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Biology 11U - 2023 > Unit 3 Test Review - Evolution > Flashcards

Unit 3 Test Review - Evolution Flashcards

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1
Q

3.8-3.5 billion years ago

A

Prokaryotic cells first appear in the fossil record

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2
Q

3.5 billion years ago

A

Fossils of primitive cyanobacteria first appear in the fossil record

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3
Q

2.5-2.0 billion years ago

A

Eukaryotic cells first appear in the fossil record (these were the cells that made organisms more complex)

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4
Q

1.5 billion years ago

A

Multicellular eukaryotic organisms first appear in the fossil record

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5
Q

590 million years ago

A

Bilateral invertebrate animals first appear in the fossil record

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6
Q

543 million years ago

A

Shelled animals first appear in the fossil record

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7
Q

533-525 million years ago

A

Cambrian explosion creates diverse animal life

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8
Q

520 million years ago

A

First vertebrates; first land plants

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9
Q

450 million years ago

A

Large terrestrial colonization by plants and animals

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10
Q

400 million years ago

A

Seed plants first appear in the fossil record; tetrapods and insects first appear in the fossil record

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11
Q

300 million years ago

A

Reptiles first appear in the fossil record

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12
Q

225 million years ago

A

Dinosaurs and mammals first appear in the fossil record

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13
Q

160 million years ago

A

Birds first appear in the fossil record

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14
Q

135 million years ago

A

Flowering plants first appear in the fossil record

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15
Q

7 million years ago

A

Hominids first appear in the fossil record

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16
Q

Explain Aristotle’s theory of evolution

A

-Believed that all organisms that ever would exist were already created
-These organisms were permanent and perfect, thus would not change
-Creator who formed the entire universe

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17
Q

Explain Hutton’s theory of evolution

A

-Geologist, one of the first people to challenge the notion that Earth was young
-Proposed that rock formations are continually formed by molten material being forced up to the Earth’s surface to form rock, where it is eroded away
-The sediment from the erosion is washed into the sea and eventually compacts to form sedimentary rock
-Studied the rates of present-day erosion and sedimentation and the thickness of bands of sedimentary rock
-Concluded that it must have taken millions of years, not thousands, to form the current landscapes

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18
Q

Explain Leclerc/Buffon’s theory of evolution

A

-Noted similarities between humans and apes and speculates that they might have a common ancestor, suggesting species change over time

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19
Q

Explain Cuvier’s theory of evolution

A

-Largely credited with developing the science of paleontology (the study of ancient life through examination of fossils)
-Found that each stratum (layer of rock) is characterized by a unique group of fossil species, the deeper (older) the stratum, the more dissimilar the plant and animal life are from modern life
-He found evidence that new species appeared and others disappeared over time
-CATASTROPHISM: Cuvier proposed the idea that Earth experienced many destructive natural events in the past, where these events (revolutions) were violent enough to have killed species each time they occurred, and species from a nearby area would repopulate these areas - he used this to explain the appearance of new species in the fossil records of a region

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20
Q

Explain Lyell’s theory of evolution

A

-Principles of Geology, rejected catastrophism
-He proposed, based on the work of Hutton, that geological processes operated at the same rates in the past as they do today in a process called UNIFORMITARIANISM
-Slow, continuous, subtle processes could happen over a long period and could result in substantial changes

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21
Q

Explain Lamarck’s theory of evolution

A

-Species increased in complexity over time, until they achieved a level of perfection
-Organisms would become progressively better adapted to their environment
-Body parts that were used extensively to cope with conditions in the environment would become larger and stronger (USE&DISUSE)
-Proposed that characteristics acquired during an organism’s lifetime (such as short hair, and large muscles) could be passed to offspring (INHERITANCE OF ACQUIRED CHARACTERISTICS)
-Though incorrect, visionary because it suggests that adaptation to the environment plays a role in evolution (giraffes stretched necks to reach higher foliage, long necks passed down)

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22
Q

Explain Malthus’ theory of evolution

A

-All living organisms could increase exponentially if allowed to reproduce unchecked (population checks exist), however eventually a population is reduced due to starvation, disease..
-Populations grow faster than their food supply

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23
Q

What are the four parts of Darwin’s theory of evolution:

A

1) Genetic Variation: desirable characteristics must be passed
2) Overproduction of Offspring: individuals produce more than can survive
3) Struggle for existence: excess results in competition for space and food
4) Differential survival and reproduction: individuals with traits best suited to the environment will survive over time and reproduce to pass on these valuable traits (leads to gradual adaptation over time)

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24
Q

Artificial Selection

A

Directed breeding in which individuals that exhibit a particular trait are chosen as parents of the next generation; it is used to produce new breeds or varieties of plants and animals

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25
Q

What are the evidences of evolution?

