Unit 5.3 Evolution and speciation

Question 1

Evolution

Answer 1

The change in the heritable characteristics of a population over time

Question 2

Theory

Answer 2

An explanation for a very general class of phenomena or observations that are supported by a wide body of evidence

Question 3

Homologous structures

Answer 3

Similar in structure, but may have different functions. They are present in organisms that descended from a recent common ancestor as a result of evolution

Question 4

Selective breeding

Answer 4

Is the process of humans choosing plants or animals with desirable traits to breed together and produce offspring with more of those desirable traits

Question 5

Common ancestor

Answer 5

One individual, or a pair of individuals, from whom all individuals in a group have descended e.g for a group of siblings the common ancestors will be their parents

Question 6

Pentadactyl limb

Answer 6

A limb with 5 digits. Pentadactyl limbs are an example of homologous structures. All organisms with pentadactyl limbs have evolved from a common ancestor. The sturcture of the limb is similar in all species, but has evolved modifications for a variety of purposes

Question 7

Population

Answer 7

Is a group of the same species, in the same place, at the same time

Question 8

Convergent Evolution

Answer 8

Is the evolution of similar structures in species not related due to a recent common ancestor

Question 9

Analogous Structures

Answer 9

the structures between two species or populations of organisms which have the same function but not the same structure, or anatomy

Question 10

Speciation

Answer 10

Is the splitting of one species into two or more species

Question 11

Species

Answer 11

Is a group of organisms capable of reproducing with each other to produce fertile offspring

Question 12

Extinction

Answer 12

Occurs when there are no living members of a species remaining.

Question 13

Reproductive Isolation

Answer 13

Occurs when there is a barrier which prevents individuals from reproducing. Speciation can only occur if populations of a species are reproductively isolated. There are 2 types: Pre-zygotic and post-zygotic

Question 14

Geographical isolation

Answer 14

Occurs when two populations of the same species are prevented from reproducing because of geographical features. Such as: rivers, mountains or being on different island