5.1, 5.2, 5.4,10.3 Evolution, Natural Selection, Clasistics, Gene Pool speciation

Question 1

Heritable

Answer 1

One generation to the next through genes

Question 2

Cumutive

Answer 2

One change is usually not enough to have a major impact on the species
More and more have to be effected over time

Question 3

Population

Answer 3

Change cannot affect only 1 individual

Question 4

Evolution

Answer 4

The process of cumulative change in the heritable characteristics of a population

Question 5

How do fossils form?

Answer 5

.1. Death
- Scavengers feed on fleshy body leaving skeleton/ shell
.2. Deposition
- Skeleton/ shell slowly becomes covered with dirt, sand/ silt
- Thousands of years pass
.3. Permineralization
- Chemicals in shell/ skeleton undergo chemical changes
- Chemicals are replaced w rock-like minerals
.4. Erosion
- Movement of earth plates move rock and fossil to surface
.5. Exposure
- Natural erosion exposes the fossil

Question 6

Fossil Record

Answer 6

• Evidence that species evolve over time based on dating rock
• The fossil record provides evidence by revealing the features of an ancestor for comparison against living descendants

Question 7

Evidence of evolution

3

Answer 7

Selective Breeding:
- A form of artificial selection, whereby man intervenes in the breeding of species to produce desired traits in offspring
- Dog breeds, chicken breeds for egg/ meat

Fossil Record:
- Evidence that species evolve over time based on dating rock

Homologous Structures
- Araise from sharing a common whereby several new species rapidly diversify from an ancestral source
- Homologous structures illustrate adaptive radiation
- 3 examples

Question 8

Homologous Structures Examples

Answer 8

Comparison of the pentadactyl limb of mammals
- Mammals, birds, amphibians and reptiles all share a similar arrangement of bones in their appendages based on a five-digit limb
- Use of locomotion (forms of getting around) to compare species

Plasma Membrane
- Structure of plasma membrane in eukaryotic and prokaryotic structures are similar
- All consist of phospholipids

Universal Genetic code
- The standard genetic code
- AUG, GCA etc.

Phalanges, Carpals, Radius, Ulna, Humorous

Question 9

Charles Darwin

Answer 9

• Discovered organisms elolve over time due to natural selection’
• Daphne Major beaks were different and evolved to suit their diet

Question 10

Peppered moth example

Answer 10

• During the industrial revolution, trees were covered in sut causing industrial melamism in over 70 species of moths.
• Natural selection –> The moths melanin increased to change the colour from white to brown so they could camouflage on the darker trees
  = For vs against in different environments

Question 11

Natural Selection

Answer 11

• The mechanism for evolution –> elolution occurs bc of it.
• Can only occur if there is variation amoung members of the same species (for vs against certain traits)
• Mutation, meiosis and sexual reproduction in organisms that reproduce causes variation in species due to heritable traits

Question 12

Adaptations

Answer 12

• Adaptations are features of organisms that aid their survival by allowing them to be better suited to their environment

Can be:
Structural: Physical differences in biological structure
Behavioural: Differences in patterns of activity
Physiological: Variations in detection and response by vital organs
Biochemical: Differences in molecular composition of cells and enzyme functions
Developmental: Variable changes that occur across the life span of an organism

Question 13

Darwins theory

Answer 13

Variation exists amoung individuals within species

Variations arise from:
- Mutation
- Crossing over during prophase 1
- Random assortment of chromosomes during metaphase one
- Sexual reproduction

Organisms have more offspring than the environment can handle

Competition amoung individuals
- Intraspecies = Same
- Interspecies = Different

Best fitted variations that fit to environment are likely to survive and reproduce and pass on characteristics to next generation

Question 14

Gene Pool

Answer 14

A gene pool consists of all the genes and their different alleles, present in an interbreeding population.
- Sum of all the alleles

Question 15

Evolution and alleles

Answer 15

Evolution requires that allele frequencies change with time in populations.

Changes to allele frequency within a gene pool (evolution) can result from five key processes

Missing one is sexual reproduction

Question 16

Reproductive isolation

Answer 16

Can be temporal, behavioural, or geographic

Question 17

Reproductive isolation due to behaviour

Answer 17

• When two populations exhibit different specific courtship patterns
• Species used to be the same, but natural selection differenciates them due to bahaviours.

Question 18

Temporal Reproductive Isolation

Answer 18

When two populations differ in their periods of activity or reproductive cycles

Question 19

Geographic Reproductive Isolation

Answer 19

when two populations occupy different habitats or separate niches within a common region
- Change due to diversing in geographic location

Question 20

Speciation

Answer 20

When populations gradually diverge into seperate species by evolution

Question 21

Pace of elolutionary change

Answer 21

Punctual = missing intermediate fossils in the fossil record
- species remain stable for long periods before undergoing abrupt and rapid change
- Sudden changes in environment (industrial revolution)

Gradual = Steady change
- speciation generally occurs uniformly, via the steady and gradual transformation of whole lineages

Question 22

Genetic drift

Answer 22

The change in the composition of a gene pool as a result of change or random events

Bottle neck:
- when an event reduces population size by over 50%

Flounder effect:
- small group breaks away from the population to establish themselves in a new territory

Question 23

Allele frequences

Answer 23

• represent the prevalence of a particular allele in a population, as a proportion of all the alleles for that gene
• represented as a percentage or 0.0 - 1.0

Question 24

Stabilising Selection

Answer 24

• Where an intermediate phenotype is favoured at the expense of both phenotypic extremes
• Results in removal of extreme phenotypes

Question 25

Directional Selection

Answer 25

- Where one phenotypic extreme is forced to change due to the environment - This causes the phenotypic distribution to clearly shift in one direction

Question 26

Disruptive selection

Answer 26

- Where both phenotypic extremes are favoured at the expense of the intermediate phenotypic ranges - This causes the phenotypic distribution to deviate from the centre and results in a bimodal spread

Question 27

Polyploid

Answer 27

- Organism w/ more than 2 sets of homol. chromosomes. - Resulting from hybridization between different species or from the same ancestral species when chromosomes duplicate in preparation for meiosis but then meiosis doesn’t occur

Question 28

Clades

Answer 28

A group of organisms that have evolved from a common ancestor

Question 29

Analoguous and Homologuous

Answer 29

**Homologous** - Similar because of similar ancestry (ex. Pentadactyl limbs) **Analogous** - Similar because of convergent evolution - (human & octopus eye – function the same, but evolved independently)

Question 30

Cladograms

Answer 30

Are tree diagrams that show the most probable sequence of divergence in clades Show evolutionary relationships and demonstrate how recently two groups shared a common ancestry | Could be data base questions

Question 31

Reclassification of the figwort family using evidence from cladistics

Answer 31

- DNA evidence identified different common ancestors - Analoguous (convergent evolution)