CLASSIFICATION + EVOLUTION (3.4.4, 3.4.5, 3.4.7)

Question 1

What is genetic diversity?

Answer 1

The number of different alleles of genes in a population

Question 2

What does genetic diversity enable?

Answer 2

Enables natural selection to occur

Question 3

The principles of natural selection in the evolution of populations:

Answer 3

• random mutation can result in new alleles of a genes
• many mutations are harmful but, in certain environments, the new alleles of a gene might benefit its possessor, leading to increased reproductive success
• the advantageous allele is inherited by members of the next generation
• as a result, over many generations, the new allele increases in frequency in the population

Question 4

What is directional selection?

Answer 4

Selection may favour individuals that vary in one direction from the mean of the population

Question 5

What is directional selection exemplified by?

Answer 5

Antibiotic resistance

Question 6

What is stabilising selection?

Answer 6

Selection favours average individuals

Question 7

What is stabilising selection exemplified by?

Answer 7

Human birth rates

Question 8

What does natural selection result in?

Answer 8

Species which are better adapted to their environment

Question 9

What may the adaptations to make species better suited to their environment be?

Answer 9

Anatomical, physiological, behavioural

Question 10

Process of directional selection in antibiotics:

Answer 10

• a spontaneous mutation occurred in the allele of a gene in an bacterium that enabled it to make a new protein which in an enzyme that broke down the antibiotic penicillin before it was able to kill the bacterium
• the bacterium happened, by chance, to be in a situation where penicillins as being used to treat an individual. Therefore the mutation gave the bacterium an advantage in being able to use penicillinase to break down the antibiotic and so survive while the rest of the population of bacteria were killed by it
• the bacterium which survived was able to divide by binary fission to build up a small population of penicillin resistant bacteria
• members of the population of penicillin-resistant bacteria were more able to survive and multiply
• population of penicillin-resistant bacteria increased and frequency of the allele enabled the production of penicillinase to increase in population
• populations normal distribution curve shifted in the direction of a population having greater resistance to penicillin

Question 11

Process of stabilising selection:

Answer 11

• if environment,entail conditions remain stable, it is the individuals with phenotypes closest to the mean that are favoured
• these individuals are more likely to pass their alleles on to the next generation
• individuals with phenotypes at extremes are less likely to pass on their alleles

Question 12

How do we know if two individuals belong to teh same species?

Answer 12

They are able to produce fertile offspring

Question 13

What is courtship behaviour?

Answer 13

• members of the same species have similar, or the same genes and therefore resemble each other physically and biochemically
• behaviour of members of the same species is more alike than members of another species
• necessary precursor to successful mating

Question 14

What does courtship behaviour help to do?

Answer 14

• helps to distinguish members of their own species to those of another species

Question 15

What does courtship behaviour enable individuals to do?

Answer 15

• recognise members of their own species
• identify a mate capable of breeding
• form a pair bond
• synchronise mating
• become able to breed

Question 16

Principle of classification:

Answer 16

Grouping of organisms is known as classification, the theory and practice of biological classification is called taxonomy

Question 17

Main forms of classification:

Answer 17

• artificial classification
• phylogenic classification

Question 18

What is artificial classification?

Answer 18

divides organisms according to differences at the time, may include features such as colour, size and number of legs (analogous characteristics)

Question 19

What is phylogenic classification?

Answer 19

• based upon evolutionary relationships between organisms and their ancestors
• classifies species into groups using shared features derived from their ancestors
• arranges the groups into a heirarchy, in which the groups are contained within larger composite groups with no overlap
• each group is called a taxon (plural taxa)

Question 20

What are the three domains?

Answer 20

• bacteria
• arches
• eukarya

Question 21

What are bacteria?

Answer 21

Group of single celled prokaryotes

Question 22

What are archea?

Answer 22

Group of single-celled prokaryotes (originally bacteria)

Question 23

What are eukarya?

Answer 23

Made up of eukaryotic cells

Question 24

Classification hierarchy:

Answer 24

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

Question 25

Classification hierarchy acronym:

Answer 25

Do King Prawns Call Oysters Fussy Good Species

Question 26

What are the 4 ways to investigate diversity?

Answer 26

1) frequency of measurable or observable characteristics 2) the base sequence of DNA 3) the base sequence of mRNA 4) the amino acid sequence of the proteins encoded by DNA and mRNA

Question 27

How would you measure diversity by measuring frequency of measurable or observable characteristics?

Answer 27

- how genetic diversity was measured traditionally - each observable characteristic is determined by a gene or genes (with environmental influences) - the variety within a characteristic depends on the number and variety of alleles of that gene - HOWEVER, large number of characteristics are polygenic (coded for by more than one gene), meaning they are not discrete from one another but vary continuously - characteristics can also be modified by the environment

Question 28

How would you measure diversity by using the base sequence of DNA?

Answer 28

- each nucleotide is tagged with a different coloured fluorescent dye- produces a series of coloured bands + compare how diverse they are - also determines evolution between species

Question 29

How would you measure diversity using the base sequence of mRNA?

Answer 29

- mRNA is coded for by DNA - based sequences on mRNA are complementary to those of the strand of DNA from which they were made - measure DNA diversity, therefore genetic diversity, by comparing the base sequence of mRNA

Question 30

How would you measure diversity by using the amino acid sequence?

Answer 30

- determined by mRNA, in turn, DNA - genetic diversity within + between species can be measured by comparing the amino acid sequences of their proteins - degree of similarity in the amino acid sequence of the same protein of two species will reflect how closely related the two sequences are

Question 31

What is a population?

Answer 31

A group of individuals of the same species that live in the same place and can interbreed

Question 32

What is a species?

Answer 32

Consists of one, or more populations