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Biology Unit 2 > Evolution > Flashcards

Evolution Flashcards

1
Q

Buffon

A
  • 1749
  • Found similarities between apes and humans and speculated a common ancestor
  • suggested earth was older than 6000 years, which was commonly believed
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2
Q

Curvier’s fossils

A
  • largely credited for developing the science of paleontology (the study of ancient life through the examination of fossils)
  • found that each layer of stratum (layer of rock in the ground) is characterized by a unique group of fossil species
  • found that deeper (older) the stratum, the more dissimilar the species are from modern life. In other words, the deeper the stratum, the more ORIGINAL it is.
  • as he worked from stratum to stratum, he found evidence that new species appeared and others disappeared over the passage of time.
  • this evidence showed species could become extinct.
  • to explain his observations, he suggested the idea that earth experiences many destructive natural events, such as floods and volcanic eruptions in the past.
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3
Q

Lyell

A
  • principles of geology
  • rejected curvier’s idea of revolutions (destructive events).
  • proposed that geological processes operated at the same rates in the past as they do today
  • if geological changes are slow and continuous rather than catastrophic, then earth might be more than 6k yrso
  • earth changes slowly
  • his idea inspired darwin
  • theorized that slow, subtle processes could happen over a long period of time and could result in substantial changes.
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4
Q

Lamarck

A
  • the inheritxance of acquired characteristics
  • By comparing currecnt species of animals with fossil forms, he observed what he interpreted as a “line of descent,” or progression, in which a series of fossils (older > recent) led to a modern species.
  • believed new simple species were always being created by spontaneous generation
  • thought organisms then have a ‘desire’ to change for the better
  • Darwin supported this view
  • thpught species increased in complexity overtime until they became perfect.
  • thought that characteristics that an organism that has scquired in its lifetime, like muscles, can be passed on to its offspring. he called this the inheritance of acquired characteristics
  • noted that an organisms adaptations to the environment resulted in characteristics that could be inherited by offspring.
  • at the end of 1800s, as biologists learned more ab cells, genes, and heredity, lamarks mechanism for inheritance was rejected
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5
Q

Darwin (Wallace)

A
  • 1831
  • knew populations changed overtime but didnt know how
  • thomas malthus proposed that populations produced far more offspring than their environments (ex; their food supply) could support and were eventually reduced by starvation or disease
  • according to them, individuals with physical, behavioural, or other traits that helped them survive in their local environments were more likely to survive and pass on these traits to their offspring
  • reasoned that individuals that had favourable traits were likely to win competiton against the same species for limited resources. soon, entire population will have these traits cus everyone else dies (natural selection)
  • hypothesized species evolve in one location and then spread out to other regions
  • species on differnt land masses looked different (finch species on galapagos)
  • fossil deposits of coral in the andes
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6
Q

Origin of species

A
  • present forms of life have arisen by descent and modification from an ancestral species
  • the mechanism for modification is natural selection working for long periods of time.
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7
Q

theory of natural selection (5 points)

A
  1. inherited variations within species
  2. more offspring that can survive
  3. populations are a stable size
  4. constant struggle to survive
  5. favorable variations = survival
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8
Q

biological species

A

a group of reproductively compatible populations

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9
Q

populations

A

the number of species in one area at a time

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10
Q

community

A

all the species that are in 1 area

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11
Q

fossil record

A

sedimentary rock with fossils provides a fossil record of the history of life by showing species that were alive in the past

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12
Q

fossil records provide the following evidence:

A
  • fossils found in young layers of rock (from recent geological periods and usually closer to the surface) are much more similar to species alive today than fossils found deeper and older layers of rock
  • Fossils appear in chronological order in the rock layers. so, probable ancestors for a species would be found in older rocks, which would usually lie beneath the rock in which the later species was found.
  • not all organisms appear in the fossil record at the same time
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13
Q

transitional fossils

A

fossils that showed intermediary links between groups of organisms
- help fill in ‘gaps’ in the fossil record

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14
Q

variability- asexual

A

low variablity and few traits that can be selected for.
- this is because they do not need sperm and eggs, since an organism splits into 2 organisms that have the same combination of genes

