10.4 Evidence for Evolution

Question 1

What is the evidence for evolution?

Answer 1

• PALAENTOLOGY
  
  • study of fossils
• COMPARATIVE ANATOMY
  
  • similarities & differences in anatomy
• COMPARATIVE BIOCHEMISTRY
  
  • similarities & differences in chemical makeup

Question 2

What is palaentology?

Answer 2

study of fossils & fossil record

Question 3

What evidence for evolution does the fossil record give?

Answer 3

• SIMPLE life forms GRADUALLY EVOLVED into COMPLEX
  
  • simple organisms (e.g bacteria + algae) found in oldest strata + more complex ones found only in more recent strata
• indicates ECOLOGICAL LINKS
  
  • plants found in older strata, animals only come about in older strata - consistent with animals require plants to survive
• RELATIONSHIPS between EXTINCT + LIVING organisms

Question 4

What are the disadvantages to the fossil record?

Answer 4

• incomplete
• some soft-bodied organisms decompose before fossilisation
• some fossils destroyed due to geological movements

Question 5

What is comparative anatomy?

Answer 5

study of similarities & differences in anatomy of organisms

Question 6

What are homologous structures?

Answer 6

structures which look superficially different

but have a same underlying structure

Question 7

What do homologous structures provide evidence for?

Answer 7

divergent evolution.

(homologous structures can suggest recent common ancestor)

Question 8

What is divergent evolution?

Answer 8

process by which:

species diverge over time into 2 different species

resulting in a new species becoming less like the original one

Question 9

What is comparative biochemistry?

Answer 9

study of similarities & differences

in proteins & other molecules which control life processes - highly conserved

Question 10

What are the 2 molecules which are commonly studied in comparative biochemistry?

Answer 10

Cytochrome c

Ribosomal RNA

Question 11

Why are cytochrome c & ribosomal RNA particularly well suited to be studied in comparative biochemistry?

Answer 11

well conserved

so changes can identify evolutionary links

Question 12

How can comparative biochemistry be used to provide evidence for evolution?

Answer 12

Similarities/differences in proteins & DNA

used to identify evolutionary links

e.g cytochrome C, rRNA

species which are closely related have more similarities in these molecules

Question 13

Describe what is shown on a phylogenetic tree:

Answer 13

evolutionary relationships

closer branches of tree = more closely related