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Freshman (semester 2) > Biology 112 - Exam 1 > Flashcards

Biology 112 - Exam 1 Flashcards

Natural Selection and Evolutionary Processes

1
Q

Evolution is a scientific theory, which is defined as:

A

A broad class of observations that is widely supported by overwhelming evidence.

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2
Q

Observations about the natural world (that are facts) v.s. Mechanism that produces what is observed

A

Pattern v.s Process

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3
Q

Hypothesis

A

A testable statement that explains a phenomenon or set of observations

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4
Q

Descent with modification

A

Evolution

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5
Q

The process where individuals with heritable traits tend to produce more surviving offspring than individuals without those traits, leading to a change in the populations genetic makeup.

(key term: fitness)

A

Natural Selection

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6
Q

What were Darwin’s 3 observations on populations

A
  1. Overproduction
    a) More individuals are born than the environment can handle
  2. Limited Resources
    a) Resources such as food, water, sunlight, and shelter stay constant
  3. Variation
    a) No two individuals are alike
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7
Q

Darwin concluded that ___ was a factor for all living things.

A

Competition

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8
Q

True or False:

  • Individuals evolve
  • Natural selection only works on heritable traits
  • Evolution has a goal
A

False: Natural selection acts on individuals, but only populations evolve

True

False: Evolution is random and is only in response to current environmental conditions

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9
Q

The earth is around ___ billion years old, and the earliest signs of life (fossils) are about ___- ___ billion years old.

A

4.6
3.4-3.8

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10
Q

What % of all species that have ever lived are now extinct?

A

99%

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11
Q

Traits in fossil species that are intermediate between ancestral (old) and derived (younger) species.

A

Transitional features

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12
Q

Similarity that exists in species descended from common ancestor

A

Homology

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13
Q

What three levels can homology be studied at?

A
  1. Genetic
  2. Developmental
  3. Structural
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14
Q

Genetic homology refers to the similarity in ___.

A

DNA (nucleotide sequences)

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15
Q

Developmental homology refers to similarity in ___.

A

developmental structures or processes that are not present in adult forms

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16
Q

Structural homology refers to ___ and ___ indicating that a group of organisms may share a ____.

A

anatomy and embryology;
common ancestor

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17
Q

A reduced or incompletely developed structure in an organism that has little to no function.

A

Vestigial trait

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18
Q

Vestigial traits are evidence of ___ over time.

A

change

(basically evolution)

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19
Q

Process that results in one species splitting into two or more descendant species.

A

Speciation

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20
Q

Null v.s. Alternative Hypothesis

A

If the null hypothesis is correct, it means whatever you were tested for had no observed effect.

If the alternative hypothesis is correct, it would mean the opposite.

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21
Q

Peer review is an important part of what process?

A

Scientific process/method

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22
Q

Evolution by natural selection was proposed by which two scientists?

A

Darwin and Wallace

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23
Q

Carrying capacity

A

The environment can only support so much of ___

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24
Q

Non-random dating

A

Organisms only mate with other organisms that carry certain traits.

