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SAT II Biology > Chapter 8 > Flashcards

Chapter 8 Flashcards

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1
Q

Evolution

A

the change in genes of a population on Earth over time

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1
Q

Evolution

A

the change in genes of a population on Earth over time

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2
Q

Microevolution

A

the changes in one gene pool of a population over generation

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3
Q

Macroevolution

A

speciation, the formation of an entirely new species

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4
Q

Individuals never

A

change or evolve

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5
Q

What is the smallest group that can evolve?

A

population

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6
Q

Population

A

consists of all the members of one species in 1 place

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7
Q

There are 6 areas of scientific study that provide evidence for evolution

A 
Fossil record
Comparative anatomy
Comparative biochemistry
Comparative embryology
Molecular biology
biogeography
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8
Q

Fossil Record

A

reveals existence of species that have become extinct or have evolved into other species.

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9
Q

Fossil record shows us

A
  • 99% of all organisms that ever lived on earth are now extinct
  • Prokaryotic cells are the oldest fossils and were the first organisms to develop on Earth
  • Earth is about 4.6 billion years old (we know through studies of radioactive dating and half-life)
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10
Q

Paleontologists have discovered many transitional fossils

A

that link older extinct fossils to modern species

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11
Q

Archaeopteryx is a fossil that shows

A

both reptile and bird characteristics

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12
Q

Hyracotherium (Eohippus), the ancient horse

A

is an ancestor of the modern horse, Equus

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13
Q

Comparative Anatomy

A

organisms that have similar anatomical structures are related to each other and share a common ancestor

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14
Q

Example of comparative anatomy

A

Ex. comparing dental structures in chimps and humans demonstrates that we are related + share a common ancestor

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15
Q

Comparative Anatomy:

Homologous structures

A

the same internal bone structure although the function of each varies , homologous structures are examples of divergent evolution

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16
Q

Examples of homologous structures

A

the wing of a bat, the lateral fin of a whale, and the human arm show that we are all mammals and diverged from a common ancestor

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17
Q

Comparative Anatomy:

Analogous Structures

A

have the same function but not the same underlying structure, the similarity is superficial and reflects adaptation to a similar environment

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18
Q

Analogous structures are not evidence of

A

a common origin or ancestry but of convergent evolution

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19
Q

Example of Analogous Structures

A

Ex. bat’s wing and a fly’s wing have the same function but diff underlying structure

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20
Q

Comparative anatomy:

Vestigial Structures

A

structures that are remnants of an earlier active structure, such as the appendix, they are evidence that animals have evolved

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21
Q

Example of Vestigial Structures

A

Appendix is an example of a structure needed when our ancient ancestors ate a different diet

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22
Q

Comparative Biochemistry

A

organisms that have a common ancestor will have common biochemical pathways

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23
Q

The more closely related organisms are to each other, the more

A

similar their biochemistry is.

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24
Q

Examples of comparative biochemistry

A

Ex. humans and mice are both mammals, this relationship is the reason medical researchers can test new medicines on mice and extrapolate the results to humans

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25
Q

Comparative Embryology

A

closely related organisms go through similar stags in their embryonic development because they evolved from common ancestor

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26
Q

Example of comparative embryology

A

Ex. all vertebrate embryos go through a stage in which they have gill pouches on the sides of their throats, in fish, pouches develop into gills. In humans, they develop into eustachian tubes that connect the middle ear with the throat

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27
Q

Molecular Biology:

Since all aerobic organisms contain cells that carry out respiration and require ETC

A

they also all contain the necessary polypeptide, cytochrome c.

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28
Q

A comparison of the amino acid sequence of cytochrome c among different organisms shows

A

which are most closely related

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29
Q

Example of molecular biology

A

Cytochrome c in human cells is identical to that of a chimp but differs from that of a pig and is vastly different than that found in paramecia or oak leaves

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30
Q

Biogeography

A

theory of continental drift states that about 250 million years ago, the continents were locked together in a single super-continent known as Pangaea which separated into 7 continents over the course of the next 150 million years.

