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Ecology > Chapter 7 > Flashcards

Chapter 7 Flashcards

0
Q

DNA

A

A double stranded molecule in the form of a double helix

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1
Q

How does genetic variation allow evolution?

A

Natural selection

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2
Q

What is DNA made of?

A

Nucleotides

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3
Q

What are nucleotides made of?

A

Sugar
Phosphate group
Nitrogenous base

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4
Q

Nitrogenous bases

A

Adenine
Guanine
Cytosine
Thymine

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5
Q

Chromosomes

A

Long strands of DNA wound around proteins

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6
Q

Genes

A

Regions of DNA that code for particular proteins and affect particular traits

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7
Q

Alleles

A

Different forms of a gene

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8
Q

Diploid

A

2 sets of chromosomes

One allele from mother gamete and the other from father gamete

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9
Q

Polygenic traits

A

When a single trait is affected by alleles of several genes

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10
Q

Pleiotropy

A

When a single gene affects multiple traits

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11
Q

Epistasis

A

When the expression of one gene is controlled by another gene

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12
Q

Heterozygous

A

When an individual has two different alleles of a particular gene

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13
Q

Homozygous

A

When an individual has two identical alleles of a particular gene

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14
Q

Co dominant

A

When two alleles both contribute to the phenotype

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15
Q

Dominant

A

An allele that masks the expression of the other allele

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16
Q

Recessive

A

An allele whose expression is masked

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17
Q

Gene pool

A

Collection of alleles from a particular population

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18
Q

Sources of genetic variation

A

Random assortment
Mutation
Recombination

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19
Q

Random assortment

A

Random combination of alleles are placed in the gamete

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20
Q

Mutation

A

Random change in the sequence of nucleotides in DNA that controls gene expression

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21
Q

Recombination

A

The reshuffling of gene that can occur as DNA is copied during meiosis

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22
Q

Crossing over

A

Happens during meiosis

Homologous chromosomes exchange DNA

23
Q

How does recombination help the immune system rapidly evolve?

A

Recombination creates high genetic variation

High genetic variation allows hosts to match rapid evolution of parasites

24
Q

When are mutations passed on?

A

When they increase fitness

25
Q

Genetic drift

A

Occurs when genetic variation is lost

More common in small pops

26
Q

Bottleneck effect

A

Reduction of genetic diversity in a population due to a severe reduction in pop size
Survivors carry small fraction of the genetic diversity of original pop

27
Q

Founder effect

A

When a small number of individuals leave and colonize a new area
Bring a small amount of genetic variation

28
Q

How long does genetic variation remain low after founder effect?

A

Until enough time has passed to accumulate new mutations

29
Q

Selection

A

Process by which certain phenotypes are favored to survive and reproduce over other phenotypes

30
Q

3 types of selection

A

Stabilizing
Direct
Disruptive

31
Q

Stabilizing selection

A

Intermediate phenotypes have higher survival and reproductive success than extreme phenotypes
Generates little evolutionary change

32
Q

Distribution for stabilizing selection?

A

Progeny will have a more narrow curve

33
Q

Why is stabilizing selection called genetic housekeeping?

A

Removes harmful genetic variation

34
Q

When does stabilizing selection occur?

A

When the environment is unchanging

35
Q

Directional selection

A

Favors one extreme

36
Q

Disruptive selection

A

Favors both extremes

37
Q

Which process will decrease the magnitude of phenotypic variation between generations?

A

Stabilizing selection

38
Q

Microevolution

A

Evolution of populations

39
Q

Artificial selection

A

Humans decide which individuals will breed

40
Q

Natural selection

A

Ecological process

Traits favored for a particular environment are selected to be passed on through interaction

41
Q

How are traits selected?

A

The difference between two types

42
Q

How does selection operate?

A

By favoring certain heritable traits over others

43
Q

What type of traits does natural selection favor?

A

Ones that provide higher fitness

44
Q

Industrial melanism

A

Industrial activities cause habitats to become darker due to pollution
Selection favors darker phenotypes

45
Q

The primary difference between artificial and natural selection?

A

Natural selection only selects traits that increase fitness

46
Q

Speciation is a form of…

A

Macroevolution

47
Q

Macroevolution

A

Evolution at higher levels of organization

48
Q

Speciation

A

Evolution of a new species

49
Q

Phylogenetic trees

A

Hypothesized patterns of relatedness among different groups

50
Q

Allopatric speciation

A

Evolution of new species through the process of geographic isolation
Over time pops become so different they can interbreed and evolve into new species

51
Q

When does allopatric speciation occur?

A

When individuals colonize a new area

When a pop is separated by a geographic event or barrier

52
Q

Sympatric speciation

A

Evolution of a new species without geographic isolation

53
Q

How does sympatric speciation occur?

A

Through polyploidy

54
Q

Polyploid

A

Contains 3 or more sets of chromosomes

55
Q

When does polyploidy occur?

A

When chromosomes don’t separate completely during meiosis

Ecology (8 decks)

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