What are the 6 different evidences for evolution?
- Comparative studies: Biochemistry (DNA& proteins), Embryology, Anatomy( homologous structures)
- vestigial organs
- biogeography
- fossils
What are phylogenies trees?
A diagram showing evolutionary relationships between organisms; also called a dendogram
How is biochemistry used in compariative studies?
EVRs
Mitochondrial DNA
Protein sequences
What are bioinformatics?
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
What are comparative genomics?
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,
What are the 2 main categories of dating methods? ( for fossils)
Absolute dating and relative dating
What does relative dating do?
Actual age
What does absolute dating do?
Tells you if one sample is older or younger than other fossils
Define half life?
Time it takes for radioactive elements to decompose by half
What is potassium argon dating?
Measures the rate of radioactive potassium decay to form calcium and argon
Limitations of potassium argon dating?
- 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
What is carbon 14 dating?
- 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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Limitations of carbon 14 dating?
- 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
What is dendrochronology?
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
Limitations of dendrochronology
- timber rarely preserved for more that a few thousand years
- particular conditions necessary for the method do not occur often
What is stratigraphy?
Study of layers of strata. They use two principles to do this
- principle of superposition
- correlation of rock strata
What is principle of superposition?
Layer on top younger than the ones below
What is principle of correlation of rock strata?
Matching layers of rock from different layers
What are index fossils used for?
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
What is fluorine dating?
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
Limitations of fluorine dating?
- fluorine levels in water differs from area to area
- can only compare fossils from the same location.
What are evrs
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
How can PCR be used in evidence for evolution
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
How can DNA profiling be used in evidence for evolution
Can be invaluable in tracing ancestry and relationships btwn individuals and groups
