Biology

Question 1

Define evolution

Answer 1

The genetic change in the characteristics of an organism over many generations.

Question 2

What is a generation?

Answer 2

The time between a creature’s birth and having off-spring of its own.

Question 3

Describe three changes in the structure of the horse, over evolutionary time.

Answer 3

Toes
Size
Larger teeth

Question 4

Two species that share genes must have had the same…

Answer 4

… ancestor

Question 5

Homologous structures are likely to be formed by the same… even if they have different…

Answer 5

…gene

…function

Question 6

Analogous structures are likely to be formed by different… even though they have the same…

Answer 6

…genes

…functions

Question 7

For example, dolphins and sharks have similar body shapes because they evolved in similar…

Answer 7

…environments

Question 8

List the five main steps in the theory of natural selection

Answer 8

Variation at the start within the species.
Selective pressure, anything that causes a struggle for survival.
Fittest survive.
Inheritance for the next generation, gene passed on.
Populate, breed and pass on the gene.

Question 9

What is artificial selection?

Answer 9

When humans interfere with natural selection. Humans breed two creatures of the same species for a common desirable characteristic.

Question 10

How is it that domestic budgies now look different (in the range of colours) to wild budgies?

Answer 10

Originally some budgies showed different colours in the wild. Humans then bred these budgies until they were the desired colour.

Question 11

What is cross breeding?

Answer 11

When two creatures of different species are bred to have off-spring.

Question 12

Are lions and tigers the same species? why/ why not?

Answer 12

No, because they can not have fertile off-spring.

Question 13

How does embryology show evidence for evolution?

Answer 13

The similarity between organisms when they are in the embryo stage shows that they have a common ancestor.

Question 14

How do fossils prove evolution?

Answer 14

Fossils increase in complexity as you go up layers (from old to young) and increase in number, showing that organisms are increasing in complexity. There are also transitional fossils which show changes in organisms-evolution.

Question 15

How can DNA and protein prove evolution?

Answer 15

Some organisms have very similar protein and DNA sequences showing that they are closely related. (come from a common ancestor)

Question 16

How can geographical distribution prove evolution?

Answer 16

Island species closer to the mainland are most similar to mainland species, which is exactly what we would expect if those organisms came from the mainland and then evolved because they were isolated.

Question 17

List 5 examples of things that can split a population up in two.

Answer 17

There are many but some include mountains, rivers, natural disasters, fire, ocean currents and religion.

Question 18

There is an ongoing argument about whether evolution occurred or not. Give 3 alternative explanations for the things often used as evidence for evolution.

Answer 18

Natural Selection is the main way of explaining why evolution occurred, but it contradicts evolution by only taking the best of what is already there, never adding anything to the genetic code.

Vestigial Structures, organs that have no use in our bodies are used as evidence in the sense that we needed them at one point, but not any more, but we just haven’t discovered how they work yet.

Dolphins and sharks have a similar build but have nearly complete opposite genetic codes, this is often used as evidence for evolution, but could just be that way because it’s the best build for their environment.