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31
Q

The study of the location of fossils confirms the theory that

A

marsupials migrated by land from South America across Antarctica to Australia before those 2 became separate continents about 55 million years ago
-as a result most of the world’s marsupials are isolated in australia

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32
Q

Lamarck was

A

a contemporary of Darwin

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33
Q

Lamarck was

A

a contemporary of Darwin

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34
Q

Lamarck’s theory focused on

A

inheritance of acquired characteristics and use and disuse → stated that individual organisms change in response to their environment

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35
Q

Lamarck’s theory focused on

A

inheritance of acquired characteristics and use and disuse → stated that individual organisms change in response to their environment

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36
Q

Example of Lamarck theory

A

Giraffe developed a long neck because it ate leaves of the tall acacia tree for nourishment and had to stretch to reach them and passed the acquire trait to their offspring
-widely accepted theory in the early 19th century

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37
Q

Darwin

A

a naturalist who developed the theory of natural selection → explains how populations evolved and how new species develop

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38
Q

What did Darwin publish?

A

Published “On the Origin of the Species” in 1859

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39
Q

Darwin’s Theory of Natural Selection

1 “Sub-Theory”

A

Populations tend to grow exponentially, to overpopulate, and exceed their resources→ developed this after reading Malthus who published a treatise on population growth, disease, and famine in 1798

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40
Q

Darwin’s Theory of Natural Selection

2nd Sub-Theory

A

Overpopulation results in competition and a struggle for existence

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41
Q

Darwin’s Theory of Natural Selection

3rd Sub-Theory

A

In any population, there is variation and an unequal ability of individuals to survive and reproduce → no one understood genetics or mutation which would have given a base for understanding variation ( had Medel and Hugo de Vries respectively been more ‘popular’)

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42
Q

Darwin’s Theory of Natural Selection

A

Only best-fit individuals survive and get to pass on their traits to offspring→ survival of the fittest. The degree of fitness is measured by the ability of an individual to survive and to reproduce in its environment.

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43
Q

Evolution occurs as

A

advantageous traits accumulate in a population

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44
Q

What’s the weakest part of Darwin’s theory?

A

His inability to explain the sources of diversity of a population

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45
Q

How the Giraffe Got Its Long Neck:

According to Darwin’s theory

A

Ancestral giraffes = short necked → length varied between individuals

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46
Q

According to Darwin’s theory of the giraffe’s long neck :

Since population of animals competing for limited food supply increased:

A

taller individuals and a better chance of surviving than those with shorter necks

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47
Q

Darwin: Over time, proportion of giraffes in the population with longer necks increased until only long-necked giraffes existed

A

correct theory:average length of the neck in the population changed not an individual animal

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48
Q

Until 1845 in England, most peppered moths

A

were light colored; few dark ones could be found

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49
Q

How the Peppered Moth Changed from Light to Dark

A

Increasing industrialization→ increased pollution→ some and soot made all plants + roots black
By the 1950s all moths in the industrialized regions were dark and only a few were light

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50
Q

Before industrial revolution

A

light moths were camouflaged and dark moths were easy prey for predators (birds)

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51
Q

After industrial revolution

A

dark moths were camouflaged and had the selective advantage

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52
Q

After 100 yrs dark replaced light in the population

A

this darkening is due to industrialization and is referred to as industrial melanism

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53
Q

No single individual moth changed but the

A

frequency of an allele (for color) in the population changed

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54
Q

Natural selection can produce

A

very rapid shifts in populations

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55
Q

Examples of rapid shifts in populations

A

Only a few years after the discovery of antibiotics, bacteria appeared that were resistant to these drugs

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56
Q

Appearance of antibiotics did not induce mutations for resistance, it just

A

killed susceptible bacteria

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57
Q

Only resistant individuals survived to reproduce –>

A

next gen was resistant to antibiotic they were exposed to

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58
Q

An entire population of bacterium can ‘become’

A

resistant to a certain antibiotic in a matter of months

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59
Q

individual bacteria do not evolve

A

the population evolves

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60
Q

Current treatment for AIDS

A

Current treatment is a cocktail of drugs including AZT, which slows the progression of the disease

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61
Q

One reason we have not been able to cure aids:

A

Some patients have been taking cocktail for years and the virus that causes AIDS suddenly becomes resistant and patient quickly sickens

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62
Q

AIDS virus has the ability to mutate and evolve rapidly

A

viruses that are susceptible to the drugs become inactivated, while those that have mutated are resistant.

