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Final Exam Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What is evolution?

A
  • Descent with modification
  • Change in a population over time
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2
Q

What demonstrates that morphological changes in a population can occur?

A

Domestication and artificial selection.

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3
Q

Can changes in living species be observed in museums and in the field?

A

yes

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4
Q

Galapagos finches

A

Measured beak shape over many years and recorded feeding preferences. Average beak sizes increase when only large and tough seeds were available.

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5
Q

What do fossils show?

A

Fossils show transitional series over large time scales.

Generally speaking, fossils occur to the parts that do not decompose. Soft parts are much less likely to be preserved.

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6
Q

Archeopteryx and Tiktaalik

A

Archeopteryx - Early bird fossil, lived 150 MYA, had feathers and light bones, had teeth long tail and claws on its wings.

Tiktaalik - Fish with “limbs”, had gills, was aquatic, had forelimbs with a humerus, radius, and ulna, wrist bones, and fingers, lived in 370 MYA.

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7
Q

LTEE

A

Long Term Evolution Experiment; shows the origin of new species of bacteria have been documented.

Bacteria evolved to use a novel carbon source after 35,000 generations.

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8
Q

Life is diverse, how can we categorize it?

A

We group organisms by their similarities.

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9
Q

Carolus Linnaeus proposed what?

A

A genus species naming classification, which is still used today, where similar organisms are grouped together.

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10
Q

Georges Cuvier recognized…

A

That species went extinct, observed that organisms changed from one strata (rock layer) to the next.

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11
Q

Richard Owen proposed

A

that vertebrates were all built from an archetype with a head, tail, vertebral column, etc.
According to Owen, the similarity of vertebrate limbs represented variations on an archetype pattern for a limb.

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12
Q

Charles Darwin

A

Went on a trip around south America (HMS Beagle), found many fossils of organisms living in the area but slightly different. The organisms are very well adapted to their environment.

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13
Q

Darwin explained hypothesis that organisms evolve by…

A

Natural selection: Competition, variation, and heritable traits.

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14
Q

The Origin of Species by Natural Selection was published

A

Darwin didn’t publish this until prompted to by Alfred Wallace who was another scientist that also arrived at this conclusion.

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15
Q

Life is diverse, how can we explain it?

A

Organisms are similar if they are closely related to each other.
Diversity arises by species diverging and evolving over long expanses of time.

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16
Q

How else besides evolution can we explain evolution?

A

Remove Variation
Natural Selection
Sexual Selection- Reproduction is not random.
Genetic Drift - Random chance influences reproductive success.

Add Variation
Gene Flow - Genetic variation is altered by the arrival of new individuals (and their genes).
Mutation - Can change alleles/traits.

It is helpful to think of evolution in terms of changes in allele frequencies over time.

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17
Q

Natural Selection is the only evolutionary force that can consistently produce adapted populations. Types of selection:

A

Directional - One end of the variation is selected against.

Stabilizing - Both ends of the variation are selected against.

Disruptive - The mid range of variation is selected against.

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18
Q

Can genetic drift explain evolution?

A

Genetic drift refers to the fact that allele frequencies within a population can change due to chance.

Genetic drift can happen to traits in a population when the trait is variable, and heritable, but the trait doesn’t influence survivorship.

Small populations are more likely to experience significant changes to allele frequencies than larger populations, due to chance. (Any one individual represents a significant percentage of the population/alleles.)

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19
Q

Bottlenecking of a population

A

Can occur if a catastrophic event causes most individuals in a population to die.

Founder effect - When a few individuals inhabit a new area.

Both phenomena reduce genetic diversity and make new population highly susceptible to genetic drift because small population size.

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20
Q

Can gene flow cause a population to evolve?

A

Yes

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21
Q

Sexual Selection

A

One sex (usually female) “choose” males to mate with based on sexually dimorphic characters.

Can lead to behavioral characteristics such as singing or direct competition between males.

Can lead to characteristics that are mal-adaptive for natural selection.