A

-fossil record & vestigial structures
-biogeography
-anatomy (homologous and analogous structures)
-embryology
-molecular biology (DNA)

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26
Q

Explain fossil records and vestigial structures
*evidence for evolution

A

-Fossils in younger (closer to surface) rock are more similar to current species than those in deeper strata
-Fossils appear in chronological order, and probable ancestors of a species are found in older rocks
-Not all organisms appear in the fossil record at the same time, showing the successive evolution of groups (kingdoms of species)
-Transitional fossils show an intermediary link between past and present groups of organisms
VESTIGIAL STRUCTURES: reduced versions of what were once functional structures in an ancestral species. A key piece of evidence of a fossil record that shows the once functional use of a present-day vestigial structure.

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27
Q

Explain biogeography
*evidence for evolution

A

-The study of the past and present geographical distribution of organisms, Darwin and Wallace supported their theories with biogeographical evidence showing that species evolved in one location and spread out to other regions.
-Geographically close environments are more likely to be populated by related species
-Animals found on islands often closely resemble animals on the nearest continent
-Fossils of the same species can be found on the coastlines of neighbouring continents

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28
Q

Explain anatomy (homologous and analogous structures)
*evidence for evolution

A

-The study of anatomy provides the evidence of homologous and analogous structures
Homologous structures: those that have similar structural elements and origin but may have a different function. They originate from a common ancestor.
Analogous structures: do not have common evolutionary origins but perform similar functions. These provide evidence for adaptation to suit the environment.

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29
Q

Explain embryology
*evidence for evolution

A

-The study of pre-birth stages of an organism’s development. It has been used to determine evolutionary relationships between animals.
-Generally, related species share common embryological stages and timings of structural development

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30
Q

Explain molecular biology (DNA)
*evidence for evolution

A

-Evolutionary relationships are reflected in DNA since DNA carries genetic information from generation to generation
-Species that have similar DNA share a common ancestor
-DNA evidence supports conclusions about relationships and common ancestry provided by other areas of evidence

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31
Q

Macroevolution / Speciation

A

The formation of new species from existing species. Two populations become reproductively isolated over time if there is little or no gene flow between them. Without gene flow, the populations may become different species.

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32
Q

Microevolution

A

The change in percentages or frequencies of alleles within populations. These are the small events that lead to evolution within a population.

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33
Q

What are the six processes in which allele frequencies in a population change within microevolution?

A

-mutation
-gene flow (migration)
-non-random mating
-genetic drift (including founder effect and bottleneck effect)
-natural selection (directional, stabilizing, or disruptive selection)
-sexual selection

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34
Q

What are mutations?
*microevolution allele frequencies changing in population

A

-Permanent change in a cell’s DNA, ranging from changes in a single base pair to deletions of large sections of chromosomes, can be beneficial, neutral, or harmful
-The more genetic variation there is in a population, the greater the genetic diversity of the population and the greater the chance of a selective advantage to some individuals in a changing environment
-Mutations are the source of genetic variation, and thus the evolutionary factor

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35
Q

What is gene flow (migration)?
*microevolution allele frequencies changing in population

A

-Movement of genes across two different populations, migration
-Gene flow describes the net movement of alleles from one population to another as a result of the migration of individuals

36
Q

What is non-random mating?
*microevolution allele frequencies changing in population

A

-Mating among individuals based on a particular phenotype or due to inbreeding. In animals, individuals may choose mates based on their physical or behavioural characteristics. This will affect the alleles in the gene pool of the next generation.
-Inbreeding occurs when closely related individuals breed. This can occur naturally or by human-led breeding programs.
-In nature, plants self-fertilize, this increases the expression of harmful recessive alleles
-Breeding programs attempt to select for a particular desirable trait, this pure-breeding often results in health problems in animals

37
Q

What is genetic drift?
*microevolution allele frequencies changing in population

A

-The change in frequencies of alleles due to random events in a small breeding population, the smaller the population the less likely it is that the parent gene pool will be reflected in the next generation
-The change in a population can be regarded in many situations (bottleneck effect, founder effect, variations, endangered species, natural disaster)

38
Q

What is the founder effect, within genetic drift?
*microevolution allele frequencies changing in population

A

-New populations in areas like islands are formed by only a few individuals or founders. These founders carry some but not all of the alleles from the original population’s gene pool. They may also not be typical of the population they came from. The gene pool is reduced.

39
Q

What is the bottleneck effect, within genetic drift?
*microevolution allele frequencies changing in population

A

-If a population is reduced by starvation, disease, or a natural catastrophe, the surviving population likely only has a fraction of the alleles that were present before the population decline
-The gene pool will have lost its diversity and the allele frequencies will have changed.

