1. Finger Mitosis/Meiosis
Video link

2. Chapter 8: Reproduction
Today: mostly focusing on animal reproduction

3. Learning Objectives You should be able to:
Define, compare and contrast sexual and asexual reproduction
Describe and identify binary fission, fragmentation, budding, conjugation, internal/external fertilization
Assess the merits of internal and external fertilization

4. Reproduction Makes new members of species
Many species able to reproduce in more than one way

5. Asexual vs Sexual reproduction
Asexual Reproduction
Sexual Reproduction
One parent
Offspring genetically identical to parent
All prokaryotes, some eukaryotes
Binary fission, fragmentation, budding, (parthenogenesis)
Two parents
Offspring a combination of parental genes
Conjugation in prokaryotes
In eukaryotes, involves meiosis (gametes) and fertilization

6. Binary Fission
Used by single-celled organisms (including all prokaryotes)
Mitosis (basically)

8. Fragmentation
Parent splits: new organisms grow from different fragments
E.g. segmented worms, echinoderms (sea stars, sea urchins)

9. Fragmentation
Parent splits: new organisms grow from different fragments
E.g. segmented worms, echinoderms (sea stars, sea urchins)
But just because we can, doesn’t mean we should…

10. Budding
Make small, genetically identical polyps that ‘bud off’ from parent
Mature polyps then break off, form new organisms
E.g. hydra, yeast

11. Parthenogenesis (not testable)
Unfertilized egg develops into clone
In one type of parthenogenesis, egg fuses with polar body  diploid
E.g. insects (bees, stickbugs), some snakes

12. Practice: What type of reproduction?
1) Poros

13. Practice: What type of reproduction?
2) Female New Zealand mud snails are able to produce viable offspring that develop into mature adults from unfertilized eggs.

14. Practice: What type of reproduction?
3) In a species of yeast, a new individual develops as an outgrowth on a parent, which then separates from the parent once it has matured.

15. Practice: What type of reproduction?4)
parthenogenesis

16. Practice: What type of reproduction?
Challenge)
parthenogenesis

17. Asexual vs Sexual reproduction
Asexual Reproduction
Sexual Reproduction
One parent
Offspring genetically identical to parent
All prokaryotes, some eukaryotes
Binary fission, fragmentation, budding, (parthenogenesis)
Two parents
Offspring a combination of parental genes
Conjugation in prokaryotes
In eukaryotes, involves meiosis (gametes) and fertilization

18. Conjugation Genetic transfer between bacteria
Requires cell-to-cell contact
(image details not testable)

19. Internal Fertilization
Fertilization inside one parent’s body (usually via sexual intercourse)
Different kinds of embryo development:
Inside mother (gestation, like in humans)
Outside mother (egg, fed by yolk)

20. External Fertilization
Sperm and egg join outside of body
Spawning: releasing eggs and sperm into water
E.g. marine animals (amphibians, fish, invertebrates)

21. Pros and Cons Internal Fertilization External Fertilization
High cost per offspring (yolk, parenting)
Few offspring produced
High survival rate
Requires physical contact between parents
Low cost per offspring
Many offspring produced
Low survival rate
No physical contact between parents (good for sessile* or slow-moving species)
* sessile: unable to move from one spot (e.g. plants, anemones)

22. Discussion
How does bacterial conjugation differ from other forms of reproduction? - Does not produce new offspring

23. Reproducing in more than one way
(Following examples for illustrative purposes only: NOT testable)

24. Sea Stars Asexual: fragmentation
Sexual: external fertilization (video)
Gametes being released from madreporite (hole on dorsal side): just can’t see it

25. E. coli Asexual: binary fission Sexual: conjugation
Gametes being released from madreporite (hole on dorsal side): just can’t see it

26. Homework Study for Quiz Nov. 21/22 Nov. 21/22 marks cutoff
Mitosis, meiosis, asexual/sexual reproduction
No MC; some drawings (bring coloured pencils/pens)
Cheatsheet: one-sided index card permitted
Nov. 21/22 marks cutoff
Finish mitosis/meiosis activity
Not handing in, but good practice
Answer key on website