Lecture 7 -- Populations

Question 1

What are the two key characteristics that define a population?

Answer 1

(1) interbreeding group of individuals in a species…

(2) that live in the same area

Question 2

What are the three patterns of dispersion found in populations? And what are two things that commonly determine the pattern of dispersion for a particular population?

Answer 2

Random, clumped, uniform.

Usually decided by resource distribution and nature of interactions b/t individuals

Question 3

What is demography?

Answer 3

The study of Factors that affect growth and decline

Question 4

What’s the difference between an exponential and logistic growth curve?

Answer 4

Exponential Growth under indeal conditions and has no carrying capacity. (looks like hockey stick)

Logistic Growth: S-shaped curve because there is a plataeu at the carrying capacity

Question 5

K is the mathematical term for the thing that limits population growth in a logistic growth curve. What is the concept that K stands for?

Answer 5

Carrying Capacity- There is a natural limit to amount of resources etc.. that a environment can maintain.

Question 6

Given a list of various factors that affect the carrying capacity of an environment, be able to tell which factors are density-dependent and which are density-independent. E.g. food, annual temperature variability, available mates, disease…..

Answer 6

Density- Dependant: As pop. density increases, so does death rate or reproduction rate (usually limited resources reduce # of births)
–Factors: Biotic Factors, Stress, Predation, Food & Shelther Availability

Density Independent: Density has no effect on population
– Factors: Climate Variability, Natural Disasters, Anthropogenic Disturbance

Question 7

n a different lecture, there was an example of the predatory Pisaster starfish which controls the population size of mussels. This is an example of a density-___ factor that limits the carrying capacity of the habitat for mussels.
If there were a major winter storm with powerful waves that scraped off a bunch of mussels from a stretch of rocky shoreline, this would be an example of a density- ___ factor.

Answer 7

1. Dependent

2. Independent