40
Q

What is natural selection?
*microevolution allele frequencies changing in population

A

-Selective forces such as competition and predation affect populations. Some individuals are more likely to survive and reproduce than others. Alleles that are selected for by environmental conditions will increase in frequency over time.

41
Q

What are the three types of natural selections regarding allele frequencies changing over time in microevolution?

A

-Stabilizing selection: favours an intermediate phenotype and acts against extreme variants of this phenotype. This improves the adaptation of the population to aspects of the environment that remain fairly constant.
(distribution gets narrow)

-Directional selection: favours the phenotypes at one extreme over the other. This selection is common during times of environmental change or when a population migrates to a new habitat.
(peak shifts)

-Disruptive selection: favours two extremes of a population, and as a result intermediate phenotypes can be eliminated from the population.
(two peaks form)

42
Q

What is sexual selection?
*microevolution allele frequencies changing in population

A

-Involves the competition between males through combat or visual displays. It also includes the choices females make in mates.
-Some animal species are sexually dimorphic, where the males and females look markedly different and this also contributes to competition and choice
-Sexual selection changes the allele frequencies of the population

43
Q

What are the outcomes of sexual selection?
*microevolution allele frequencies changing in population

A

-Speciation through adaptive radiation after geographical isolation
-Speciation through genetic drift after a bottleneck effect
-Species endangerment and/or extinction due to insufficient genetic diversity from population isolation

44
Q

What are the two reproductive isolating mechanisms within macroevolution?

A

Pre-zygotic and Post-zygotic

45
Q

What are pre-zygotic isolating mechanisms within macroevolution?

A

-These mechanisms either impede mating between species or prevent fertilization of the eggs if individuals from different species do mate

The mechanisms can prevent mating:
-Behavioural isolation
-Temporal isolation
-Ecological/habitat isolation

The mechanisms can prevent fertilization:
-Mechanical Isolation
-Gametic Isolation

46
Q

Explain each of the pre-zygotic isolating mechanisms within macroevolution

A

Prevent mating:
Behavioural isolation: any signals/behaviours that are species-specific prevent interbreeding with closely related species

Temporal isolation: two species occupy the same habitat and have timing barriers

Habitat/ecological isolation: two species live in the same general region but in different habitats, so rarely encounter one another

Prevent fertilization:
Mechanical isolation: two closely related species may attempt to mate but are unsuccessful due to anatomical incompatibility

Gametic isolation: gametes from two different species may meet but do not fuse to form a zygote

47
Q

What are post-zygotic isolating mechanisms within macroevolution?

A

-In rare cases, the sperm and egg of different species produce a zygote. Post-zygotic isolating mechanisms prevent such hybrids from developing into viable, fertile individuals. Thus, the original parental species are proven to be separate species, according to the definition of species.

Prevents hybrids:
-Zygotic mortality
-Hybrid inviability
-Hybrid infertility

48
Q

Explain each of the post-zygotic isolating mechanisms within macroevolution

A

Prevent hybrids:
Zygotic mortality: mating and fertilization are possible, but genetic differences result in a zygote that is unable to develop properly

Hybrid inviability: a hybrid individual develops but either dies before birth or, if born alive, cannot survive to maturity

Hybrid infertility (sterility): The hybrid offspring remain healthy and viable but are sterile, representing a reproductive barrier

49
Q

How does speciaiton occur?

A

Once an isolating mechanism has prevented gene flow, populations must remain genetically isolated from each other for speciation to occur.

50
Q

What are the two types of speciation, explain them

A

Sympatric speciation:
-occurs when populations that live in the same habitat diverge genetically and become reproductively isolated
-more common in plants than animals, chromosomal changes in plants or non-random mating in animals alters gene flow
-this result is reproductive incompatibility without geographical isolation

Allopatric speciation:
-occurs when populations are separated by a geographical barrier and diverge genetically
-this speciation occurs when a population is split into two or more isolated groups by a geographical barrier
-Eventually, the gene pool of the split population becomes so distinct that the two groups are unable to interbreed when re-introduced

51
Q

What is polyploidy

A

This can lead to the formation of new species through sympatric speciation

52
Q

What is adaptive radiation (geographic isolating mechanism)

A

Occurs when a single species evolves into a number of distinct but closely related species, and each new species fills a variety of formerly empty ecological niches

53
Q

What is divergent evolution?

A

A pattern of evolution in which species that were once similar to ancestral species diverge, or become increasingly distinct. In other words, as a population they adapt, and they become less and less alike

54
Q

What is convergent evolution?

