Brainscape's Knowledge GenomeTM

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


See full index

Biology > Unit 7 - Population Dynamics > Flashcards

Unit 7 - Population Dynamics Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Describe 3 different measurements scientists use to describe populations

A
  1. Population characteristics
  2. Population size and density
  3. Mark-recapture sampling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Compare population size and population density

A

Population Size: the number of individuals of a specific species occupying a given area/volume at a given time

Population Density: the number of individuals of the same species that occur per unit area or volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why do “smaller organisms usually have higher population densities than larger organisms”?

A

They are smaller, so they can live closer together

They have a smaller footprint, and so can support a larger population without depleting resources

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Compare crude density and ecological density. Which is typically higher?

A

Crude Density: population density measured in terms of number of organisms of the same species within the total area of the entire habitat

Ecological Density: population density measured in terms of the number of individuals of the same species per unit area or volume actually used by the individuals

Crude density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define population dispersion

A

Population Dispersion: the general pattern in which individuals are distributed through a specified area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Explain clumped dispersion pattern

A

Clumped Dispersion: the pattern in which individuals in a population are more concentrated in certain parts of a habitat (most common)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Explain uniform dispersion pattern

A

Unifrom Disperion: the pattern in which individuals are equally spaced throughout a habitat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Explain random disperion pattern

A

Random Disperion: the pattern in which individuals are spread throughout a habitat in an unpredictable and patternless manner

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What determines the type of disperion pattern a species exhibits in an area?

A

Ultimately, environmental conditions, suitable niches, and social behaviour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

State the equation for the mark-recapture method

A

total # marked / total population = # of recaptures marked / size of second sample

M/N = m/n

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is meant by the term ‘environment’?

A

The surroundings or conditions in which an organism operates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

State some biotic and abiotic resources that may be limited in an ecosystem at a given time

A

Biotic: prey, plants

Abiotic: space, light, temperature, water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define carrying capacity

A

Carrying Capacity: the maximum number of organisms that can be sustained by available resources over a given period of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What determines carrying capacity?

A

The environment; abiotic and biotic variability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Define fecundity

A

Fecundity: the potential for a species to produce offspring in one lifetime

Ex., high fecundity = starfish

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Outline type 1 survivorship and provide an example

A

Species exhibiting a type I survivorship pattern have very low mortality rates until they are beyond their reproductive years

Ex: humans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Outline type 3 survivorship and provide an example

A

Species with a type III survivorship curve have very high mortality rates when they are young while those individuals that do reach sexual maturity have a greatly reduced mortality rate

Ex: sea turtles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Outline type 2 survivorship and provide an example

A

Type II species are intermediate between these forms and tend to show a uniform risk of mortality throughout their life.

Ex: lizards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

State the formula for changes in population size

A

Population change = (birth + immigration) - (death+emmigration) / initial population size x 100%

Population change = (b + i) - (d + e) / n x 100%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Compare open and closed populations

A

Open Population: a population in which change in number and density is determined by births, deaths, immigration, and emigration

Closed Population: a population in which change in size and density is determined by natality (birth rate) and mortality (death rate) alone

21
Q

What is biotic potentional?

A

Biotic Potential: the maximum rate a population can increase under ideal conditions

22
Q

State the equation for geometric growth

A

N(t + 1) / N(t) = lambda (growth rate)

N(t+1) = t0 x lambdat

23
Q

Define density-dependent factor

A

Density Dependent Factor: a factor that influences population regulation, having a greater impact as population density increases or decreases

24
Q

State examples of density-dependent factors

A

Availability of food, predation, disease, and migration

25
Q

How did Charles Drawin use density-dependent factors in his Theory of Evolution?

A

Darwin recognised the struggle for available resources within a growing population would inherently limit population size (natural selection, the fittest survive)

26
Q

Compare interspecific vs. intraspecific competition

A

Intraspecific Competition: an ecological interaction in which individuals of the same species or population compete for resources in their habitat

Interspecific Competition: interactions between individuals of different species for an essential common resource that is in limited supply

27
Q

Explain consequences for increased population density

A

More competition for resources, leading to decreased growth

28
Q

Define predation

A

Prediation: an ecological interaction in which a predator (a member of one species) catches, kills, and consumes prey (usually a member of another species)

29
Q

Explain how predation is a density-dependent factor

A

Example: A population of sharks searching for prey can hunt several species of fish for food. However, faster prey may escape the shark predators and survive. Fish that are slower may be easier prey for the sharks and be their food of choice. The shark population, therefore, will regulate fish populations that are their prey

30
Q

Explain how disease is a density-dependent factor

A

A potential risk of increased population density is that it can allow disease to spread more rapidly, resulting in a reduction in population size. (spread of disease is density-dependent)

31
Q

Explain the allee effect and proviede an example

A

Allee Effect: Allee effect density-dependent phenomenon that occurs when a population cannot survive or fails to reproduce enough to offset mortality once the population density is too low; such populations usually do not survive

Passenger pigeon: Three centuries ago, passenger pigeons were the most common bird in North America. As a result of uncontrolled hunting and destruction of the birds’ habitats, the passenger pigeon drastically declined in numbers. The population could not recover since the pigeons laid only one egg per nest and would breed only in large colonies.

