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Biology 30 > HW Theory and Population Dynamics: Chapters 24-29 > Flashcards

HW Theory and Population Dynamics: Chapters 24-29 Flashcards

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1
Q

Population

A

Group of organisms of the same species that live together in a defined area and time.
- If populations become fragmented (ex. divided by a barrier in their habitat) the individuals on either side of the barrier may form separate populations.

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2
Q

Community

A

All the organisms in all the interacting populations in a given area.

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3
Q

Gene pool

A

Sum of all the alleles for all the genes in a population. (Aka sum of all the genetic variation that can be passed onto the next generation.)

  • In general, more variety there is in the gene pool, the better the population can survive in a changing environment.
  • Described in terms of genes and alleles.
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4
Q

Genotype frequency

A

Proportion of a population with a particular genotype.

  • Described with a decimal.
  • Can be calculated with individuals with (individuals with genotype/total amount of individuals) = genotype frequency
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5
Q

Phenotype frequency

A

Proportion of a population with a particular phenotype.

- Described with a decimal.

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6
Q

Allele frequency

A

Rate of occurrence of a particular allele in a population.
- Described with a decimal.
- Since diploid organisms have two possible alleles for every gene, the total number of alleles in a population is twice the number of individuals.
Ex. 200 mice = 400 coat colour alleles.

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7
Q

5 conditions for Hardy-Weinberg principle to be true.

A
  1. Large enough population that genetic drift will not alter allele frequencies.
  2. Random mating.
  3. No mutations.
  4. No migration (immigrants and emigrants).
  5. No natural or artificial selection against the phenotypes.
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8
Q

Genetic equilibrium (Hardy-Weingberg equilibrium)

A

If there is no change in allele frequencies over time, the population is said to have genetic equilibrium.
- The population is not changing or evolving.

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9
Q

Variable p

A

Frequency of dominant allele

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10
Q

Variable q

A

Frequency of recessive allele

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11
Q

Variable p2

A

Frequency of homozygous dominant individuals

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12
Q

Variable 2pq

A

Frequency of heterozygous dominant individuals

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13
Q

Variable q2

A

Frequency of homozygous recessive individuals.

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14
Q

Microevolution

A

The gradual change in allele frequencies in a population.
- Ex. Development of DDT-resistance mosquitoes. The mosquitoes carry the parasitic protozoan Plasmodium, which causes malaria in humans. The DDT pesticide had been used successfully to eliminate these flies, but resistance in some species led to the ineffectiveness of DDT over time.

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15
Q

Genetic diversity

A

The degree of genetic variation within a species or population.

  • The more genetic variation there is in a population, the greater the chance that a variation will be present and provide a selective advantage in a changing environment.
  • Genetic diversity can only be increased through the accumulation of mutations over a couple of generations.
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16
Q

Mutations

A

Change that occurs in the DNA of an individual.

  • An inheritable mutation has the potential to effect an entire gene pool.
  • Beneficial mutations can save populations.
  • Back mutations reverse the effect of former mutations.
  • Ex. The immunity gene in mountain gorillas.
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17
Q

Gene flow

A

Net movement of alleles from one population to another due to the migration of individuals.

  • As a result, genetic diversity in an environment can increase, which increases survival.
  • Reduces genetic differences among populations as well.
  • Gene flow can increase frequencies as interbreeding happens from one population to another.
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18
Q

Genetic drift

A

Changes in allele frequencies due to chance events, usually in smaller populations.

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19
Q

Founder effect

A

Gene pool change that occurs when a few individuals start a new, isolated population. (Ex. Islands.)

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20
Q

Bottleneck effect

A

Gene pool change that results from a rapid change in population size. (Ex. 50% of an ant colony is squished.)

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21
Q

Natural selection

A

Process whereby the characteristics of a population of organisms change over time because individuals with certain inheritable traits survive specific local environmental conditions, and, through reproduction, pass on their traits to their offspring.
-With natural selection, certain frequencies can disappear as they are not reproducing.

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22
Q

Heterozygote advantage

A

A survival benefit for those individuals who inherit two different alleles for the same trait (Aa), compared to those who are homozygous dominant or homozygous or homozygous recessive.

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23
Q

Population density and formula

A 
Population density (DP): Defined as the number of individual organisms (N) in a given area (A) or volume (V).
D=N/A or D=N/V
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24
Q

Uniform distribution

A

Individuals are evenly spaced out over a defined area, so individuals have control over their resources in their immediate area.
- Tells us the individuals are a little bit territorial, and the area has ample resources.

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25
Q

Clumped distribution

A

Members of a population are found in close proximity to each other in various groups within their habitat.

  • Caused by patches of resources in specific areas or behavioral interactions between members of a species.
  • Species are not very territorial.
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26
Q

Random distribution

A

Where resources are very abundant and population members do not have to compete with one another or group together for survival.
- There is no pattern due to lack of repulsion or attraction between members.

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27
Q

3 distribution patterns

A

Uniform, clumped, random.

28
Q

4 processes that change the size of a population and formula

A
  • Increase: Births (b) and immigration (i)
  • Decrease: Deaths (d) and emigration (e)
  • ΔN = (b+i) - (d+e)
29
Q

Population explosion

A

Population grows too rapidly before it can be contained.

30
Q

Population crash

A

Population decreases significantly

31
Q

Growth rate and formula

A

(gr) Change in population size (ΔN) over a specific time frame (Δt)
- gr = ΔN/Δt
- Can be positive (increasing population) or negative (decreasing population)

32
Q

Per capita growth and formula

A

(cgr) Change in population size per individual over a time frame.
- cgr = ΔN/N
or
cgr = Nfinal-Ninitial/Nintial

33
Q

Birth potential (r)

A

Highest possible per capita growth rate for a population, given unlimited resources and ideal living conditions.
-Population that is growing at its biotic potential would be expected to grow exponentially.

