10.3-4 Phylogeny and evidence for evolution

Question 1

Phylogeny

Answer 1

the evolutionary relationships between organisms
–> phylogenetics: study of the evolutionary history of groups of organisms

Question 2

Advantages of phylogenetic classification

Answer 2

• can be done without reference to linnaean classification
  -produces a continuous tree whereas classification requires discrete taxonomical groups
  -hierarchal nature of linnaean classification can be misleading as it implies different groups within the same rank are equivalent

Question 3

Evolution:

Answer 3

theory that describes the way in which organisms evolve or change, over many many years as a result of natural selection

–> organisms best suited to their environment are more likely to survive and reproduce, passing the advantageous characteristic to their children (advantageous phenotype)

Question 4

Evidence for evolution

Answer 4

palaeontology- study of fossils and fossil record

comparative anatomy- study of similarities and differences between organisms’ anatomy

comparative biochemistry- similarities and differences between the chemical makeup of organisms

Question 5

Palaeontology: How are fossils formed?

Answer 5

when animal and plant remains are preserved in rocks.
–> over long periods of time, spediment is deposited on earth to form layers ( strata) of rock

Question 6

Palaeontology: Evidence for evolution

Answer 6

• fossils of simplest organisms are found in oldest rocks/ fossils with complex structures are found in more recent rocks

-sequences in which organisms are found matches their ecological links to each other (plants before animals)

-similarities in anatomy of fossil organisms (closely related organisms from same ancestor)

• allow relationships between extinct and living (extant) organisms to be investigated

Question 7

Comparative anatomy

Answer 7

the study of similarities and differences in anatomy of different living species

–> scientists look at other sources to determine evolutionary relationships

Question 8

Homologus structures

Answer 8

structures that appear superficially different ( & perform diff functions) in different organisms but have the same underlying structure
–> e.g. vertebrate limbs
- same bones are adapted to carry out a whole range of different functions

Question 9

Comparative biochemistry

Answer 9

study of similarities and differences in proteins and other molecules that control life processes
- some change over time whilst others stay highly conserved

Question 10

Comparative biochemistry: two useful molecules

Answer 10

cytochrome c (a protein involved in respiration)

ribosomal RNA