Populations and their Growth

Question 1

What are the roles of models in studying population ecology?

Answer 1

Models allow us to:

• explore the consequences of our assumptions - different projections
• build towards better assumptions
• express hypotheses precisely

Question 2

Describe pattern fitting model

Answer 2

Pattern Fitting Model

Describes the pattern but not the underlying processes

• Useful when underlying conditions do not change
• allow us to predict future events from past data
• not useful if there is an underlying change - e.g global warming makes it more difficult to predict future of pattern

Question 3

Describe the mechanistic model

Answer 3

Mechanistic Model

Explains underlying processes of pattern

4 factors affecting population size:

1. births
2. deaths
3. immigration
4. emigration

Question 4

What are limits to population growth?

Answer 4

Exponential growth is the exception not the norm.

There are factors which limit exponential growth - e.g food, space, resources, environmental conditions, predation/disease

Malthusian Trap - is the idea that population growth is potentially exponential while the growth of the food supply or other resources is linear
- occurs when population growth outpaces agricultural production, causing famine or war, resulting in poverty and depopulation