34
Q

Exponential growth pattern (J curve)

A

Growth with a brief lag phase and a steep increase in growth.

  • Shows that as population increases, rate of growth increases,
  • Types of organisms: Bacteria, smaller animals,r-selected organisms.
  • This population is regulated by density independent (abiotic) factors.
  • Usually followed by rapid decline due to the inability to sustain.
35
Q

Logistic growth pattern (S curve)

A

Population increase that results in a S-shaped curve; growth is slow at first, steepens in an exponential pattern, and then levels off due to environmental resistance such as competition at the carry capacity (K).

  • Controlled by density dependent (biotic) factors.
  • Shown by k-selected organisms.
  • More stable model.
36
Q

Carrying capacity (k)

A

Theoretical maximum population size that the environment can sustain over an extended period of time; may change over time as the habitat changes.

  • When populations shoot above carrying capacity, they are usually followed by a crash.
  • Reflection on amount of food, predators. Affected by both density independent and dependent factors.
37
Q

Density independent factors

A

Factors affecting population that are unrelated to the density of the population. (Aka abiotic factors.)
- Ex. Precipitation, bad weather, natural disasters.

38
Q

Density dependent factors

A

Factors that affect the growth of the population that are related directly to the density of the population. (Aka biotic factors.)
- Ex. If population has high density, there is less resources, and more chance of disease which is less of a factor with smaller populations.

39
Q

Environmental resistance

A

Combined effects of various interacting factors that limit population growth; prevents a population from growing at its biotic potential and determines the carrying capacity of the habitat.
- Mostly consists of predators and disease

40
Q

K selected strategies

A

A life strategy designed to take advantage of a stable environmental conditions; characterized by the production of a few offspring with much attention give to offspring survival; organisms that exhibit this strategy include mammals and species that live close to the carry capacity (K) of their habitats.

  • Larger
  • Slow development
  • Delayed development
  • Low reproductive rate
  • Logistic growth
  • Density dependent factors
41
Q

r-selected strategies

A

A life strategy designed to take advantage of favourable conditions; characterized by a high reproductive rate with little or no attention given to offspring survival; organisms that exhibit this strategy include bacteria and species that reproduce close to their biotic potential (r).

  • Rapid development
  • Reproductive rate is very high
  • Rapid maturity
  • Large number of offspring
  • Experience exponential growth
  • Density independent factors
42
Q

Intraspecific competition

A

Competition for limited resources among members of the same species for a limited resource.

  • Density dependent factor that limits the growth of a population.
  • Plays important role in natural selection.
43
Q

Interspecific competition

A

Competition between two or more species for the same resource.

44
Q

Predators:

A

Organisms that kill and consume other organisms.

45
Q

Prey

A

Organism that is killed and consumed by another organisms.

46
Q

Predator/prey relationship

A

The predator/prey relationship mirrors one another. If prey pop is large, then it attracts more predators. This puts a strain on prey pop, which decreases predator population.

  • Also influences the natural selection for adaptive traits.
  • A factor in boom and bust cycles.
47
Q

Protective colouration

A

Adaptation that helps individuals avoid predation; includes camouflage, mimicry, and using body colors as a warning signal.

48
Q

Cryptic colouration

A

Camouflage that makes potential prey difficult to spot.

49
Q

Aposematic colouration

A

Conspicuous colours to warn other organisms in the wild that you are very dangerous.

50
Q

Mimicry

A

Where one species mimics the characteristics of another species that is dangerous.

51
Q

Batesian mimicry

A

Where a particular species come to resemble another, well-protected species.

52
Q

Mullerain mimicry

A

2 dangerous species come to resemble each other. Both species benefits because if one of them is attacked, a predator will learn to avoid both species because they look the same.

53
Q

Symbiosis and types

A

Direct, close relationship between individuals of different species that live close together.

  1. Mutualism
  2. Commensalism
  3. Parasitism
54
Q

Succession

A

The sequence of invasion and replacement of a species in an ecosystem over time.
- As succession progresses, variation in an ecosystem increases.

55
Q

Primary succession

A

The development of a new community in a previously barren area where there is no soil present (ex. bare rock)

56
Q

Secondary succession

A

The regrowth of a previously existing community after an ecological disturbance, such as a forest fire, flood, or agricultural activity; has soil.

57
Q

Pioneer community

A

The first species to colonize an area and initiate succession.

58
Q

Climax community

A

The latecomers in the process of succession. May remain relatively stable if there are no major environmental changes.

59
Q

Ecological disturbance

A

Event that changes the structure of a community, sometimes destroying all actively growing organisms.

60
Q

Growth pattern of human population

A
  • Currently in a state of exponential growth.
  • Humans have K-selected strategies.
  • Over time, as living conditions became more favourable, global population increased.
61
Q

Age pyramid

A

Representation of the age structure of a population to show the proportion of individuals in the population in each age class; used by demographers to assess a population’s potential for growth.
- Can be used to see the proportion of a population in the three stages of development: the pre-reproductive stage (0-14 y/o), reproductive stage (14-44) and the post-reproductive stage (45+).

62
Q

Upright triangle age pyramid

A

Rapid growth, shows more births than deaths

63
Q

Rectangle age pyramid

A

Stable population, roughly has the same amount of people in each stage of development, number of births relatively equal to number of deaths.

64
Q

Inverted triangle age pyramid

A

Decline in population, less amount of births that most of the stages.

65
Q

Gause’s principle

A

No two species with the same niche can remain in competition indefinitely. One of the two species will always be slightly more efficient and will win out in the struggle, causing the other species to decline.

Biology 30 (7 decks)

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