Week 3 Flashcards
(14 cards)
What is a Population?
A group of individuals belonging to one species (of bacteria, fungi, plant, or animal) living in an area.
What are examples of density dependent population regulation factors?
- Disease
- Competition
- Predation
- Space
- Food
How do density-dependent factors influence population size?
They may influence the size of the population by changes in reproduction or survival.
What is the relationship between density-dependent factors and population size?
Can be a positive or negative correlation with population size.
What do survival patterns reflect?
The predictability of the environment and the evolution of life histories.
What are the characteristics of R-strategists?
- Many offspring
- Early reproduction
- Frequent reproduction
- Short life span
What environments are R-strategists broadly related to?
Patchy resources and unpredictable environments.
What are the characteristics of K-strategists?
- Few offspring
- Delayed reproduction
- Infrequent reproduction
- Long lifespan
What environments are K-strategists broadly related to?
Predictable environments.
What is the significance of r and K selection?
It is relative to other species.
What might be an advantage of higher relative reproduction rate?
______
What are the causes of extinction?
- Demographic factors
- Environmental factors
What demographic factors can lead to extinction in small populations?
- Only older, non-reproductive individuals remain
- Altered sex ratio by chance leading to too few of one sex
What are examples of environmental factors that can cause extinction?
- Hurricanes
- Drought
- Fire
- Floods
