Evolution

Question 1

What is evolution

Answer 1

Evolution is a change in allele frequency in a population over time.

Question 2

What is Darwin observe

Answer 2

Darwin observed that organisms produce more offspring than can survive and reproduce and there was variation among offspring.

Question 3

What did Darwin conclude

Answer 3

Darwin concludes that organisms struggle for existence due to different selection pressures and individuals that are best adapted survive and reproduce

Question 4

What is process of evolution

Answer 4

Process of evolution ism
Mutations occur leading to new alleles arising in genotypes and variation in phenotypes of population. Selection pressure occurs so certain alleles may become advantageous.
Differential survival, some organisms are more likely to die than others. Individuals with advantageous alleles are more likely to survive and reproduce. Next generation will have a higher proportion of favourable alleles. This process results in evolutionary change over many generations.

Question 5

What is a molecular clock and how is it used

Answer 5

Molecular clock is that, as species evolve, they accumulate random mutations at a regular rate, becoming genetically more different. For a given gene, mutation rate is fairly constant and this molecular change in DNA over time can be used as a molecular clock.
This is used to compare number of differences between species, which makes it possible to calculate how long ago they shared a common ancestor.

Question 6

What are degrees of hybridisation and what is this determined by

Answer 6

Degrees of hybridisation are
Complete (organisms are identical), partial (organisms related) and none.
This is determined by temperature needed to separate hybridised strands, the higher the temperature required to separate, 5e more closely related the species

Question 7

How can DNA and protein sequencing be used to compare organisms

Answer 7

DNA and protein sequencing can be used to compare species by comparing DNA and proteins, it is possible to determine how closely related they are. If there are lots of differences in sequences then species are less closely related and have a less recent common ancestor than 2 species which are more related.

Question 8

How can DNA profiling be used to compare organisms

Answer 8

DNA profiling can be used to compare organisms by comparing position of bands, size of bands and number of bands to determine how closely related species are.

Question 9

What is process of population growth

Answer 9

Process of population growth is:

1) Population grows slowly due to low numbers of reproductive individuals who may be widely dispersed.
2) population grows exponentially, few factors limiting growth, predation and disease are low
3) population growth slows, factors limit growth death rate increases and /or birth rate decreases
4) birth rate and death rate balance, population has reached carrying capacity of environment

Question 9

Why doesn’t everyone believe in evolution

Answer 9

Not everyone believes in evolution because:
Creationists accept literal teaching of bible
Incomplete fossil records
Impossible to experiment as time scale is too big

Question 10

What is differential survival

Answer 10

Differential survival is best adapted of individuals survive and reproduce

Question 11

DNA hybridisation

Answer 11

DNA hybridisation is :
Have 2 organisms DNA
Both strands of DNA are heated to separate strands, breaking H bonds between bases.
Combine the 2 single strands of DNA
Cool to allow resaturation of strand
The more similar they are, the better the strands stick together
DNA relatedness is measured by temperature needed to denature hybrid DNA.