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22
Q

Can mutations create new allelic variations that other forces can act on?

A

Yes

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23
Q

If none of these phenomena occur, there will be no evolution,

A

Natural selection – Won’t occur if the specific trait does not influence survival.

Genetic drift – Negligible if the population is very large.

Gene flow – If there is no migration between populations (or if their alleles are similar) there will be no gene flow.

Sexual selection – If there is none, then mating will be random and all alleles have an equal chance of contributing to the next generation.

Mutation – If mutation rates are low, or mutations are either neutral or lethal then allele frequencies will not be effected.

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24
Q

How can we tell if evolution is occurring?

A

By measuring allele frequencies in a population from one generation to another.

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25
Q

What evolves, populations or individuals?

A

Populations

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26
Q

Saltation

A

Macromutations are needed for a new species to arise.

Goldschmidt was able to induce large phenotypic changes by manipulating the environment that butterflies developed in.

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27
Q

Saltatory evolution hypothesis: Speciation by macromutation.

A

Speciation occurred by mutations to controlling genes or chromosomal rearrangements.

This hypothesis doesn’t reject microevolution but claims that microevolution is insufficient to explain macroevolution.

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28
Q

Hardy-Weinberg Equation

A

p^2 + 2pq + q^2 = 1 (genotypes)

p + q = 1 (alleles)

p^2 = the expected frequency of the genotype pp.

2pq = The expected frequency of the pq genotype.

q^2 = the expected freqency of the genotype qq.

Allele frequency is the sqrt of p^2 or q^2.

29
Q

Darwin stated that

A

microevolution + time = macroevolution (within species can lead to new species)

30
Q

If the population has a recessive phenotype frequency of .6, the recessive allele (q) and dominant allele (p) have frequencies of…

A

(q) - sqrt(.6) = .775
(p) - 1-.775 = .225

31
Q

What did the “New Synthesis” show?

A

That microevolution was sufficient to explain macroevolution, using mathematical models that were tested with real world data.

32
Q

What was realized after the “New Synthesis” became scientific consensus?

A

That most traits are more complex than thought to be.

33
Q

Biological Species Concept

A

A group of organisms that can (and do) interbreed.

Individuals that can interbreed are grouped as a species.

34
Q

Reproductive isolation example:

A

Eastern and Western spotted skunks mate at different times during the year.

35
Q

Do any species break the rules (under biological species concept)?

A

Grizzly and Polar bears are closely related species, there are some cases where grizzly and polar bears mate and create a hybrid bear.

36
Q

2 populations of large cats in laboratory setting, hybrids can exist via artificial insemination, but there are no known hybrids between them in the wild or captive settings. Would you call these the same or different species?

A

I would call them the same species because they have the ability to reproduce.

37
Q

Does the biological species concept work for asexual organisms?

A

No

38
Q

What is the morphological species concept, what is it used for?

A

The morphological species concept is a biological concept for defining species based on their morphological characteristics, which include physical features such as size, shape, color, and other observable traits.

Fossils

39
Q

Ecological species concept

A

Groups of similar organisms that are ecologically similar.

Essentially the same as the biological species concept but allows for definition of asexual organisms.

May group two very different species together if they have converged on an ecological role.

40
Q

Phylogenic species concept

A

The smallest group of similar organisms with a common ancestor is a species.

41
Q

Can new species arise through hybridization?

A

Yes

42
Q

Can a new species arise through errors in cell division?

A

Yes

Ex: There is a common cell division error in plants that doubles the chromosome number.
This can lead to a new species because plants often self-fertilize.

43
Q

Allopatric Vs Sympatric Speciation

A

Allopatric Speciation: A population may split into two species if they become physically separated for a period of time.

Sympatric Speciation: A population may split into two species if they are not physically separated, but another mechanism (i.e. behavior) separates the population. Sympatry may result from divergent selection.

44
Q

What did the experiments confirm about allopatric speciation in a laboratory setting?

A

Artificially spit a single population into multiple populations with different food sources.

