Evidence For Evolution

Question 1

What are the 6 different evidences for evolution?

Answer 1

• Comparative studies: Biochemistry (DNA& proteins), Embryology, Anatomy( homologous structures)
• vestigial organs
• biogeography
• fossils

Question 2

What are phylogenies trees?

Answer 2

A diagram showing evolutionary relationships between organisms; also called a dendogram

Question 3

How is biochemistry used in compariative studies?

Answer 3

EVRs
Mitochondrial DNA
Protein sequences

Question 4

What are bioinformatics?

Answer 4

Multidisciplinary field that combines all areas of biological science with computer science, statistics and applied mathematics to help understand biological processes
In practical terms is use of computers to describe molecular components

Question 5

What are comparative genomics?

Answer 5

Is a field of biological research in which the genome sequence of different species are compared. It allows researchers to identify regions of similarity and difference,

Question 6

What are the 2 main categories of dating methods? ( for fossils)

Answer 6

Absolute dating and relative dating

Question 7

What does relative dating do?

Answer 7

Actual age

Question 8

What does absolute dating do?

Answer 8

Tells you if one sample is older or younger than other fossils

Question 9

Define half life?

Answer 9

Time it takes for radioactive elements to decompose by half

Question 10

What is potassium argon dating?

Answer 10

Measures the rate of radioactive potassium decay to form calcium and argon

Question 11

Limitations of potassium argon dating?

Answer 11

• can only date volcanic rocks older than 100000 to 200000

- not all rock types are suitable for this method can only be used for volcanic rocks

Question 12

What is carbon 14 dating?

Answer 12

• carbon 14 ( radioactive) decays to nitrogen, half life is 5730 years and ratio of C14:c12 provides an absolute date for the fossil

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Question 13

Limitations of carbon 14 dating?

Answer 13

• amount of carbon 14 in air varies
• material to be dated must contain organic compounds
• requires at least 3 grams of organic material
• can not be used to date back more than about 60000

Question 14

What is dendrochronology?

Answer 14

Ring dating, counting the centric rings of surface of cut tree trunk.
Each ring= one year of growth
Difference in width= indicates how favourable the growing season was

Question 15

Limitations of dendrochronology

Answer 15

• timber rarely preserved for more that a few thousand years

- particular conditions necessary for the method do not occur often

Question 16

What is stratigraphy?

Answer 16

Study of layers of strata. They use two principles to do this

• principle of superposition
• correlation of rock strata

Question 17

What is principle of superposition?

Answer 17

Layer on top younger than the ones below

Question 18

What is principle of correlation of rock strata?

Answer 18

Matching layers of rock from different layers

Question 19

What are index fossils used for?

Answer 19

Index fossils allow for more precise relative dating. They are used to define and identify geological time periods as they were only in existence for a specific time.

Eg, fossilised pollen grains

Question 20

What is fluorine dating?

Answer 20

Relative dating method, when a bone is left in the soil fluorine ions which are present m water in the soil replace some of the ions in the bones
So the older the fossil= more fluorine

Question 21

Limitations of fluorine dating?

Answer 21

• fluorine levels in water differs from area to area

- can only compare fossils from the same location.

Question 22

What are evrs

Answer 22

Endogenous retrovirus
Junk DNA. It is a viral sequences hat has become part of an organisms genome. Comparing humans and chimps, same evrs are found in the same locations on chromosomes

Question 23

How can PCR be used in evidence for evolution

Answer 23

PCR can be used to amplify minute amounts of DNA so that can be used to facilitate the sequencing of the genome.
Can be Useful with fossils where sometimes only small amounts of DNA may be available

Question 24

How can DNA profiling be used in evidence for evolution

Answer 24

Can be invaluable in tracing ancestry and relationships btwn individuals and groups

Question 25

How can mitochondrial DNA be used in evidence for evolution

Answer 25

Human mtDNA has been slowly diverging from the mtDNA from our original female ancestors and the amount of mutation is roughly proportional to the amount of time that has passed.

Question 26

Define ubiquitous protein?

Answer 26

One of a group of proteins that appear to be in all species from bacteria to humans.
Eg. cytochromes

Question 27

What is embryology?

Answer 27

Comparing the very early stages of the development of organisms

Question 28

What are homologous organs?

Answer 28

Organs that are similar in structure but are used in different ways
….

Question 29

What are vestigial organs?

Answer 29

Organs that may have once been important but have lost or changed their functions

Question 30

Examples of vestigial organs?

Answer 30

Nicitating membrane
Muscles to move ears
Wisdom teeth + pointed canines 
Nipples on males
Hair on body
Appendix 
Coccyx

Question 31

Define fossil?

Answer 31

Evidence of or remains of an organism that lived long ago

Eg. footprints, burrows, faeces or impressions of an animal or plant

Question 32

Define artefacts?

Answer 32

Objects that have been deliberately made by humans eg. stone heads, carvings and charcoal from cooking fires

Question 33

What is accelerator mass spectrometry (ams) radiocarbon dating?

Answer 33

A more refined technique that can be used to date a sample as small as 100 micrograms

Question 34

List some absolute dating methods?

Answer 34

Dendrochronology
Carbon 14
Protactinium
Uranium thorium
Potassium argon
Electron spin resonance
Fission tracks
Thermoluminescence

Question 35

Define index fossil?

Answer 35

Fossils or organisms that were on the earth for only a short period of time and are therefore useful in relative dating of rock strata