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Biology 4 > Changes in biodiversity overtime > Flashcards

Changes in biodiversity overtime Flashcards

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1
Q

What is the theory of special creation? (3)

A

Each species was separately and independently created.

  • would not be capable of change
  • would not be able to produce different descendent species.
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2
Q

What is the view of the transmutation of species?

A

Species that were not fixed but capable of change over successive generations.

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3
Q

What are sources of evidence for evolution? (6)

A
  • Palaeontology – The interpretation of fossils
  • Embryology – The study of embryonic development
  • Comparative anatomy – The study of particular structures
  • Biochemistry – DNA similarities
  • Biogeography – Geographic distributions of organisms
  • Taxonomy – Classification similarities
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4
Q

What is planetology?

A

Involves the study of ancient life represented by fossils

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5
Q

What is the fossil record?

A

Refers to the total number of fossils that have been discovered, providing evidence of evolution through geological time

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6
Q

What is a fossil?

A

Preserved remains or impression of once-living organisms.

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7
Q

What is relative age?

A

The age of the fossil is estimated relative to the known age of the layers of rock above and below the layer in which the fossil is found.

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8
Q

What are the disadvantages of relative dating?

A
  • ## Relative dating can be difficult in areas where rock layers have been eroded away, or where rocked have been buckled, moved or reburied.
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9
Q

What is the strategic method of relative dating fossils?

A

Gives relative ages of rock strata by using the principle of superposition:
States that for rock layers or strata, the oldest strata are at the bottom and progressively younger layers lie above.
- only used to identify strata in the same sequence

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10
Q

How can index fossils be used for the relative dating of fossils?

A

Used to identify relative ages of fossils in different locations based on the law of fossil succession:
- changes that occur over time in the kinds of fossils that exist in rocks from different locations with similar fossils can be assumed to have similar ages.

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11
Q

What are index fossils?

What does their use allow for?

A

Fossils of geologically short-lived species that are widely distinctive but found in a restricted depth of rock.
This allows rocks of the same age to be identified.

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12
Q

What is absolute age?

A

Absolute dating is a method of determining the specific date of a paleontological or archaeological artifact.

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13
Q

What type of dating is absolute dating?

Explain.

A

A radiometric technique.

Technique used for estimating the absolute ages of rocks using the rate of decay of certain radioactive isotopes.

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14
Q

What are the conditions required for fossilisation? (4)

A
  • Low oxygen
  • Rapid burial by sediments
  • A stable and moist environment
  • Organism typically needs to contain hard/bony parts
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15
Q

What are the steps of fossilisation?

A
  1. Typically occurs underwater.
  2. An organism dies and sinks to the bottom of a water body. Its body is rapidly covered by sediments.
  3. The pressure of more sediment layers building up and the weight of the water over a long time can turn the sediments into rock (e.g. sandstone, mudstone, siltstone, shale.)
  4. Generally, the hard, bony parts are preserved.
  5. It needs to be left undisturbed for a very long time.
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16
Q

What does the fossil record show? (4)

A
  • Life in the past appears to have been relatively simple
  • Many species that used to exist are now extinct
  • Many extant species don’t seem to have existed in the past
  • Modern species can be traced through fossils to distant origins
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17
Q

What are the limitations of absolute dating?

A

Cannot be applied to sedimentary rocks that are derived from erosion of pre-existing rocks because minerals they contain were formed prior to sedimentary rocks themselves.

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18
Q

What does absolute dating depend on?

A
  • the fact that various elements exist as two or more isotopes
  • the rate at which the specific isotopes decay
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19
Q

What is a half-life?

A

The amount of time it takes for half of the material to decay.

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20
Q

What is potassium-argon dating?

A

Decay of radioactive potassium-40.

Based upon the decay of radioactive potassium-40 to radioactive argon-40 in minerals and rocks ( igneous rocks )

21
Q

What is Carbon-14 dating?

A

Decay of Carbon 14.
Carbon 14 is unstable. Over time it decays into Nitrogen 14. It has a half-life of 5730 yrs.
C- 14 is present in the same concentration in all living things, meaning that we can measure the amount of C- 14 in the remains of an organism to determine how old it is.

22
Q

What are the limitations of carbon-14 dating?

A

Due to the relatively short half-life it is only useful up to 50,000 years. It requires remains of the organism to be present, so it cannot be used for ‘true’ fossils (mineral, casts, moulds), however these are almost always older than 50,000 years anyway.

23
Q

What is carbon-14 dating useful for?

A

Dating bones and artefact.

24
Q

How does life form change over time?

A

Evolution.

Life began at sea (before multicellular), then soft bodied animals appeared (before exosckeleton).

