Unit One- Evolution (Chp. 16, 17, 18) Flashcards
1
Q
Evolution
A
change occurring in a line of decent over time
2
Q
Evolution may occur due to:
A
Natural Selection
Artificial Selection
3
Q
Natural Selection
A
found in nature
4
Q
Artificial Selection
A
impacted by man or mans activities
5
Q
We know Evolution Exists by the study of:
A
Anatomy
Embryology
Biogeography
Molecular Biology
6
Q
We know Evolution exists by the presence of:
A
Genetic variation within species
Transitional forms in fossil record
Imperfection and vestigial structures
Antibiotic resistant bacteria
7
Q
Individuals of a population vary in __, ___, __, due to genetic differences which are heritable
A
Form, function, and behavior
8
Q
Some traits (defined by genetics) are ____ ____ to the changing environment than others
A
More Adaptive
9
Q
More offspring are produced than are able to survive so resources for survival and reproduction are ___
A
Limited
10
Q
Inherited characteristics that allow offspring to best compete for limited resources will survive and reproduce have variations that are _____ favorable.
A
More
11
Q
Results of differences in _____ and _____ leads to Natural Selection
A
Survival
Reproductive rates
12
Q
Over time, Natural selection produces organisms that are “better fit” for the prevailing conditions, meaning
A
“Survival of the Fittest”
13
Q
A population
A
a group of individuals of the same species that live in an area in which they can survive and interbreed
14
Q
a ___ evolves, NOT an _____
A
population
individual
15
Q
Evolution can only occur if there is _____
A
Variation (could refer to genes, nature or both)
16
Q
An Adaptation
A
a heritable trait that helps the survival and/or reproduction of an organism in its present environment
(ex. white winter coat of an artic fox)
17
Q
Charles Darwin
A
a naturalist who was part of a survey expedition and proposed the idea of evolution and natural selection in his book On The Origin of Species
18
Q
Alfred Wallace
A
studied wildlife and independently came to the same conclusion of Darwin and presented his hypothesis in 1858
19
Q
What causes Genetic Variation?
A
different alleles of shared genes are the basis of variation within a population
20
Q
Dimorphic traits
A
traits with two distinct forms
(ex. purple and white flower colors in pea plants)
21
Q
Polymorphic traits
A
have more than two distinct forms
(ex. blood types in humans)
22
Q
Mutations
A
a change in DNA patterns (the raw material of evolution)
23
Q
Mutations occur at ____ rates for each species
A
definite
(ex. in humans each child is born with an average of 64 new mutations in the ~20,000 genes present)
24
Q
Mutation types:
A
Neutral mutation
Lethal mutation
Beneficial mutation
25
Neutral mutation:
has no effect on survival or reproduction
26
lethal mutation:
results in death
27
beneficial mutation:
bestows a slight advantage toward survival or reproduction
28
Sources of Mutations
random genetic changes
crossing over at meiosis I
independent assortment as meiosis I
fertilization
29
random genetic changes
creates new alleles in sperm or egg that is transmitted to the next generation
30
crossing over at meiosis I
mixes up maternal and paternal alleles on homologous chromosomes for forthcoming gametes
31
independent assortment at meiosis I
randomly distributes homologous chromosomes into gametes
32
fertilization
combines alleles from two different individuals creating organisms with genes unlike either parent
33
gene pool
the sum of ALL of the genes in a population
34
allele frequency
the rate at which a specific allele appears within a population
35
microevolution
change in allele frequency in the gene pool of a population or species
(always occurring in natural populations due to mutations/natural selection)
36
macroevolution
large scale evolutionary pattern above the species level
37
The Galapagos Finches
studied by Darwin and also present day as a demonstration of Evolution
38
Divergent Evolution
changes in body form (morphological divergence) from a common ancestor
(ex. homologous structures)
39
homologous structures
structures in organisms that share the same basic form but appear in separate lineages because they evolves from a common ancestor
(ex. limbs in human, dog, bird, or whale)
40
vestigial structures
structures that exist in organisms but have no apparent function at all
(ex. appendix, remnants of pelvis in snakes, wings that don't fly, eyes that don't see)
41
body parts that appear similiar in different species are __ ____ homologous
Not Always
42
convergent evolution
when similar traits evolve independently in species that do not share any recent common ancestry
43
analogous structures
look alike but evolved independently
(ex. wing of bird, bat, and butterfly)
44
transitional forms
an intermediate form of an organism linking two other organisms together
45
Patterns of Natural Selection:
Directional selection
Stabilizing selection
Disruptive selection
46
Directional selection
an extreme trait is more favorable
47
stabilizing selection
an intermediate trait is more favorable
48
disruptive selection
extremely different traits are more adaptive
49
a selective pressure that can shape form and behavior
competition for mates
50
sexual dimorphism
traits that differ between males and females (occurs in plants and animals)
due to sexual selection
51
sexual selection
individuals with features (courtship displays) that better attract mates out-reproduce others
(females choose the mate/mates or males compete for access to females)
52
balanced polymorphism and the heterozygote
two or more alleles continue circulating at a relatively high frequency in a population)
can arise in environments that favor heterozygous individuals
(ex. individuals that are heterozygous for sickle-cell anemia are resistant to malaria but don't suffer from sickle-cell anemia)
53
genetic variance
the diversity of alleles and genotypes within a population (maintained with sexual reproduction- asexual production leads to clones)
54
Non-Selective Evolution
Evolution by Chance
55
genetic drift
random change in an allele's frequency over time by chance alone (right place at the right time or wrong place at the wrong time)
56
bottleneck
results when a large portion of the genome suddenly gets wipe out- drastic reduction in population size can reduce genetic diversity
57
founder effect
a small group establishes a new population and the genetic structure changes to match the new populations founders
(if founding group does not have high alleles variation neither will the new population)
58
fixed allele