A

A pattern of evolution in which similar traits arise because different species independently adapted to similar environmental conditions

55
Q

What is mimicry?

A

Another type of species adaptation that occurs when a harmless species resembles a harmful species in colouration or structure

56
Q

What are the two models that have been proposed to explain the speed at which evolution occurs?

A

-Gradualism
-Punctuated Equilibrium

57
Q

Explain gradualism according to evolutionary change

A

-view evolutionary change as slow and steady before and after a divergence
-supported since Darwin’s time

58
Q

Explain punctuated equilibrium according to evolutionary change

A

-views evolutionary history as long periods of stasis, or equilibrium that are interrupted by periods of divergence
-proposed in 1972 by Niles Eldredge and Stephen Jay Gould

59
Q

Explain the impact of human activities on evolution

A

-have had a great impact on speciation, population decline, and extinction as human activities essentially isolate populations
-some human-made barriers are resulting in allopatric speciation such as the conversion of wilderness into cropland, the development of areas for tourism, and the building of urban subdivisions/ roads

60
Q

Where did life emerge from according to evolution?

A

Chemistry

61
Q

What were the two things needed for early life according to evolution?

A

a cell membrane, and genetic material

62
Q

What is RNA made up of?

A

a sugar, a base, and a phosphate

63
Q

What did John Sutherland figure out?

A

-the intermediate step was needed to form the basics of nucleotides, he used a hybrid (sugar and half a base that came together by evaporation and precipitate from the sky to meet the other,and needed to combine in a warm pond environment, making a ribonucleotide C, exposing this to sunlight helped scientists find the natural pathway to make ribonucleotide U’s bringing steps closer to making RNA, and essential component of life.

64
Q

How long did life exist on Earth before anything remotely resembling human beings showed up?

A

4 billion years

65
Q

When did humans start wearing clothes?

A

170 thousand years ago

66
Q

When did humans start living in dwellings?

A

500 thousand years ago

67
Q

When did humans start using fires?

A

800 thousand years ago

68
Q

When did humans lose body hair?

A

3 million years ago

69
Q

When did humans start tool-making?

A

3.3 million years ago

70
Q

Explain mass extinctions

A

The environment has a strong influence on extinction, selective pressure of the environment produces new species, but they can also cause extinction.
The general trend is usually an increase, but in total, it has caused 5 mass extinctions.
Mass extinctions decrease the number of species, however, they can also allow for adaptive radiation of surviving species that evolve into new species. The general trend is overall an increase in species throughout Earth’s history.

71
Q

Species (Evolution)

A

a group of organisms that can interbreed and produce fertile offspring

72
Q

Cladistics

A

a method of classifying organisms by the characteristics they have in common

73
Q

Clade

A

a group that includes a common ancestor and all the descendants (living and extinct) of that ancestor

74
Q

Cladogram

A
  • a diagram showing evolutionary relationships
    -it is assumed that the more characteristics the two organisms share, the more recently they diverged from a common ancestor
  • we use cladograms to examine the relationships between different species
75
Q

Primate

A

a group of relatively large-brained, mostly arboreal mammals that includes prosimians, monkeys, apes, and humans

76
Q

Anthropoid

A

the group of primates that includes monkeys, apes, and humans

77
Q

Hominid

A

all species descended from the most recent common ancestor of chimpanzees and humans that are on the human side of the lineage

78
Q

Alfred Russel Wallace

A

Outlined his theory of evolution identical to Darwins, but Darwins released his first

79
Q

Natural Selection

A

the way in which nature favours the reproductive success of some individuals within a population over others

80
Q

Adaption

A

a characteristic or feature of a species that makes it well-suited for survival or reproductive success in its environments

81
Q

Four parts of a theory

A

Observations, laws, hypotheses, inferences

82
Q

Evolution

A

the scientific theory that describes changes in species over time and their shared ancestry

83
Q

Fact vs Theory vs Hypothesis

A

A fact is proven to be true, supported by evidence, and has been verified through observation and experiments

Theory is an explanation of a collection of facts and observations, supported by a large body of evidence and is comprehensive enough to explain them

A hypothesis is an educated and proposed explanation that is tentative to prior limited knowledge

84
Q

Neutral mutation

A

mutation that doesn’t result in a selective advantage or disadvantage

85
Q

Harmful mutation

A

a mutation that reduces the reproductive success of an individual, does not accumulate over time, it is selected against

86
Q

Beneficial mutation

A

a mutation that increases the reproductive success of an individual, beneficial mutations are favoured by natural selection and accumulate over time

87
Q

Artificial selection

A

directed breeding in which individuals that exhibit a particular trait are chosen as parents of the next generation, used to produce new breeds of plants and animals

Biology 11U - 2023 (4 decks)

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