3.7.3 - EVOLUTION + SPECIATION

Question 1

variation in flower colour is considered one of the factors involved in the evolution of the following two species of monkeyflower.

• erythranthe lewisii (great purple monkeyflower), which has pink flowers, is mostly found at higher altitudes (1600-3000 metres) and attracts bumblebees.
• erythranthe cardinalis (scarlet monkeyflower) which has red flowers, is mostly found at lower altitudes (up to 2000 metres) and attracts hummingbirds.

bumblebees and hummingbirds are important in the pollination of flowers. pollination involves the transfer of male gametes to female gametes.

explain the different processes that may have been involved in the evolution of these two species of monkeyflower. use the information provided to justify your answer (5)

Answer 1

1. geographical isolation due to altitude
2. allopatric speciation due to isolation
3. different selection pressures OR environment
4. however, both plants found in same habitat
5. so possibly sympatric speciation
6. variation due to mutations
7. reproductive isolation due to different altitudes
8. change in allele frequency
9. different species can no longer breed to produce fertile offspring

Question 2

suggest two reasons for conserving rainforests (2)

Answer 2

1. reduces climate change
2. conserve species OR for biodiversity
3. conserve/provides habitats