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EVOLUTIONARY BIOLOGY > Forces of Evolution > Flashcards

Forces of Evolution Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

a change in the heritable characteristics of biological populations over successive generations

A

EVOLUTION

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2
Q

Change in the gene pool of populations over time

A

EVOLUTION

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3
Q

What changes populations?

A

evolutionary forces

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4
Q

Evolutionary Forces

A
  1. Genetic drift
  2. Gene flow
  3. Mutation
  4. Natural Selection
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5
Q

a heritable factor that can control a specific characteristics

A

gene

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6
Q

specific forms of a gene differing by one or a few bases and occupying the same gene locus

A

alleles

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7
Q

made up of DNA and proteins

A

duplicated chromosome

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8
Q

the whole of the genetic information of an organism found in the nucleus of eukaryotes

A

genome

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9
Q

difference between gene and DNA

A

gene - sequence of DNA / RNA that codes for a molecule that has a function the transmission of genes to an organism’s offspring is the basis of the inheritance of phenotypic traits

DNA - a molecule composed of two chains which coil around each other to form a double helix carrying the genetic instructions used in the growth, development, functioning of all known living organisms

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10
Q

collection of genes within a population

A

Gene Pool

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11
Q

indicates the alleles that the organism has inherited regarding a particular trait (Letters)

A

Genotype

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12
Q

The actual visible trait of the organism

A

Phenotype

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13
Q

provides a framework for understanding how populations evolve;

is a type of model. Biologists use model to study populations. Note: individuals do not evolve, populations do EVOLVE.

A

Hardy-Weinberg equilibrium

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14
Q

The Hardy-Weinberg Principle

A

p^2 + 2pq + q^2 = 1

p^2: frequency of homozygous dominant genotype
2pq: frequency of heterozygous genotype
q^2: frequency of homozygous recessive genotype

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15
Q

states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences.

A

The Hardy-Weinberg Principle also known as the Hardy-Weinberg equilibrium, model, theorem, or law

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16
Q

is used to predict genotype frequencies in a population.

is based on Mendelian genetics. It is derives from a simple Punnett square in which p is the frequency of the dominant allele and q is the frequency of the recessive allele.

A

The Hardy-Weinberg equation

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17
Q

Genotypic frequencies stay the same if all these conditions are met. (5)

A
  1. very large population: no genetic drift
  2. no emigration or immigration: no gene flow
  3. no mutations: no new alleles added to gene pool
  4. random mating: no sexual selection
  5. no natural selection: all traits aid equally in survival
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18
Q
  • a random evolutionary change.
  • changes allele frequencies within a population due to CHANCE alone.
  • it may happen that some alleles are completely lost within a generation due to ______, even if they are beneficial traits.
  • it is not expected to results in adaptation to the environment because it is CHANCE EVENTS rather than natural selection that determines which individuals will reproduce.
A

genetic drift

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19
Q

Small populations are ______ affected by genetic drift. In large populations, such random events are ______.

A

hugely,

insignificant

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20
Q

Two types of genetic drift

A

bottleneck effect
founder effect

21
Q

SUDDEN SHARP DECLINE in a population’s size since sometimes, a population is subjected to near extinction because of a natural disaster such as earthquake, fire or slaughter by humans.

CHANCE ALONE determines which individuals survive these unfavorable times, preventing the majority of genotypes from participating in the production of the next generation.

A

bottleneck effect

22
Q

bottleneck effect example

A

Case study of the Northern Elephant Seal

100,000 (early 1800’s)
50 (due to hunting)
150,000 (present-day)

Southern Elephant Seal
- ‘no environmental pressure’

23
Q

DNA (mitochondrial)

  • researchers found out that diversity in pre-bottleneck was _____ than in post-bottleneck.
  • present population looks very similar than the ‘pre-bottleneck’ population
A

higher

24
Q

Symmetry indicates _____ in a population

A

‘fitness’

25
Q

forming of new colonies;

newly founded populations don’t always represent the genetic diversity in their sources.

