1
Q
What is Evolution?
A
Descent with modification
2
Q
3 people who proposed populations of organisms changed over time in ancient times?
A
Anaximander (6th Century BC) - species formed from water, humans descended from fish
Empedocles (5th Century BC) - heads, limbs & organs joined at random, only some combinations fit for survival
Plato (4th Century BC) - each natural object in observed world is imperfect manifestation of ideal
3
Q
Describe the Theory of Special Creation
A
- Created by a Deity
- Species created independently of one another
- Species remain unchanged since their creation
- Variability within a species is minor/limited
- Creation event occurred 26th October 4004 BC @ 9:00 am
4
Q
Who proposed the Theory of Special Creation?
A
Archbishop James Ussher (1581 - 1656)
5
Q
Who is Carolus Linnaeus and what did he do?
A
Swedish naturalist, classified plants based on morphology into Kingdom, Classes, Orders, Genus & Species
Introduced system of nomenclature for species identification (genus name + species name - used to this day)
6
Q
What did Erasmus Darwin contribute to the Theory of Evolution?
A
“The final course of this contest among males seems to be, that the strongest & most active animal should propagate the species which should thus be improved”
7
Q
What did Jean Baptiste Lamarck contribute to the Theory of Evolution?
A
Lamarckism - all species derived by gradual change from other species, inheritance of acquired characteristics
Organs become improved if used a lot, reduced to vestiges from disuse. Require bodily changed have a way to be registered in germ cells
8
Q
Difference between Catastrophism and Uniformitarianism
A
Catastrophism - biblical interpretation of the history of the Earth (Earth created by supernatural means approx. 6000 years ago)
Uniformitarianism - modern view of Earth’s history (unimaginably old, landforms result of geological processes still occurring today - James Hutton)
9
Q
What did Charles Lyell contribute to the Theory of Evolution?
A
Challenged prevailing beliefs regarding Earth’s history & age - argued Earth is hundreds of million of years old - geology created by natural forces
10
Q
3 observations from Darwin’s trip down the East coast of South America
A
- Species can/do go extinct (fossils of animals no longer extant in region)
- Species have ancestors & change through time (fossils of animals in region different from modern day equivalents)
- Species differ across space/geographical distance (travelling North to South, species replaced by similar, but slightly different species)
11
Q
What are the 2 model organisms Darwin used in the Galapagos?
A
- Tortoises
- Finches
12
Q
What are Vestigial Organs?
A
Functionless/rudimentary versions of a body part that has an important function in other, closely allied species
13
Q
What is Homology?
A
The same organ in different animals under every variety of form and function
14
Q
What is Artificial Selection?
A
Over time humans have modified species to suit their needs through careful breeding programs - “caused” evolution of several species from single ancestral species
15
Q
What was Thomas Robert Malthus’ main idea?
A
Reproductive capacity of human population exceeds food supply available to nourish expanding population, humans compete among themselves
Struggle exists in nature - constitute “natural” selection process
16
Q
What is Wallace’s Line?
A
Line separating Indonesian islands (species different on either side)
17
Q
When was “The Origin of Species” published?
A
24th November, 1859
18
Q
What is the Linnean Society of London?
A
Forum of discussions on genetics, natural history, systematics, biology & history of plant/animal taxonomy
19
Q
Regarding his theory of natural selection what two pieces could Darwin not explain?
A
- How a given trait is transmitted from parent to offspring?
- Where/how new traits suddenly appeared?
20
Q
What are the 2 principles of Gregor Mendel’s work?
A
- Principle of Segregation - each gamete can carry only one allele from a parent at a given gene
- Principle of Independent Assortment - segregation of members of one pair of alleles occurs independently of the segregation of the members of another pair of alleles during gamete formation
21
Q
Simple definition of Microevolution
A
Species change over time
22
Q
Simple definition of Speciation
A
Lineages split & diverge
23
Q
Simple definition of Macroevolution
A
New lifeforms derive from older forms
24
Q
Simple definition of Common Ancestry
A
All lifeforms are related
25
What are 2 examples that show Microevolution?
1. Selective Breeding (Artificial Selection)
2. Vestigial Structures
26
What is the Biological Species Concept?
Species are populations, or groups of populations within and among which individuals actually or potentially interbreed and outside of which they do not interbreed
27
What 2 examples show the existence of Macroevolution?
1. Extinction & Succession
2. Transitional Forms
28
Difference between Homology & Analogy
Homology - if they are derived, evolutionarily & developmentally, from the same source structure
Analogy - if they have similar functions but are derived evolutionarily & developmentally, from different source structures
29
What is the definition of Evolution?
