Change in Species Over Time

Question 1

evolution

Answer 1

the change in genetic composition of populations over time

Question 2

population

Answer 2

all the members of a species in a location at a time

Question 3

Permineralisation

Answer 3

Minerals in the sediment fill cellular spaces in the hard parts of the organism (ie bones)
The dissolved minerals crystallise and produces rocks in the shape of the organism

Question 4

steps to fossilisation

Answer 4

death and decay (hard remains left)
deposition (covered by sediment layers)
permineralisation (pressure from layers force minerals to replace hard remains)
exposure (displacement of fossils and expose it to the surface)

Question 5

trace fossils

Answer 5

evidence of activity and behaviour of organisms
(poo, nests, burrows, imprints of leaves/feet)

Question 6

transition fossils

Answer 6

fossils that show the link between species (exhibits common traits in both the ancestor and predicted descendants)
ie archaeopteryx

Question 7

relative dating

Answer 7

a method of dating geological deposits based on the relative order of strata and the fossils in the layers
- stratigraphy
- law of faunal succession

Question 8

Law of faunal succession

Answer 8

the stratigraphic principle that the fossils in rock strata succeed one another in a predictable order

Question 9

stratigraphy

Answer 9

analysis and comparison of sedimentary rock strata and the fossils in other strata

Question 10

Law of superposition

Answer 10

older layers are below and new layers are above

Question 11

index fossils

Answer 11

used in relative dating
- widespread across the world
- abundant
- existed for a short period of time
- easy to recognise

Question 12

absolute dating

Answer 12

a direct, quantitative method of determining the age of a rock or object using radioactivity
- radiometric dating

Question 13

radiometric dating

Answer 13

absolute dating using radioactive isotopes to calculate the age of rocks
- uses the half lives of the isotope to determine the age of rocks
- ie carbon-14 (12,000 - 70,000 years)

Question 14

half life

Answer 14

the time taken for half the original radioactive isotope to decay

Question 15

species

Answer 15

a group of individuals that are genetically similar enough to interbreed and produce viable and fertile offspring

Question 16

speciation

Answer 16

the evolutionary process by which populations evolve to become distinct species

Question 17

steps to speciation

Answer 17

• phenotypic variation
• allo/symp speciation
• reproductive isolation (prevents gene flow)
• further genetic divergence (natural selection + mutations)

Question 18

allopatric

Answer 18

evolution of a new species from a common ancestor by a geographical barrier

Question 19

sympatric

Answer 19

evolution of a new species from a common ancestor by a behavioural or reproductive barrier