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15
Q

variablity- sexual

A

much more variability than asexual.
- because the sperm and egg that are produced contain different combinations of genes than the parent organisms

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16
Q

variability- sexual (3)

A
  • 2 parents 2 sets of genes
  • unique sets of genes even within siblings
  • ## often have different mates– increased variablity even more
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17
Q

effect if mutations (3)

A
  • mutations occur in the dna of organisms
  • beneficial- gives advantage
  • harmful- reduces fitness
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18
Q

mutations DONT:

A
  • occur when needed during environment change
  • harmful mutations dont accumulate to degrade all species
  • does not mean evolution is a ‘chance’
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19
Q

mutations

A
  • occur in the dna of organisms
  • there may be deletions, additions, or duplications of the sequence
  • mutations can be caused by environmental factors or during replications
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20
Q

natural selection

A

-process that results when the characteristics of a population of organisms change because individuals with certain inherited traits seurvive specific local environmental conditions, and, through reproduction, pass on their traits of their offspring.
- ex; resistant bacteria
- for natural selection to occur, there must be variety or diversity within a species

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21
Q

mutations and genetic variations

A
  • mutations lead to more genetic variation in populations
  • happen continuously in the dna of any living organism
  • can occur spontaneously when dna is copied before a cell divides
  • when dna mutates, a cell may exhibit new cjaracteristics
  • if the mutation alters the dna in a body sell, the mutation disappears when the organism dies
  • if the mutation alters the dna in a reproductive cell, like egg or sperm, the mutation may be passed on to succeeding generations
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22
Q

selective advantage

A

a mutation provides an advantage to the organism in that environment that helps it to survive and reproduce

23
Q

selective pressure

A

environment favors certain characteristics

24
Q

in natural selection, do individuals or populations change?

A

individuals did not change during their lifetime, but instead, populations did.

25
Q

adaptation

A

an inherited trait which can be a: physical feature, behavior, or psychological process that helps an organism survive and reproduce in a specific environment

26
Q

mutations and reproductions cause what…

A

cause variations among individuals in a population

27
Q

darwin 5 factors

A
  1. cinherited characteristics– we now know this is due to genes
  2. population variability- different combination of genes make up the gene pool
  3. new variations- arise from mutations
  4. natural selection- traits that are better suited for survival produce more offspring w these traits
  5. evolutionary change- more successful traits become more common and change the gene pool
28
Q

biogeography

A

the study of the past and present geographical distribution of organisms
- many observations that darwin and wallace used to develop their theories were based on biogeography
- darwin and wallace hypothesized that sepcies evolve in one location and spread out to other regions

29
Q

how does biogeography support dawrin and wallace’s hypothesis? (4)

A
  1. geographically close environments are more likely to be populated by related species than are locations that are geographically separate but environmentally similar
  2. animals found on islands often closely resemble animals found on the closest continent. this suggests that animals on islands have evolved from mainland migrants, with populations becoming adapted over time as they adjust to the environmental conditions of their new home
  3. fossils of the same species can be found on the coastline of neighboring continents
  4. closely related species are almost never found in exactly the same location or habitat
30
Q

homologous structures

A

those that have similar structural elements and origin but mat have a different function. (the structural elements are arranged to be best suited for different functions)
- similar because they were inherited from a common ancestor
- differ in their anatomy based on an organism’s lifesty;le and environment. for ex, the bones in a horse’s leg are larger and heavier than the bones in a bat’s wing
-functional similarity in anatomy, however, does not necessarily mean that species are closely related. for ex, the wings of insects birds and bats are similar in function, but not in structure. these organisms evolved independently of one another and didnt share a common ancestor w wings

31
Q

analogous structures

A

body parts that perform similar functions even though the organisms do not have a common evolutionary origin
- ex: birds and insect wings

32
Q

embryology

A
  • embryos of different organisms exhibit similar stages of embryonic development
  • similarities among embryos of related groups (ex vertebrates) point to a common ancestor
  • it follows: related species would share both adult features (basic arm and bone arrangements) and embryonic features (the presences of paired pouches in the throat)
33
Q

vestigial feature

A

rudimentary (basic, primitive) structures that no longer have a purpose
-ex ; pelvic bone in the whale, leg bones in snakes, wisdom teeth

34
Q

evidence from biochemistry

A
  • comparing proteins from different species to see how closely related they are
  • the greater the variation of the amino acid sequence in the proteins, the less related the organisms are
  • if two species have similar patters in portions of their dna, it means these portions of their dna were most likely inherited from a RECENT common ancestor
35
Q

what provides evidences of evolution

A

the fossil record, biogeography, anatomy, molecular biology, and genetics +artifical seletion??

