biol10004 22 2013 gs reproduction1 notes
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BIOL10004 Lecture 22 Reproduction 1 Geoff Shaw, Department of Zoology. Ref: KLES3: ch 18; Chap 25, esp pp 608-9, Fig 25.17 KLES4: ch 19,; Ch ap 27, esp p 647-648, Fig 27.10 Two approaches to reproduction are ________________ and _______________ Sexual reproduction needs 2 sexes to make gametes, which involves _____________ cell division
Males make _______________ that are small and motile
Females make ______________ that are ___________ and ____________
Offspring are a _________________ of the genes of the parents
Reproduction involves mechanisms to get egg and sperm together to ensure ___________ and _________________..
________________ is a specialised form of cell
division where haploid _________________ fuse to
form a new _______________individual Asexual reproduction relies on _______________ cell division. Offspring are genetically _______________ to parents
Examples include ____________, _____________,
____________
Two variations on the theme are H_______________ and P__________________. Hermaphrodites are animals that can produce both eggs and sperm (not necessarily at the same time). For example Blue wrasse can change from female to male if the dominant male in the harem is removed.
Parthenogenesis is a process whereby unfertilized eggs can develop into a new individual. For example aphids use parthenogenetic reproduction to increase in numbers rapidly in summer, but sexual reproduction in autumn to produce more robust offspring to survive winter.
BIOL10004 Reproduction 1 Geoff Shaw
Two broad reproductive strategies:
Both strategies work. Circumstances may make one or the other more effective for a given species
Costs and benefits in reproductionBenefits• attracting mates• access to mates• physiology simple• make fewer eggs/sperm• high survival of young• high survival of young
Costs• attracting predators• male fighting• high loss of gametes• complex physiology• risk to preg. mother• huge investment by
parents
Mating displaysHaremsexternal fertilizationinternal fert’nviviparitypost natal care
BIOL10004 Reproduction 1 Geoff Shaw
BIOL10004 Reproduction 1 Geoff Shaw
BIOL10004 Reproduction 1 Geoff Shaw
BIOL10004 Reproduction 1 Geoff Shaw
External vs Internal Fertilization • ______________ fertilization.
– eg toad – no specialised external genitals needed, but males have _______________ on forelimbs to help grasp the female in _____________ (see fig 18.25)
• _______________ Fertilization
– requires specialization of the external genitalia to allow sperm transfer, eg ________________.
– prerequisite to __________________ (ie internal gestation and birth of live young)
Other Reproductive Organs include… ___________________,
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Other resources; http://en.wikipedia.org/wiki/Reproductive_system http://en.wikipedia.org/wiki/Male_reproductive_system, http://en.wikipedia.org/wiki/Female_reproductive_system, http://en.wikipedia.org/wiki/Hermaphrodite, http://en.wikipedia.org/wiki/Parthenogenesis, http://en.wikipedia.org/wiki/Asexual_reproduction, http://en.wikipedia.org/wiki/Sexual_reproduction.
BIOL10004 Reproduction 1 Geoff Shaw
Revision Questions
1. List the main differences between sexual and asexual reproduction
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2. List 3 different forms of asexual reproduction, and give an example of a species that
does each one.
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3. Using a simple diagram outline the alternation of haploid and diploid generations that
characterizes meiosis
4. Define a hermaphrodite _________________________________________________
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5. Why do blue wrasse change sex? __________________________________________
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6. Define parthenogenesis _________________________________________________
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7. Write a short paragraph explaining why some animals have lots of young and others
have few.
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BIOL10004 Reproduction 1 Geoff Shaw
8. What are the basic components of a reproductive system?
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9. Draw and label a male reproductive system
10. Draw and label a female reproductive system
BIOL10004 Reproduction 1 Geoff Shaw
11. Compare and contrast internal and external fertilization
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12. List 3 reproductive organs that are not part of the unrogenital tract, and list their main
reproductive functions.
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