Test mate preferences after 40 generations (1 year)

Populations raised in one environment prefer mates from the same population.

45
Q

How did new bacterial species evolve?

A

Through gradual allopatric speciation.

Bacteria evolved to use a novel carbon source after 35,000 generations.

46
Q

Is allopatric speciation common?

A

Yes

47
Q

If a population is diverging, does this mean they can never merge back together?

A

No, hybridization may not result in a new species.

Populations will only diverge as long as they are reproductively isolated.

48
Q

Lake Malawi Summary

A

Cichlids have 200 species that diverged sympatrically.

They are merging back together.

49
Q

Is evolution progressive?

A

No

This also has social consequences.

50
Q

Were prokaryotes the only living organisms for the first 2+ billion years of life?

A

Yes

51
Q

Where does most of the O2 come from?

A

A product of H2O splitting during photosynthesis.

52
Q

Oxygen Revolution

A

Rapidly increased the levels of O2 up to 10 percent of today’s levels by 2 billion years ago.

53
Q

Endosymbiont Theory

A

Eukaryotes likely evolved when archaea endosybiosed aerobically respiring bacteria (that are now mitochondria).

Same thing happened with chloroplasts.

Evidence: Eukaryotes all have introns in their DNA as do some archaea, we share more genes with archaea than with bacteria.

54
Q

When did most phyla of animals originate and what was it called?

A

535-525 million years ago

Cambrian explosion

55
Q

When did large multicellular life forms appear?

A

600 million years ago

56
Q

The energy expansion of evolution

A

Flesh (predation/herbivory)
Fire
Oxygen
Sunlight
Geochemical

The history of earth system can be divided into five ‘energetic’ epochs which are listed above.

57
Q

What was the biggest extinction ever on record?

A

Permian extinction 250 million years ago.

70 percent of land animals and plants went extinct.

96 percent of marine species went extinct.

Likely caused by massive lava flows in current day Siberia.

Roughly corresponds to the formation of Pangea

58
Q

How has the historical global climate alternated?

A

Between warm and wet, and cold and dry.

59
Q

Most boundaires between geological intervals resulted from…

A

Mass extinction events

60
Q

What was the cretaceous extinction caused by (likely)?

A

Asteroid impact

Killed dinosaurs lol

61
Q

How does mass extinctions reshape life’s diversity?

A

Eliminating many species and providing opportunities for new species to evolve.

62
Q

How far does fossil evidence for life date back?

A

3.5 billion years ago, some data suggests 4.1 billion years ago.

63
Q

What would earth have been like prior to 3.5 billion years ago?

A

Earth formed 4.6 billion years ago. Initially very hot, and frequently hit by comets and debris. Water existed as vapor and the atmosphere contained nitrogen, methane, carbon dioxide, ammonia, and hydrogen.

4.1 billion years ago earth cooled enough for water to condense and form the oceans. Life then appeared between 4.1 and 3.5 billion years ago.

64
Q

What did Miller and Urey test?

A

The hypothesis that life originated from physical-chemical processes on Earth by replicating the conditions of early Earth in 1953.

They tested this by replicating the conditions of early Earth.

Found many amino acids and other organic molecules. Modifications of this experiment have produced all of the monomers used by life: DNA, RNA, lipids, amino acids, sugars.

65
Q

Based on Miller-Urey like experiments, what is the most plausible scenario for life originating on Earth?

A

Chemical processes and natural selection.

66
Q

What was the last common ancestor to all of life like?

A

Lived in anoxic conditions, was a thermophile, and metabolized H2 for energy. (It lived in a hydrothermal vent)

67
Q

RNA World Hypothesis

A

Storage, inheritance, and expression of genetic material involves three separate types of molecules working together.

It is possible that life existed with just RNA, and DNA and protein were added afterwards through natural selection.

68
Q

What are the odds that life could have originated from physical/chemical processes on Earth between 4.1-3.5 billion years ago?

A

1 in 10^365

Biology (9 decks)

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