4.2.2 - Classification and evolution ( part 2 )

Question 1

What is the equation for spearmans rank ?

Answer 1

Question 2

What is the spearmans rank used for ?

Answer 2

Determines whether there is correlation between variables that don’t show a normal distribution

Question 3

Define ‘adaptation’ ?

Answer 3

Adaptation : A characteristics that aids an organism’s survival in its environment

Question 4

What are the different types of adaptations ?

Answer 4

• Anatomical
• Physiological
• Behavioural

Question 5

Name examples of anatomical adaptations ?

Answer 5

• Body covering ( eg. hair, scales, shells… ) : helps organsims stay warm, provide protection and prevent water loss / sun damage in plants
• Camouflage : Allows organisms to blend within its environment making it hard for predators to spot it
• Teeth : Shape and type depends an organisms diet
• Mimicry : Copying other animals appearance/ sounds allowing harmless organism to fool predators into thinking they are dangerous

Question 6

What are the types of behavioural adaptations ?

Answer 6

• Innate/ instinctive behaviours
• Learned behaviours

Question 7

What are innate/ instinctive behaviours ?

Answer 7

Behaviours due to inherited genes allowing organisms to survive in habitat in which it lives

Question 8

What are learned behaviours ?

Answer 8

They are adaptations learnt form experience/ observing other animals

Question 9

Name examples of the behavioural adaptations ?

Answer 9

• Survival behaviours : playing dead/ freezing
• Courtship : To attract a mate increasing chances of reproducing
• Seasonal : Migration/ hibernation

Question 10

What is migration and hibernation ?

Answer 10

• Migration : Animals move from and to regions and back when environmental conditions are more favourable
• Hibernation : A period of inactivity in which an animal/s body temperature, heart rate and breathing rate slow down to conserve energy reducing requirement for food

Question 11

Name examples of physiological adaptations ?

Answer 11

• Poison production : Many reptiles produce venom to kill prey/ plants to protect themselves from being eaten
• Antibiotic production : Some bacteria produce antibiotics to kill other bacteria species in surroundings
• Water holding : Allows animals to survive in the dessert/ hot environments where there is no access to water ( eg. cacti )

Question 12

Define ‘convergent evolution’ ?

Answer 12

Convergent evolution : Shared adaptations between unrelated organisms

Question 13

Explain how convergent evolution occurs ?

Answer 13

• Two species live in different parts of the world with similar environments
• Species deal with the same selection pressures
• Same characteristics are advantageous in the two environments, so individuals with these characteristics are more likely to survive and reproduce
• Over time the advantageous characteristics become widespread in both populations

Question 14

Define ‘divergent evolution’ ?

Answer 14

Divergent : Different adaptations between related organisms

Question 15

Explain how divergent evolution occurs ?

Answer 15

• The same species live in different parts with different environments
• Species deal with different selection pressures
• Different characteristics are advantageous in the two environments, so individuals with these characteristics are more likely to survive and reproduce
• Over time the advantageous characteristics become widespread throughout both populations

Question 16

Define ‘Genetic variation’ ?

Answer 16

Genetic variation : The differences in DNA base sequences between individual organisms within a species population

Question 17

Explain the process by which natural selection occurs ?

Answer 17

• Random mutation occur within population
• This introduces genetic variation in population
• Mutations may produce allele that codes for advantageous trait ( eg. antibiotic resistance )
• Selection pressure means individuals with advantageous able are better suited to the environment and have a reproductive elective advantage
• This means better suited individuals are more likely to survive and reproduce, passing on their alleles coding for advantageous trait to their offspring
• Over generations, there frequency of allele coding for desired trait will increase thin the population due to natural selection

Question 18

What are antibiotics ?

Answer 18

Chemical substances that inhibit or kill bacterial cells with little or no harm to human tissue

Question 19

Explain how antibiotic resistance develops in bacteria ?

Answer 19

• ANTIOBIOTIC ACTS AS SELECTION PRESSURE
• Mutations occur causing variation within population
• This produces new alleles that may be advantageous/ code for antibiotic resistance
• This allows bacteria contains advantageous alleles to survive and reproduce
• Non-resistant bacteria will not survive
• Advantageous alleles for antibiotic resistance are passed on to the next generation
• Over several generations, the new allele will increase in frequency in the population resulting in antibiotic resistance

Question 20

What are the two methods by which bacteria inherit antibiotic resistance ?

Answer 20

• Vertical transmission
• Horizontal transmission

Question 21

Explain how bacteria inherit antibiotic resistance via vertical transmission ?

Answer 21

• Bacteria reproduce asexually by binary fission incredibly rapidly
• If one bacterium contains a mutant gene that gives it antibiotic resistance, all of its descendants will contain antibiotic resistance
• This form of transmission enables antibiotic resistance to spread within a bacterial population

Question 22

Explain how bacteria inherit antibiotic resistance via horizontal transmission ?

Answer 22

• Plasmids often contain antibiotic-resistant genes
• During conjugation, plasmids are transferred between bacteria
• This allows a bacterium containing a mutant gene that gives it antibiotic resistance could pass this gene on to other bacteria
• This form of transmission enables antibiotic resistance to spread within or between bacterial populations

Question 23

What has led to the development of antibiotic resistance ?

Answer 23

• Overuse of antibiotics and antibiotics being prescribed when not necessary
• Large scale use of antibiotics in farming to prevent disease when livestock are kept in close quarters, even when animals are not sick

Question 24

Explain how we can reduce cases of antibiotic resistance ?

Answer 24

• Doctors avoiding the overuse of antibiotics
• Antibiotics not being used in non-serious infections
• When prescribed a course of antibiotics, the patient finishing the entire course
• Antibiotics not being used for viral infections
• The type of antibiotics prescribed being changed so that the same antibiotic is not always prescribed for the same infections

Question 25

Explain how we can reduce the spread of already-resistant strains ?

Answer 25

- Ensuring good hygiene practices such as hand-washing and the use of hand sanitisers - Isolating infected patents to prevent the spread of resistant strains

Question 26

What are pesticides ?

Answer 26

Chemicals that kill pests of any kind ( insect pests, pathogenic organisms or weeds )

Question 27

Explain how we can reduce cases of pesticide resistance ?

Answer 27

- Insecticides should be used sparingly or on rotation to avoid the evolution of resistance in pest insect populations - Using a combination of pesticides - Use Biological control (introducing a natural parasite or predator of the pest insect) - Using crops that have been selectively bred or genetically modified to be pest-resistant