Unit 8 - Ecology
| Monday, 2 May 2022 | |
| 1-minute read | |
| 149 words | |
Populations
A population is a group of individuals of:
- the same species
- in the same area
- at the same time
- rely on same resources
Factors that affect population size
Abiotic factors
- Sunlight
- Precipitation / water
- Soil / nutrients
Biotic factors
- Prey
- Competitors
- Predators, parasites, disease
Population Dispersion
Clumped
- Most common
Random
Uniform
- May result from direct interactions
Population Density
Changes to pop size
Adding/removing individuals from a popultaion
- Birth
- Death
- Immigration
- Emigration
- How can we measure population density?
Growth Rates
Factors affecting growth rate
Sex ratio
- How many females vs males?
Generation ratio
- At what age do females reproduce?
Age structure
- How many females at reproductive age?
Reproductive Strategies
k-selected
- Late reproduction
- Few offspring
- Invest a lot in raising offspring
r-selected
- Early reproduction
- Large amounts of offspring
- Little parental care
Exponential Growth Rate
Characteristic of populations without limiting factors
- Introduced to a new environment or rebounding from a catastrophe