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63
Q

The virus is able to

A

survive + reproduce an entire population that is resistant

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64
Q

A new flu vax must be developed every year because

A

the flu virus evolves so rapidly

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65
Q

Types of Natural Selection

3 types of natural selection that can alter

A

frequency of inherited traits in 3 different ways

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66
Q

3 Types of Natural Selection

A

Stabilizing selection, diversifying or disruptive selection, and directional selection

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67
Q

Stabilizing Selection

A

eliminates the numbers of extremes and favors the more common intermediate forms ,
many extreme forms are weeded out this way

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67
Q

Stabilizing Selection

A

eliminates the numbers of extremes and favors the more common intermediate forms ,
many extreme forms are weeded out this way

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68
Q

What type of selection keeps birth weights for humans between 6-9 lbs?

A

Stabilizing Selection

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69
Q

for babies much smaller or larger than 6-9 Lbs

A

mortality is greater

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70
Q

Disruptive or Diversifying Selection

A

increases the numbers of extreme types in a population at the expense of intermediate forms

71
Q

Ex. of Diversifying Selection

A single population of snails can contain animals with either striped or plain shells

A

this results in balanced polymorphism where 2 or more phenotypes coexist in a population

72
Q

Over great lengths of time

A

disruptive selection may result in the formation of 2 entirely new species

73
Q

Directional Selection

A

changing environmental conditions give rise to directional selection where one phenotype replaces another in the gene pool

74
Q

Example of Directional Selection

A

peppered moths is an example

75
Q

The sources of variation in a population are

A

mutation, genetic drift, and gene flow

76
Q

Single point mutation can introduce a

A

a new allele into a population

77
Q

Single point mutations were first identified by

A

botanist Hugo de Vries in early 1900s who was studying polyploidy in plants

78
Q

Genetic Drift

A

change in gene pool due to chance, for example, the bottleneck effect and the found effect

79
Q

The Bottleneck Effect

A

Natural disasters (fires, earthquakes, and floods) reduce the size of a population nonselectively resulting in a loss of genetic variation

80
Q

2 Factors of the Bottleneck Effect

A
  • Resulting population is much smaller and not representative of the original one
  • Certain alleles may be under or overrepresented compared with the original population
81
Q

The Founder Effect

A

When a small population breaks away from a large one to colonize a new area, it is most likely not genetically representative of the original larger population

82
Q

Gene Flow

A

movement of alleles into or out of a population

83
Q

The founder effect can occur as a

A

result of the migration of fertile individuals or gametes between populations

84
Q

Example of the Founder Effect

A

Pollen from one valley can be carried by the wind across a mountain to another valley

85
Q

Population Stability- Hardy-Weinberg Equilibrium

A

Hardy and Weinberg (2 scientists) developed a theorem that described a stable, non-evolving population, one in which allelic frequency does not change

86
Q

Example of Hardy-Weinberg

If the frequency of an allele for a particular trait is 0.5 and the population is not evolving

A

then in 1,000 years, the frequency of that allele will still be 0.5→ called Hardy-Weinberg Equilibrium

87
Q

According to Hardy-Weinberg, if the population is stable, the following must be true:

A
  • The population must be very large
  • The population must be isolated from other populations
  • There must be no mutations in the population
  • Mating must be random
  • There must be no natural selection
88
Q
  1. The population must be very large

In a small population:

A

the smallest change in the gene pool will have a major effect in allelic frequencies.

89
Q

1.The population must be very large

In a large population:

A

a small change in the gene pool will be diluted by the sheer number of individuals and there will be no change in the frequency of alleles.

90
Q

2.The population must be isolated from other populations.

There must be no

A

migration of organisms into or out of the gene pool bc that could alter allelic frequencies

91
Q
  1. There must be no mutations in the population

A mutation in the gene pool could cause

A

a change in allelic frequency or introduce a new allele

92
Q
  1. Mating must be random

If individuals select mates, then those individuals

A

who are better fit will have a reproductive advantage and the population will evolve

93
Q
  1. There must be no natural selection

Natural selection causes changes

A

in relative frequencies of alleles in a gene pool

94
Q

Hardy-Weinberg Equation enables us to

A

calculate frequencies of alleles in a population. Can be applied to complex situations of inheritance

95
Q

Hardy Weinberg Equation

A

p + q =1 or p^2+2pq+q^2=1

96
Q 
P=
Q=
 p^2 =
q^2=
2pq
A 
dominant allele
recessive 
homozygous dominant 
homozygous recessive
all hybrid
97
Q

Species

A

a population whose members have the potential to interbreed in nature and produce viable, fertile offspring.

98
Q

Anything that fragments a population and isolates small groups of individuals may

A

foster the formation of a new species

99
Q

Isolated populations are subject to different

A

selective pressures in their respective environments

100
Q

If enough time elapses, the 2 populations may become so different that, even if they were brought back together

A

interbreeding would not occur. At this point, a new species is said to have come into being

101
Q

6 Different forms of isolation cause

A

a new species to form

102
Q

6 forms of isolation are

A

geographic isolation, polyploidy, habitat isolation, behavioral isolation, temporal isolation, reproductive isolation

103
Q

Geographic Isolation

A

occurs when species are separated. Mountain ranges, canyons, rivers, lakes, or glaciers may cause significant isolation between species

104
Q

Polyploidy

A

instead of being haploid (n) or diploid(tn), polyploid organisms can be tetraploid (4n) or octoploid (8n)

105
Q

Nearly ½ of all flowering plants + vast majority of ferns are

A

polyploid

106
Q

Polyploid organisms cannot breed with organisms that

A

are not polyploid and therefore are isolated from them

107
Q

Habitat Isolation

A

occurs when two organisms live in the same area but encounter each other rarely.

108
Q

Example of Habitat Isolation

A

2 species of 1 genus of snake can be found in the same geographic area, but 1 inhabits that water and the other in mainly terrestrial

109
Q

Behavioral Isolation

A

occurs when 2 animals become isolated from each other because of some change in behavior

110
Q

Ex. of Behavioral Isolation

A

male fireflies of various species signal to females of their kind by blinking lights on their tails in a particular patter→ females only respond to characteristics of their own species, flashing back to attract males → if for any reason, the female doesn’t respond with the correct blinking pattern, no mating occurs

111
Q

Temporal Isolation

A

temporal refers to time

112
Q

Examples of Temporal Isolation

A

diff plants of 1 species living in the same area may become functionally separated into 2 populations via temporal isolation because some plants become sexually mature earlier and begin to flower in the cooler part of the season will other plants in the later, warmer part

113
Q

Reproductive Isolation

A

closely related species may be unable to mate because of anatomical incompatibility.

114
Q

Ex of Reproductive Isolation

A

For ex. A small male dog and a large female dog cannot matter because of the enormous size differences between the 2 animals

115
Q

How species evolve are classified into 5 patterns

A

divergent, convergent, parallel, coevolution, and adaptive radiation

116
Q

Divergent Evolution

A

occurs when a population becomes isolated (for any reason) from the rest of the species and becomes exposed to now selective pressures, causing it to evolve into a new species

117
Q

Homologous structure are evidence

A

of divergent evolution

118
Q

Covergent Evolution

A

when unrelated species occupy the same environment, they are subjected to similar selective pressures and show similar adaptations.

119
Q

Ex. of Covergent Evolution

A

Ex. a whale (mammal) and a fish. Both have a streamlined appearance because that is advantageous in their environment. The underlying bond structure of a whale however, reveals ancestry common to mammals, not fish

120
Q

Analogous structures are evidence of

A

covergent evolution

121
Q

Parallel Evolution

A

describes 2 related species that have made similar evolutionary adaptations after their divergence from a common ancestor

122
Q

Ex. of Parallel Evolution

A

many similarities between gray wolf of North America and Tasmanian wolf (marsupial) or Australia because they share a common ancestor and evolved in similar environments

123
Q

Coevolution

A

mutual evolutionary set of adaptations of 2 interacting species

124
Q

Ex. of Coevolution

A

pollinator-plant relationships are an example → When an insect, bird, or bat feeds on the nectar from a flower, it inadvertently ensures the reproductive success of the flower

124
Q

Ex. of Coevolution

A

pollinator-plant relationships are an example → When an insect, bird, or bat feeds on the nectar from a flower, it inadvertently ensures the reproductive success of the flower

125
Q

Adaptive Radiation

A

the emergence of numerous species from a single common ancestor introduced into an environment

126
Q

When a honeybee that lives on the nectar of the scottish broom flower, the flower has a

A

tripping mechanism that arches the stamens (male part) over the bee and dusts it with pollen, some of which will rub off onto the pistils (female part) of the next flower that the bee visits

127
Q

On the Galapagos Islands, Darwin discovered

A

14 species of finches each filling a different ecological niche, some lived on ground whale others adapted to live in trees

128
Q

Biggest variation of finches is in

A

their beaks which are adapted for different diets

129
Q

Thick, short beaks

pointy beak

A

eat seeds while longer

eat insects

130
Q

Theories About Evolution

Gradualism

A

states that organisms descend from a common ancestor gradually, over a long period of time, in a linear or branching fashion
“Big changes occur by an accumulation of many small ones”

131
Q

According to gradualism

A

fossils should exist as evidence of every stage in the evolution of every species with no missing links

132
Q

Fossil record is at odds with gradualism because

A

scientists rarely find transitional forms or missing links

133
Q

Scientists have abandoned gradualism for

A

punctuated equilibrium

134
Q

Punctuated Equilibrium (theory favored today)

A

developed by Stephen J. Gould and Niles Eldridge and it states that new species appear suddenly after long periods of no change

135
Q

Most likely, a new species arises in a different place and expands its range

A

competing with and replacing the ancestral species that becomes extinct

136
Q

Spontaneous Generation

A

the theory that living things emerge from nonliving or inanimate objects

137
Q

Spontaneous generation was disproved by

A

Franceso Redi (17th cen.)

138
Q

Franceso Redi (17th cen.)

A

who put decaying meat into a group of wide-mouthed jars-some covered with lids, others with cheesecloth, and some open → demonstrated that maggots arose only where flies were able to lay eggs

139
Q

Louis Pasteur

A

used a goosenecked flask to prove that microorganisms appeared only as contaminants from the air and not spontaneously
1860s

140
Q

Organism alive today represent

A

3% of all organisms that ever lived meaning 97% of all life has gone extinct

141
Q

After the big bang formed the planets, v

A

Earth’s outer surface cooled and solidified to form a crust.

142
Q

The ancient environment most likely consisted of

A

CH4 (methane), NH3 (ammonia), H20 (vapor), and N2 but lacked free oxygen.

143
Q

What created energy for many chemical reactions with produced?

A

Intense heat + lightning + UV radiation

the 1st cell

144
Q

A.I. Oparin and J.B.S. Haldane, 1920s

A

separately hypothesized that under the conditions of early Earth, organic molecules could form

145
Q

A.I. Oparin and J.B.S. Haldane stated that

A

in the absence of corrosively reactive molecular oxygen that would react with + degrade them, organic molecules could form and persist

146
Q

Stanley Miller and Harold Urey, 1950s

A

tested Oparin-Haldane hypothesis and proved that almost any energy source would have converted inorganic molecules in the early atmosphere into a variety of organic molecules, including amino acids

147
Q

Stanley Miller and Harold Urey 1950s

Used electricity to

A

mimic lightning and U.V light that must have been present in great amounts in the early atmosphere

148
Q

Sidney Fox

A

recent years, produced membrane-bound, cell-like structures he called proteinoid microspheres, which would last for several hours in a lab

149
Q

The 1st organisms on Earth were

A

anaerobic heterotrophs

150
Q

Heterotroph Hypothesis

A

states that 1st cells on Earth were anaerobic heterotrophic prokaryotes

151
Q

Anaerobic heterotrophic prokaryotes

A

Simply absorbed organic molecules from the surrounding primordial soup to use as a nutrient source

152
Q

Fossil record states that the 1st cell evolved about

A

3.5 billion years ago

153
Q

Eukaryotic cells w/ a nucleus+other organelles evolved

A
  1. 5 billion years ago
    - this occurred as tiny bacteria took up residence inside large prokaryotic cells and performed important functions for the host cell
154
Q

Beneficial symbiotic relationships resulted in nuclei, chloroplasts, and mitochondria , this theory of endosymbiosis was

A

developed by Dr. Lynn Margulis

155
Q

Fossil record states that the 1st multicellular animals appeared about

A

565 million years ago → over a span of 40 million years, every major phylum of animal appeared

156
Q

Cambrian explosion

A

animals moved from oceans to the land filling every available niche as competition for limited resources increased in the oceans and as they evolved the traits necessary to lived in a dry environment

157
Q

Several characteristics enabled animals to move to land:

A

lungs, skin to keep animals from drying out, limbs to move, mechanisms for internal fertilization, shell to protect their eggs and keep them from drying out

158
Q

Several characteristics enabled plants to move to land:

A

Roots that anchor them into soil + absorb water, supporting cells to enable them to compete for light, vascular tissue to carry water upward, waxy molecule (cutin) to protect leaves frond dehydrating, seeds (protective package for the embryo + its food)

159
Q

Mammal appeared about

A

210 million years ago, primates (including apes), appeared about 25 million years ago

160
Q

Humans did NOT

A

evolve from apes; we both evolved from a common ancestor about 7 million years ago, human ancestors arose in Africa

161
Q

Homosapiens (modern humans) arose about

A

150,000 years ago

162
Q

A species may go extinct for many reasons

A

habitat destruction or drastic environmental change

163
Q

Even if physical factors (temperature, humidity, CO2 levels) remain stable

A

because so many species are interdependent, the extinction of one species can result in the extinction of another

164
Q

How many major extinction events have there been?

A

5 major extinction events in the past 500 million years

165
Q

The two most important extinction events were

A

permian extinction

cretaceous mass extinction

166
Q

The Permian extinction (250 million years ago)

A
  • occurred during a period of enormous volcanic eruptions in what is now Siberia
  • Lava, 100s of 1000s of meters thick, covered an area the size of Europe
167
Q

The eruptions during the Permian extinction emitted enough CO2 into the atmosphere to

A

cause the global climate to increase 6 degrees C. Life on Earth was almost wiped out

168
Q

The Cretaceous mass extinction (65 million years ago)

A

10km wide asteroid crashed into the Yucatan peninsula, Mexico , the scar can be seen from space

169
Q

Theory about the Cretaceous mass extinction is that this collision caused a

A

huge cloud of debris to billow into the atmosphere blocking sunlight for months → resulted in the extinction of many marine and land animals including all the dinosaurs, excluding birds

170
Q

Summary: Evolution is not always a slow process

A

a population of bacteria can develop resistance to a particular antibiotic after only a few months of exposure

171
Q

Summary: Evolution does not occur at the same rate in all organisms

A

humans have changed a great deal in the last 100,000 years, whereas the horseshoe crab has hardly changed at all

172
Q

Summary: Evolution does not always cause organisms to become more complex

A

instead it may cause complex forms to create simpler ones

173
Q

Early embryo of the sea star is bilaterally symmetrical (similar to human development) considered to be advanced and complex

A

but the adult sea star, shows radial symmetry which is considered simple and primitive

174
Q

Summary: Evolution occurs in populations not individuals

A

A single giraffe did not develop a long neck because it needed it, instead short-necked giraffes could not compete in a competitive environment and died out→ only long-necked giraffes survived

175
Q

Summary: Evolution is directed by changes in the environment

A

animals that evolved int he ocean must be streamlined in order to move freely

SAT II Biology (15 decks)

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