Evolution

Question 1

Evolution

Answer 1

The change in the genetic composition of a population during successive generations which may result in the development of new species

Question 2

3 Modes of Evolution

Answer 2

Allopatric, sympatric, parapatric

Question 3

Allopatric Evolution

Answer 3

Gene flow is disrupted as populations become physically separated through geographic isolation. Due to genetic drift or different selecting pressures on the two populations, the populations diverge and become new species

Question 4

Sympatric Evolution

Answer 4

The evolution of two or more new species from a single population within the same place. Requires a reproductive barrier that isolates members of a population from the rest of the population in the same area

Question 5

Parapatric Evolution

Answer 5

Could arise if members of a population expand into surrounding areas where conditions favor a set of alleles different from the main population. Gene flow would still continue in the bordering areas but over time the populations would diverge to become better adapted to different conditions in different areas. A hybrid zone would form where the populations meet, hybrids are often less fit than either populations and reinforce reproductive barriers: spatial distance, patchy, changed habitats

Question 6

Divergent Evolution

Answer 6

Occurs when a population splits into two or more species. This may be due to competition, or when a new niche becomes available in an environment. Individuals that have variation due to mutations that are beneficial for the new environment have an advantage

Question 7

Adaptive Radiation

Answer 7

The evolutionary process where organisms diversify rapidly from an ancestral species into several divergent species

Question 8

Parallel Evolution

Answer 8

Independent evolution of similar traits in species that once shared a common ancestor meaning two or more species in the same environment develop similar adaptations or characteristics; closer ancestral relationship

Question 9

Convergent Evolution

Answer 9

The independent development of similarities between species as a result of them having similar ecological roles and selection pressures; more distant ancestral relationship than parallel evolution

Question 10

Coevolution

Answer 10

When two or more species reciprocally affect each other’s evolution. When two species are very reliant on each other, each species exerts a strong selective force on the other

Question 11

Macroevolution

Answer 11

The variation of allele frequencies at or above the level of species, over geological time, resulting in the divergence of taxonomic groups from the ancestors

Question 12

Speciation

Answer 12

The evolution of one or more new species from an ancestral species

Question 13

Mechanisms of Isolation

Answer 13

Geographical: seas, mountains, distance or habitat
Temporal (Time): breed different times of the year or times of the day
Behavioural: courtship patterns
Morphological: different reproductive structures

Question 14

Gene Frequency

Answer 14

There are different alleles for one gene and their frequency in a population depends on the environmental selection pressures. If a particular phenotype is advantageous than the frequency will increase and if it is selected against, it will decrease in a population