Change in genetics/allele frequency in a population over time
30
What are the 5 mechanisms of Evolution?
1. Natural Selection
2. Mutation
3. Genetic Drift
4. Gene Flow
5. Non-Random Mating
31
What are the 4 postulates of the Theory of Evolution by Natural Selection?
1. Individuals of a population differ from one another
2. The differences are, at least in part, passed from parent to offspring
3. Some individuals are more successful at surviving & reproducing than others
4. The more successful individuals are not merely lucky; instead, they succeed because of the variant traits they have inherited & will pass to their offspring
32
What does natural selection act on?
Phenotypes
33
What is Fitness?
Ability of an individual to survive & reproduce in its environment
34
What is fitness compared to?
Relative to fitness of other members of a population
35
What is an Adaptation?
A trait that increases the ability of an individual to survive & reproduce compared with individuals without that trait
36
What is a Trait?
Any characteristic of an individual ranging from outward appearance to molecular characteristics
37
General Summary of Natural Selection
Alleles associated with higher fitness increase in frequency from one generation to the next
38
What is Differential Selection?
Probability of surviving is linear with an increase or decrease in a trait
39
What is Stabilizing Selection?
Probability of surviving increases closer to the mean
40
What is Disruptive Selection?
Probability of surviving increases with departure from the mean
41
Where are the 3 ways variation in an individual can occur?
1. Environmental Variation - phenotypes different from exposure to different environments (epigenetic)
2. Genetic Variation - different genotypes cause different phenotypes
3. Genotype by Environment Interaction
42
What is Phenotypic Plasticity?
Refers to the fact that genetically identical individuals can have different phenotypes in different environmental conditions
43
What is the Reaction Norm?
Refers to the pattern or range of phenotypes that the same genotype can possess as a result of different environments
44
What is the ultimate source of genetic variability?
Mutations
45
What kind of impact do mutations have on their own to population allele frequencies
Low
46
2 main causes of mutation
1. Mutation due to DNA alteration
2. Mutation due to DNA copying error
47
What is a Point Mutation? And what does it result in
Single base pair changes resulting in new alleles
48
What is a Transition & Transversion? And what is more common?
Transition - purine --> purine, or pyrimidine --> pyrimidine
Transversion - purine --> pyrimidine (vice versa)
Transitions are more common
49
3 mutations resulting from point mutations
1. Synonymous - no change in amino acid (due to redundancy in genetic code)
2. Non-Synonymous - change in amino acid
3. Nonsense - premature STOP (non-functional protein)
50
2 methods of new gene formation
1. Gene Duplication
2. Derived from Scratch
51
2 Mechanisms of Gene Duplication
1. Unequal Crossing Over - have same introns as original gene, and occur in tandem with original gene
2. Duplication by Retroposition - new copy of existing gene, usually a pseudogene, can gain function with addition of regulatory sequence
52
2 Types of Chromosomal Mutations
1. Inversions - gene order flipped
2. Genome Duplication - polyploidization
53
Is mutation rate subject to evolution?
Yes, replication machinery subject to natural selection
54
3 ways of determining genotypes
1. Infer Genotype Based on Phenotype
2. Examine Proteins Encoded by Alleles (electrophoresis)
3. Examine the DNA Itself (PCR & gel electrophoresis)
55
5 Assumptions of Hardy-Weinberg Principle
1. No Selection
2. No Mutation
3. No Gene Flow
4. No Genetic Drift (large population size)
5. Random Mating
56
What does Panmictic mean?
Sexually reproducing population where each male has an equal probability of mating with each female and vice versa
57
What 2 principles are brought forth from the H-W Principle?
1. Genotype frequencies can be predicted from allele frequencies
2. Allele frequencies will remain stable in a population over time
58
What is the H-W Equation?
p^2 + 2pq + q^2 = 1
59
Selection is ____ when a recessive allele is common & lethal
Selection is _____ when a recessive allele is rare & lethal
Rapid
Slower
60
What is Heterozygote Advantage
The fitness of the heterozygotes is greater than any homozygote
61
What is Frequency Dependent Selection?
The frequency of the rarer allele will increase, while the frequency of the abundant allele will decrease
62
What is Mutation-Selection Balance?
When the rate at which new copies of a deleterious allele are produced by mutation equals the rate at which selection removes them
63
What is Gene Flow?
The transfer of alleles from the gene pool of one population to the gene pool of another
64
What does Gene Flow tend to do to allele frequencies?
Tends to homogenize allele frequencies - prevent divergence and decrease population level impact of natural selection
65
What is Fst?
