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A2 Biology - Evolution Questions

I hate this topic :redface: I have some answers, but I doubt they're correct, so any help would be appreciated (rep for answers!).

In feb 2001, the BBC reported that scientists had discovered a 'new species' of camel in a remote part of Asia. These camels differ from domesticated Bactrian camels in the following ways:

- 3% of their DNA vase sequences are different.
- Their humps are father apart
- They have harier knees
- There is no freshwater and they survive by drinking salty water.

One possibility is that domesticated camels were bred from this wild stock many generations ago.


a) Describe how the changes in DNA could have occured (3)

(Is it asking about mutation / natural selection?)

b) Describe what further evidence is required to show that this 'new species' is a different species from domesticated camels (3)

(... Possibly by breeding the 'new' species with the 'old' one and seeing if the offspring is fertile?)

c) explain the effect on body tissues of drinking only salty water (2)

(I'm guessing it's something to do with osmotic properties...)

d) Suggest 2 physiological adaptations that would allow some camels to survive when their only source of water is salty. (2)

e) Explain how genetic variation in the ancestral wild camel population enable the devopment of this 'new' species.(2)
Reply 1
LS.
a) Describe how the changes in DNA could have occured (3)

(Is it asking about mutation / natural selection?)

b) Describe what further evidence is required to show that this 'new species' is a different species from domesticated camels (3)

(... Possibly by breeding the 'new' species with the 'old' one and seeing if the offspring is fertile?)

c) explain the effect on body tissues of drinking only salty water (2)

(I'm guessing it's something to do with osmotic properties...)

d) Suggest 2 physiological adaptations that would allow some camels to survive when their only source of water is salty. (2)

e) Explain how genetic variation in the ancestral wild camel population enable the devopment of this 'new' species.(2)

a) Yep, focus on DNA mutation mainly

b) I think thats the correct answer

c) Yep

d) -Extra long tubules in kidney for more ultrafiltration?
-More protein carrier/channels for removal of Na+ ions in tubules?
-Membrane in contact with the ions are not so permeable [ie lack of protein carriers/channels] eg in oseophagus, intestines etc?

e) Natural selection type answer required leading to new species
Reply 2
Thanks very much 2776 :smile: