Evolution Unit Review Flashcards
How does a penguin’s flipper show that a
penguin is more closely related to flying birds
than to a shark?
penguins flippers and bird’s wings are homologous structures, demonstrating that they share a common ancestor because of their similar structures
What is the primary abiogenesis theory?
first living things on Earth arose from non-living material
Using the Urey Miller experiment diagram, explain what each part of the Miller-Urey experimental set-up represented and explain the significance
of this experiment to the primary
abiogenesis theory
-heat mimics the sun
-water above heat mimics the ocean
-lollipop glass with gases mimics the atmosphere
-gases evaporating mimics clouds
-clouds cooling forms rain and precipation goes back into ocean
-electrodes mimic early lightning/energy
-created organic molecules from inorganic matter
-mimicked water cycle and simulated early earth
Explain the significance of adding oxygen to
Earth’s atmosphere
-crucial step in the development of more
complex organisms
-these prokaryotes were now aerobic, meaning they can function in the presence of oxygen
What is the geological time scale?
-the geologic time scale, or geological time scale, is a representation of time based on the rock record of Earth and organizes Earth’s geological history into distinct blocks of time
-used primarily by Earth scientists to describe the timing and relationships of events in geologic history
How are homologous structures evidence
for divergent evolution?
In divergent evolution, homologous structures are structures indicating a species is diverging from its ancestor
How are analogous structures evidence for
convergent evolution?
in convergent evolution, organisms with analogous structures evolved independently in different organisms because the organisms lived in similar environments or experienced similar selective pressures.
What role does the environment play in
convergent evolution?
Environmental circumstances/pressures that require similar developmental or structural alterations can lead to convergent evolution even though the species differ in descent.
What do stromatolites tell us about
evolution?
stromatolites: layered rocks that form when certain prokaryotes bind thin layers of sediment together
-contain fossils resembling photosynthetic
prokaryotes that are measured to be about 3.5 billion years old and tells us when they first evolved
-evidence that photosynthetic prokaryotes existed
3.5 bya suggests that life in simpler forms began even earlier
What do cladograms show?
diagram that shows relationships between species, these relationships are based on observable physical characteristics
-e.g. the horse, wolf, leopard, and house cat all
have hair
-this derived character unites a clade that
excludes the turtle
-the turtle would be included in a broader clade
of animals with backbones
Evolution is more likely to occur when a small
population has been separated from the main
population. Explain this phenomenon
-if a reproductive or geographic barrier separates a small “splinter” population from its main population and prevent them from mating, it can cause speciation
-this leads to the formation of a new species
and evolution occurs
Place the following items in order of occurrence:
oxygen in the atmosphere, multicellular
organisms, heterotrophic eukaryotes,
prokaryotes, autotrophic eukaryotes.
1) prokaryotes
2) oxygen in atmosphere
3) heterotrophic eukaryotes
4) autotrophic eukaryotes
5) multicellular organisms
Why is the development of sexual reproduction
so important in the history of life?
-plays a major part in evolution
allows organisms to begin combining genes, allowing the next generation to do more than its parents; increasing their chance of survival
What are the roles of homologous structures
and molecular data in phylogeny?
-organisms with homologous structures share a common ancestor, which can help you find out more about its phylogeny (evolutionary history)
-molecular data can be used in the classification of a species, and by comparing the genes and proteins in organisms, it can measure the relatedness of species, which also tells us information about its phylogeny
The initial population of lizards has a mix of green and yellow lizards on a yellow leaf. Several generations later, the population consists of mostly yellow lizards and rarely any green lizards.
(a) How would Darwin explain the change in
the population?
natural selection because the lizards have different variations and the environment selected the yellow trait since they are more successful(fit) and better adapted to the environment(yellow leaf)
The initial population of lizards has a mix of green and yellow lizards on a yellow lead. Several generations later, the population consists of mostly yellow lizards and rarely any green lizards.
(b) How would Lamarck explain the change in
the population?
he would explain the change in population with his “tendency towards perfection” theory (organisms continually change and acquire features in order to be more successful in their environments)
-he would say that the yellow lizards acquired their yellow colour in order to be more fit and successful in their environment
A mutation occurs in an individual in a population. What events must take place for the trait the mutation produces to become established in the population?
N.S- (survival of the fittest?)
Must take place and favour the mutation for it to become established in the pop.
This will increase the fitness of the trait, which means it will be passed on to the viable offspring
Birds build nests. How might this behaviour contribute to fitness?
Protects organisms from predators and increases their ability to survive and reproduce, which therefore increases their fitness
Identify the similarities and differences between each of the following pairs of concepts.
(a) fitness and adaptation
Similarities:
helps them to adapt and survive in their environment
both part of natural selection
Differences:
Fitness affects the organisms’ offspring because it’s how they survive and reproduce in their environ.
Adapation affects the current organisms because it’s how they evolve and respond to their environ.
Identify the similarities and differences between each of the following pairs of concepts
(b) artificial selection and natural selection
Similarities:
They both can decrease genetic variation because they both involve favouring one breed or trait in a pop.
Differences:
AS is when humans select the traits and NS is when the environment favours the trait
Organisms in NS are chosen based on their fitness and adaptations that help them survive
Organisms in AS are chosen based on looks and preferences
How is artificial selection proof of natural selection?
Artificial selection provides a model that helps us understand natural selection. It is a small step to go from humans selecting desirable traits in plants and animals to envisioning natural conditions acting selectively on populations and causing natural changes, especially over geological timescales.
How do each of the following provide evidence for evolution?
(a) A girl gets frequent strep throat infections. Over time the antibiotic she is given no longer cures the infection
Antibiotic resistance in bacteria
-bacteria can become resistant to antibiotics through mutations that alter targets of antibiotics or by acquiring resistance genes from other bacteria
How do each of the following provide evidence for evolution?
(b) In order to increase milk yield of his herd,
a farmer selectively breeds only those cows
that produce the most milk
Artificial Selection
-provides a model that helps us understand evolution
-evolutionary process in which humans consciously select for or against particular features in organisms by choosing which individuals to save seeds from or breed from one generation to the next
How do each of the following provide evidence for evolution?
(c) The embryos of primates, birds, and fish all
have pharyngeal pouches
Comparative Development
-embryos of closely related organisms often have similar stages in development
-similarity of these structures at early stages is further evidence that all vertebrates evolved from a common ancestor (evolution)
Some mobile molluscs, such as octopuses,
developed a centralized brain and head. Other
molluscs that do not move, such as clams, did
not develop a centralized brain and head. Form
a hypothesis to explain this observation
Cumulative selection (evolution of simple structure into complex structure through small adaptations)
-molluscs that don’t move are simple and don’t require complex adaptations
-their simple structures are obviously enough to meet these animals’ needs
Suppose that, in the laboratory, you were able
to mate two organisms successfully and the
hybrid produced viable offspring. Does this
mean that the two populations belong to the
same species?
-2 parents aren’t the same species
(morphological species concept)
-could eventually become the same species over
time
How can the study of evolution help us
understand the following.
(a) pesticide resistance in insects
Pesticide Resistance: Directional Selection in Action
-most survivors of the first pesticide treatments were insects with genes that somehow enabled them to resist the chemical attack
-their offspring inherited the genes for pesticide resistance
-in each generation, the percentage of
pesticide-resistant individuals in the insect population increased
-the population underwent directional selection
-the alleles that produce higher pesticide resistance increase in the population
How can the study of evolution help us
understand the following.
(b) high frequencies of Huntington’s disease
among Afrikaners
The Founder Effect (genetic drift)
-genetic drift in a new colony is known as
the founder effect because the change in allele frequencies relates to the genetic makeup of the founders of the colony
-dutch immigrants from a few families that
happened to have Huntington’s disease (neuromuscular disorder) established the Afrikaner population in South Africa.
-therefore, today we can see higher frequencies of Huntington’s in Afrikaners than among the Dutch in Holland
How can the study of evolution help us
understand the following.
(c) diversity of tortoise species on the
Galapagos Islands
adaptive radiation/divergent evolution (evolution from a common ancestor that results in diverse
species adapted to different environments)
species vary locally
-he noticed that related animal species that occupied different habitats within a local environment had different features
-tortoises on Isabela island have adaptations that allow them to reach the abundant vegetation close to the ground
-española Island is hot, dry, and nearly barren
-the Española Island tortoises have different
adaptations to allow them to reach the high, sparse vegetation
-have longer necks as well as a notches in
their shells to allow their necks to reach
further upward
Many diseases, such as sickle-cell disease, are
caused by recessive alleles. Give two reasons
why natural selection has not eliminated these
diseases completely from the population
-makes some people (with sickle cell disease) resistant to malaria
-people that are heterozygous (has recessive in it) can transfer allele to offspring and they will be resistant to malaria
A bridge is being constructed to cross a canyon.
Predict how this might affect the evolution of
species on each side of the canyon
geographic isolation
-can separate different populations of one species
-The separation of a small “splinter” population from its main population is a crucial event in the origin of species.
-Once separate, the splinter population may follow its own evolutionary course.
-Changes in the allele frequencies caused by genetic drift and natural selection can
accumulate in the splinter population, making it less and less like the main population
-if changed too much, can’t interbreed, speciation occurs
Suggest reasons why genetic drift is not as big a
factor in present-day human evolution as it was
20 000 or more years ago
-population is way higher now so it’ll have smaller effects
-bottleneck effect: disasters won’t have as big of an impact because pop. is so big
-founder effect (globalization): there’s no island or place that’s really isolated now, as well since we have airplanes there are no barriers now
Explain how flowering plants and pollinators co-evolved
-flowering plants have a mutualistic relationship
with their pollinators
-mutations that produce large, bright petals and a strong scent would attract more insect pollinators and therefore would be favoured over small, dull flowers with little scent.
-similarly, pollinators that were more attracted to brighter flowers got more nectar and were more likely to survive
-the shape of the flower can also co-evolve with a pollinator species
A species of grass that was eaten by many
species of herbivores develops a mutation that
makes its leaves toxic to the animals that eat it.
Predict what might happen to the herbivores
that eat the plant
-once the plants began producing poisons,
natural selection favoured any variation in insect populations that could alter, inactivate, or eliminate these poisons
-different insect species have developed adaptations to cope with the poisons
-some species like the monarch caterpillar found a way to store the toxin in its tissues to make itself poisonous to others.
Why are geological changes often accompanied
by mass extinctions?
many organisms cannot adapt or cannot adapt quickly enough to the new environmental conditions that may result from the geological changes
Form two hypotheses to account for the sudden
appearance of species in the fossil record
1) punctuated equilibrium: sudden appearance of morphologically distinct new species in the fossil record
2) after catastrophism happens, then it would just be new organisms evolving in their new environment
Compare the extinction of species through natural selection and mass extinction
Species become extinct in natural selection because they can no longer survive and reproduce in their altered environment.
-If members cannot adjust to change that is too fast or drastic, the opportunity for the species’ evolution is lost
A mass extinction event is when species vanish much faster than they are replaced due to a geographic change
Why is it sometimes difficult to establish
whether two fossils are of the same species or
belong to similar yet different species, using
fossil evidence alone?
-if speciation occurred, then two species can look similar but would be considered different species because they can no longer reproduce
-gradualism + punctuated equilibrium-: if the species goes through a transitional change, all the fossils throughout the change might not be in the record, so it can be difficult to establish whether they’re the same species
Homo sapiens do not have tails, are bipedal,
have a relatively large brain, and do not walk
on their knuckles. Chimpanzees do not have
tails, are not bipedal, have a relatively small
brain, and walk on their knuckles. Fossil
evidence suggests Ardipithecus ramidus had
no tail, was bipedal, had a relatively small
brain, and did not walk on its knuckles.
(a) What characteristic do all three species
have in common?
bipedalism
Homo sapiens do not have tails, are bipedal,
have a relatively large brain, and do not walk
on their knuckles. Chimpanzees do not have
tails, are not bipedal, have a relatively small
brain, and walk on their knuckles. Fossil
evidence suggests Ardipithecus ramidus had
no tail, was bipedal, had a relatively small
brain, and did not walk on its knuckles.
(b) What feature did chimpanzees develop after
the point at which ancestral chimpanzees
and hominids diverged?
the habit of knuckle walking seen in chimpanzees and other apes may have evolved after the human and ape lineages diverged
Explain each of the following human traits in
terms of the theory of natural selection.
(a) high variation of hair types
doesn’t matter in natural selection since it isn’t required for survival
