rabbit population:

Answer 6

• Population of species increases when resources are plentiful.
• More organisms competing for the same amount of space and food.
• Resources like food and space will become limiting.
• Population begins to decline.
• Smaller population means less competitiion, which is better for growth and reproduction.
• Population increases.

Question 7

Predation

Answer 7

Where an organism kills and eats another organism.

Question 8

Describe the predator-prey cycle:

Answer 8

• Prey population increases.
• More food for predators, so predators population grows.
• More prey is eaten so prey population begins to fall.
• Less food for predators, so population decreases.

Question 9

What other factors can make predator-prey relationships more complicated?

Answer 9

Availability of food