29) Unit 2 - Rate of Evolution and Co-Evolution

Question 1

what causes the rate of evolution to become rapid/increase

Answer 1

high selection pressure

Question 2

Name factors that can increase the rate of evolution

Answer 2

• Higher selection pressures
• shorter generation times
• warmer environments
• sharing of beneficial DNA sequences (sexual reproduction or horizontal gene transfer)

Question 3

describe how higher selection pressures increase the rate of evolution

Answer 3

• Selection pressure affect the heritability of traits
• Increase in the inheritance of beneficial traits and reduction in the inheritance of harmful traits
• This increases evolution because more traits are being favoured/selected

Question 4

describe how shorter generation times increase the rate of evolution

Answer 4

• if generation times are short there are more generations in a set period
• Since evolution happens over generations, having more generations provide more opportunities for selection pressures to operate and change the frequency of traits in a population

Question 5

describe how sexual reproduction increases evolution rate

Answer 5

• Combining two individuals genetic material during sexual reproduction increases variation shown by the offspring
• Greater variation leads to more selection and a faster rate of evolution

Question 6

Describe how horizontal gene transfer increases evolution rate

Answer 6

• Horizontal gene transfer allows the sharing of beneficial DNA sequences between different lineages of bacteria, using plasmids to transfer genetic material
• This increases evolution because beneficial sequences of DNA can be shared quickly

Question 7

how does warmer environments increase the rate of evolution

Answer 7

• When temperature increases germ cells which produce gametes by meiosis divide more frequently
• More DNA replication means greater chance of mutation which brings new variation which has more chance for selection

Question 8

Where is co-evolution usually seen and give 2 examples

Answer 8

Seen in pairs of species that interact frequently or closely

• Pollinators and plants
• Parasite and host

Question 9

In co-evolution the change in the traits of one species acts as a ____________ __________ on the other speices

Answer 9

in co-evolution the change in the traits of one species acts as a SELECTION PRESSURE on the other species

Question 10

what does the red queen hypothesis state

Answer 10

States that both organisms must keep running(evolving) in order to stay still

Question 11

when are hosts considered to have good fitness

Answer 11

Hosts better able to RESIST and TOLERATE parasitism have greater fitness and therefore selected

Question 12

when are parasites considered to have good fitness

Answer 12

Parasites Better able to FEED, REPRODUCE and FIND NEW HOSTS have greater fitness and are therefore selected