32
Q

Define minimum viable population size

A

Minimum Viable Population Size: the smallest number of individuals needed for a population to continue for a given period of time

33
Q

Define density-independent factor

A

Density-Independent Factors: factors that influence population regulation regardless of population density

34
Q

State examples of density-independent factors

A

Weather, climate change resulting in population reduction, as well as insecticide use and human intervention

35
Q

Define biomagnification

A

Biomagnification: the concentration of toxins in an organism as a result of its ingesting other plants or animals in which the toxins are more widely disbursed.

36
Q

Define limiting factor

A

Limiting Factor: any essential resource that is in short supply or unavailable

37
Q

What usually occurs when a population surpasses its carrying capacity in an environment?

A

Deaths increase and the number of births decline resulting in a reduction in population size

38
Q

Why do biologists monior fluctuations in size and density of populations?

A

The natural fluctuations of such things are monitored in hopes of further understanding the natural patterns as well as predict an organism’s ability to withstand certain factors and impacts. This is especially important to environmental scientists that analyze the destructive human impact on certain species and their environments.

39
Q

Define ecological niche

A

Ecological Niche: an organism’s biological characteristics, including use of and interaction with abiotic and biotic resources in its environment

40
Q

Compare fundamental niche and realized niche

A

Fundamental Niche: the biological characteristics of the organism and the set of resources individuals in the population are theoretically capable of using under ideal conditions (i.e. no competition)

Realized Niche: the biological characteristics of the organism and the resources individuals in a population actually use under the prevailing environmental conditions

Interspecies competition prevents these from being identical

41
Q

State the five categories of interactions between species

A
42
Q

Define symbiosis

A

Symbiosis: various interactions in which two species maintain a close, usually physical, association; includes parasitism, mutualism, and commensalism

43
Q

Explain the three likely results of interspecific competition

A

The results of interspecific competition take on several forms:

  1. The population sizeof the weaker competitor could decline.
  2. One species could change its behaviour so that it is able to survive using different resources.
  3. Individuals in one population could migrate to another habitat where resources are more plentiful
44
Q

Explain the two ways in which interspecific competition can occur and provide an example

A

Interference Competition: interspecific competition that involves aggression between individuals of different species who fight over the same resource(s)

Exploitative Competition: interspecific competition that involves consumption of shared resources by individuals of different species, where consumption by one species may limit resource availability to other species

An example of interference competition is the fighting that sometimes occurs between tree swallows and bluebirds over birdhouses.

An example of exploitative competition occurs when both arctic foxes and snowy owls prey on the same population of arctic hares

45
Q

What did Gause do?

A
  • Hypothesized that two species with similar requirements could not coexist in the same community. He predicted that one species would consume most of the resources and drive the other species to extinction.
  • Gause’s experiments led to the conclusion that if resources are limited, no two species can remain in competition for exactly the same niche indefinitely. This became known as Gause’s principle.
46
Q

Define resource partitioning and provide an example

A

Resource Partitioning: Avoidance of/reduction in competition for similar resources by individuals of different species occupying different nonoverlapping ecological niches

To minimize competition for food, several species of Anolis lizard partition their tree habitats by occupying different perching sites

47
Q

Define character displacement and provide an example

A

Character Displacement: an evolutionary divergence that occurs when two similar species inhabit the same environment. Ex., Darwin’s finches

48
Q

Do resource partitioning and character displacement provide direct or indirect evidence for competition?

A

Character displacement: indirect, species characteristics are no longer similar which we infer is due to competition

Resource partitioning: indirect, species migrate or switch to different resources due to competition

49
Q

Explain the predator-prey relationship + diagram

A

Predation is an example of an interspecific interaction in which the population density of one species—the predator—increases while the popu lation density of the other species—the prey—declines.

When the prey population increases, there is more food for predators and this abundance can result in an increase in the size of the predator po pulation.

As the predator population increases, however, the prey population decreases. The reduction of prey then results in a decline in the predator population, unless it has access to another food source.

In conclusion, the predator population responds to changes in prey abundance

Biology (7 decks)

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