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Biology 151 > Exam 3 > Flashcards

Exam 3 Flashcards

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1
Q

Why do we study evolution?

A

because evolution is the major unifying theme in biology

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2
Q

What negative impacts does evolution have on us?

A

-insecticide resistant mosquitos that transmit disease
-plants resistant to herbicides which decrease food production
-HIV evolves to have resistance to drugs that treat it
-coronavirus evolves to have new variants
-resistance of bacteria to antibiotics
EVOLUTION IS RESPONSIBLE FOR ALL OF THIS

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3
Q

Misunderstandings of evolution

A

-Eugenics movement: we can improve the human race to decide better characteristics and who gets to reproduce (stop criminals, mentally ill, poor by sterilizing them)
-“fitter family” competitions: blond hair, blue eyes, lots of kids

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4
Q

Why is the eugenics movement a misunderstanding of evolution?

A

-we can’t change characteristics in the human race
-we can’t eliminate genes from the genes pool

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5
Q

Theory (in laymen’s terms)

A

a theory is just an idea that lives in someone’s head, rather than an explanation rooted in experiment and testing. Anybody can choose to believe or not believe this
ex) speculation, ideas, hypothesis

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6
Q

A scientific theory

A

an explanation of some aspect of the natural world that has been substantiated (proven) through repeated experiments or testing, it is accepted as fact to nearly every scientist
-facts about the natural world

ex) can’t choose to not believe in the theory of gravity, you will fall off the cliff

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7
Q

Progressive Theory of Evolution

A

*evolution was not a new idea in the mid-1800s
-Lamarck said “things change over time”
-inheritance of acquired traits improves the population (so it’s an adaptation)

ex) giraffes necks increase over time to reach leaves

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8
Q

Jean-Baptiste Lamarck

A

-1744-1829
-progressive theory of evolution

1) adaptations are acquired by individuals ex) the characteristics of an individual change over time
2) acquired characteristics (traits) are passed on to offspring
3) so species change over time

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9
Q

Modern def of evolution

A

evolution: a change in heritable characteristics (traits or allele freq.) in a population over time
-contains patterns of evolution and processes of evolution

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10
Q

Patterns of evolution

A

observations of the natural world (what we see)

1) species change over time
2) species are related (based on similarities with other species)
3) species are adapted to environments in which they live
4) new species develop (speciation)

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11
Q

processes of evolution

A

the mechanisms that produce the patterns of evolution

1) involve natural selection
2) involve mutations for adaptations to form
3) gene flow- adaptations occur because moved around
4) genetic drift

*mechanisms scientists have helped us discover to learn more about the world around us

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12
Q

Which of the following would Lamarck and Darwin have agreed upon?

I. species are not unchanging, fixed types
II. individuals change traits to adapt to their environments
III. species evolve to become more complex over time
IV. traits are passed on yo offspring

A

answer: I and III

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13
Q

Theory of Evolution by Natural Selection

A

-the idea of evolution by natural selection jointly proposed in 1858 by Darwin and Wallace was new
-“survival of the fittest”

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14
Q

What inspired the theory of evolution by natural selection?

A

1) world travel: saw lots of patterns in natural world (Darwin was around the world over 5 years, Wallace was in Amazon and Maylasia)
2) artificial selection: breeding of different animals (both did it, Darwin used pigeons)

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15
Q

Charles Darwin

A

wrote the book “On the Origin of Species”

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16
Q

Alfred Russell Wallace

A

-came up with the idea independently in his book later
-forced Darwin to publish his book

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17
Q

Charles Lyell

A

-wrote “Principles of Geology” which said that most geological processes are small changes except rarely when there are earthquakes
-the earth is very old and what we se is a result and sudden events happening
-more offspring are reproduced (humans), more offspring caused more competition, there is a limit they can survive to reproduce

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18
Q

Thomas Malthus

A

-economics
-wrote essay on population increase
-said that resources are limited

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19
Q

Four Postulates for Evolution by Natural Selection

A

1) individuals in a population vary in their characteristics (genetic variation)
2) characteristics of individuals are passed onto the offspring (heritability)
3) unequal reproduction among individuals in the population (differential reproduction) bc…
4) individuals with favorable characteristics, or traits, produce more offspring “survival of the fittest”

20
Q

What does natural selection act on?

A

individuals

21
Q

What changes as a result of natural selection?