36
Q

what have we learned about life on earth with molecular biology?

A
  • all cells consist of membranes filled w, among other components, water, genetic material, proteins, lipids, and carbohydrates
  • proteins called enzymes control biochemical reactions in all organisms
  • in all organisms, all cells that can replicate contain DNA. scientists can determine how related 2 organisms are ny comparing their dna. similar portions of dna = these portions were most likely inherited from a recent common ancestor
37
Q

evidence of evolution from biogeography

A
  1. geographically close environments are more likely to be populated by related species
    2/ animals found on islands are often closely found related to animals found on the closest continent
  2. fossils of the same species xan be found on the coastline of neighbouring continents
  3. closely related species are almost never found in exactly the same location or habitat
38
Q

can biological species that are geographically isolated interbreed?

A

no

39
Q

what are some ex. of reproductively isolated traits in species

A
  • different physique (elephants and frogs)
  • different breeding time period (spring, fall)
  • different mating call (finches)
  • different courtship shit (finches)
40
Q

speciation

A

formation of a new species. population of old species cant breed w new species

41
Q

transformation

A

when a new species gradually develops as a result of m,utation and adaptation to changing environmental conditions and the old species is gradually replaced

42
Q

evidence from artificial selection

A
  • human selected traits that are desired
  • can be dramatic changes in short time
  • humans choose the appearance, behavior and chemical makeup of bplants and animals
  • ex many tyoes of cabbage, kale, etc. all came from sea cabbage
43
Q

divergence

A

when one or more species arise from a parent species that continues to exist
- result of natural selection
- increases biodiversity

44
Q

geogrphical barriers

A

prevent interbreeding and result in speciation because they keep populations physically separated (ex, mountains and rivers)
- maintained long enough for populatirons to change

45
Q

biological barriers

A

keeps species isolated
- behavior. ex; courtship songs of birds (behavioural)
- pheromones. ex female spiders use pheromones to attract mates of the same species
- same general area but different habitat. for ex, one species lives near water and the other one rarely goes there. this isnt like geo. barrier because therw is no physical impediment keeping populations apart

46
Q

how do some animals become reproductively isolated within the geographical range of a aprent population

A

if they begin to use resources that arent used by their parents

47
Q

adaptive radiation

A

the diversification of a common ancestral species into a variety of species , all of which are differently adapted.

48
Q

pace of evolution- gradualism

A

gradual changes occur steadily, in a linear fashion.
- aka small changes in a species over a long period of time

  • however, the fossil record rarely reveals fossils that show this gradual transition. it is often found by paleontologists that species that appear suddenly in the fossil record disappear just as abruptly.
49
Q

pace of evolution- punctuated equilibrium

A

many species evolve rapidly, intermediate (in between) fossils are rare, they then do not change very much
- evidence in fossil record show periods of rapid change (rapid speciations after mass extinctions) led to this theory.
- stable populations, little evolutional change for most of its geological history

-consists of long periods of equilibrium, interrupted by periods of speciation

50
Q

what two pathways can a new species form

A

tranformation or divergence

51
Q

what causes speciation

A

when two populations are prevented from interbreeding, barriers to reproduction can be geographical or biological.
- speciation has occured when populations become reproductively isolated

52
Q

allopatric speciation

A

a mode of speciation that occurs when biological poulations bevome geographically isolated from each other– prevents interbreeding
1. geographical barrier
2. due to a mutation in one of the groups and different selective pressures, one group will evolve differently
3. in time, physical/behavioural differences isolate the 2 groups and they are no longer the same species

53
Q

divergent evolution

A

occurs when related species develop unique traits due to different environments or selective pressures
- evolution into many different species
- occurs after cataclysmic event
- this has happened w the end of dinosaurs

Biology Unit 2 (2 decks)

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