1. 19-1 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Part 4: Animal form and function Chapter 19: Animal reproduction

2. 19-2 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Reproduction Asexual reproduction –one parent –new individuals genetically identical to parent and to each other Sexual reproduction –two parents –new individuals genetically unique (novel combination of genes from both parents)

3. 19-3 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Asexual reproduction New individuals produced through mitotic cell division Limited genetic diversity Occurs by: –regeneration –budding –parthenogenesis

4. 19-4 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Regeneration Production of new individuals –cellular replication by mitosis –differentiation of tissues Reproduction by fragmentation –example: aquatic annelids Regeneration of individuals from body parts –example: starfish

5. 19-5 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Budding Production of new individuals –outgrowth of body wall of parent Break off to form individual –example: Hydra Remain attached to form part of colony –example: corals

6. 19-6 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Parthenogenesis Production of new individuals –egg cells develop into embryos without fertilisation –offspring usually female Obligate parthenogenesis –example: Heteronotia binoei (Binoe’s gecko) Cyclical parthenogenesis –example: some species of aphids

7. 19-7 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Parthenogenesis (cont.) Ants, bees and wasps (Hymenoptera) –females produced by sexual reproduction –males produced by asexual reproduction (parthenogenesis) Unfertilised eggs (n) –undergo mitosis, but do not divide into two cells –nuclei fuse to produce a diploid cell (2n) –cell develops as if fertilised

8. 19-8 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Sexual reproduction New individuals produced through fusion of haploid cells (gametes) from parents –egg (ovum) –sperm (spermatozoon) Increases genetic diversity

9. 19-9 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Gametes Two types of gametes Similar structure –isogamy Different structure –anisogamy –smaller of gamete pair = male

10. Fig. 19.5a & d: Gametes 19-10 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University

11. 19-11 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Male and female Different mating types = sex –male, female Males –produce sperm only Females –produce eggs only

12. 19-12 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Mating systems Organisms with separate sexes –dioecious Organisms with both sexes in one individual –monoecious or hermaphroditic

13. 19-13 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Hermaphroditism Hermaphrodites produce both male and female gametes Problems of self-fertilisation limited by separation of male and female gametes –anatomy  male and female reproductive tracts separate –behaviour  complex courtship and mating –time  eggs become fertile after sperm are no longer functional  sex change

14. 19-14 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Changing sex Some species avoid self-fertilisation by sex changes –alternate between male and female at different stages of life cycle Protandry: male  female –Example: clownfish Protogyny: female  male –Example: parrot fish

15. 19-15 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Reproductive strategies Developmental strategies vary Indirect development –offspring pass through one or more larval stages before they attain adult form Direct development –offspring hatch or are born resembling miniature adults

16. 19-16 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Indirect development Many eggs produced –small amount of yolk in each egg –limits time for embryonic development Free-living larval forms Metamorphosis (change in form from larva to adult) –examples: butterflies, flies, beetles, frogs

17. Fig. 19.8: Indirect development 19-17 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University

18. 19-18 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Direct development Few eggs produced –large amount of yolk in each egg –embryo nourished by yolk Embryo develops in egg Hatches/born with adult form –examples: land snails, reptiles, birds, mammals

19. 19-19 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Fig. 19.9: Direct development Copyright © 18.9 Jan Aldenhoven/AUSCAPE

20. 19-20 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Development in mammals Direct development –but eggs have small amount of yolk Young develop in uterus Nutrients provided to developing young –before birth  uterine secretions  placenta –after birth  milk

21. 19-21 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Development in mammals (cont.) Variation in patterns of reproduction –young born at different stages of development Marsupials and eutherians –live young (viviparous)

22. 19-22 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Development in mammals (cont.) Monotremes –lay eggs (oviparous)

23. 19-23 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University The costs of sexual reproduction Parental investment in reproduction –varies depending on reproductive strategy Includes –production of gametes –increased risk of predation –competition for mates –parental care Cost must not outweigh benefit Caring for young –increases chances of offspring surviving to maturity –reduces ability of one (or both) parents to find food and avoid predators

24. Question 1: What benefits of sexual reproduction would outweigh the costs? a)Increased ability to produce genetic diversity b)Ability to produce variable offspring which could have a greater chance of success in a new environment c)Reduction in deleterious mutations having an effect on offspring d)All of the above 19-24 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University

25. 19-25 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Gametogenesis Primary sex organs = gonads Male gonad = testis –produces sperm (spermatozoa) Female gonad = ovary –produces eggs (ova) Process of gamete production = gametogenesis –spermatogenesis –oogenesis

26. 19-26 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Mitotic divisions Primordial germ cells undergo a series of mitotic divisions Give rise to multiple diploid (2n) oogonia/ spermatogonia After the final mitotic division, these cells are termed oocytes/spermatocytes

27. 19-27 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Meiotic division Primary oocyte (product of mitotic divisions) First meiotic division –primary oocyte gives rise to  secondary oocyte  first polar body Second meiotic division –secondary oocyte gives rise to  ovum (egg)  second polar body –first polar body gives rise to  polar bodies

28. 19-28 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Meiotic division (cont.) Primary spermatocyte (product of mitotic divisions) First meiotic division –primary spermatocyte gives rise to  secondary spermatocytes Second meiotic division –secondary spermatocytes give rise to  spermatids

29. 19-29 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Fig. 19.20a: Oogenesis

30. 19-30 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Fig. 19.20b: Spermatogenesis

31. 19-31 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Maturation of gametes Spermatocyte –loss of most of cytoplasm –development of long flagellum (tail) –formation of secretory acrosome at anterior of head section Oocyte –increase in organelles –increase in nutritive materials –development of protective extracellular membranes, e.g. vitelline membrane

32. 19-32 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Fertilisation Fusion of egg and sperm Egg activation –inactive egg is activated by fusion of plasma membranes of egg and sperm –resumes synthetic activity Nuclear fusion –pronuclei of egg and sperm fuse –creates diploid zygote

33. Fig. 19.25: Fertilisation 19-33 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University

34. 19-34 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Methods of fertilisation Methods of bringing egg and sperm together External fertilisation –takes place outside body –examples: corals, frogs Internal fertilisation –takes place inside body –examples: land snails, mammals

35. 19-35 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Internal fertilisation Sperm must be transferred to female reproductive tract Intromittent organ –penis, claspers Spermatophore –packet of sperm Injected through body wall –example: leeches

36. Question 2: Which of the following is/are disadvantages of internal fertilisation? a) gametes and embryo will be prevented from desiccation b) independence from external water source c) complicated behaviour must be evolved to bring the male and female into intimate contact d) the need for an intromittent organ 19-36 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University

37. Summary Asexual reproduction means having a single parent Sexual reproduction requires two parents Reproduction can be costly Successful reproduction between male and female animals requires the proper timing and control of a complex sequence of events Animals employ different strategies to maximise their chances of reproductive success 19-37 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University