Chapter 10 - Evolution Evidence

Question 1

How Electron Spin Resonance Works

Answer 1

Minerals collect electrons in crystal lattice over a period of time. Trapped electrons are mildly magnetic and give electron spin resonance reading.
Accumulated electrons divided by rate of electron radiation = age of fossil

Question 2

Homologous structures:

What are they, what do they imply

Answer 2

Organs which retain same basic structure even though their function my be slightly different.
Indicative of divergent evolution.

Question 3

Analogous structures:

What are they, what do they imply

Answer 3

Organs which have different structure even though their function my be similar.
Indicative of convergent evolution.

Question 4

Vestigial Organs:

What are they, what do they imply

Answer 4

Natural organs that have little or no function

example of homologous structures, divergent evolution

Question 5

Conditions for fossilisation

Answer 5

RUDD
Rapid burial
Undisturbed by scavengers and other events
Decomposers absent
Downward pressure

Question 6

What are index fossills

Answer 6

Fossils with perviously identified to be a absolute age.

Similar fossil found in different location is assigned its age.

Question 7

Relative Dating

Answer 7

Process where previous knowledge of fossils and the concept that deeper rock strata are the oldest is used to determine the relative age of the fossils.

Question 8

Radiometric Dating

Answer 8

Using radio-isotopes known half lives to deduce absolute age of a fossil by comparing current and initial concentrations of a radioisotope.

Question 9

Biogeography evidence for evolution

Answer 9

Continent splits isolating populations causing allopatric speciation.
Trace related organisms to single starting location and common ancestor from which they evolved

Question 10

DNA sequencing
Chromosomal
Mitochondrial
Chloroplast

Answer 10

DNA sequences of nucleotides in DNA fragments differ from species to species. More similar base sequence reveals closer species relatedness.
Mitochondrial DNA mutates faster and at a set rate.
Both Chloroplast DNA and mitochondrial acts as molecular clock

Question 11

Protein analysis (Evidence for evolution)

Answer 11

protein structures change slightly from species to species.
similarity of structure can be used to point to relatedness of a species.
Eg.) Cytochrome C (In all living things) or heamoglobin

Question 12

comparative embryology

Answer 12

Compare structural features during developmental phases. The later during embryonic development an organisms posses similar features the more closely related they are.

Question 13

DNA Hydridisation Steps:

Answer 13

1. ) DNA fragments are denatured and split in two
2. ) Strand fragments from opposite species are allowed to hybridise and cool.
3. ) Strands are heated to split them apart. Higher temperature required for denaturation = more bonds = more complementary bases = closely related

Question 14

Carbon dating timespan limititation

Answer 14

50,000 years