Fixation index - measure of population differentiation
Values range from 0 - 1
0 = all populations have identical allele frequencies
1 = no alleles shared among populations
66
What does Gene Flow do to Fst?
Reduces Fst
67
What is Genetic Drift?
Random, unpredictable changes in allele frequencies from one generation to the next
68
What happens to the rate of Genetic Drift as population size decreases?
Increases
69
Does Genetic Drift lead to adaptation?
No
70
What 2 things does Genetic Drift usually lead to?
1. Fixation or Loss of Alleles
2. Decline in Heterozygosity
71
What is Effective Population Size?
Ideal theoretical population size that would lose heterozygosity at the same rate as the actual population size?
72
Why is Effective Population Size always lower than actual?
Not all individuals in a population will pass on alleles to the next generation
73
2 Events that can cause Genetic Drift
1. Founder Events
2. Bottleneck
74
4 forms of Non-Random Mating
1. Inbreeding - closely related
2. Outbreeding - non-closely related
3. Positive Assortative Mating - between individuals with similar phenotype
4. Negative Assortative Mating - between individuals with dissimilar phenotypes
75
Does inbreeding effect genotype of allele frequencies?
Genotype Frequencies - increases rates of homozygosity
76
What is Inbreeding Depression?
Reduction in average fitness of individuals within a population due to inbreeding
77
What does Inbreeding Depression result from?
1. Exposure of recessive deleterious alleles to selection and/or
2. Loss of heterozygote advantage
78
What is Phylogenetics?
The study of ancestor descendant relationships. The objective of phylogeneticists is to construct phylogenies
79
What are Phylogenies?
Hypothesis of ancestor-descendant relationships based on some character
80
What is Pleisomorphy?
Refers to the ancestral state
81
What is Apomorphy?
Character state different than the ancestral state (derived state)
82
What is Synapomorphy?
Derived character state shared by 2 or more taxa due to inheritance from a common ancestor (phylogenetically informative)
83
What is Autapomorphy?
Uniquely derived character state
84
What is a Monophyletic Group?
Consists of an ancestor and all of its descendants (clade)
85
What is a Paraphyletic Group?
Consists of a common ancestor & some, but not all of the descendants
86
What is a Polyphyletic Group?
Consists of some of the descendants of as common ancestor, but not all, & also excludes the common ancestor
87
What identifies monophyletic groups?
Synapomorphies
88
What is Homoplasy?
Describes similarity of character state due to independent evolution
89
3 Ways Homoplasy can occur
1. Parallel Evolution - independent evolution of same feature from same ancestral condition
2. Convergent Evolution - independent evolution of same feature from different ancestral condition
3. Secondary Loss - reversion to ancestral condition
90
What is Parsimony?
The simplest scientific explanation to fit the evidence is preferred
91
What is the Molecular Clock?
Some types of DNA sequences change in a regular fashion, neutral changes in DNA should accumulate in populations at a rate equal to the mutation rate
If mutation rate stays constant & generation times remain similar, # of neutral molecular differences between 2 taxa should be proportional to the age of their most recent common ancestor
92
3 Notes on Adaptations
1. Not all variation among populations is adaptive
2. Not all traits are adaptive
3. Not all adaptations are perfect
93
4 Limitations on Adaptations
1. There is only so much energy to invest in traits
2. There are constraints (morphological, physiological) that limit trait variation
3. There is limited genetic variation
4. There are ecological constraints
94
What is Life History?
The pattern of allocation of time & energy to various fundamental aspects of life including growth & reproduction
95
What is Parthenogenesis?
Asexual reproduction where offspring develops from unfertilized eggs
96
What are Hermaphrodites?
Have both male & female sex organs & are capable of self-fertilization
97
3 Sexual Reproduction Advantages
1. Where father provide support for care of offspring, females can produce more offspring
2. Meiosis with crossing over - genetic diversity
3. Mating between unrelated individuals
98
What is Sexual Dimorphism?
Differences between males & females of a species
99
Why is there Sexual Dimorphism?
Explained by sexual selection - if there is heritable variation in a trait that affects the ability to obtain a mate, then these successful variants will increase in frequency
100
What is the main difference between Natural and Sexual Selection?
In sexual selection, individuals compete against other members of the same sex, instead of against all other individuals in the population
101
What is Sexual Selection driven by?
Must act on sexes differently
Driven by difference in reproduction allocation
102
What is Reproduction Allocation?
How much energy invested into producing a gamete (females are usually much higher than males)
103
If the goal is to have as many offspring as possible, how do females and males go about this?
Females - mate once per breeding season
Males - mate multiple times per breeding season
104
How should males act & how should females act when it comes to mating?
