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Biology 3051 & 3052 SPECIATION > BIO 3051 EVOLUTION PATTERNS > Flashcards

BIO 3051 EVOLUTION PATTERNS Flashcards

1
Q

Adaptive radiation

A

Rapid evolution of ancestral (single) species into several lineages, each with their own unique adaptations

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2
Q

Co-evolution

A

A change in the genetic composition of one species in response to a genetic change in another species.

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3
Q

Two aspects of study of evolution

A

Patterns (products of evolution)
• adaptive radiation
• parallel
• co-evolution

Processes underlying these patterns

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4
Q

Key people involved in study of evolutionary biology

A

-Lamarack
-Malthus
-Darwin
-Wallace

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5
Q

Lamarack

A

-French naturalist
-species themselves had a role in determining their evolution
-e.g. giraffe obtains a long neck by striving to reach higher to get food
-characteristics developed in the life of indiv could be inherited by next gen.
-inheritance of acquired characteristics & was misleading

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6
Q

Malthus

A

-british economist
-essay on human populations
-showed that human population could increase in size exponentially if it wasn’t for limits to resources
-respurces such as food, shelter, build up of wastes degrading environment
-catastrophic collapse in population size

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7
Q

Darwin

A

-despite Malthus’ predictions of rapid increase, natural populations tend to remain at the same size
-most offspring must die before maturity
-lots of variation within a species

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8
Q

Wallace

A

-as environment changes, or species moves into different range, environment would select different characteristics so that the population would gradually change some of its characteristics
-about 8 million species alive on earth

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9
Q

Give evidence to support the theory of evolution as well as deductions .

A

Observation (evidence)
-indiv in a population have a great reproductive potential
-variation between inidv exist in all populations
-numbers of indiv in a population remain fairly constant

Deductions
-must be a struggle for existence between indiv in a population
-variation must underpin evolution
-in struggle for existence & survival those individuals showing features best adapted to their environment at that point in time must have a reproductive advantage and will therefore produce more offspring than less well-adapted individuals.

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10
Q

Phenotype is the result of an interaction between environment and gene expression

A
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11
Q

How is variation caused

A

By differences between individuals at genetic level

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12
Q

How is evolution made possible

A

Because of the differences between individuals in terms of the allele combinations they carry.

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13
Q

Fossil

A

-Preserved remains or traces of past life forms
-Important dating method to look into the past
-at least 10 000 years ago
-oldest fossil 3.4 billion years old
-preserve only parts, teeth, bones, calcium- or chitin-rich exoskeletons

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14
Q

Linnaeus taxonomy

A

-classified all organisms within a hierarchy
-at the top, living organisms are placed in one of three kingdoms
-archaea, bacteria and eukaryota

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15
Q

Phylogenetic tree of life

A
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16
Q

Explain the hierarchy of living organisms

A

-kingdoms
-classes
-orders
-families
-genera

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17
Q

Species

A

A group of individuals that interbreed and produce fertile offspring

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18
Q

Macro-evolution

A

Evolution on a larger time scale, such as thousands or millions of years.
Changes that happen at or above the species level.

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19
Q

Micro-evolution

A

The changes in allele frequencies that take place within a population. Micro-evolution tends to cover a small period of time such as about 100 years

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20
Q

Explain “evolution is descent with modification”

A

-charles darwin
-suggested all species alive today are descendants of ancestral species
-ancestors were different from the species alive because of different environments.
-would require for species to have different adaptations and different survival strategies

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21
Q

Adaptations

A

Inherited characteristics of organisms that enhance their survival and reproductive success in a specific environment at a specific point in time

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22
Q

Ancestral species

A

Species from which a number of new species are descended.

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23
Q

How are ancestral species vulnerable to mammalian predation

A

-strong body odor
-often live and nest on the ground
-may be slow-moving
-long-lived and breed slowly
-many bird species lost power of flight because there was no threat of predation on the ground.

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24
Q

Genetic vatiation and evolution

A

-for evolution to occur, genetic variation os needed
-changes have to be incorporated from one generation to the next
-need several generations for changes to show up in phenotype means that time plays an important part

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25
Q

Dating methods

A

-the direct and indirect methods used to determine the order of past events or age of fossil evidence
-DNA analysis
-protein analysis
-biogeography

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26
Q

Biogeography

A

The study of the distribution of species in geographic soace and through geological time.

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27
Q

Why would the fossil record be patchy.

A

-long periods of history, conditions for preserving fossils are unfavorable and there is no record.
-some places where there were many different forms of life, landscape was eroded away and wiped clean of fossil records.
-by pure chance that fossils become exposed
-small land mass, and varied habitats
-fossils are of a variety of forms & very few contain original plant or animal material

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28
Q

Petrified wood

A

Wood in which all the organic molecules, including DNA, have been replaced by minerals such as quartz

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29
Q

Give assumptions made when fossils are located in undisturbed rock formations

A

-any rocks found under the fossils are older than the fossils. Recording different depths, order of succession is revealed and is especially clear in sedimentary rocks because the layers were formed with new ones on top

-identifying similar fossils in seperated rock formations is used to decide which rock layers are of the same age.

