Ch. 11 Lecture Flashcards Preview

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Flashcards in Ch. 11 Lecture Deck (35)
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1
Q

Populations can grow _____ when conditions are favorable, but this growth cannot continue _____.

A

populations can grow EXPONENTIALLY when conditions are favorable, but this growth cannot continue INDEFINITELY.

2
Q

Human population reached ___ in 2016, more than double the population in ___.

A

Human population reached 7.3 BILLION in 2016, more than double the population in 1970.

3
Q

From _______ human population _____ in size, and energy consumption increased _______.

A

From 1860 TO 1991 human population QUADRUPLED in size, and energy consumption increased 93-FOLD.

4
Q

Human population reached 1 billion for the first time in ___.

A

Human population reached 1 billion for the first time in 1825.

5
Q

Human population adds ____ people every ____.

A

Human population adds 1 BILLION people every 13 YEARS.

6
Q

In 1975, the population was growing at an ________ of ____. At this rate, a population will ____ in size every ___. If this growth rate were sustained, we would reach ______.

A

In 1975, the population was growing at an ANNUAL RATE of NEARLY 2%. At this rate, a population will DOUBLE in size every 35 YEARS. If this growth rater were sustained, we would reach 32 BILLION BY 2080.

7
Q

Geometric Growth

A

When a population reproduces in SYNCHRONY at regular TIME INTERVALS (discrete time periods), and growth rate remains the same. The population increases by a CONSTANT PROPORTION, so the number of individuals added to the population becomes larger with each time period.

8
Q

Geometric Growth: graph

A

J-shaped set of points, straight line when on log scale

9
Q

Exponential Growth

A

When a population reproduces CONTINUOUSLY, and GENERATIONS can OVERLAP. These populations increase by a CONSTANT PROPORTION.

10
Q

Exponential Growth: graph

A

J-shaped curve, straight line when on log scale

11
Q

lambda=1 or r=0

A

population stays the same

12
Q

lambda<1 or r<0

A

population size will decrease

13
Q

lambda>1 or r>0

A

population grows geometrically or exponentially. ideal conditions.

14
Q

Why don’t populations expand infinitely?

A
  1. run out of resources
  2. other species consume their resources
  3. disturbances happen
15
Q

Resources

A

features of the environment that are in SHORT SUPPLY that are required for growth, survival, or reproduction, and which can be CONSUMED to the point of DEPLETION.

16
Q

Physical Factors

A

affect population growth rates but are NOT consumed or depleted (i.e. temp, wind, pH)

17
Q

Density-Independent Factors

A

factors that are not dependent on density.

-floods, fires, drought, irregular growth bursts, hurricanes

18
Q

Density-Dependent Factors

A

cause birth rates, death rates, and dispersal rates to change as the density of the population changes.

density ^ = birth rates v = death rates ^ = emigration ^ = population size v

19
Q

Population Regulation

A

occurs when density-dependent factors cause populations to increase when density is low and decrease when density is high.

-food, space, or other essential resources in short supply, then population size decreases.

20
Q

Allee Effects

A

population growth rate decreases as population density decreases; individuals have difficulty finding mates at low population densities.

“extinction vortex”.

  • american passenger pigeon
  • northern right whales
  • shearwaters
21
Q

Logistic Growth

A

population increases rapidly at first, then stabilizes at the carrying capacity, because resources such as food, water, or space begin to run short.

22
Q

Carrying Capacity

A

maximum population size that can be supported indefinitely by the environment. growth rate=0, so population size does not change.

23
Q

Logistic Growth: graph

A

S-shaped curve in natural population

24
Q

Populations show “boom and bust” dynamics: r- or k-selected species?

A

r-selected species

25
Q

Populations exist at carrying capacity: r- or k-selected species?

A

k-selected species

26
Q

Environments which benefit r-selected species

A

Highly disturbed environments

27
Q

Environments which benefit k-selected species

A

Stable environments

28
Q

Environments where r-selected species may evolve to k-selected species (poison arrow frogs)

A

Highly Stable environments

29
Q

What will limit human populations?

A

(RODS-FLY)

  • Resources
  • Overgrazing
  • Disease
  • Sahel region
  • Firewood and deforestation
  • Loss of top soil
  • Your ecological footprint
30
Q

Geometric Growth: equation

A

Nt+1=lambdaNt

OR

Nt=lambdatN0

31
Q

lambda

A

geometric growth rate; (per capita) finite rate of increase

32
Q

Exponential Growth: equation

A

dN/dt=rN

dN/dt: rate of change in population

r: exponential population growth rate; (per capita) intrinsic rate of increase

33
Q

relationship between lambda and r

A

lambda=er

r=ln(lambda)

34
Q

Logistic Growth: equation

A

dN/dt=rN(1-(N/K))

OR

dN/dt=rN(K-N/K)

N: population density

r: per capita growth rate

K: carrying capacity

35
Q
A