evolution, fossils speciation and classification (paper 2)

Question 1

define evolution

Answer 1

change in the inherited characteristics of a population over time through a process of natural selection which may result in the formation of a new species

Question 2

what does the theory of evolution by natural selection state?

Answer 2

that all species of living things have evolved from simple life forms that first developed more than three billion years ago

Question 3

define breed

Answer 3

same species

Question 4

define interbreed

Answer 4

different species

Question 5

list the 3 types of variation

Answer 5

genetic
environmental
mutations

Question 6

when did life first develop?

Answer 6

more than three billion years ago

Question 7

explain Charles Darwins theory of evolution by natural selection (4)

Answer 7

• individual organisms within particular species shows wide range of variation for a characteristic
• mutation can also give rise to new variants
• individuals with characteristics most suited to the environment are more likely to survive to breed successfully
• the characteristics that have enabled these individuals to survive are then passed on to the next generation

Question 8

why was Darwins theory only gradually accepted at first? (3)

Answer 8

• challenged idea that god made all animals + plants that live on earth
• insufficient evidence at the time the the theory was published to convince many scientists
• mechanism of inheritance + variation wasn’t known until 50 years after the theory was published

Question 9

how does antibiotic-resistant bacteria occur? (5)

Answer 9

• variation in all populations including bacteria
• mutations also occur naturally and spontaneously
• mutations can occur in pathogen bacteria
• this produces new strains of bacteria
• some strains might be resistant to antibiotics

Question 10

how does antibiotic resistant bacteria survive and reproduce? (7)

Answer 10

• specific antibiotic will kill specific bacteria when taken
• however antibiotic-resistant bacteria aren’t killed by antibiotic
• antibiotic-resistant bacteria survive and reproduce
• less competition for nutrients + resources so the antibiotic-resistant bacteria can reproduce very successfully
• causes population of antibiotic-resistant to rise
• antibiotic-resistant can then be spread to other uninfected people
  -antibiotic-resistant then spread further and there’s no effective treatment

Question 11

3 ways the rate of development of antibiotic resistant strains can be reduced

Answer 11

• doctors shouldn’t prescribe antibiotics inappropriately
• patients should complete their course of antibiotics so all bacterias killed
• agricultural use of antibiotics should be restricted

Question 12

define fossils

Answer 12

remains of organisms from millions off years ago which are found in rocks

Question 13

3 ways fossils may be formed

Answer 13

• from parts of organisms that have not decayed
• when parts of organisms are replaced by minerals as they decay
• as preserved traces of organisms e.g. footprints

Question 14

when do extinctions occur?

Answer 14

when there are no remaining individuals of a species still alive

Question 15

5 ways extinction may occur

Answer 15

• changes to environment over time
• new predators
• new diseases
• new, more successful competitors
• a single catastrophic event

Question 16

define mass extinction

Answer 16

loss of many different species at the same time

Question 17

define speciation

Answer 17

where evolution takes place over time through the process of natural selection which may result in the new formation of a species

Question 18

list Wallaces beliefs on the steps which give rise to new species (6)

Answer 18

• variation exists within a species
• populations of species becomes isolated from each other
• separate populations are exposed to different environmental conditions
• natural selection occurs in both populations
• occurs over many generations
• if the 2 populations are reunited they are no longer able to interbreed successfully

Question 19

Kylie
plays
cards
or
fights
Garys
sister

Answer 19

kingdom
phylum
class
order
family
genius
species

Question 20

what do all individuals within a population have to compete for? (4)

Answer 20

mates
space
food
shelter

Question 21

2 types competition may be

Answer 21

interspecific
intrespecific