Population Growth and Regulation II

Question 1

Exponential Growth

Answer 1

Continuous growth with “unlimited” resources without limitation

Question 2

Geometric Growth

Answer 2

Seasonal growth with “unlimited resources”

Question 3

Logistic Growth

Answer 3

“Limited resources”. Intraspecific competition.

Question 4

Modeling Population Age Structure

Answer 4

A solution to birth and death rates being constant and not varying with age. Influenced by the proportions of individuals in different age classes. Also, in size and life history classes. Age structure pyramids

Question 5

Life Table Analysis

Answer 5

Growth in a structured population

Question 6

Life Table Analysis Terminology

Answer 6

x=age

nx=number of individuals surviving to age x

sx=age-specific survival

bx=age-specific fecundity, births

Question 7

Step One Life Table Analysis

Answer 7

Sum up age classes to get No, the initial female population size.

Question 8

Step Two Life Table Analysis

Answer 8

Multiply number of females in EACH age class by sx, age specific survival rate. This gives number surviving to next age class. (remember to put this is next level)

Question 9

Step Three Life Table Analysis

Answer 9

Calculate new sum of survivors

Question 10

Step Four Life Table Analysis

Answer 10

Calculate offspring per age class. Multiply the per capita fecundity (bx) but each number of survivors per age class. This gives the number of new offspring for each age class.

Question 11

Step Five Life Table Analysis

Answer 11

Add up offspring.

Question 12

Step Six Life Table Analysis

Answer 12

Calculate new age classes and population. Transfer total newborns in top row, and individual survivor classes in other rows. Add this total up. In reality the answer will be the same as just adding survivors + offspring.

Question 13

If asked how many total individuals in new population and your original table analyses gave you 112, what would your answer be?

Answer 13

224, because chart only looks at females and usually males and females are about 50-50

Question 14

After many generations of life table analysis…

Answer 14

The population will grow geometrically at a stable rate of increase. The population will reach a stable age distribution.

Question 15

After initial fluctuations, per age class may go up or down but … stays the same

Answer 15

proportion

Question 16

Survivorship

Answer 16

The probability of surviving from birth to any later age class. Denoted Ix.

Question 17

Survivorship curves

Answer 17

Looks at chances of mortality throughout life

Question 18

Type 1 Survivorship Curve

Answer 18

High mortality later in life

Question 19

Type 2 Survivorship Curve

Answer 19

Constant mortality

Question 20

Type 3 Survivorship Curve

Answer 20

High Mortality Early in Life

Question 21

Calculating Survivorship (Ix)

Answer 21

First age class is always 1. Multiply survivorship by survival rate. Fill in the product in new row of survivorship column.

Question 22

Net Reproductive Rate (Ro)

Answer 22

Average number of female offspring per female over her lifetime.

Question 23

Calculating Net Reproductive Rate (Ro)

Answer 23

Multiply survivorship by fecundity rate.

Question 24

What can you do with individuals post reproduction?

Answer 24

Add to new nx in new life table

Question 25

Cohort Approach

Answer 25

Follow a group of same aged individuals (cohort) throughout lives. **Easy to apply to organisms that are sessile (dont move much) or easily tracked throughout lives. Results can be confounded with environmental change.

Question 26

Static Approach

Answer 26

All individuals (of all ages) at a particular point in time. “snapshot”. Can be applied to more mobile and long lived organisms. Must identify age though. Multiple samples advised because of potential unusual age distribution and environmental conditions.