unit test 2 (Ch.18-20) Flashcards
(126 cards)
1
Q
What are taxons?
A
A way to classify the diversity of organisms
2
Q
What do taxons include?
A
kingdom-King
Phylum-Phillip
Class-Cried
Order-Out
Family-For
Genus-Good
Specis-Sex
3
Q
How was it determined that the earth was a lot older than originally thought (Think James Hutton)?
A
erosion work over long periods of time in geology
4
Q
What did Malthus identify?
A
That the human population could outgrow their supply of food
5
Q
what was a consequence of Malthus’ claim?
A
population growth was slowed
6
Q
what did Lamarck propose?
A
organisms could change over time based on 2 principles
7
Q
what are the 2 principles that Lamarck proposed about the changing of organisms?
A
-Use and disuse
-Inheritance of acquired traits
8
Q
What is an example of use and disuse of an organisms physical properties?
A
A giraffe’s neck could elongate if a food source was out of reach
9
Q
How did Darwin come up with his claim that the earth is much older than we think?
A
-geologicl processes occur very slowly
10
Q
What did Darwin say about populations and their food?
A
if populations grew faster than their food supply, this applied to animals as well. This could influence subsequent generations to be more suited to their environments.
11
Q
What did the inheritance of traits from 1 generation to the next imply?
A
Organisms become better suited to their environments as the environments themselves change
12
Q
Where did darwin find most of his evidence for adaptations, ‘inheritance characteristics that improve survival in an environment and increase reproductive success’?
A
Galapagos islands
13
Q
What was the 2 main ideas of Darwin’s theory?
A
-Natural selection
Descent with modification
14
Q
What are the pressures that Darwin considered on organisms in an environment ?
A
-resources are finite and limit population growth (next generation won’t thrive)
-Limited resources can lead to organisms to struggle to survive (Organisms will fight for their life)
-Characteristics of individuals in a population vary greatly (no one is exactly the same in characteristics)
-Not all individuals in a pop. will reproduce succesfully (organisms better suited to their environment –> leave behind better offspring more suited to their environment = Fitness)
15
Q
what does fitness mean in evolution?
A
Reproductive success of an individual
16
Q
Greater fitness means that the organism will leave…
A
More offspring tha individuals that display less fitness
17
Q
Over generations, traits providing adavantages in a given environment will accumulate in a population. What is this called?
A
natural selection = survival of the fittest
18
Q
What does it mean when the generations are slightly different that the genrations before that?
A
descent with modification
19
Q
does evolution work on individuals?
A
No only on populations
20
Q
does evolution act on traits that aren’t heritable?
A
No only heritable traits
21
Q
what is an example of evidence for evolution?
A
Soapberry bugs feed on fruit with the help of beak length
-If beak length is variable and heritable, we might expect beak length to vary in 2 populations (1 in south Florida and 1 in central Florida) which they do!
22
Q
what is homology?
A
describes a characteristic that is similar between organisms as a result of common ancestry
23
Q
What causes the characteristics of organisms to be no longer identical?
A
adaptive radiation
24
Q
what is adaptive radiation?
A
where organisms evolve and adapt to new environments, causing modifications to original characteristics.
25
what is an example of adaptive radiation?
human, cats, whales and bats all display similar bones in their limbs; humerus, ulna, radius, carpals, metacarpals..
26
what is an example of homologous structures?
**embyos** of varius animal species;
embryos of fish, amphibians, reptiles and mammals display **similar structures early in development **which **develop into homologous structures** in adulthood
27
what are analogous structures?
characteristics that are similar between ***unrelated*** organisms
28
do analogous structures evolve from common ancestry?
no, they eveolve from **similar selective** **pressures **from their ***environment***
29
What is an example of analogous structures?
the wings of bats, birds, and insects:
**common ancestors** of these organisms **did not** **have wings** but* selective pressures* in the **environment** caused them to **evolve wings**
30
What was Pangaea?
Supercontinent, all continents put together
31
what supports the theory of Pangaea?
Fossil record and carbon dating these fossil
32
what is a population?
**all individuals** of the same species that live in a particular **place** at the **same** **time**
33
do individuals in a population vary in their traits?
yes
34
how does variation occur in a population?
**selective pressures** from the **environment** and** inheritance of genes**
35
how is evolutionary change inherited?
1 generation to the next
36
what do individuals of a population share? (think genetics)
same **number** of genes
37
since there is a lot of variation in populations and individuals in a population share the same number of genes, what is an important cause of the variation which is linked to their genes?
alleles
38
what is a gene pool?
**all** **alleles** for **all** **genes** present in a **population**
39
True or False? diploid organisms can have 3 alleles for each gene
no, it can only have up to 2 alleles
40
do the 2 alleles of diploid organisms represent all the possible alleles for a gene?
no, there are more possible alleles for that gene
41
what is microevolution?
Includes
-**creation of new alleles** from **mutations**
-the **change** in **proportions** of **alleles** in a **population's gene pool** from **1 generation** to the **next**
42
what is a basic (easy) defenition of microevolution?
if **proportion** of individuals of any **genotype** **changes** from **1 generation** to the **next**
43
what is genotype frequency?
