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Flashcards in Evolution Deck (48):

What is essentialism?

A plato belief that species are fixed within a grand scale of nature (scala naturae)


What is Aristotle thinking ?

This was an early attempt at classification where keen observations were made between animals and plants.


With the Aristotle method what two groups were animals divided up into?

With or without red blood.


Who developed the coherent (binomial) system for describing, classifying and naming organisms?

Carl von Linne (Linnaeus)


What year was the binomial system (Systema Naturae) created?



What is creationism?

Living things and Earth physical structure are permanent.


What is catastrophism?

Geologically only catastrophic events had changed the geological structure of the earth.


How did Cuvier explain changes seen within fossilized bones?

Result of a previous catastrophic event.


What was the first step progressive step towards a more accurate evolutionary theory?

When looking at a sample from the Quarries of the Paris Basin.

1st uppermost layer: Lots of lake and freshwater marsh fossils and plants


What was the first step progressive step towards a more accurate evolutionary theory?

When looking at a sample from the Quarries of the Paris Basin.

1st uppermost layer: Lots of lake and freshwater marsh fossils and plants.

2nd layer: Sandstone with marine fossils.

3rd layer: Gypsum, limestone and marine fossils and a few freshwater forms.

4th layer: Course grained limestone and marine fossils and some freshwater forms.

5th layer: Chalk, clay, sand and freshwater shells and driftwood.


What were Darwin's key observations on his voyage on HMS Beagle?

The succession of types: Similarity between extinct Glyptodonts and skeletons of living armadillos.

Representative types: Geographical grouping of different types of Rhea.

Evidence from islands: Animals on oceanic islands resembled those on nearest mainland but also varied slightly between islands.


What were Darwin's reasons for his evolutionary theory?

That the world is continually changing so life must also change to survive.

Nature provides an unlimited supply of unsolicited, fortuitous and hereditary novelties.

The fertility of nature leads to a struggle for existence.

Individuals with favourable novelties survive and reproduce better and leave more descendants.


What were the key points Darwin made in his book Origin of Species?

Species were Immutable (not fixed)
He recognised that artificial selection (breeding dogs) can change the morphology of organisms to suit man. So natural selection can change morphology to suit the environment.
This could eventually lead to a new species.


What are the conditions required for evolution?

More individuals are produced than can survive.

There is heritable variation between individuals.

Some individuals will be better adapted than others.

Best adapted (fittest) individuals will leave behind the most offspring.


What influential people opposed Darwin's book, Origin of Species and why?

Adam Sedwick, Louis Agassiz, Richard Owen and Bishop Samuel Wilberforce.
Because of their religious views.


What was one of the main 19th century criticisms made by biologist St George Mivart?

How does natural selection explain the evolution of such complex structures like the eye?


In answer to St George Mivart's critisism, how can you evolve the eye in 2000 steps?

The shape of the eye changes at random by 1%. Because selection retains only those changes that improved the optical performance of the eye. 2000 steps would generate a vertebrate eye.


For realistic values of heritabilty and strength of selection, it would take 400,000 generations to evolve a vertebrate eye. If one generation = one year, how many years would it take to evolve?

Half a million years.


If evolution occurs by accumulation of small changes, why are so many
intermediate types absent from the fossil record?

This is due to a sudden rapid mutation over time in between each stasis.


What was Lord Kelvins criticism against Darwin's theory?

Earth too young to have allowed evolution by natural selection to
generate such diversity. This was due to limited technology.


What evidence do we base the age of the earth on?

Age is based on evidence from radiometric age dating of meteorite material and is consistent
with the ages of the oldest-known terrestrial and lunar samples.


What is the 'blending theory'?

Blending theory assumes ‘genetic factors’
are infinitely divisible, so new variation would
automatically distribute itself in ever
diminishing amounts.


Gregor Mendel did experiments with peas, what was it he discovered?

Showed that genetic factors were 'particulate' and occured in pairs.
He also discovered that pairs of genetic factors would 'segregate' into gametes and that different pairs of genetic factors pass into offspring independently.


What did three geneticists (R.A. Fisher, J.B.S Haldane, S.G. Wright) do to form the new synthesis for evolution?

Used mathematics to model gene flow in populations.

Showed that genes conferring only small advantages would rapidly spread.

Showed the relative importance of mutation, sex, genetic drift and gene flow between populations.


What are the existing evidence for evolution?

Sequence of fossil types.

Existence of rudimentary organs.

Ontogeny recapitulates phylogeny.

Common underlying plan.

Artificial selection.

Unexpected creatures.


What is the evidence for comparative anatomy?

Homologous structures and divergent evolution.

Embryonic development.

Vestigial organs.


What are structures called when they are from unrelated groups of animals?

Analogous structures.


What are the three types of evolution?

Divergent, convergent and parallel evolution.


What is convergent evolution?

Organisms with similar but analogous structures which have resulted from adaptation to the same environment.


give an example of convergent evolution.

The fins of aquatic animals.


What is parallel evolution?

Organisms living in different places but in similar environments tend to have the same morphology.


Give an example of parallel evolution.

Many marsupial and placental mammals that resemble each other but are unrelated,


What does ORP stand for?

Ontogeny Recapitulates Phylogeny


Describe the hypothesis for Ontogeny Recapitulates Phylogeny

Parallelism is seen in embryonic form as all vertebrate embryos develop gills and a tail but as they develop more they become more specialised.


Give an example of vestigial structures giving clues to the animals ancestors.

Snakes and whales have vestigial bones that indicates their ancestors had legs.


What does relative dating assume?

Assumes that the oldest fossils are found in the deepest rock strata.


Why is relative dating unreliable?

Because geological processes are complex. eg
Topography modifies upper layers.

Dike-youngest cuts older rocks.


What is radiometric dating?

Dating based on measuring the rate of decay of radioisotopes.


Explain why the carbon14 system is best known for radiometric dating and how it works.

Because the ratio of C14:C12 is constant in the atmosphere, new C14 is constantly created through cosmic ray bombardment which then decays to N14.

In living organisms the ratio of C14:C12 is in equilibrium with the atmosphere so when organisms die and become fossilised, the system becomes closed and no further carbon exchange can occur. Therefore the ratio of C14:C12 begins to change.


What is the half life of C14?

5730 years.


What isotopes are useful for ageing fossils

C14 to N14


What isotopes are useful for ageing fossils >300,000?

K40 to Ar40


What isotopes are useful for ageing rocks?

Rubidium 87 to Strontium 86
Uranium 238 to Lead 206


Give an example of an 'intermediate form'

Archaeopteryx which is a fossil that looks like a bird and a reptile.


What are monotremes and give an example of some.

These are the only mammals that lay eggs instead of giving birth.
Short beaked echidna and the platypus.


Give three examples of observed natural selecetion.

Industrial melanism and the peppered moth.
El Nino and Darwins finches.
Bacterial resistance in antibiotics.


What evidence does biochemistry give for evolution?

All life use DNA (viruses RNA)
All have same genetic code.
All share same vital proteins.

Shared DNA points to common ancestry.
Group organisms according to DNA sequence similarity - groups typically congruent with traditional taxonomic groups.


Give an example of fossilised genes.

Notothenioideil: Ice fish have no red blood cells.