Lecture 8- K and r selected species

Question 1

WHat are two types of population growth models?

Answer 1

Exponetial growth model and logistic growth model

Question 2

Exponential growth model

Answer 2

No limits to population growth, where r is at its maximum value (brief periods)

Question 3

Logistic growth model

Answer 3

Limits to pop growth, pop size fluctuated aroung K (longer periods)

Question 4

What are life history strategies?

Answer 4

A suite of traits a species uses to maintain (or increase) its pop size (includes longevity, parental care, size and number of offspring, age of maturity, # of reproductiove epidsodes in a lifetime)

Question 5

What are characteristics of K selected species?

Answer 5

Stable environments
Strong competitors
Long lives, few offspring, large in size

Question 6

What are characteristics of r selected species?

Answer 6

Unstable environments
Poor competitors
Shorter lifes, many off spring, small in size

Question 7

What is a life history model for plants? who developed it?

Answer 7

Grime developed the CSR model, stress and disturbance affect growth and reproduction of vascular plants

Question 8

What are some traits of competetive plants?

Answer 8

Rapid growth
High phenotypic plasticity
Low rates of seed production/long lives

Question 9

What are some traits of stress-tolerant plants?

Answer 9

High nutrient retention
Slow growth
Long-lived leaves
Low rate of seed prod
Long life span

Question 10

What are some traits of distubance-tolerant plants?

Answer 10

Small size
rapid growth
high rates of seed prod
Short life span

Question 11

What is demography

Answer 11

Scientific study of population descriptive traits (size, age, growth rate, distribution, age) and factors that cause changes in the pop size (B,D,E,I)

Question 12

What are different types of life tables?

Answer 12

1. cohort- age specific (actively follow a cohort throughout its life)
2. Static- time specific- (age distribution data are collected in one moment of time

Question 13

What are the 5 assumptions of static life tables

Answer 13

1. Individuals have same prob of being sampled
2. Ages are assessed accurately
3. Survival and Fecundity rates may change with age, but not over time
4. Age distribution does not change over time
5. Population size does not change over time

Question 14

What are some benifits and costs of cohort life tables

Answer 14

B: very accurate, ages are known, track changes in pop through time
C: Time and resource intensive

Question 15

What are some benefits and costs of static life tables?

Answer 15

B: only requires data from one time period
C: assumptions are rarely met, relies on accurate aging

Question 16

What two variables do you need data for to construct life tables?

Answer 16

1. Age specific Survivorship (lx)

2. Age specific fecundity (mx)

Question 17

How do we obtain life table data?

Answer 17

• Fecundity
• Survivorship
• Generation Time

Question 18

What is Generation time?

Answer 18

Mean time between birth of a female and a birth of her offspring

Question 19

What is net reproductive rate? (Ro)

Answer 19

Mean number of female offspring produced by a female during her lifetime

Question 20

What do semelparity and iterparity mean and how are they different?

Answer 20

Semel parity an individual reproduces once in its life, iteroparity an individual reproduces multiple times in its life. G has large effect on r ( r declines as G increases)

Question 21

Why are life tables important to management and population ecologists?

Answer 21

help identify the ages at which survival/fecundity is particularly low or high. this can be used to focus harvest on particulcar age classes to achieve desired management outcome

Question 22

What are the 3 types of survivorship curves?

Answer 22

Type 1. low mortality for most of life, high mortality in older individuals
Type 2. constant rate of mortality throughout life
Type 3. High mortality of younger individuals, then low most of life

Question 23

What 3 factors mainly influence r?

Answer 23

1. # of offspring at each reproductive event ( more= higher r)
2. # of reproductive events (more = higher r)
3. Age at first reproduction (younger = higher r)

Question 24

What is population regulation?

Answer 24

Factors that affect vital rates (reproduction, growth, survival) and therby regulates pop growth

Question 25

What is Density independant factors?

Answer 25

How much these factors affect r is independant of pop density (weather, habitat disturbances, density independant disease (cancer)

Question 26

What are Density-Dependant factors?

Answer 26

how much these factors affect r depends on pop density (food, space, parasites)

Question 27

What is negative and positive density dependence?

Answer 27

(-) as pop increases some factors leat to lower vital rates, crowding leads to competition, and incresed disease transmission
(+) When pop is low, some factors lead to higher vital rates

Question 28

What are the two types of mortality?

Answer 28

Compensatory mortality- Causes no reduction in total survival (harvest compensation for starvation)
Additive mortality- Cause an immediate reduction in total survival (harvest is additive to all other sources of mortality)

Question 29

What is a Sink population?

Answer 29

population where r<0 (population relies on immigration from source populations)

Question 30

What is a source population?

Answer 30

Pop where r>0 (dispersal of surplus individuals can provide a source for sink pop)

Question 31

How do meta populations function?

Answer 31

They act as a source pop and allow emigration to occupied and unoccupied habitats. if a pop is extirpated from an area, but the metapop is still intact, individuals can still immigrate into the extirpated area from the meta pop

Question 32

how do metapopulations relate to restoration?

Answer 32

Justifies the use of greenways and the importance of connectivity between areas ith meta pop and habitats that van be used by the pop. We can design our plans and protected areas around re-establishing/maintaining connectivity among habitat patches.

Question 33

What are the 2 types of competition?

Answer 33

Interference: one species bullied from resource by another
Exploitative: some individuals exploit a resource more/better than others

Question 34

What is the difference between bottom up and top down trophic effects?

Answer 34

Bottom up: When abundance of prey affects the abundance of predators
Top down: when abundance of predators affects the number of prey