Lecture 3: How we do science and its application to evolution

Question 1

Describe Carl Woese and George Fox’s evolutionary model

Answer 1

• In 1977, they published a paper that established the existance of the 3 domains of life.
• Archaea was established as the 3rd kingdom of life.
• This model was consistent with LUCA.

Question 2

What is LUCA?

Answer 2

The Last Universal Common Ancestor

Question 3

How many years ago was LUCA said to have existed?

Answer 3

3.5 to 3.8 billion years ago

Question 4

Describe W Ford Doolittle’s Web of Life

Answer 4

• He outlined there being 3 domains of life based upon the sharing of genes by Horizontal Gene Transfer (HGT)

Question 5

In 2011, what did a comparison of genomes and protein functional studies suggest?

Answer 5

That there were similarities between eukaryotes and TACK archaea in :

• Proteins involved in cytokinesis (cell division)
• Cell shape determination
• Protein Recycling
• Membrane remodelling (cellular compartmentalisation )

(These features were previously thought to be unique to eukaryotes)

Question 6

What are the 4 TACK archaea?

Answer 6

• Thaumarchaeota
• Aigarchaeota
• Crenarchaeota
• Korarchaeota

Question 7

Describe Hug et al’s tree of life

Answer 7

• In 2016, Hug et al came up with a new view of the Tree of Life, which was a comparison of: 92 bacterial phyla, 26 archaeal phyla, and all 5 of the Eukaryotic supergroups.
• His tree of life was based upon the sequence of 16 ribosomal proteins.

Question 8

In which years were different trees of life made?

Answer 8

• In 1977
• In 2000
• In 2016

Question 9

Who created a tree of life in 1977?

Answer 9

Carl Woesse and George Fox

Question 10

Who created a tree of life in 2000?

Answer 10

W Ford Doolittle

Question 11

Who created a tree of life in 2016?

Answer 11

Hug et al

Question 12

Can new discoveries overturn previously accepted knowledge?

Answer 12

Yes

Question 13

What are the 6 steps on how science is done?

Answer 13

1) Science is performed in a rational naturalistic framework

2) Experimental/observational support is required

3) Proceed with the simplest explanation consistent with all the data

4) Inductive reasoning allows you to draw conclusions

5) Compile and disseminate your knowledge

6) Accept Uncertainty

Question 14

Who was the first good scientist?

Answer 14

Alhazan, c964-c1040

Question 15

Who stated that a hypothesis must be supported by experiments based on confirmable procedures or mathematical evidence?

Answer 15

Alhazan

Question 16

Who said that “Everything should be made as simple as possible, but no simpler.”

Answer 16

Albert Einstein

Question 17

Define evolution

Answer 17

How the genetic content of a population changes over time

Question 18

Define microevolution

Answer 18

The changes in allele frequencies in a population of a species over time.

Question 19

What are the 3 main mechanisms of microevolution

Answer 19

• Natural selection
• Genetic Drift
• Gene flow

Question 20

Define macroevolution

Answer 20

Change in allele frequencies at or above the level of the species.

Question 21

Did Darwin note variation in nature?

Answer 21

Yes, and he wondered why there was so much variation, and why species and variants were so hard to tell apart at times.

Question 22

What did Darwin note about variation and selective breeding?

Answer 22

That variation could be amplified by selective breeding

Question 23

What was Darwin’s theory of evolution by natural selection in ‘on the origin of species’ based upon?/ Darwin’s postulates

Answer 23

• For any particulate trait, individuals within a species are variable;
• (At least) some of this variation is heritable;
• Reproduction is not random, but is selected by Nature: individuals that reproduce the most are those with the most favourable variations (survival of the fittest).

(he had no experimental evidence at this time)

Question 24

What is general relativity?

Answer 24

the Theory that gives the simplest description of Cosmology that is consistent with all known experimental and observational data

Question 25

1852…

Answer 25

…William Rowan Hamilton described Occam as using a metaphorical ‘razor’ to shave off unnecessary hypotheses.