The Fossil Record

Question 1

Evolution can only occur if variation exists. List 3 causes of evolutionary change

Answer 1

• natural selection
• gene flow
• genetic drift

Question 2

define gene flow

Answer 2

movement of genes between populations.

-introduces genes into a population, increasing genetic variation

Question 3

define Genetic drift

Answer 3

• random changes in the gene frequency in a population

- new population can become genetically distinct from original population

Question 3

Taxonomy of Human

Answer 3

Kingdom- Animalia
Phylum- Chordata
Class- Mammalia
Order- Primates
Family- Hominidae
Genus- Homo
Species- sapiens

Question 4

what is the Founder Effect

Answer 4

New populations that became isolated from the parent population carry only the genetic variation of the founders

Question 6

define Homology

Answer 6

Similarity of trait resulting from shared ancestry

Question 7

define Analogy

Answer 7

Similarity of traits resulting from similar use, not due to shared ancestry

Question 8

define Homoplasy

Answer 8

process that leads to the development of analogies

Question 9

define Ancestral traits

Answer 9

traits inherited from ancestors

Question 10

dfine derived traits

Answer 10

traits that are evolved from the ancestral condition

Question 11

define phylogeny

Answer 11

family tree

Question 11

Biological species concept

Answer 11

• a group of organisms that have the ability to interbreed and produce viable offspring
• are reproductively isolated from all other such groups

Question 12

define clade

Answer 12

cluster of species linked by a set of unique traits

Question 14

define Speciation

Answer 14

the process by which a new species evolves from an earlier species

Question 15

define Anagenesis

Answer 15

• one species evolves into another over time.

- first species no longer exists

Question 16

define cladogenesis

Answer 16

• a species branches into two or more new species

- first species may or may not still exist

Question 16

Punctuated Equilibrium

Answer 16

involves long periods of stasis punctuated by bursts of change

Question 17

define Gradulaism (gradual evolution)

Answer 17

involves small, steady changes over vast amounts of time

Question 18

The fossil record

Answer 18

the remains of once-living things, wholly or partially transformed into rock through chemical replacement

Question 19

The more fossils we have, the better our understanding. List 3 reasons why the record is incomplete;

Answer 19

• palaeontologists have searched in some places but not all
• fossils have been preserved in some places but not others
• rock sequences containing fossils are not complete in all places

Question 20

Mammals are vertebrates. Define vertebrate

Answer 20

• have spine with sheath of nerves leading to brain and skull
• have four limbs with pentadactyl ends (e.g. fingers and toes)

Question 21

Early mammals evolved from?

Answer 21

cynodonts

Question 23

define Adaptive radiation

Answer 23

massive increase in species from a single stem group