**proportion** of a **specific genotype** in population
Ex: there are 490 individuals with the genotype AA in a population of 1000 so the genotype frequency is 0.49
44
what is an allele frequency?
**proportion** of a **specific allele** in a population
Ex:
-490 AA
-420 Aa
so 490 x2 + 420=1400
total number of alleles in this population is 2000 (All A & a's)
allele frequency = 1400/2000= 0.7
45
What does it mean if the allele frequency is changing over generations?
evolution is occuring
46
how do allele frequencies change?
influence of outside factors
47
what does Hardy-Weinberg Principle explain?
if **allele & genotype *frequencies*** do NOT change over time, population is NOT evolving
48
what do we say if there is no change in allele or genotype frequency?
populaion is at **equilibrium** and NOT evolving
49
Is it rare for a population to be in Hardy-Weinberg equilibrium?
Yes, because microevolution includes ANY force or pressure that could CHANGE proportion of alleles or genotypes in 1 generation to the next
50
what could prevent a population from evolving? (5)
-no mutations
-Random mating
-No natural selection
-having an extremely large population size
-no migration (transfer of alleles from another population)
51
What does 'p' represent in H-W equation (p+q=1)
p= frequency dominant allele
52
what does 'q' represent in H-W equation (p+q=1)
q= frequency of recessive allele
53
Say there is
-320 C^RC^R
-160 C^RC^W
-20 C^WC^W
what is 'p' in H-W equation?
C^R is the dominant allele...
p= frequency of dominant allele
320x2 (C^RC^R)=640
+160(C^R)
=800/1000 (pop.)
=0.8 is 'p'
54
what is p^2 in the H-W equation
(p^2 + 2pq + q^2 = 1)
p^2 = AA freq
(homozygous dominant)
55
what is 'pq' in H-W equation ?
(p^2 + 2pq + q^2 =1)
pq= Aa freq
(heterozygous)
56
what is 'q^2' in the H-W equation?
(p^2 + 2pq + q^2 =1)
q^2= aa freq
(homozygous recessive)
57
What equation do we use for **the allele frequencies** for a **gene** with only **2 alleles**?
p + q =1
58
what type of equation do we use for expected genotype frequencies?
p^2 + 2pq + q^2 =1
59
what factors cause microevolution? (5) (think opp of what causes no variation through generations)
-Mutations
-Choice of mating partners
-natural selection
-Genetic drift
-Gene flow from migration
60
what do mutations cause?
changes in genetic sequences --> new alleles
61
what does natural selection cause?
selects best suited individuals (survival of the fittest)
62
What does fitt mean in evolution terms?
best suited individuals will often be chosen for mating because they create better offspring
63
what is the cause of genetic drift?
a random sample of a small group of organisms from a large population
64
what is the cause of gene flow?
**flow of alleles** into or out of a population VIA** migration**
65
what is sexual recombinations?
produces new combinations of alleles--> produce genetic variation that natural selection relies on
66
if in 1 generation the allelic frequency is 0.7 for genotype C^R and changes in generation 2 to 0.5 then to generation 3 being 1, what type of **factor** is causing this type of evolutionary change?
genetic drift
67
what are 2 examples of genetic drift?
-Bottleneck effect
-Founder's effect
Both randomly **change** the **frequency of alleles**
68
true or false? Genetic drift simply randomly selects individuals from a larger population to continue perpetuating species
true
69
what is the bottleneck effect?
genetic drift example that happens when the **number** of **individuals in a larger population** is **drastically reduced by a disaste**r.
70
what is the founder's effect?
genetic drift example that happens when **individuals** become **isoalted from a larger population **
71
Does gene flow cause a population to gain alleles or lose?
Both. 1 population might gain some and the other might lose Vise-versa
72
In gene flow, what does the mixing of individuals from different populations result in?
reduces differences between populations over time
73
what is the only factor that can cause adaptive evolution?
**natural selection **leads to **adaptation **of an organism to it's **environment**
74
what is macroevolution?
combination of **positive mutations** and **natural selection**
75
will natural selection create entirely new genotypes?
no, it will only **i****ncrease the frequencies** of certain genotypes
76
true or false? natural selection increases the frequency of **beneficial alleles**?
yes
77
how does natural selection increase the frequency of beneficial alleles?
1-beneficial alleles arise due to a mutation
2-natural selection occurs --> proportion of alleles in gene pool increase
3-Beneficial allele eventually replace all other alleles in a population
78
what is a negative selection?
natural selection that **decreases** **frequency** of **harmfu**l allele
79
what is a positive selection?
natural selection increases the frequency of a favorable allele
80
what effects can natural selection have on the distribution of phentoypes in a population? (3)
-directional selection
-disruptive selection
-stabilizing selection
81
what is directional selection?
-shifts a population's phenotypic traits in 1 direction or the other of a curve
-population's environment changes or members of a population migrate to new habitat.