A

the population (through changes in the species traits, characteristics)

22
Q

Absolute Fitness

A

the number of surviving offspring

23
Q

Relative Fitness

A

*best biographic one
-ability of the individual to successfully reproduce, in a a particular environment, relative to other individuals

24
Q

Adaptation

A

Heritable trait has an increased fitness
ex) diving bell spider (8 legs isn’t an adaptation, but air bubble underwater is)

25
Q

Case study of tuberculosis in the book- did evolution by natural selection occur? Address all four criteria (postulates)

A

Yes

1) variation among individuals in resistance to Rifampin in populations (mutation allowed for resistance to the drug) GENETIC VARIATION

2) HEREDITY: resistance or nonresistance to R is passed onto the offspring

3) variability in the reproduction (DIFFERENTIAL REPRODUCTION)
*ind more fit will pass on genes to the next, survival and reproduction in non-random (4. SURVIVAL OF THE FITTEST) and population will become more drug resistant in the population over time (this is evolution)

26
Q

If a bacterium experiences a cost for maintaining one or more antibiotic-resistance alleles, what would happen in environments that lack antibiotics?

A

These bacteria would be outcompeted and replaced by bacteria that do not have these alleles

27
Q

Genetics and Heritability: What are two key issues that slowed acceptance of Darwin’s theory of evolution by natural selection?

A

it took about 70 years to get answers for our questions because
1) why/how is variation in a population? shouldn’t all ind reproduce similar over time. MUTATIONS WERE NOT WELL UNDERSTOOD
2) How was the variety in a population inherited from parents to offspring

28
Q

A brief introduction to genetics

A

how variation is passed to offspring

29
Q

gene

A

a section of DNA that codes for a specific product (ex: protein) which then influences some trait or characteristic (ex: eye color)

30
Q

allele

A

different versions of the same gene

31
Q

genotype

A

combinations or PAIRS alleles in an individual organism
*genetics of the organism, what alleles are perceived in that organism

32
Q

diploid

A

Diploid is a term that refers to the presence of two complete sets of chromosomes in an organism’s cells, with each parent contributing a chromosome to each pair. Humans are diploid, and most of the body’s cells contain 23 chromosomes pairs.

2 BLANK with same of genes (identical) that have the same genes on both chromosomes ex:human and tight parents contribute an allele to each chromosomes

gamete/sex cells: sperm or eggs

33
Q

homozygote genotype

A

contains 2 copies of the same allele in the same genes ex) AA or aa

34
Q

heterozygote genotype

A

contains 2 different allele flows on in the same gene ex) Aa

35
Q

phenotype

A

the observable traits of an organism, the characteristics we can see

36
Q

Single gene genetic inheritance: snapdragon example

A

red and white flower together (genotypes of RR and rr) with create all pink flowers (genotype of Rr) and this is the phenotype

if pink and pink cross (Rr and Rr) will get one red RR, one white rr, and two pink Rr

37
Q

Discontinuous traits

A

Characteristics fall into distinct categories
ex) red eyes OR white eyes

38
Q

Continuous (quantitative) traits

A

-continuous because there is a continuum of variation
-quantitative because phenotype must be measured
ex) shell size in snails

39
Q

Histogram

A

graph that shows continuous traits (3 of ind from y axis and the multiple trait categories on x axis)

40
Q

why might the avg of a continuous trait change over time? ex: the height of men

A

environmental changes causing medicine and nutrition to improve dramatically since the 1890s

41
Q

Phenotypic Variation

A

Vp
-variation ion the observable traits or characteristics of an organism

42
Q

What influences phenotypic variation?

A

-Genetic variation (VG) and environmental variation (VE)
-VP=VG+VE

43
Q

Heritability

A

= proportion of the phenotypic variation in a population due to the genetic differences (genetic variability)

H= VG/VP
H will be in between 0-1 because it is a proportion

44
Q

What proportion of the phenotypic variation in a population is due to genetic differences (heritability)? There are two ways to measure heritability

A
  1. Mid-parent vs mid-offspring regression method
  2. “Common Garden” experiments method
45
Q

Mid-parent vs mid-offspring regression method

A

Determine the mid-parent value and compare this to the mid-offspring value of the trait (averages of each)

-tells us how much this variation is due to heritability

-if best fit line slope has a 1:1 ratio then the variation is due to heritability
-if it’s a flat line it’s due to all environmental
-if it’s in btwn it’s a mix btwn environment and genetics

Biology 151 (7 decks)

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