Evidence of evolution

Question 1

What is evolution?

Answer 1

• The cumulative changes in allele frequencies within a population over time
• Over multiple generations

Question 2

What shows that evolution occured? What influences characteristics?

Answer 2

• When the heritable characteristics of a species change over time
• Heritable characteristics are encoded for by genes, transferred as alleles

Question 3

When does something provide evidence for evolution?

Answer 3

• When it demonstrates a change in characteristics from an ancestral form

Question 4

In what way do fossil records provide evidence for evolution?

Answer 4

• Show that over time changes have occurred in the features of living organisms
• Features of an ancestor compared against living descendants

Question 5

Give 2 examples of the way fossil records provided evidence for evolution.

Answer 5

1. Direct evidence: Preserve remains of ancestral forms such as bones, teeth, shells
2. Indirect evidence: Traces of ancestral forms such as footprints, tooth marks, faeces

Question 6

What can be observed from sedimentary rock layers?

Answer 6

• The layers (strata) develop in chronological order (new at top)
• Dead organisms are trapped in the strata, harder material (bone) preserved

Question 7

What is the law of fossil succession?

Answer 7

• The ordered succession of fossils in the sedimentary rock suggests newer species evolved because of changes to ancestral species

Question 8

What are transitional fossils?

Answer 8

• Fossils that show links between ancestral groups
• Only hard parts preserved, fossil record is incomplete
• Transitional fossils show the intermediate forms that occurred over the evolution pathway
• Establish links between ancestors and species that share common traits
  E.g. archaeopteryx (dinosaurs)

Question 9

What is selective breeding?

Answer 9

• A form of artificial selection, humans intervene in the breeding of species to produce desired traits in offspring
• Breeding animals with desired trait, increases trait frequency in next generations

Question 10

How does selective breeding provide evidence of evolution?

Answer 10

• Targeted breeds can show significant variation in a short period
• Changes within a species can be seen due to genetic selection

Question 11

How does selective breeding of domesticated animals show how artificial selection cause evolution?

Answer 11

• Dog breeds show a lot of variety due to the targeted selection of particular traits by humans
• Ancestors, wolves, similar physical features
• Dogs bred for traits to benefit humans
• Hunting dogs: small to enter fox holes (beagles)
• Herding dogs: heightened intelligence for commands (sheep dogs)
• Racing dogs: sleek and fast (greyhounds)

Question 12

What is a breed?

Answer 12

• Group of animals within a species that have specific and similar characteristics
• Strong evidence for microevolution, time efficient

Question 13

What can comparative anatomy of groups of organisms show? Define homologous structures.

Answer 13

• Show structural features that are similar, implying common ancestry
• Homologous structures: anatomical features that are similar in structure, position or origin but used in different ways
• More similar homologous structures between two species, more closely related

Question 14

What is divergent evolution?

Answer 14

• An accumulation of differences between groups which led to the formation of new species e.g. pentadactyl limb

Question 15

What is adaptive radiation?

Answer 15

• Form of microevolution within a species that uses the same structure for different functions due to their varying environmental niches (homologous structures)
• New species rapidly diversify from ancestral source

Question 16

What is the pentadactyl limb?

Answer 16

• A limb with five digits found in amphibians, reptiles, birds and mammals
• Homologous structure (same position, structure)
• Animal limbs may be differently adapted according to the use of it
• Human hands used for tool manipulation, grip. Birds adapted for flying, whale fins for swimming

Question 17

What is the difference between divergent and convergent evolution?

Answer 17

• Convergent, different origin (ancestors) but the structures develop to resemble each other and have the same function
• Divergent, same origin (ancestor) but the end point have different structures and functions

Question 18

What does analogous mean? Give an example.

Answer 18

• Performing similar function but have different evolutionary origin (convergent)
  E.g. whale and shark fins for swimming

Question 19

What type of variation is the genetic variation in a population?

Answer 19

• Continuous, follows a normal distribution curve. Rate of change is gradual
• A wide range of characteristics for each trait, CANNOT be put into distinct categories
• Characteristics that display continuous variation are influenced by the environment

Question 20

For the rest check book