5.2 NATURAL SELECTION

Question 1

OCCURRENCE OF NATURAL SELECTION

Answer 1

within a species, different individuals of that species show genetic variation

individuals that are best suited for their environment will survive and reproduce

Question 2

IF THERE WAS NO VARIATION WITHIN A SPECIES

Answer 2

then all individuals would be the same and no individual would be favoured over the other and natural selection would not take place

Question 3

SEXUAL REPRODUCTION CAN PRODUCE

Answer 3

variation in a species through fertilization and meiosis

Question 4

SEXUAL REPRODUCTION OCCURS WHEN

Answer 4

2 different members of a species create offsprings that have a combination of genetic material contributed from both parents

Question 5

ESSENTIAL IDEA

Answer 5

the diversity of life has evolved and continues to evolve by natural selection

Question 6

VARIATION BETWEEN MEMBERS SPECIES IS DUE TO (3)

Answer 6

random mutation

• -> DNA replication
• -> viral infection

sexual reproduction

• ->meiosis
• —-> crossing over P1
• —-> random assortment of chromosome M1

random fertilization

Question 7

NATURAL SELECTION AND MUTATIONS

Answer 7

Mutations that give an advantage are selected for.

Mutations that give a disadvantage are selected against

Question 8

FINCHES

Answer 8

Beak shape changes according to the food

environmental change causes change in available food

Question 9

STRUGGLE FOR SURVIVAL

Answer 9

If there are too many organisms, the demand for resources increases.

However, there is a limited supply of resources in an ecosystem.

Overpopulation and a limited amount of resources creates competition within a population.

They have to compete for mates, food, space, predation, and disease.

Question 10

OFFSPRING PRODUCTION AND STRUGGLE FOR SURVIVAL

Answer 10

Populations tend to produce more offspring than the environment can support or that could survive in a particular community or ecosystem.

When parents don’t spend a lot or even any time caring for their young, they produce many offspring. This is a reproductive method used to make sure
some offspring make it to the next generation.

Parents that put a lot of time and energy protecting and raising their young tend to have far smaller litters, i.e. most mammals.

Question 11

WITHIN A POPULATION

Answer 11

Within a population, there is genetic variation between the individuals in the population.

Question 12

ORGANISMS WITH BENEFICIAL CHARACTERISTICS

Answer 12

The organisms with the beneficial characteristics will be able to out-compete the other individuals with the less beneficial or harmful genetic traits for
limited resources and mates.

Question 13

CONSEQUENCE OF ORGANISMS WITH BENEFICIAL CHRACTERISTICS

Answer 13

Therefore, these individuals will survive and reproduce and pass these genetic traits onto the next generation of offspring.

Question 14

ORGANISMS WITH LESS DESIRABLE TRAITS

Answer 14

Organisms with less desirable traits will die or produce less offspring

Question 15

ACCUMULATION OF BENEFICIAL TRAITS

Answer 15

Over many generations the accumulation of these beneficial genetic traits may result in a change in the population known as evolution.

Question 16

FOR ANOTHER SPECIES TO DEVELOP

Answer 16

For another species to develop, these genetically different individuals eventually have to become reproductively isolated (separated from the general
population) where they will only reproduce with individuals with similar genetic traits.

Question 17

ACQUIRED CHARACTERISTICS

Answer 17

Acquired characteristics of an individual such as large muscles are not passed on to an organism’s offspring

Question 18

OVER PRODUCTION OF OFFSPRING EXAMPLES

Answer 18

Fish produce thousands of eggs but only few make it to adulthood.

Plants also can produce hundreds or thousands of seeds to be released into the environment.

Question 19

ANTIBIOTICS

Answer 19

Antibiotics kill bacteria directly or weaken the bacteria so your immune system can fight and destroy the invading pathogen.

Question 20

BACTERIAL INFECTION

Answer 20

If a patient has a bacterial infection, when antibiotics are given to fight the infection the majority of the original population of bacteria will be destroyed.

Question 21

ANTIBIOTIC RESISTANCE

Answer 21

However, some of these bacteria might not die because of changes within their DNA. These changes could be caused by mutations within their genome
or the transfer of an antibiotic resistant gene from another bacterium.

Question 22

LIKELINESS OF ANTIBIOTIC RESISTANCE

Answer 22

Resistance is more likely to occur if the proper amounts of antibiotics aren’t taken or if a patient doesn’t finish the prescription.

Question 23

CONSEQUENCE OF ANTIBIOTIC RESISTANCE

Answer 23

These resistant bacteria will survive and reproduce, creating more identical resistant bacteria.

These resistant bacteria will make the person sick again in the future.

However if given the same antibiotic, these bacteria will no longer be destroyed.

Resistance can be passed onto other pathogenic bacteria, creating more species of resistant bacteria.

Question 24

ANTIBIOTIC RESISTANCE SOLUTION

Answer 24

Another antibiotic can be prescribed to kill these new resistant bacteria.