Evolution

Question 1

Define evolution

Answer 1

the process by which different kinds of living organism are believed to have developed from earlier forms during the history of the earth.

Question 2

Define microevolution

Answer 2

evolutionary change within a species or small group of organisms, especially over a short period.

Question 3

Define macroevolution

Answer 3

major evolutionary change, especially with regard to the evolution of whole taxonomic groups over long periods of time.

Question 4

What are comparative genomics

Answer 4

Comparative genomics is a field of biological research in which researchers use a variety of tools to compare the complete genome sequences of different species. By carefully comparing characteristics that define various organisms, researchers can pinpoint regions of similarity and difference.

Question 5

Define natural selection

Answer 5

Natural selection is the process through which species adapt to their environments. It is the engine that drives evolution.

Question 6

When does natural selection occur?

Answer 6

When the pressures of environmental selection confer a selective advantage on a specific phenotype to enhance its survival (viability) and reproduction (fecundity)

Question 7

What are the three types of selection

Answer 7

Stabilising
Direction
Disruptive

Question 8

What are 4 environmental selection pressures

Answer 8

• Climate
• Competition
• Mate availability
• Predator abundance

Question 9

Define selective advantage

Answer 9

When a particular phenotype gives that individual a survival or reproductive advantage over another individual with the same phenotype.

Question 10

Positive selection vs Negative selection

Answer 10

Positive selection favours a trait, is likely to increase allele frequency within a population

Negative selection is selection against an unfavourable trait, causes reduced allele frequency in that population

Question 11

Describe the Graphs for stabilising, disruptive and directional selection.

Answer 11

Stabilising - Skinny and tall compared to original
Directional - shifted in one direction from the original
Disruptive - “w” shape, opposite on each side of the original.

Question 12

Define gene flow

Answer 12

Gene flow, also called gene migration, the introduction of genetic material (by interbreeding) from one population of a species to another, thereby changing the composition of the gene pool of the receiving population. The introduction of new alleles through gene flow increases variability within the population and makes possible new combinations of traits.

Question 13

Define genetic drift

Answer 13

variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce.

Question 14

What do speciation and macroevolutionary changes result from?

Answer 14

An accumulation of microevolutionary changes over time

Question 15

What are the 4 patterns of diversification between species

Answer 15

Divergent, Convergent, parallel and coevolution

Question 16

What are the 3 modes of speciation

Answer 16

allopatric, sympatric and parapatric

Question 17

What is allopatric speciation?

Answer 17

Allopatric speciation is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow.

Question 18

What is parapratric speciation

Answer 18

In parapatric speciation, two subpopulations of a species evolve reproductive isolation from one another while continuing to exchange genes.

Question 19

What is sympatric speciation

Answer 19

Sympatric speciation is the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region.

Question 20

What are the 4 different methods of isolation

Answer 20

• Geographic (Environmental disasters, habitat fragmentation)
• Reproductive
• Spatial
• Temporal

Question 21

How do populations with reduced genetic diversity face an increased risk of extinction?

Answer 21

Populations with reduced genetic diversity face an increased risk of extinction due to several critical factors:

Increased Vulnerability to Diseases: Reduced genetic diversity means a limited gene pool, making populations more susceptible to diseases. With fewer genetic variations, there’s a higher chance that more individuals within the population could be susceptible to the same diseases, reducing their ability to combat new or existing pathogens.

Reduced Adaptability: Genetic diversity allows populations to adapt to changing environments. When diversity is low, there’s a lack of genetic variations that might be advantageous in responding to environmental changes, such as climate shifts or new predators. This decreased adaptability reduces the population’s resilience and survival capacity.

Inbreeding Depression: Inbreeding within a population with low genetic diversity leads to inbreeding depression. This condition results in the expression of harmful recessive traits due to the mating of closely related individuals, impacting the population’s overall health and reproductive success.

Loss of Evolutionary Potential: Genetic diversity is the raw material for natural selection and evolution. Reduced diversity limits the potential for populations to evolve in response to changing conditions, decreasing their ability to survive and thrive in the long term.

Overall, diminished genetic diversity compromises the adaptive capacity of a population, making it more prone to diseases, environmental changes, and reducing its ability to withstand various challenges, thus increasing the risk of extinction.

Question 22

Why do some animals, given the opportunity, move into new environments?

Answer 22

In order to outcompete their competition, the species must search for more food, water and other resources.