Topic 14 Flashcards Preview

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Flashcards in Topic 14 Deck (31)
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1
Q

Life tables can be used to..

A

determine if a population grows from one generation to the next

2
Q

Population growth models are used to..

A

estimate population size many generations in the future.

3
Q

Imagine a closed population

A
  • no immigration
  • no emigration
  • births increase population
  • deaths decrease population
4
Q

To determine a change in population size (N) from one point in time to sometime later =

A

N (later) = N(now) + Births - Deaths

5
Q

Geometric model assumes..

A

discrete breeding

6
Q

Geometric model

A

population only grows during the breeding season.

7
Q

Average number of offspring left by an individual during one time interval

A

greek symbol upside down Y (same as R0)

8
Q

Population increases by…

A

factor of upside down Y ^ of breeding interval

9
Q

Exponential model assumes..

A

continuous breeding

10
Q

Exponential model

A

population grows continuously through the year. population increases by factors of e^r

11
Q

r =

A

= b - d

exponential growth rate of the population between time 0 and time t (not the same as R0)

12
Q

e =

A

base of natural logarithm

13
Q

Rate of change in a population size over a specific time person is equal to the..

A

average birth rate minus the average death rate multiplied by the number of individuals in the population at the start of the time period

14
Q

dN/dt =

A

slope of population growth curve at a particular point in time

15
Q

Rate of population growth directly effects the ..

A

size of the population (increased exponentially)

16
Q

Intrinsic rate of increase

A

r is considered to be an instantaneous rate of increase

17
Q

Underlying principles of intrinsic rate of increase

A
  • r is individual or “per capita” contribution to population growth
  • dN/dt varies in direct proportion to N at that instant
  • r is constant through time
18
Q

Geometric vs exponential

A

curves depicting geometric and exponential population growth can be superimposed there is direct relationship between them

19
Q

Exponential model assumptions

A
  • all individuals have the same average b and d rates
  • b and d are constant through time
  • b and d occur continuously
  • no migration (I or E) the population is closed
  • resources are unlimited
20
Q

When population size is low..

A

no competition (resources are unlimited). populations grows at the intrinsic rate of increase r (exponential growth = highest growth potential)

21
Q

When population size is high..

A

competition increases (resources become limited). population size levels off and r = 0

22
Q

1 underlying assumptions violated

A

all individuals have the same average b and d rates. (diff age classes generally have diff b and d rates)

23
Q

2 underlying assumptions violated

A

b and d (r) are constant through time.

24
Q

Populations rarely have constant b and d because

A
  • age distribution of a population changes through time

- environmental conditions change through time and continuously influence b, d and r (=b-d)

25
Q

Consider r the highest growth rate that the population have potential to achieve if

A
  • the population have a stable age distriubtion

- b and d remain constant over time

26
Q

3 underlying assumptions violated

A

no migration (I or E) the population is closed

27
Q

4 underlying assumptions violated

A

resources are unlimited

28
Q

A large population with a relatively low growth rate can still.

A

greatly increase in size

29
Q

Universe is limited to ..

A

10^80 atoms

30
Q

A single E. Coli with its high growth rate (r) would otherwise reach a population size of 10^80 individuals in just..

A

6 days

31
Q

Resources are never truly ..

A

unlimited!