Population analysis L4

Question 1

What are the four factors that regulate biotic potential?

Answer 1

1. Max # of offspring per birth
2. Chance that offspring will reach reproductive age
3. # of times per year organism reproduces
4. Age at which reproduction begins

Question 2

What is carrying capacity?

Answer 2

The ability for an environment to support a population

Question 3

What is density-dependent factors?

Answer 3

Biotic; limit reproduction as pop’n increases (e.g. disease, predation)

Question 4

What are density-independent factors?

Answer 4

Abiotic; work regardless of pop’n size (e.g. floods, drought)

Question 5

What is environmental resistance?

Answer 5

Environmental conditions limit a species from growing out of control – influenced by abiotic and biotic factors

Question 6

What is a J-curve?

Answer 6

• Demonstrate exponential growth – increase in population size at an increasing growth rate
• Usually occur in closed systems (e.g. aquarium containing bacteria, algae, yeast, etc.)
• Often microorganisms with short life spans
• Exception: humans!

Question 7

What is an S-curve?

Answer 7

• Most natural populations demonstrate an S-shaped curve
• Population increases until limiting factors cause it to reach carrying capacity - as long as resources maintained, population size stabilized
• Density dependent/independent factors may initiate death phase

Question 8

What does K-selected mean?

Answer 8

K-selected strategies – generally slow reproduction, long life span, longer offspring
rearing, later reproductive maturity
* E.g. Elephants, moose, humans

Question 9

What does r-selected strategies mean?

Answer 9

r-selected strategies – rapid reproduction, short life span, little/no rearing, early reproductive age
* E.g. Bacteria, yeast, mice

Question 10

What is a type I survivorship curve?

Answer 10

Large mammals, few offspring, low infant mortality, extended life span (e.g. humans)

Question 11

What is a type II survivorship curve?

Answer 11

Chances of survival or death are about the same at any age (e.g. squirrels)

Question 12

What is a type III survivorship cure?

Answer 12

Low survivorship or high mortality rates early in life (e.g. oysters)

Question 13

What is a histogram?

Answer 13

Useful for studying human populations to see trends and make predictions

• Often take shape of pyramid

Question 14

What does a double histogram include?

Answer 14

Age and sex of a population