25
Q

What are the three types of fossils?

Provide a description.

A
  • Physical fossils: remains of all/ part of the structure of an organism
  • Trace fossils: provide evidence of the activities of an organism
  • Biosignature: chemical or physical traces that can be inferred to have resulted from the action of life forms
26
Q

What are the features if index fossils? (4)

A
  • Distinctive
  • Abundant
  • Wide geographic distribution
  • Short time in geological history
27
Q

Provide an example of the three types of fossils.

A
  • Physical fossils: bones, teeth
  • Trace fossils: footprints, marks, teeth
  • Biosignature: can be preserved in minersl, rocks and sediment
28
Q

What is the difference between a mould fossil and a cast fossil?

A

Mould fossil: Bone decomposes very slowly and leaves a hole in the sedimentary rock that has formed around it. When the rock is eroded to that location, there is an impression in it.
Cast fossil: Rock (e.g. from a volcano) forms in a mould, this rock erodes slower than the sedimentary rock around it, making it visible.

29
Q

What is a transitional fossil?

A

A fossil that shows the characteristics of an ancestral and a descendant group.

30
Q

How can the presence of transitional fossils in the fossil record help provide evidence of evolution?

A

They exhibit features present in ancestral and descendant groups of organisms. They have characteristics that are intermediate in nature to organisms that existed both prior to it and after it. Transitional fossils are evidence of evolution as they indicate the progression of from species just as evolutionary theory predicts.

31
Q

What is structural morphology?

A

The comparative analysis of patterns of the locus of structures within the body plan of an organism, and forms the basis of taxonomical categorization.

32
Q

What are the three types of structural morphology?

A
  • homologous structures
  • analogous structures
  • vestigial structures
33
Q

How do homologous structures provide evidence of evolution?

A

Provide evidence of species sharing a common ancestor as different species that have a similar structure but a different function.

34
Q

What are homologous structures?

Provide an example.

A

Features in different species that have a similar structure but a different function.
Eg. bones of the mammalian forelimbs

35
Q

What are analogous structures?

Provide an example.

A

Structures that have the same function in different species but may have different structures.
Eg.

36
Q

What are vestigial structures?

Provide an example.

A

A structure that was fully functional in an ancestor but has no significant function in the current organism.
- usually reduced in size
Eg. presence of vestigial hind limbs in whales reflects the fact that whales evolved from four-limbed terrestrial mammals

37
Q

What is comparative embryology?

A

Comparing the embryos of different species. Early embryos of some species appear to similar other species, suggesting a common start to life and a common ancestor

38
Q

What are some examples of comparative embryology?

A
  • a tail, located posterior to the anus
  • a cartilaginous notochord, located in the dorsal midline
  • a hollow nerve cord, located dorsally
  • pharyngeal arches.
39
Q

What is biogeography?

A

Distribution of species and communities on different continents. Shows that organisms evolve to suit their conditions.

40
Q

How does biogeography provide evidence of evolution?

A

Each geologically separated/ isolated region has distinct endemic species, even when environmental conditions are similar. Therefore different areas will unique/ different species.

41
Q

What can be predicted if it was known that new species arise by biological change or evolution?

A
  • native species in different isolated regions will be distinctive, each group having evolved from different ancestral species
  • modern species native to a given region will be more similar to species that lived in that region in the past than modern species living in a distant region with similar environmental conditions
  • the same ecological niche in different isolated regions will be occupied by different species (descended from different ancestral species that once lived in that region).
42
Q

Define divergent evolution.

A

Outcome that results when, over time, one ancestral species changes to give rise to several new species each occupying a different niche.

43
Q

Define convergent evolution.

A

When two species, which do not share a recent common ancestor, independently develop similar features due to similar selection pressures

44
Q

What is divergent evolution? (3)

A
  • Two closely related species become more different over time
  • Different selection pressures
  • Have homologous structures
45
Q

What is convergent evolution?

A
  • Two unrelated species become more similar over time
  • Similar selection pressures
  • Have analogous structures
46
Q

What is extinction?

A

When all members of a species permanently dies out.

47
Q

How can an extinction occur?

A
  • Generally occurs when the species is unable to adapt
    to a new selection pressure e.g. due to a change in the climate or the introduction of a new species (might act as a predator or eat the main food source of the original species).
  • Species with limited genetic diversity are more at risk from extinction
48
Q

What is a mass extinction?
What does this allow for?
Provide an example.

A
  • a period of time during which an abnormally high number of species died out in a short time span.
  • E.g. the extinction of the dinosaurs around 65 mya
  • Allows surviving species to expand and diverge

Biology 4 (9 decks)

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