5. Further Evidence for Evolution

Question 1

What are domesticated animals (animals reared for human use) related to?

Answer 1

• your mum
• wild species
• in many cases, the domestic and wild animals can still interbreed*

*NB: If the two populations (domesticated and wild) could interbreed, the ‘wild species’ answer would change to ‘wild population’.

Question 2

How have domesticated breeds been developed?

Answer 2

domesticated developed from wild species:

- selecting individuals with desirable traits, and breeding them

Question 3

Define selective breeding.

Answer 3

selecting individuals with desirable traits, and breeding them

Question 4

How does selective breeding contribute (as a piece of evidence) to the theory of evolution?

Answer 4

striking differences between heritable characteristics of domesticated breeds = evidence that species evolve

Question 5

What else, apart from selective breeding, has given us strong evidence for evolution?

Answer 5

research into fossils

Question 6

Give some examples of organisms that have been found as fossils.

Answer 6

trilobites and dinosaurs

Question 7

Can any organisms alive today be found as fossils?

Answer 7

no

Question 8

What does the fossil record suggest?

Answer 8

that organisms change over time

Proof:

• we have found fossils
• they are very old, no fossils have been found of organisms that are alive today
• this shows that organisms change over time (as the theory of evolution states)

Question 9

What does dating rocks allow us to do?

Answer 9

we can deduce the age of the fossils that lived in the rock

from that we can deduce when they lived on the earth

Question 10

What does the sequence in which organisms appear in the fossil record match?

Answer 10

the sequence with which organisms appear in the fossil record matches their complexity, going from less to more complex as the fossils get closer to the present day

Question 11

What appears in the fossil record first? Then? When do land vertebrates begin to appear in the fossil record?

Answer 11

• bacteria and simple algae
• fungi and worms
• recently (relative to bacteria)

Question 12

So what can we deduce about a particular organism from the fossil record?

Answer 12

their likely ancestors

Question 13

Give an example of a fossil that has similarities to present day vertebrates.

Answer 13

Acanthostega

Question 14

Give similarities and differences of the Acanthostega to modern day vertebrates?

Answer 14

Similarities:
- four legs like most amphibians, reptiles and mammals

Differences:

• eight fingers, seven toes (no organism today has this)
• legs + fish like tail + gills = lived in water

Question 15

What does the Acanthostega example show?

Answer 15

that land vertebrates could have evolved from fish via an aquatic animal with legs

Question 16

What are dark varieties of light coloured insects called?

Answer 16

melanistic

Question 17

What is the most famous example of melanism as evidence for evolution?

Answer 17

Biston betularia (peppered moth)

Question 18

Which variety of the Biston betularia was rare in England pre 19th Century?

Answer 18

the melanistic variety was rare, the peppered variety was common

Question 19

What happened to the speckled variety of the peppered moth in industrial areas?

Answer 19

became much less common, the melanistic variety became more common

Question 20

Why is the Biston betularia example evidence of evolution?

Answer 20

change in heritable characteristic (appearance of wings changing colour from speckled dark bits to fully dark) is an example of evolution

Question 21

Give the simple* explanation of industrial melanism (in Biston betularia)

*the answer is very long but it is logical so it is a simple explanation

Answer 21

• adult Biston betularia moths fly at night to try and find a mate
• during the day they roost on the branches of trees
• in unpolluted areas tree branches are covered in pale-coloured lichens, so peppered moths are well camouflaged against them
• sulphur dioxide pollution kills lichens on tree branches and soot from coal burning blackens them
• melanic moths are well camouflaged against dark tree branches
• birds and other animals that hunt in daylight predate moths if they find them
• in areas that became industrial the peppered variety were mostly found and eaten and a higher proportion of the melanic variety survived to breed and pass on the dark wing colour, causing Biston betularia populations to eveolve from being peppered to melanic.