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VCE > Evolution 🧫 > Flashcards

Evolution 🧫 Flashcards

1
Q

What is a gene pool?

A

All the alleles in a population of a specific species at a particular point in time.
Or the amount of genetic diversity within a population

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2
Q

What is an allele?

A

Alternative form (different version) of a gene

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3
Q

What is a population?

A

All the members of a species in a location at a specific time

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4
Q

What is a mutation?

A

Change to the DNA of an organism that is random and unpredictable

Therefore the gene and the change within the gene cannot be predicted.

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5
Q

What are the 2 types of mutations?

A

Spontaneous mutation: A mutation that happens for no particular reason.

Induced mutation: Caused by something such as ionising radiation or chemical mutagen.

All of these are unpredictable and random.

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6
Q

What is a fossil?

A

Evidence of life from the past

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7
Q

What is a mold?

A

Impression of a living thing left in a rock

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8
Q

What is a cast?

A

When a mold is filled with sediment or minerals

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9
Q

What is a petrified fossil?

A

When minerals move into and replace the space of organic material in an organism

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10
Q

What are trace fossils?

A

Geological records of activity of an organism such as footprints or burrows

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11
Q

What is a species?

A

Group of living organisms consisting of similar individuals that could potentially mate and produce viable and fertile offspring.

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12
Q

What is the morphological species concept?

A

If a group of organisms have similar morphology (physical form/characteristics) the same they are the same species (used by palaeontologists)

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13
Q

What is the phylogenetic species concept?

A

The smallest clade (group of organisms that all have a common ancestor) that can trace its evolutionary origins to a common ancestor
- contain unique characteristics from that ancestor that sets them apart from other groups.

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14
Q

What is speciation?

A

When one species separates into and forms seperate species

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15
Q

What is allopatric speciation?

A
  1. A parent population containing variation is divided by a geographic barrier
  2. There is no gene flow (immigration and emigration) between 2 daughter populations.
  3. Mutations (may) arise in populations randomly
  4. AND/OR different selection pressures act on the populations causing natural selection

As a result the 2 populations evolve via natural selection to become so different they can no longer produce viable and fertile offspring –> leading to different species.

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16
Q

Explain the case of the: Galapogas finches

A
  • Group of 18 species of finches live on the Galapogas islands
  • These islands have different habitats on them
  • As a result, these different islands contain different environmental selection pressures
  • Natural selection acts on the finches and they rapidly evolve to become distinct/different species in a process of adaptive radiation

Example of allopatric speciation
- Process of adaptive radiation: Rapid speciation of once species into many, adapting to different ecological niches.

17
Q

What is sympatric speciation?

A

Evolution of a new species from original population of species while they inhabit the same geographical region.

18
Q

What is disruptive selection?

A
  • Cause of sympatric speciation
    If sympatric speciation occurs in animals it is thought to be because of disruptive selection.
  • Type of natural selection that favours extreme traits over intermediate traits
19
Q

Explain the case of the Lord Howe Island palms

A
  • A palm tree that once occupied the Lord Howe Islands underwent sympatric speciation to give rise to 2 types of palm trees.
  • The curly palm (howea belmoreana) and Kentia palm (howea forsteriana) both live on Lord Howe island.

They have developed physiological differences (due to soil types) which cause them to be reproductively isolated due to a difference in flowering times H. Belmoreana flowers 6-7 weeks later than H. Forsteriana (as a result of the different soils)

Though there is difference in elevations on the Lord Howea Islands as well

20
Q

Where does the howea belmorana grow (curly palm)?

A

In nutrient rich volcanic soils that have low pH

21
Q

Where does the howea forsteriana (kentia palm) grow?

A

In nutrient poor calcarenite soils which have high pH

22
Q

What is the significance of the different soils the palms of Lord Howe Islands grow in?

A

That are believed to have caused the shift in their flowering times causing reproductive isolation hence different species –> speciation

Example of disruptive selection

23
Q

What is relatedness?

A

Refers to how recently species split from common ancestor
If species are related y evolution, should show similarities in biochemical and genetic composition

Greater degree of similarity if species are more closely related due to being split from shared common ancestor more recently

24
Q

What is molecular homology

A

Homology is the existence of a shared ancestry between a pair of DNA sequences, proteins or amino acid sequences (shows a common evolutionary origin)

The more mutations that accumulate in DNA sequence between species, the more time will have passed since the 2 species diverged from common ancestor

Sequences from different organisms are homologous if they follow the same basic pattern, implying that molecules have a shared evolutionary history.

25
Q

What is a monophyletic group

A
  • Includes a common ancestor and all its descendants
  • can be removed from phylogenic tree with one cut of its branch
26
Q

What is a taxonomic group?

A

Groups that do not share a common evolutionary ancestor but appear similar

27
Q

What are the requirements for something to be fossilised?

A
  • Must die underwater
  • Be buried in sediment almost immediately with the absence of oxygen (to prevent bacteria from decomposing the specimen)
  • Be left undisturbed for a long period of time
  • Have hard body parts
  • They form in sedimentary rocks
28
Q

What is the process of fossilisation?

A
  1. Death and decay: The soft body parts of an organism decompose or are scavenged, leaving only hard body remains.
  2. Deposition: The hard body parts are covered by sand and overtime more layers form.
  3. Permineralisation: The pressure from the layers formed cause the hard body parts to be replaced by minerals.
  4. Erosion/exposure: The movement of the tectonic plates displaces the fossil and return it to the surface for discovery
29
Q

The fossil record

A

The total number of fossils and their placements in rocks

30
Q

What are transitional fossils?

A

If a species has evolved, it is believed that the fossil record would show fossils of the intermediate form.

31
Q

What is relative dating based off?

A

Stratigraphy

32
Q

What is stratigraphy?

A

The study of positioning of rock strata (layers of rock), some in which containing fossils

The oldest rocks are at the bottom whilst the younger is towards the top (principle of superposition)

33
Q

What is an index fossil?

A

Fossils used to identify and define geological time periods

34
Q

Requirements of an index fossil

A
  • Lived within a short range
  • Abundant
  • Wide geographic distribution
  • Distinct and easily recognisable.
35
Q

What is absolute dating (radiometric dating)?

A
  • Used to determine the actual ages of rocks
  • Uses the presence of radioactive isotopes in rocks
  • Parent isotopes decay at a known and regular rate to produce a stable daughter product
  • over a given period, half life, half of the parents isotopic atoms are converted to atoms of its daughter isotope.
36
Q

What is radiocarbon dating?

A
  • In an organisms life the ratio of stable carbon 12: radioactive carbon-14 is constant and matches the carbon dioxide in the atmosphere.
  • Though after the death of an organism the amount of carbon 14 decreases therefore changing the ratio
  • via half life of the parent isotope and comparing to the daughter the approximate age of a fossil can be found.

VCE (4 decks)

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