A

Founder effect

26
Q

the transfer of genes from the gene pool of one population to another

  • change the allele or gene frequencies in the population
A

gene flow (gene migration)

27
Q

example of gene flow in plants

A

plant populations can experience gene flow by spreading their pollen long distances away to other populations by means of wind or through birds or insects

28
Q

What does gene flow do to the populations?

A
  • maintains variation within a population
  • reduces variation between populations
29
Q
  • permanent alteration of the nucleotide sequence of the genome of an organisms
  • are the ONLY ORIGINAL SOURCE OF ALLELE CHANGES
  • _____ rates are quite low
A

Mutations

30
Q

Effects of germ line mutations

A single germ line mutation can have a range of effects

A

a.) No change occurs in phenotype
b.) Small change occurs in phenotype (ex: Scottish Fold)
c.) Big change occurs in phenotype

31
Q
  • when mutation occurs in a stretch of DNA with no function
  • or perhaps mutation occur in a protein-coding region, but ends up not affecting the amino acid sequence of the protein

NOTE: more the 90% is non-coding

A

No change occurs in phenotype

32
Q

How does mutation affect protein formation?

A

By changing a gene’s instructions for making a protein, a variant can cause a protein to malfunction or to not be produced at all.

PROTEINS CODES DNA AND RNA.

33
Q

is the process in which RNA codons are decoded into amino acids that make up an amino acid chain (a polypeptide)

A

Translation

34
Q

Types of Mutation

A
  1. Silent point mutation
  2. Missense point mutation
  3. Nonsense point mutation
  4. Insertion mutation (frameshift)
  5. Deletion mutation (frameshift)
  6. Inversion mutation
  7. Translocation mutation
35
Q

Change one nucleotide to another but do not change the amino acid sequence of the protein

A

Silent point mutation

36
Q

Change one nucleotide to another, resulting in a different amino acid sequence of the protein

A

Missense point mutation

37
Q

Change the DNA sequence in a way that results in an early stop codon

A

Nonsense point mutation

38
Q

Insert one or more extra nucleotides into the DNA sequence.

often alter the reading frame of the gene such that every codon after the insertion is altered.

A

Insertion mutation

39
Q

Remove one or more nucleotides from the DNA sequence such that the reading frame is altered. Every codon after the _______ is altered.

A

Deletion mutation

40
Q

A group of DNA nucleotides are turned over to be read in reverse order. This changes the amino acid sequence in that location.

A

Inversion mutation

41
Q

The movement of segments of DNA from one chromosome to another can fuse portions of different genes together.

A

Translocation mutation

42
Q
  • mutations that occur in non germline tissues,
  • cannot be inherited,
  • DO NOT MATTER FOR EVOLUTION,
  • frequently caused by environmental factors e.g. exposure to UVR or to certain chemicals
A

Somatic mutations

43
Q

mutations present in egg or sperm, can be inherited, cause cancer family syndrome

A

Germline mutations

44
Q
  • is the process by which population become adapted to their environments
  • organisms that are better adapted to an environment are more likely to survive and reproduce than organisms that are less well adapted
A

Natural Selection

45
Q

Factors that affect natural selection

A
  • overproduction
  • adaptation
  • competition
  • variation
  • nonrandom mating
    • positive assortative mating
    • physical location
46
Q

Most species produce far more offspring than will/can survive

A

Overproduction

  • Malthus’ Basic Theory
  • Point of Crisis
47
Q

A key to variation is _________.

A

Sexual reproduction

48
Q

-when individuals nonrandomly mate with other individuals

  • individuals prefer mates
  • hence, traits that lead to more mating for individuals lead to a higher frequency of that train in the population
A

Nonrandom mating

(Sexual Selection)

49
Q

individual preference to mate with partners that are phenotypically similar to themselves

A

positive assortative mating

EVOLUTIONARY BIOLOGY (2 decks)

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