5.1 evidence for evolution

Question 1

evolution

Answer 1

the cumulative change in the heritable characteristics of a population

Question 2

3 evidences for evolution

Answer 2

fossil record, selective breeding, homologous structures

Question 3

transitional fossils

Answer 3

demonstrate the intermediary forms that occurred over the evolutionary pathway taken by a single genus

Question 4

example of a transitional specie

Answer 4

archaeopteryx
(transition to from dinosaurs to birds)

Question 5

how does the fossil record show evolution?

Answer 5

Fossils can be dated by determining the age of the rock layer (strata) in which the fossil is found.

Sedimentary rock layers develop in a chronological order, such that lower layers are older and newer strata form on top.

Question 6

law of fossil succession

Answer 6

chronological sequence of complexity by which characteristics appear to develop. This ordered succession of fossils suggests that newer species likely evolved as a result of changes to ancestral species

Question 7

fossil sequence of animal phyla (7)

Answer 7

shelled invertebrates, fish, amphibians, reptiles, mammals, birds, man

Question 8

fossil sequence of plant phyla

Answer 8

algae, bryophytes, filicinophytes, gymnosperms, angiosperms

Question 9

how do transitional fossils show evolution?

Answer 9

They establish the links between species by exhibiting traits common to both an ancestor and its predicted descendents

Question 10

selective breeding

Answer 10

a form of artificial selection, whereby man intervenes in the breeding of species to produce desired traits in offspring

Question 11

how does selective breeding prove evolution?

Answer 11

targeted breeds can show significant variation in a (relatively) short period

Question 12

examples of selective breeding (domesticated animals)

Answer 12

horses, cows, dogs

Question 13

how do homologous structures prove evolution?

Answer 13

Comparative anatomy of groups of organisms may show certain structural features that are similar, implying common ancestry

Question 14

homologous structures

Answer 14

Anatomical features that are similar in basic structure but have different functions

Question 15

adaptive radiation

Answer 15

whereby several new species rapidly diversify from an ancestral source, with each new species adapted to utilise a specific unoccupied niche

Question 16

example of homologous structure

Answer 16

pentadactyl limb

Question 17

how has the pentadactyl limb adapted for different species?

Answer 17

• Human hands are adapted for tool manipulation (power vs precision grip)
• Bird and bat wings are adapted for flying
• Horse hooves are adapted for galloping
• Whale and dolphin fins are adapted for swimming

Question 18

convergent evolution

Answer 18

when species have different origins but have become similar bc they perform the same or similar function

Question 19

vestigial organs

Answer 19

reduced structures that serve no function anymore (ex: appendix)
- Changes to the environment have rendered these organs redundant and so over time they have lost their functionality

Question 20

speciation

Answer 20

populations of a species can gradually diverge into separate species by evolution

Question 21

how does speciation work?

Answer 21

• 2 populations of a species separate & do not interbreed
• the two populations will adapt to the different environmental conditions and gradually diverge from one another
• the longer they’re apart, the more variation (divergence)
• at a certain point they can no longer interbreed, and are therefore 2 separate species

Question 22

analogous structures

Answer 22

features of diff. species that are similar in function but not necessarily in structure, and do not have a common ancestor

Question 23

examples of analogous structures

Answer 23

wings of birds and butterflies, flippers of penguins and dolphins, eyes of octopus and mammals, sweet potato and potato

Question 24

allopatric speciation

Answer 24

a species population becomes separated by a geographic barrier, whereby reproductive isolation evolves producing two separate species

Question 25

continuous variation

Answer 25

a type of variation that is controlled by many genes, has a wide range of variability and is easily influenced by the environment