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30
Q

Global geochronological scale

A

The overall international time scale.
-give relative time - order of events in relation to each other

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31
Q

Indirect dating method

A

When age of a fossil is related to the age of the layers of rock in which it is found

32
Q

Geomagnetic polarity

A

-at mid-ocean ridges, new ocean floor is moving up and adding to the tectonic plates which move horizontally away from the ridge.

-when new rock is beginning to solidify, some minerals in it become lined up with the earth’s magnetic field.

-at intervals, earth’s polarity reverses and a band of rock with reversed magnetic particles forms. Forms a pattern which is symmetric accross the ridge

-compare arrangements of magnetic patterns from different places, rocks can be corelated with each other and their dates calculated.

33
Q

Isotopes

A

-dating life forms in absolute time, is dating back to the time they were alive.
-measure levels of radioactive isotopes of elements that were incorporated into the plant or animal
-as isotopes give off radiation, atoms change at a known rate
-smaller amount of radioactive isotope present in the sample, older the sample is

34
Q

Direct methods

A

-dating methods which use information from the fossil or organism itself
-e.g. measuring of the level of silicon-32 in a sponge spicule to give an absolute value to the fossil’s age

35
Q

Give the 5 dating methods

A
  1. Protein
  2. Molecular clocks
  3. DNA annealing
  4. Microsatellites
  5. Mitochondrial DNA
36
Q

Explain protein as a dating method

A
  1. Sequencing protein
    - by finding sequence of amino acids in protein molecule from different species, calculations can be made :
    • how closely related they are
    • time frame diverging from a common ancestor

The greater the difference, the more time has elapsed for the cytochrome to change.

37
Q

Relative times of divergence

A

Order in which species appeared

38
Q

Explain molecular clocks as a dating method

A

DNA mutations occur in some genes at regular intervals. So, by examining related species for similar genes, it’s possible to work out how far back in time their common ancestors seperated from each other. Mutations can be used as a molecular clock.

E.g. specific gene mutates once every 12 million years
So if two species with this gene are known to have five base differences between them, the age of their lineage would be 60 million years (5 x 12 mil years).

And both species have been evolving at the same time so actual time lapse is 30 million years (60 mil / 2)

39
Q

Explain DNA annealing as a dating method

A

-DNA is heated, hydrogen bonds are broken resulting in two single DNA strands.
-If cooled, they join again by reforming hydrogen bonds between complimentary base pairs.
-So, double stranded DNA forms again.
-more bonds formed = more energy required to seperate them
-if annealing takes place between closely related species, many bonds are formed because more base sequences match
-high temperature is required to seperate them
-if very different species, fewer bonds will form between opposing strands and annealing temp will be lower.

40
Q

3 key points of annealing

A
  • If mixture of DNA is made from different species, then heated and cooled, there will not be as many bonds and strands will seperate at a lower temperature

-By annealing DNA from different species and finding melting point of the combines strands, a tree showing how closely related the species are can be constructed

-Thermal seperation of DNA strands causes them to denature and then anneal, or join together when cooled.

41
Q

DNA ANNEALING

A
42
Q

Describe microsatellites as a dating method

A

-defined as loci (regions within DNA base sequences) where short sequences of DNA are repeated in arrays. Which means that the sequences are repeated one right after the other.

-di tri or tetra nucleotides are most common

-repeat sequences do not code for proteins sk they are not directly expressed in the cells. As they don’t change phenotype, they’re not affected by environmental selection pressures.

-useful for dating as frequency in population is not so affected by natural selection as other loci are

-microsatellites are inherited within a species like alleles (but with no phenotype). By comparing same region of DNA in individuals from different species, it is possible to deduce how long since species seperated.

43
Q

Explain mitochondrial DNA as a dating method

A

-mitochondria are structures found in living cells
-involved with cellular respiration, which produces energy rich compound ATP.
-each mitochondrion has DNA which contains genes for synthesis of molecules needed to carry out cellular respiration.
-in many animals, mitochondrial DNA from sperm does not enter the egg.

-result is that mitochondria of an individual are all obtained from the egg, therefore from the mother only.
-by extracting dna and sequencing it, able to compare mtDNA from different animals.
-appears to mutate at a fast rate it can provide an indication of how long it has been since the two species or populations seperated

44
Q

Gradualism

A

A slow accumulation of changes producing new species over time

45
Q

Punctuated equilibrium

A

The rapid appearances of new life forms seperated by long periods without change

46
Q

Adaptive radiation

A

The evolution of many species from a common ancestor as they form populations in a variety of niches

47
Q

Fossil evidence

A

Shows specific times when a large number of new life forms appear in a very short period of different genera and families. Mass extinctions are followed by the appearance of new forms.

48
Q

Cladogram

A

Diagram to show an organism’s evolutionary history

49
Q

Divergent evolution

A

Process of two or more related species becoming more and more different. Adaptive radiation is a form of divergent evolution.

