Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Ecology 2483 > Lecture 8 > Flashcards

Lecture 8 Flashcards

1
Q

Abundance

A
  • Can change over time and space
  • Fluctuating abundance could reflect changes in environmental factors (nutrient supplies, temperature, or predator abundance)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Types of Patterns of Population Growth

A
    1. exponential growth
    1. logistic growth
    1. Fluctuations
    1. regular cycles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Patterns of Population Growth

A
  • These four patterns are not mutually exclusive
  • A single population can experience each of them at different times
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Exponential Growth

A
  • Population increases by a constant proportion at each point in time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Exponential Growth When Conditions are Favourable

A
  • a population can increase exponentially for a limited time
  • When a species reaches a new area, the population may grow exponentially until density-dependent factors regulate its numbers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Logistic Growth

A
  • Populations first increase and then fluctuate by a small amount around carrying capacity
  • Limited by space or food
  • Used broadly to indicate any population that increases initially, then levels off at the carrying capacity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Population Fluctuation

A
  • Numbers rise and fall over time
  • Fluctuations can be deviations from a growth pattern or erratic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Population Outbreak

A
  • the number of individuals increases rapidly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Long Term Data Sets

A
  • can help solve applied problems
  • An outbreak of a new disease in 1993 in New Mexico was caused by a new strain of hantavirus, carried by the deer mouse
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Delayed Density Dependence

A
  • Delays in the effect that density has on population size
  • Commonly, the number of individuals born in a given time period is influenced by population densities that were present several time periods ago
  • can cause populations to fluctuate in size
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Population Extinction

A
  • Becoming very common because of various land pressures
  • The risk of extinction increases greatly in small populations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What Can Affect a Population’s Risk of Extinction

A
  1. Fluctuations in growth rate
  2. Population size
  3. Chance events
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The Geometric Growth Equation

A
  • can include random variation in the finite rate of increase
  • Random variation in environmental conditions can cause λ to change from year to year
    (good years and bad years for growth)
  • Fluctuations increase the risk of extinction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Chance Events

A
  1. Genetic
  2. Demographic
  3. Environmental Events
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Genetic Chance Event

A
  • Genetic drift
  • Allele frequencies can change at random from one generation to the next and genetic variation is reduced
  • Much lower genetic diversity by chance in small populations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Genetic Drift Definition

A
  • chance events influence which alleles are passed on to the next generation
17
Q

Demographic Chance Event

A
  • Chance events affect the survival and reproduction of individuals
  • birth and death rates are constant, but the actual fates of individuals differ
  • The environment is stable, but you have bad luck
18
Q

Environmental Chance Event

A
  • Unpredictable changes in the environment that can cause extinction of small populations
  • Change in average birth or death rates from year to year because of random changes in environmental conditions (environment changes)
  • Can play a role in the extinction of small populations
19
Q

Allee Effects

A
  • At low densities, individuals have difficulty finding mates, so the growth rate decreases as population density decreases
  • Can reduce small population size even further
20
Q

Natural Catastrophes

A
  • floods, fires, etc
  • Eliminate or greatly reduce even large populations and play a role in extinctions
    (Ex. heath hens)
21
Q

Extinction Vortex

A
  • see notes
22
Q

Types of Events in the Black Sea Ecosystem

A
    1. Bottom-up Control
    1. Top-down Control
  • both can be very important for regulating populations
23
Q

Bottom-up Control

A
  • increased nutrient inputs
  • caused eutrophication
  • increased phytoplankton biomass
  • decreased oxygen
  • fish die-offs
24
Q

Top-down Control

A
  • top predators control the abundance of populations.
  • Overfishing of predators is an example of top-down
25
Q

Population Cycles

A
  • Have alternating periods of high and low abundance at regular intervals
  • Different factors may drive population cycles in rodents
  • Some population cycles may stop if certain environmental factors change

Ecology 2483 (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions