5.2 natural selection

Question 1

ICE AGE

Answer 1

Inherited variation exists within the population
Competition results from an overproduction of offspring
Environmental pressures lead to differential reproduction
Adaptations which benefit survival are selected for
Genotype frequency changes across generations
Evolution occurs within the population

Question 2

10-step process of natural selection

Answer 2

1. more individuals are born than can possibly survive
2. individuals show variation b/w one another (mutation & sexual reproduction)
3. some variation is heritable
4. there is a struggle for survival
5. some individuals possess traits that give them an advantage over other individuals + more likely to survive
6. they will then have a greater chance of reproducing + passing on their genes
7. if the variation can be inherited, the favorable characteristics will be passed on to their offspring, thus increasing their frequency
8. less favorable traits will decrease in frequency and these individuals may become extinct
9. the allele frequencies change over time and thus,
10. the population evolves

Question 3

population

Answer 3

a group of individuals of the same species. are interbreeding + able to produce offspring that are fertile

Question 4

selective pressure

Answer 4

smth that challenges the survival of individuals in a population (ex: disease)

Question 5

adaptations

Answer 5

features of organisms that aid their survival by allowing them to be better suited to their environment

Question 6

types of adaptations

Answer 6

Structural
Behavioural
Physiological
Biochemical
Developmental

Question 7

example of adaptive radiation

Answer 7

finches on Daphne Major (Galapagos Islands) have specialised beak shapes depending on their primary source of nutrition (e.g. seeds, insects, nuts, nectar)

Question 8

antibiotics

Answer 8

chemicals produced by microbes that either kill (bactericidal) or inhibit the growth (bacteriostatic) of bacteria

Question 9

describe the Evolution of antibiotic resistance in bacteria

Answer 9

• When treated with antibiotics, the resistant bacteria will survive and reproduce by binary fission (asexual reproduction)
• The antibiotic resistant bacteria will flourish in the absence of competition from other strains of bacteria (killed by antibiotic)
• Antibiotic resistant bacteria may also confer resistance to susceptible strains by transferring plasmids via bacterial conjugation
• The introduction of antibiotic (selection pressure) has caused the antibiotic resistance gene to become more frequent (evolution)

Question 10

examples of bacterial infections

Answer 10

tuberculosis (TB), gonorrhea, MRSA