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Biology 101 > Exam 4 > Flashcards

Exam 4 Flashcards

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1
Q

What are the contributions of Greek philosophers and French naturalists to the history of evolutionary biology?

A
  • Aristotle developed the scientific method and though species were fixed
  • Aniximander proposed that organisms have changed and evolved to their present forms
  • Cuvier established extinction as a fact
  • Buffon said diversity of life is the result of evolution
  • Lamarck said interactions with environment causes evolution of individuals
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2
Q

What was the mechanism of evolution proposed by Lamarck?

A

interactions with environment causes evolution of individuals via use and disuse, which is incorrect

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3
Q

What was the mechanism of evolution proposed by Darwin/Wallace?

A

organisms interacting with their environment produced change in populations overtime, evolution

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4
Q

What experiences and ideas helped Darwin develop and support the theory of evolution by natural selection?

A
  • observed varying looking finches and correlated traits with environmental challenges
  • Darwin read Thomas Malthus’ essay saying as population size increases, resources dwindle, and conflict increases
  • Evidence: biogeography, comparative morphology, domesticated animals, geology
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5
Q

What is the difference between micro- and macro- evolution?

A

Microevolution: changes to the gene pool of a population over time (can be adaptive)

Macroevolution: formation or loss of a species

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6
Q

What is the relationship between micro and macro evolution?

A

Over time, microevolution can lead to macroevolution

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7
Q

What is the relationship between microevolution and genetic equilibrium?

A

GE is opposite of microevolution

Allele frequencies stay the same

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8
Q

What are the five conditions of genetic equilibrium?

A
  1. no mutation
  2. random mating
  3. gene doesn’t affect survival or reproduction
  4. large population
  5. no immigration/emigration

All must be present for equilibrium

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9
Q

What is the purpose of the Hardy-Weinberg rule/equation?

A

To tell if a population is staying in equilibrium from one generation to the next

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

Freq of allele A = p
Freq of allele a = q
p+q=100%

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10
Q

What are the five mechanisms of microevolution?

A
  • mutation
  • natural selection
  • non-random mating
  • migration (gene flow)
  • genetic drift
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11
Q

What is a mutation and how can it change the gene pool of a population?

A
  • change in the DNA sequence of an organism, which can occur naturally or due to environmental factors
  • can introduce new genetic variations into a population’s gene pool, potentially leading to evolutionary changes over time
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12
Q

What is natural selection and how can it change the gene pool of a population?

A
  • difference in the survival and reproductive success of different phenotypes
  • acts directly on phenotypes and indirectly on genotypes
  • can lead to adaptations
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13
Q

What are some examples of natural selection changing a gene pool?

A
  • pesticide resistance
  • antibiotic resistance
  • sickle cell trait
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14
Q

What is non-random mating and how can it change the gene pool of a population?

A
  • selection favors certain secondary sexual characteristics
  • results in alleles for preferred traits increasing
  • leads to sexual dimorphism
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15
Q

What is the genetic problem created by non-random mating?

A
  • inbreeding
  • homozygosity (loss of alleles)
  • can lower fitness
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16
Q

What is a migration, and how can it change the gene pool of a population?

A
  • physical flow of alleles into a population
  • keep gene pools of populations similar
  • counters differences that result from mutation, natural selection, and genetic drift
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17
Q

What is genetic drift and how can it change the gene pool of a population?

A
  • random change in allele frequencies brought about by chance
  • most pronounced in small populations
  • similar to sampling error
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18
Q

What are bottlenecks and founder effects and how do they contribute to genetic drift?

A
  • a severe reduction in population size
  • causes pronounced drift

-effect of drift when small number of individuals start new population
- allele frequencies of founders may not be same as those in original population
- effect pronounced on isolated islands

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19
Q

What are the two most common species concepts?

A

morphological- based on physical traits of organisms

biological- based on the potential to share genes

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20
Q

What are the advantages and disadvantages of each species concept?

A

morphological: A) easy to use and may be only option
D) not useful in distinguishing species

biological: A) emphasizes reproductive isolation
D) not applicable to asexual organisms

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21
Q

What is genetic divergence and how does it relate to speciation?

A
  • gradual accumulation of differences in the gene pools of populations
  • gene flow counters divergence (speciation)
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22
Q

What is the relationship between reproductive isolation and the biological species concept?

A

speciation = genetic isolation
speciation is the attainment of reproductive isolation

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23
Q

Define pre and post zygotic isolation

A

Pre:
- mating or zygote formation is prevented
post:
- takes effect after hybrid zygotes form
- zygotes may die early, be weak, or be sterile