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25
True or False: Genes can be turned off
True, think of vestigial traits. For example, whales and snakes have tiny hip bones that do not help them swim or slither, but their DNA still coded for it.
26
Descent with modification
Evolution
27
Fossils are evidence for ___.
evolution
28
When branches on a phylogenetic tree stop, what does it mean?
It means the animal is extinct.
29
A heritable trait that increases an individual's fitness in a particular environment relative to individuals lacking that trait.
Adaptation
30
Differential reproduction as a result of heritable variation. ## Footnote heritable variation: variety of heritable traits differential reproduction: differences between individuals
Selection
31
True or False Giraffe necks grew longer over evolutionary time because giraffes stretched their necks to reach leaves higher in the treetops.
False. Giraffes who could reach food in higher areas were the ones who could live longer and have higher fitness.
32
True or False You can adapt to the cold temperature in a classroom.
False, adaptations are based on heritable traits so, in this scenario you are ACCLIMATING.
33
True or False Rose plants needed to protect themselves so they evolved sharp thorns.
False, roses have evolved to have sharp thorns because the ones who didn't have that trait, didn't live long enough to reproduce. they were EATENNN
34
True or False Since humans have tailbones, they must be adapted for something
False, this is just evidence for vestigial traits
35
What causes allele frequencies to change randomly?
Genetic drift
36
Occurs when individuals leave one population, join another, and breed.
Gene flow
37
Modifies allele frequencies by continually introducing new alleles.
Mutation
38
Why is genetic drift more likely to happen on an island compared to a large population?
Genetic drift often leads to less diversity and eventually a decrease in population. This would have a greater effect on allele frequencies within a small population (like on an island) compared to a large population.
39
A segment of DNA coding for a trait.
Gene
40
Variations of a gene
Allele (AA, aa)
41
Genetic make-up
Genotype
42
Serves as a mathematical null hypothesis for studying evolutionary processes.
Hardy-Weinberg principle
43
Which hypothesis specifies what the results of an experiment will be if the main hypothesis is wrong?
Null
44
p+q =1
"A" frequency is p "a" frequency is q represents the frequency of two alleles
45
Population genetics focuses on matings among...
individuals in an entire population
46
When allele frequencies don't change, the population is in equilibrium and ___ evolving.
NOT
47
What are the 5 assumptions the Hardy-Weinberg principle makes?
1. Random mating (gametes combine randomly) 2. No natural selection (individuals have equal contribute to the gene pool) 3. No genetic drift (random allele frequency changes) 4. No gene flow (no new alleles added or lost from gene pool) 5. No mutations (no new alleles added to gene pool)
48
What is the Hardy-Weinberg Equation? Break it down.
p^2 + 2pq + q^2 (p^2) --> % of homozygous dom. (2pq) --> % of heterozygous (q^2) --> % of homozygous rec.
49
What is the difference between allele and genotype frequency?
Allele frequency has to do with the frequency of "a" and A". Genotype frequency has to do with the frequency of homozygous recessive, heterozygous, and homozygous dominant.
50
Self-fertilization is the most extreme form of ___.
inbreeding
51
Homozygous parents that self-fertilize produce all ___ offspring.
homozygous
52
Heterozygous parents that self-fertilize produce homozygous and heterozygous in what ratio?
1:2:1
53
This type of selection changes the average value of a trait.
Directional
54
This type of selection increases variation in trait.
Disruptive/Diversifying
55
This type of selection reduces variation in trait.
Stabilizing
56
Sexual selection can lead to sexual ___, which is when traits differ between sexes of the same species.
dimorphism
57
When a group of individuals establish a new population in a new area, ultimately forming a new gene pool.
Founder event
58
The founder effect and bottleneck affect are types of ...
Genetic drift
59
Sudden decrease in population size in large population. Generally caused by disease outbreaks or natural catastrophes.
Population bottleneck
60
What equalizes/homogenizes allele frequencies between source and recipient populations?
Gene flow just think movement of alleles!
61
Mutations are ... a) beneficial b) neutral c) harmful d) possibly all of the above
d
62
Asymmetry of sex
-females can be more picky when it comes to choosing a mate because their investment per offspring is higher -males have to compete for females by signaling their fitness
63
Sexual dimorphism
The physical and behavioral differences between males and females. ex: male peacock feathers are colorful, females are brown/gray ex: male elephant seals are fucking massive compared to the females
64
Honest signals
Indicate individual quality/genetic fitness ex: male peacock color and length
65
Asymmetry of sex leads to...
sexual dimorphism
66
Extinction leads to new...
composition of species
67
Point mutation
Change in a single nucleotide
68
Chromosomal mutation
Change in chromosome structure or number of chromosome, can have significant impact on organism
69
Lateral gene transfer
The movement of genetic material between organisms other than the transmission of DNA from parent to offspring. FOR MICROBIAL EVOLUTION!
70
Whales came from land mammals evidence
Molecular, fossil, structural
71
Modern-day speciation examples
Peppered moths, whales
72
What does Hardy-Weinberg predict about alleles?
They can always change.
73
Inbreeding depression
Leads to reduced biological fitness due to an increased number of homozygotes.

Freshman (semester 2) (7 decks)

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