10Reprod06x

10Reprod06x - Reproduction Patterns - ancestral vs....

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
Reproduction
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Patterns - ancestral vs. currently predominant? - which fitter? but, usu. some form of sex; why?
Background image of page 2
Benefits of sex? 1. repair accumulated mutations - cultures die if sex prevented - good for sp.? 2. variation in offspring - some survive; e.g., disease i. aphids parthenogenetic but late ♀s produce winged sexuals; eggs laid that overwinter on new plants
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
ii. NZ snail asexual in lakes without trematodes, sexual in lakes with iii. monocultures iv. sexual reproduction more common where communities diverse (e.g. tropics) Red Queen hypothesis: “Now here you see, it takes all the running you can do to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that.”
Background image of page 4
Costs? 1. “locally adapted gene complexes” 2. “meiosis” if ♀ produces 2 offspring: asexually = 2 copies of own genes sexually = 1 copy (0.5 in each) 3. if local mate competition , “sons” 9 daughters, 1 son = 90 grandchildren 5 daughters, 5 sons = 50 grandchildren
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4. “mating” - gamete production, find, compete, accept 5. sexually transmitted diseases costs make sex difficult to explain from individual perspective
Background image of page 6
Why 2 sexes? - ancestral state? - isogamy in water; fusion to form zygotes to an isogamy? - tradeoff; provisioning vs. finding gametes - to specialisation (blackboard)
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Gamete size Frequency Large, nutrients Small, speed Medium, OK at both Disruptive selection
Background image of page 8
Evolution of 2 sexes - def’n? ♂ vs. ♀ in ALL
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/08/2010 for the course BIOL 3143 taught by Professor Daveshutler during the Winter '10 term at Acadia.

Page1 / 23

10Reprod06x - Reproduction Patterns - ancestral vs....

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online