Lec 13 Ecology

Question 1

Define population ecology:

Answer 1

studies how the populations of groups for the same species may change over time

Question 2

Define community ecology

Answer 2

How interactions of different species affects their organization

Question 3

Define ecosystem ecology

Answer 3

studies how energy flows and ecosystems affect organisms’ living and non-living resources

Question 4

Define global ecology

Answer 4

How local/regional interactions affect global changes in energy and specie dynamics

Question 5

Define population:

Answer 5

group of individuals that are of the same species and live in the same area

Question 6

Define population ecology:

Answer 6

observation of population size and questions how or why they change over time

Question 7

Define ecology:

Answer 7

interactions between organisms and their living/non-living environment

Question 8

What is an example of an animal that helps our population ecosystem?

Answer 8

Vultures. They eat dead carcasses, thus minimizing disease. Without them, animals and humans risk of disease increases monumentally

Question 9

How do we determine the number of individuals in a population without counting them?

Answer 9

Mark-recapture method

Question 10

What is the mark-recapture method?

Answer 10

Capture and mark a set of individuals, release to population, use proportion of re-caught individuals in second capture to est. total population

Question 11

Describe the mark-recapture method setup:

Answer 11

First, capture a set of the species population. Then, send them back into the total population of unknown size, Afterwards, capture another subset for a second time. Finally, assess the marking in probability of capture.

Question 12

For the mark-recapture method, what explains the reason if you don’t recapture marked individuals a second time around?

Answer 12

1. You have underestimated the population size; You didn’t mark enough individuals
2. Trapping can traumatize animals, causing them to avoid cages. OR animals realize they don’t get hurt when they’re trapped but come for the snacks.

Question 13

How can you estimate the Mark-Recapture population?

Answer 13

To find the population total (=N), the first number of individuals in the first capture (=s) are sent out. After a second recapture, calculate the mean number of marked individuals (=S). Calculate the total number of individuals caught in the second capture (=n).

Equation: x/n = s/N

Question 14

Describe the mark-Recapture estimation calculation:

Answer 14

number marked 2nd time (x) / total caught in 2nd sample (n) = number marked in 1st sample (s) / size of whole population (N)

Equation: x/n = s/N

Question 15

Describe patterns of population growth:

Answer 15

periodic monitoring of population sizes for assessment of changes in pop. size over time

Question 16

What population growth would we expect to see if they’re growing with unlimited resources, no predators and no external factors limiting reproduction?

Answer 16

Exponential growth

Question 17

What population growth would we expect to see if they’re growing with limited resources?

Answer 17

Linear growth

Question 18

What variables control population size (what means are indiv. added to and removed from pop.) ?

Answer 18

Adds: Birth and Immigration
Removes: Death and Emigration

Question 19

How can we establish change in population size?:

Answer 19

(Birth+immigration) - (death+emigration) = pop. change

Question 20

Changes in population size are determined how?

Answer 20

It’s the number of inidivudals added to a population over time

Question 21

What equation can we use to establish change in pop. size?

Answer 21

Change in number of individuals in a pop. / change in time

Question 22

What does the change in pop. size = ?

Answer 22

Births-deaths

Question 23

____ numbers of births and deaths is _____ to a _____ population:

Answer 23

Exact numbers of births and deaths is specific to a single population:

Question 24

Average ____ of birth and death can be applied to populations of ____ _____

Answer 24

Average rate of birth and death can be applied to populations of any size

Question 25

Define per capita birth rate (b):

Answer 25

number of offspring produced per individual per unit of time

Question 26

Define per capita death rate (d):

Answer 26

number of individuals that died per individual member per unit of time

Question 27

Equation for per capita birth rate (b):

Answer 27

b = b/n (number births/N)

Question 28

Equation for per capita birth rate (d):

Answer 28

d = d/N

Question 29

How do you calculate expected number of Births and Deaths?

Answer 29

B = b*N

Question 30

How can you calculate change in pop/change in time? (N/T)

Answer 30

bN-dN

Question 31

Define final model translation:

Answer 31

determining net births and deaths

Question 32

What is a net effect?

Answer 32

the sum of both births and deaths

Question 33

Define per capita population growth rate (r):

Answer 33

number of individuals added per pre-existing individual in pop. when accounting for both births and deaths

Question 34

How do you calculate r?

Answer 34

r = b-d

Question 35

What is final model simplification?

Answer 35

use b and d to calculate r

Question 36

How can you find the per capita population growth rate in the population?

Answer 36

N/T = rN

Question 37

You have a population of 2500 marmots. In a year, 315 marmot babies are born, 22 marmots die. Calculate r.

