Variation

Question 1

What is variation?

Answer 1

Living organism that belong to same species resemble each other, but usually differ in a number of ways.

Question 2

What are the 2 causes of variation?

Answer 2

Genetics
The environment

Question 3

How can genetics be varied?

Answer 3

Mutations in the DNA.
Through sexual reproduction.

Question 4

What are some examples of genetic variation?

Answer 4

Eye colour
Blood group
Tongue-rolling
Genetic conditions - cystic fibrosis, Down’s syndrome

Question 5

How can the environment be varied?

Answer 5

Climate
Nutrient availability
Soil, e.g. pH or moisture levels
Lifestyle

Question 6

What are some examples of environmental variation?

Answer 6

Height of pea plant
Shoe size

Question 7

What type of variation is genetic variation?

Answer 7

Discontinuous variation

Question 8

What type of variation is environmental variation?

Answer 8

Continuous variation

Question 9

What type of graph can be used to showcase continuous variation?

Answer 9

Histogram

Question 10

How does a histogram showcase continuous variation?

Answer 10

Gradual change
No distinct groups
Values over a range

Question 11

What is special about a histogram?

Answer 11

No spaces between bars.

Question 12

What type of graph can be used to showcase discontinuous variation?

Answer 12

Bar chart

Question 13

How does a bar chart showcase discontinuous variation?

Answer 13

Distinct groups
No overlap

Question 14

What is special about a bar chart?

Answer 14

Spaces between bars.

Question 15

What are some examples of discontinuous variation?

Answer 15

Blood groups
Tongue-rolling
Attached/detached ear-lobes
Shoe size

Question 16

What is continuous variation?

Answer 16

Type of variation shown by gradual change in a characteristic in a population.

Question 17

What is discontinuous variation?

Answer 17

Other type of variation in which all individuals can be clearly divided into two or more groups and no intermediate states.

Question 18

What is natural selection?

Answer 18

Process in which better adapted individuals survive (at expense of less well adapted ones) and pass on their genes to their offspring.

Question 19

Where is natural selection important?

Answer 19

Where there is competition for natural resources.

Question 20

What are the 3 elements of natural selection?

Answer 20

Difference between phenotypes
Differential survival
Differential reproductive success

Question 21

What is an example of the 3 elements of natural selection?

Answer 21

1. Some grey squirrels can run faster than others and get away from predators.
2. Fastest squirrels survive while slower ones get caught.
3. Fastest squirrels will pass their genes to their offspring.

Question 22

What is an example of natural selection in action?

Answer 22

Antibiotic resistance

Question 23

What is involved in antibiotic resistance?

Answer 23

When treated with antibiotic some bacteria may already be resistant due to mutation.

These bacteria survive as rest are killed and reproduce with less competition from non-resistant bacterial strains.

Resistance bacteria survive to breed and pass on resistant gene to offspring.

Over time antibiotic resistant bacteria become dominant type in population.

Question 24

What is evolution?

Answer 24

A continuing process of natural selection that leads to gradual changes in organisms over time, which may lead to formation of a new species.

Question 25

What are the reasons that some people do not accept the theory of evolution?

Answer 25

1. Contradicts some religious beliefs. 2. Very long time scales means very difficult to see it happening.

Question 26

What is extinction?

Answer 26

When there are no living members of a species left.

Question 27

What are some examples of species that were not well enough adapted to survive?

Answer 27

Mammoths and dinosaurs.

Question 28

What does endangered mean?

Answer 28

Risk of extinction.

Question 29

What are some reasons for why many organisms are endangered?

Answer 29

Climate change Hunting by humans Habitat destruction

Question 30

What are some examples of endangered species today?

Answer 30

Mountain gorillas and many species of large cats

Question 31

How can we slow down the rate of extinction?

Answer 31

Legislation preventing hunting of endangered species. International climate change agreements. Nature reserve to protect habitats. Education to help people protect their environment.

Question 32

What are fossils?

Answer 32

Fossils are the remains of living organisms that have been preserved (usually in rock) for millions of years.

Question 33

How can fossils provide good evidence for evolution?

Answer 33

Scientists can compare fossils of different stages to see how species have changed over time. Different stages can be dated as possible to date rocks. Fossil record can also show when new species appeared and give information about environment an animal lived in.

Question 34

What is selective breeding?

Answer 34

Selection and subsequent breeding of organisms chosen by humans for their desirable properties. Takes many generations and long time to reach stage of desirable characteristics.

Question 35

What are some examples of selective breeding for desirable traits in crops?

Answer 35

Increased crop yield, e.g. larger head of grain. Peak quality. Hardiness e.g. shorter stalk length. Disease resistance. Longer shelf life.

Question 36

What are some examples of selective breeding for desirable traits in animals?

Answer 36

Dog coat / colour / temperament. Dog agility, e.g. greyhounds. Cow, e.g. milk yield, muscle mass, easy to calve, high quality milk.