Changes in a species over time

Question 1

Define an index fossil

Answer 1

Geographically widely spread
Abundant
Easily identifiable
only existed for a short time span

Question 2

Where would the youngest rocks be found in a rock profile?

Answer 2

at the top

Question 3

Define a transition fossil

Answer 3

are intermediate between current and ancestral form.

Question 4

What is an absolute age

Answer 4

determines the age of rock around a fossil using radiometric dating giving it an actual number

Question 5

What is a relative age?

Answer 5

gives a relative order of events, does not predict actual age.

Question 6

What is the half life of Carbon 14?

Answer 6

5730 Years

Question 7

What is the maximum age you can use C14 for dating?

Answer 7

60,000 years

Question 8

What type of radiometric dating is used for rock millions of years old?

Answer 8

Uranium Lead or Potassium Argon

Question 9

What are the conditions required for fossilisation?

Answer 9

Hard parts that are rapidly covered in sediment
There is no oxygen present (decrease the rate of decomposition).
Low temperature (to also decrease the rate of decomposition)
Hidden from scavengers.
Left undisturbed for a long time.

Question 10

What is a direct fossil?

Answer 10

Fossils where the entire organism or parts of the organism are preserved.

Question 11

What is a trace fossil?

Answer 11

Fossils showing the signs or remains of an organism?s activities e.g. footprints, bite marks.

Question 12

What has ocurred in the fossil record at the end of each period of geological time?

Answer 12

Mass extinction

Question 13

What is a fossil?

Answer 13

the remains or traces of pre-existing life forms preserved in rock, ice or amber

Question 14

Define biogeography

Answer 14

the distribution of plants and animals in a particular area.

Question 15

Define divergent evolution

Answer 15

Divergent evolution is when species that share a recent common ancestor become more dissimilar over time. These species share homologous structures.

Question 16

Define homologous structures

Answer 16

Homologous structures have a similar structure but have different functions.

Question 17

Define convergent evolution

Answer 17

Convergent evolution is when species independently develop different structures that have a similar function.

Question 18

Define analogous structures

Answer 18

Have a similar function, but are not structurally the same.

Question 19

What is adaptive radiation?

Answer 19

Adaptive radiation is a form of divergent evolution where a number of different species form from a single recent common ancestor.

Question 20

What is the cause of divergent evolution?

Answer 20

This is due to experiencing different selective pressures.

Question 21

What is the cause of convergent evolution?

Answer 21

This is due to experiencing similar selection pressures.
The species do not share a recent common ancestor.

Question 22

What is a vestigial organ?

Answer 22

An organ or structure that is functionless in an organism - remnant feature from an ancestor.

Question 23

Allopatric speciation scaffold

Answer 23

Two populations of ______ are geographically isolated by a permanent geographical barrier of _______.
There is no gene flow.
There are different selection pressures acting on each population of ________.
Mutations accumulate over many generations in each population.
Eventually they can no longer interbreed to produce fertile and viable offspring and would be considered 2 separate species.

Question 24

Compare sympatric speciation with allopatric speciation

Answer 24

Sympatric speciation occurs in the same geographical area (e.g. Lord Howe Island) whereas allopatric speciation is in different geographical areas (e.g different Galapagos islands).
With sympatric speciation there is reproductive isolation whereas allopatric speciation there is isolation by a permanent geographical barrier.