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24
Q

Examples of prezygotic isolation

A
  • temporal isolation
  • habitat isolation
  • behavioral isolation
  • mechanical isolation
  • gametic mortality
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25
Examples of postzygotic isolation
- hybrid inviability - hybrid sterility - zygotic mortality
26
What are possible geographic relationships among populations during speciation?
- allopatric speciation - sympatric speciation - adaptive radiation
27
What are some examples of allopatric and sympatric speciation?
Allopatic: speciation in geographically isolated populations sympatric: species forms within the home range of the parent species
28
What is adaptive radiation and how does it relate to allopatric and sympatric speciation?
- combo of allo and symp - colonization of islands followed by genetic divergence between and within islands leads to speciation
29
What is polyploidy and how could it lead to speciation?
- change in chromosome number - cannot breed with parent population - common mechanism of speciation in flowering plants
30
What types of data do we use to study evolutionary history?
- fossil records - comparative anatomy - embryology
31
What is a fossil?
Recognizable evidence of ancient life - fossilized hard parts (most common) - trace fossils (indirect evidence)
32
How do fossils form?
1. organism buried in ash or sediments 2. rapid burial and a lack of oxygen 3. organic remains become infused with metal and mineral ions
33
How can we determine the relative age of two fossils?
Stratification - layers closest to the top were formed most recently
34
How can we determine the actual age of a fossil?
radiometric dating
35
How does the process of radiometric dating work?
Measure the ratio of the original radioactive isotope to the new, stable isotope formed from its decay. Because the rate of decay (known as the half-life) is consistent and known for specific isotopes, the ratio of isotopes indicates how much time has elapsed since the rock or fossil was formed.
36
What events are used to determine the beginning and end of geological eras?
Geologic time scale - boundaries based on abrupt transitions in fossil records - correspond to mass extinctions
37
How can we tell where the continents have been in the past?
Evidence of movement - cited from glacial deposits and fossils - magnetic orientations in ancient rocks do not align with the magnetic poles
38
What causes continents to move?
- Seafloor spreading - plate tectonics
39
What are some of the supercontinents of past eras?
- Pangea - Laurasia - Gondwana
40
What is comparative morphology?
comparing body forms and structures of major lineages - evolution tends to follow the path of least resistance
41
What are homologous structures and what do they tell us about shared ancestry?
traits that have common origin, but may serve different functions change from the body form of a common ancestor
42
What is comparative development?
Each animal or plant proceeds through a series of changes in form - similarities may be clues to evolutionary relationships
43
Why do developmental genes have such a big impact on evolution?
Some mutations shift a step in a way that natural selection favors
44
How is pedomorphosis related to developmental changes?
Adult forms can retain juvenile features
45
What are some examples of pedomorphosis?
- proportional changes in skull
46
What is comparative biochemistry?
types and amounts of biochemical traits species share is a clue to proximity of relation - more similar = more closely related
47
What kinds of molecules are used to study evolution?
DNA, RNA, proteins
48
How do we determine evolutionary relationships among species?
homologous structures used to determine evolutionary relationships
49
What is extinction, and why is it important in the evolutionary process?
Irrevocable loss of a species - reduced diversity is followed by adaptive radiation
50
What kinds of data are used to determine evolutionary relationships?
- genetic data - morphological data - developmental data
51
How does evolution via cladogenesis differ from anagenesis?
Clado: - branching pattern - lineage splits, isolated populations diverge Ana: - no branching - changes occur within single lineage
52
What is taxonomy?
field of biology concerned with identifying, naming, and classifying species
53
What is the taxonomic system devised by Carl von Linne?
Binomial system - two part latin name - first is generic - second is specific
54
What are the higher-level taxonomic groups above species
55
Give timeline of major events in the history of life on Earth
4.5B yrs: Earth made 3.5B yrs: prokaryotes appeared 2.5B yrs: Oxygen production began 1.7B yrs: single-celled eukaryotic organisms evolved
56
What were the original animals on Earth?
Prokaryotes
57
What are the key branch points used to determine to classify animal phyla?
1. true tissues 2. bilateral/radial symmetry 3. body cavity presence 4. pseudocoelom/true coelom 5. coelom from cell masses/coelom from digestive tube
58
What are true tissues?
no cell walls
59
Radial vs bilateral symmetry
60
What is the difference between a pseudocoelom and a true coelom?
pseudocoelom doesn't support or connect digestive system
61
What is an invertebrate?
animals without backbones
62
Sponges
63
Cnidaria
64
Platyhelminthes
65
Nematoda
66
Mollusca
67
Annelida
68
Arthropoda
69
What are the four main groups of arthropods?
- arachnids - crustaceans - millipedes/centipedes - insects
70
Echinodermata (all marine)
71
Chordata
72
What are the four traits shared by all chordates?
1. dorsal, hollow nerve cord 2. notochord 3. pharyngeal slits 4. post-anal tail
73
What are the major groups of organisms in the phylum Chordata?
- vertebrates - tetrapods - amniotes
74
How do amphibians differ from terrestrial tetrapods?
amphibians usually need water to reproduce
75
What are three important adaptations found in reptiles, birds, and mammals that make them successful on land?
1. scales/keratin to prevent from dehydration 2. lungs for breathing 3. amniotic egg
76
What are some adaptations of birds for flight?
- honeycombed bones = lighter weight - absent organs to reduce weight
77
What are the two traits found in all mammals?
- hair - mammary glands
78
What are the three reproductive methods of mammals?
1. Monotremes (egg-laying) 2. Marsupials 3. Eutherian (placental)
79
In which geological era did primates evolve?
Cretaceous period
80
What are the characteristics of primates?
- limber shoulder joints - opposable thumbs - front facing eyes - good hand-eye coordination - extensive parental care
81
What are the major divisions within the pimate order?
- Prosimians (lemurs, lorises, tarsiers) - Anthropoids (monkeys, apes, humans)
82
Approximately how long ago did hominids diverge from apes?
7-8 million years ago
83
What is a major characteristic that defines the family Hominidae?
Bipedalism
84
On what continent did hominids evolve?
Africa
85
How old is our species, Homo Sapiens?
300,000 years

Biology 101 (4 decks)

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