82
an example of directional selection?
resistance of microbes to antibiotics: Antibiotics selects for microbes that already have resistance which make the bacteria multiply and thrive..not good
83
what is Disruptive selection?
when **conditions favor** individuals at both extremes of **phenotypic range** for example
small-billed birds feed on soft seeds but large-billed birds specialize in cracking hard seeds
84
What is stabilizing selection?
**conditions** act **against both extreme phenotypes** and **favours intermediate **variants
85
out of the 3 selections, which reduces variation?
stabilizing selection
86
what is speciation?
process of which **1 species ***splits* into **2 or more new species**
87
what is marcoevolution?
evolutionary change **above species level** over **long periods** of time
88
what does evolutionary theory explain?
how new species originate in addition to how populations evolve
89
what is a species? (think a human and a cat)
individuals that can breed with eachother in nature to produce viable offspring
90
what does the biological species concept emphasize?
**reproductive** isolation
91
what causes memebers of *common species* to **not** be able to **reproduce with eachother?**
reproductive barriers
92
what are the 5 types of prezygotic barriers? (zygote never produced)
-habitat isolation
-temporal isolation
-behavioral isolation
-mechanical isolation
-gametic isolation
93
why can't the common species mate if habitat isolation is implied? (prezygotic)
because the 2 species occupy different habitats so they can't mate
94
why can't 2 common species mate when temporal isolation is implied? (prezygotic)
the 2 species breed during different times of the day, month, years so the species can't mate
95
why can't 2 common species mate when behavioral isolation is implied?
because the 2 species mating calls/ rituals don't attract eachother
96
why can't 2 common species mate when mechanical isolation is implied?
the 2 species **cannot physically have sex **because of **morphological differences**.
97
why can't 2 common species mate when gametic isolation is implied?
sperm of 1 species cannot fertilize eggs of another species
98
what are the 3 postzygotic barriers?
-reduced hybrid viability
-reduced hybrid fertility
-hybrid breakdown
99
what is reduced hybrid viability? (postzygotic)
**genes** of *different* parent **species** interact in ways that **impair** hybrid's **development** or **survival**
100
what is reduced hybrid fertility?
hybrids are healthy but sterile (can't reproduce)
101
what is hyrbid breakdown? (postzygotic)
1st generation hybrids= viable and fertile
but when they mate, they can't produce offspring that will be able to reproduce
102
how can we define a species? (3)
-**morphological** species concept
-**ecological** species concept
-**phylogenetic** species concept
103
what does the morphological species concept define?
characterizes a species by it's body shape, size and structural features
104
how does an ecological species concept define a species?
views species in terms of it's **ecological niche**
105
how does phylogenetic species concept define a species?
phylogenetic history of organisms
106
how does speciation occur?
reduced gene flow
107
what are the 2 ways gene flow is reduced?
-allopatric speciation
-sympatric speciation
108
what is allopatric speciation?
geographic separation of populations which restricts gene flow (genes in and out of a population)
109
what is sympatric speciation?
geographically **overlapping** populations when biological factors like chromosomal changes and non random mating reduce gene flow.
110
is there physical separation in sympatric speciation?
no, a population experiences different selective pressures without physical separation.
111
how does sympatric speciation occur? (2 ways)
-change in behavior
-change in habitat (niche with same geographic area)
112
what does sexual selection help?
maximize reproductive success
113
what are the 3 types of sexual selection?
-intersexual selection
-intrasexual competition
-mate choice
114
what is intersexual selection?
selects **features** that make an **organism** more **attractive** to the **opposite** **sex**
115
what is intrasexual competition?
selects **features** that **help** an **individual** **intimidate** or** fight off same-sex rivals**
116
what is mate choice? (like a dating show)
selection of nonrandom process in which females select males based on a certain appearance
117
What is the **handicap theory**? (think of how hard it must be to raise a handicap kid)
they are **indicator traits** that suggest their **features** are **condition-dependent** and have a **cost**. If individuals *can handle the cost*, it can suggest superior **genetic quality**
118
What is the **Hamilton-Zuk** hypothesis?
an extension of the handicap theory that posits **sexual ornamnets **are indicators of **parasite** and **disease-resistance **
119
what gender is intrasexual competition more apparent in?
male-male features = competition for the female
120
can speciation cause major changes in physical appearances over time?
yes
121
can natural selection anticipate future environments by selecting for characters that will suit a future environment?
no,
122
what is evolutionary novelties?
changes in genetics lead to phenotype changes which lead to changes in adult phenotypes.
123
what can evolutionary novelties arise from?
-gradual **refinement** of existing structures
-major changes in body can result in **developmental** **genes **or **genes** that **control spatial organization** of body parts
124
how are mutations in genes that control spatial organization formed?
products of 1 class of genes; Hox genes = provide positional information in an animal embryo
125
what happens if Hox genes are duplicated?
1 gene will continue **coding for proteins** that regulate normal development
126
what could happen if further mutations were to happen to these hox genes?
can give rise to **new physical features**