Males should be competitive
Females should be choosy
Function of reproduction allocation
105
4 Examples of Male-Male Competition
1. Combat
2. Alternative Mating Strategies
3. Sperm Competition
4. Infanticide
106
4 reasons why a female should be choosy
1. Acquiring genes for her sons that will make him attractive
2. Acquiring genes for her offspring that confer general fitness benefits
3. Acquire resources
4. Prefer mates that exploit pre-existing sensory biases of nervous system
107
Can behaviour be inherited?
Yes
108
4 Kinds of Social Interactions
1. Mutual Benefit (++)
2. Selfishness (+-)
3. Altruism (-+)
4. Spite (--)
109
4 Parts of Hamilton's Rule
1. An individual is rarely the sole repository of his/her alleles
2. Individuals that are closely related are likely to carry alleles that are identical by descent
3. Therefore, it's possible that the behaviour of individuals towards others has the potential to influence the probability of passing copies of their alleles to the next generation
4. Key parameter is relatedness of actor & recipient
110
What is Hamilton's Rule Equation?
Br - C > 0
111
What are the r values for a Half-Sibling? Sibling? Cousin?
Half-Sibling = 1/4
Full Sibling = 1/2
Cousin = 1/8
112
What is Direct Fitness?
An individual's direct contribution to the next generation by reproduction (# of offspring contributed)
113
What is Indirect Fitness?
Additional reproduction by relatives that results from an actor's actions
114
What is Inclusive Fitness?
Direct Fitness + Indirect Fitness
115
What is Kin Selection?
Natural selection leading to the spread of alleles that increase indirect fitness
116
What are 3 examples of Parent-Offspring Conflict?
1. Weaning Conflict - towards end of nursing, mothers decrease nursing, but offspring demand care
2. Recruitment as Helpers
3. Siblicide - should occur if the individual killing the other gains enough direct fitness benefits by removing competition for food to outweigh the indirect costs of killing a sibling
117
What is Reciprocity?
Exchange of favours among non-kin
118
Reciprocity is most likely to evolve under 4 conditions
1. Repeatedly interact with one another
2. Have many opportunities to return favours
3. Sometimes need a favour & sometimes can offer a favour
4. Have good memories
119
What is the Morphospecies Concept?
Based on careful analysis of phenotypic differences in morphology
Problems:
- Criteria applied differently by different researchers
- Species of unicellular organisms might not have measurable morphological characters
120
What is the Phylogenetic Species Concept?
Species are the smallest monophyletic groups, species must have been evolutionarily independent for long enough for diagnostic traits to have evolved, populations within species must have shared derived traits
Problems:
- Which traits are worthy of being used to construct phylogeny?
- Accepting this approach likely to increase number of recognized species
121
What is the Biological Species Concept?
Based upon reproductive isolation
Problems
- How does one determine whether individuals are reproductively isolated if their range doesn't overlap?
- Reproductive isolation can't be tested for fossils or asexual species
122
5 Prezygotic Barriers
1. Habitat Isolation - don't meet
2. Behavioural Isolation - no sexual attraction
3. Temporal Isolation - mating occurs at different times
4. Mechanical Isolation - structural differences in genitalia
5. Gametic Isolation - gametes fail to attract or are inviable
123
3 Postzygotic Barriers
1. Reduced Hybrid Viability - zygote fails to develop or reach sexual maturity
2. Reduced Hybrid Fertility - hybrids fail to produce functional gametes
3. Hybrid Breakdown - offspring of hybrids have reduced viability/fertility
124
3 Stages of Speciation
1. Isolation - limited gene flow among populations
2. Divergence in Traits
3. Reproductive Isolation
125
What is Allopatry?
When the range of 2 populations don't overlap
126
What 2 ways can Isolation occur?
1. Physical Separation
2. Genetic Events (Polyploidization)
127
What 2 ways can Physical Separation occur?
1. Dispersal & Colonization (Founder Event)
2. Vicariance Events (split species distribution)
128
What are 3 ways Divergence in Traits may occur?
1. Genetic Drift - role is questioned
2. Natural Selection - most important if one population subjected to new environment
3. Sexual Selection - if mutation occurs in one population that causes selection of mates based upon different characteristic
129
What constitutes Complete Reproductive Isolation?
Natural Selection produced adaptation for different environment
Genetic Drift led to fixation of alleles, inviable in heterozygous conditions
Sexual Selection produced changes in mating system
- Hybrid offspring have lower fitness
- Selection favours individuals that choose mates from same population
130
BIOL 359
flashcards
Decks in class (1)
# Cards