condition when all individuals of a population are homozygous for an allele (common among small population- will not change unless a mutation occurs or individual with another allele enters the population)
59
gene flow
movement of alleles between populations
can result in change or stabilization of allele frequencies
60
selective and non-selective evolution can lead to ____
speciation
61
Speciation
an evolutionary process in which new species form
(occurs when populations crossbreed, increases the number of genetic differences)
**populations that have already diverged may come together and interbreed again
62
How do Species Become Seperated:
Allopatric Speciation
Parapatric Speciation
Sympatric Speciation
63
Allopatric speciation
arises from physical separation between populations
(reproduction isolation, geographic isolation)
64
reproduction isolation
biological or physical barriers to gene flow
(influenced by how an organism reproduces-can prevent interbreeding even if populations meet again)
65
geographic isolation
physical geographical barriers to gene flow
(influenced by how species travels)
66
prezygotic barriers
obstacle to mating or to fertilization of mating occurs
(geographic isolation, ecological isolation, temporal isolation, behavioral isolation, mechanical isolation, genetic isolation)
67
postzygotic isolating mechanisms
act after fertilization to prevent successful reproduction
68
hybrid invisibility
the fertilized egg may fail to develop properly
fewer young may be produced and may have a low viability (survivability)
69
hybrid sterility
hybrid of two species may be viable but sterile
(ex. mule)
70
hybrid breakdown
first generation may be fertile but subsequent generations are infertile or non-viable
71
sympatric speciation
populations inhabiting same region speciate in the absence of a physical barrier between them
(may occur when the chromosome number multiples, organisms choose different environments)
72
parapatric speciation
creates a hybrid that is often sterile
73
hybrid
a cross between 2 different species that are similar (different species may have different genes active during development so may not be possible to develop viable offspring)
ex. horse and donkey, african eagles and bald eagle, lion and tiger
74
adaptive radiation
organisms that do not go extinct may undergo adaptive radiation- one lineage rapidly diverges into several new species, usually a result of a changing environment
75
key innovation
new trait that allows one organism to exploit a habitat more efficiently or in a new way
(ex. hawaiian honeycreepers)
76
coevolution
two species evolve jointly because of a close ecological connection
(ex. Yucca plant and Sphnx Moth)
co-evolution= symbiosis/mutualism
77
4 Basic Misconceptions of Evolution
1. Evolution was mischaracterized as theory when it was actually a hypothesis
2. Individuals evolve
3. Evolution explains the origin of life
4. Organisms evolve with purpose
78
Hardy-Weinberg Equilibrium
states that a population's allele and genotype frequencies will remain constant in the absence of evolutionary mechanisms
79
genetic equilibrium can only occur under these ideal conditions:
no mutation
no gene flow
large population size
random mating
no natural selection
80
Which of the following defines an adaptation?
a) the results of differences in survival and reproductive rates
b) genetic variation within species
c) an inherited trait that helps the survival and/or reproduction of an organism
d) change occurring in a generation over time
c) an inherited trait that helps the survival and/or reproduction of an organism
81
The basis of variation of characteristics within a species is due to:
a) mutations of differing types
b) genetics
c) homologous structures
d) both a and c are correct
d) both a and b are correct
82
Which of the following evolve
a) mutations
b) populations
c) individuals
d) none of the above
b) populations
83
Evolution can only occur if there are
a) mutations
b)variation in nature
c) variation in genes
d) all of the above are correct
d) all of the above are correct
84
A change in the allele frequency in the gene pool of a population or species is called
a) allelle frequency
b) macroevolution
c) genome
d) microevolution
d) microevolution
85
Homologous structures are proof of
a) evolution from a common ancestor
b) convergent evolution
c) divergent evolution
d) both a and c are correct
d) both a and c are correct
86
When intermediate forms of a trait are selected against and 2 extremes of a trait are selected for this results in
a) directional selection
b) stabilizing selection
c) disruptive selection
d) transitional forms
c) disruptive selection
87
When organisms have phenotypic traits that differ between sexes this is called
a) sexual reproduction
b) sexual dimorphism
c) sexual isolation
d) sexual attraction
b) sexual dimorphism
88
When environmental pressures favor a heterozygote genetic makeup because the resultant trait makes an organism more successful in the environment it is called
a) incomplete dominance
b) genetic variance
c) dimorphism
d) balanced polymorphism
d) balanced polymorphism
89
When a large portion of the genome suddenly becomes wiped out it is called the
a) founder effect
b) bottleneck effect
c) gene flow
d) fixed allele
b) bottleneck effect
90
Which of the following describe evolutionary processes in which new species form
a) selective
b) non-selective
c) called speciation
d) all of the above are correct
d) all of the above are correct
91
Speciation that results from physical separation between populations within a species is called
a) allopatric speciation
b) sympatric speciation
c) parapatric speciation
d) speciation
a) allopatric speciation
92
Which of the following are examples of prezygotic reproductive isolation
a) birds using a different song to attract mates
b) sexual organisms not having a "perfect fit" for reproduction
c) organisms that rely on one another for fertilization are not active at the same time of day because of seasonal changes
d) all of the above are correct
d) all of the above are correct
93
Which of the following are reasons for the morphological change in elephants from being tusked to not being tusked?
a) because humans are killing tusked elephants for ivory
b) because tusks are no longer needed in the prevailing environmental conditions
c) because elephants without tusks are surviving better compared to elephants with tusks
d) both a and c are correct
d) both a and c are correct
94
Hardy-Weinberg Equilibrium states that genotype frequencies will remain constant in the absence of
a) mutations
b) gene flow
c) natural selection
d) all of the above must be present for equilibrium to occur
d) all of the above must be present for equilibrium to occur