50
Q

Parallel evolution

A

Development of a similar trait in related but distinct species descending from the same ancestor

51
Q

Convergent evolution

A

Development of the same biological trait (such as body form, colouration, organs) in unrelated lineages

52
Q

Different evolutionary patterns are…

A

A reflection of having different ancestors, being productively isolated, and adapting to the niches available.

53
Q

Biodiversity

A

The degree of variation of life forms within an ecosystem of the entire planet

54
Q

What is cladistics

A

A cladogram is a chart which shows the relationships between organisms as a sequence of divisions of a group into two groups (bigurcation).
Each division point on the chart is called a node and each group is located at the end of a branch.

55
Q

Cladistics

A
56
Q

Phylogenetic tree of living hominoids based on DNA-DNA hybridisation data

A
57
Q

What are ratite birds

A

They form a distinctive group of birds with unique features which makes them appear to be a naturally related group.

58
Q

Ratite evolution

A

• Distinctive group of birds with unique features which makes them appear to be a naturally related group.
• Include emu and cassowary in Australia, ostrich in Africa, rhea in South America, moa and kiwi in New Zealand.

59
Q

Explain ratite features

A
  • Feathers are soft and hairy, do not have barbells or small hooks which join together to make a vane suitable for flight.
  • Bones are not hollow and light as those of flying birds, some bones have marrow
  • Flying birds have a keel along the breast, a flat bone for the powerful muscles from wings to attach to. Ratites have no keel but a flat breastbone.
  • Heavy and flightless with powerful legs
  • Found in the southern continents, suggesting that their origins are similar
60
Q

What does nz fauna and flora reflect

A

The effect of plate tectonics, climate change, and migration

61
Q

New Zealand geography major events

A

Humans arrive
Extinctions
Plant and animal migrations
Islands forming and joining
Ice ages
Mountains form
Land sinking
Tasman sea develops
Temperature changes

62
Q

What are the two theories of ratite distribution

A
  1. Vicariance biogeography
  2. Dispersal theory
63
Q

Explain vicariance biogeography

A
  • first theory of ratite distribution
  • allopatric speciation, populations become geographically isolated by natural barriers forming in the environment.

-because ratites are flightless, they were spread out on land masses that were joined together, by walking from one place to another when southern continents were joined together.

-ratites population have been split into seperate groups as the movement of tectonic plates began to seperate the continents

-seperate populations then evolved into different species by natural selection, genetic drift, and mutations

-vicariance explains the distribution of species by tectonic plate or continental drift.

64
Q

Explain dispersal theory

A

-second theory of ratite distribution

-also a form of allopatric speciation, but the seperation of populations happen because they spread to new places and become reproductively isolated.

-considered an unlikely way for ratites to spread because they are heavy flightless birds.

-another possibility is that they drifted on floating vegetation across the oceans (not a serious possibility regarding the distances involved and the large size of the birds)

65
Q

Vicariance theory (short)

A

Ratites evolved as they were moved around on land masses as a result of continental drift or plate tectonics

66
Q

Peer review

A

Scientific journals or publishers ask experts to review new articles before they get published & evaluating research.

67
Q

Scientific debates ensures…

A

That theories of evolution are well supported by rigorously tested evidence

68
Q

Different methods of analysis could result in…

A

A different interpretation of the results

69
Q

DNA is a powerful tool in the examination of ?

A

Relatedness between species AND the time since their seperation

70
Q

Biodiversity can be affected by :

A

-size of land area
-height above sea level
-distance from the mainland

71
Q

Latitudinal diversity gradient (LDG)

A

Latitudinal diversity gradient is the decrease in variety of species from the equator towards the poles

72
Q

3 reasons for LDG

A

-near equator conditions seldom changefrom one month to another throughout the year. Plenty of light and water, providing ideal place for living organisms and so a variety of forms and types of organism can survive. Natural selection is less severe near equator than nearer the poles.

-further from equator the more often ice sheets will invade land or sea, causing some species to become extinct

-towards poles, species tend to be larger than near the equator. Therefore, not many organisms can exist in one area, as larger individuals need more food and territory than their similar counterparts in equatorial regions

73
Q

How does island size have an impact on the number of different species

A

Larger islands tend to have more species than smaller ones.

74
Q

The diversity of species in an island habitat is related to :

A

-arrival from other places / dispersion
-evolution of new species / speciation
-dying out of species / extinction

75
Q

4 reasons for endemism (paragraph question)

A
  1. Species are adapted for very specific environmental conditions & do not settle and mature in areas with different conditions. Supported by large number of species each occupying its own habitat and niche
  2. Large number of endemic species in NZ indicates that they have evolved in a large number of microhabitats & have little tolerance for slightly different conditions.
  3. Occasional events such as run-off from the land, volcanic ash eruptions and toxic algae can pose a threat to local populations.
  4. NZ waters contain a number of seamounts. These provide tremendous variety of habitats which are isolated from each other, maintaining populations of endemic species

Biology 3051 & 3052 SPECIATION (5 decks)

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