Answer 37

r = B-D B = b/N = 0.126 D= d/N = 0.0088 0.126-0.0088 -> r = 0.117

Question 38

You have a population of 2500 marmots. In a year, 315 marmot babies are born, 22 marmots die. For year 2, you have 9082 marmots in your population. How many marmots will be added to this population at the end of year 1? At the end of years 2 and 3?

Answer 38

r = 0.117 (constant), N = 9082 Year one: N/T = 9082*0.117 = 1,062.6 marmots added Pop size at end of year 1: = 9082+1062.6 = 10,144.6 marmots for year 2 Year two: N/T = 10,144.6*0.117 = 1,186.9 marmots added Pop size at end of year 2: 10,144.6+1186.9 = 11,331.6 marmots Year 3: N/T 11,331.6 * 0.117 = 1,325.8 marmots added

Question 39

Why are more marmots added each year than in the year before if per capita rate of population growth remained the same?

Answer 39

Per capita: per individual. N increased because we added more individuals. Multiplying it by a bigger number increases pop. value. Pattern of population growth is exponential growth. Happens in populations with unlimited resources.

Question 40

What is the Exponential Growth model?

Answer 40

number of individuals added over time increases as N increases with unlimited resources

Question 41

Would exponential growth occur often in nature?

Answer 41

No. Having unlimited resources are uncommon. At least one resource is limited

Question 42

What is the Logistic Population Growth model?

Answer 42

the population growth slows as it approaches carrying capacity (K)

Question 43

What is carry capacity? (K)

Answer 43

the maximum population size a given environment can sustain

Question 44

How do exponential growth and logisitc growth models compare?

Answer 44

Exponential model with forever increase, not having a limit for population growth. Logistic model has a carrying capacity, meaning it will stabilize over time

Question 45

What limiting resources determine carrying capacity?

Answer 45

Resources can vary from year to year: shelter from predators, nesting sites, food, water

Question 46

What is the exponential model equation?

Answer 46

△N/△t = bN - dN

Question 47

What happens to the population when it reaches carrying capacity?

Answer 47

It slows in growth

Question 48

What does a decrease in growth for Logistic models mean?

Answer 48

Fewer births (b) due to inadequate resources for pregnancy or increased fetal mortality. Increased death (d) due to inadequate resources to support current population

Question 49

What population growth model fits best for humans? Exponential or Logistic?

Answer 49

Exponential

Question 50

Define Survivorship

Answer 50

the percent of the population that survives a specific age cap

Question 51

How do you calculate Survivorship?

Answer 51

of surviving individuals/total # individuals you started with

Question 52

What is a survivorship curve?

Answer 52

Plots of the proportion of individuals still alive in each age

Question 53

What can survivorship curves help us discover?

Answer 53

Lifetime patterns of survival are informative about species ecology (based on species characteristic)

Question 54

Describe Type 1 Survivorship:

Answer 54

plot number of survivors on Y axis to the highest survival rates they can go (most can be old, causing it to go up in mortality for species to stay alive)

Question 55

Define Type 2 Survivorship:

Answer 55

Roughly equal proportions die in each age class (roughly 50% in ea. group)

Question 56

What traits do Type 1 Species have?

Answer 56

Relatively few offspring with high parental care with a lower death in early age

Question 57

What are examples of Type 1 Species?

Answer 57

Humans, whales, elephants

Question 58

What is an example of Type 2 Species?

Answer 58

Ground squirrels (constant av. of indiv. die across each age class)

Question 59

Define Type 3 Survivorship:

Answer 59

Very high mortality in early life but low mortality for older age groups

Question 60

What traits would you expect for Type 3 Species?

Answer 60

High reproduction rates/offspring but low parental care (on their own at birth)

Question 61

What are examples of Type 3 Survivorship?

Answer 61

Sea turtles, Oak trees, 1000s of acorns

Question 62

How can we study the human population?

Answer 62

With human survivorship curves in periods of time

Question 63

How has the global fertility rate changed over time?

Answer 63

It has decreased from 5 to 2.5 per woman.

Question 64

How is the fertility rate associated with poverty and education?

Answer 64

Fertility increases with poverty (poorer people have more children on average due to less contraceptives and family planning resources). Fertility decreases with education (women and girls with greater access to education have less children). Women have jobs (less time to take care of kids) and less economic freedom (can't provide independently). Want decisions for bodies.

Question 65

How does fertility rate vary from country to country?

Answer 65

Developed countries typically have lower fertility rate than developing countries. Mainly due to socioeconomic predictors.

Question 66

The per capita birth rate for humans globally has:

Answer 66

decreased (global fertility rate is basically a synonym for per capita birth rate)