1. Warm-up 4/13/15:
Why do you think some organisms reproduce asexually while others reproduce sexually?

2. Methods of
Reproduction:
Asexual vs. Sexual

3. Asexual Reproduction:
requires only 1 parent and the offspring are an exact genetic copy of the parent---a “clone”

4. Asexual Reproduction:
Organisms that reproduce asexually cannot develop much genetic diversity, because they are “copying” the original organism exactly.

5. Methods of asexual reproduction:
Binary fission
Budding
Fragmentation
Parthenogenesis
Regeneration
Mitosis
Spores

6. Binary fission
Single-celled organisms (Amoeba, paramecium, euglena) copy the DNA and split the cell into two identical halves

7. When conditions are good, such as plenty of water, food, optimal temperature, binary fission is an effective way of producing a large # of offspring.
For example, the cell of a Paramecium can divide, grow, and divide again in the space of 8 hours.

8. Budding- an offspring grows out of the body of the parent.
Hydra Budding
offspring
Cactus Budding

9. Budding
In yeasts, the cell does not divide equally in two halves; instead, there is a large “mother” cell and a smaller “daughter” cell.
Yeast - budding

10. -Pieces of coral broken off in storms can grow into new colonies.
Fragmentation
In this form, the body of the parent breaks into distinct pieces, each of which can produce an offspring.
-Pieces of coral broken off in storms
can grow into new colonies.

11. Fragmentation- plant cuttings
Some plants can grow from cutting them up and replanting them.

12. Green plants are quite sophisticated in their methods of asexual reproduction. Offspring may be produced by runners, bulbs, rhizomes or tubers.

13. Parthenogenesis
Parthenogenesis is when females produce eggs that develop without fertilization. It’s seen in some invertebrates, along with several fish, amphibians, reptiles, and plants.
No known cases of parthenogenesis in mammals.

14. -A new starfish can grow from
Regeneration
Regeneration is when an organism is capable of re-growing missing parts.
-A new starfish can grow from
one detached arm.

15. Mitosis
Mitosis is the division of a nucleus of multicellular, eukaryotic organisms. It’s how we grow identical body cells to create tissues and organs. It’s also how we heal and replace injured or old cells. The cells produced are identical to the parent.

16. Common micro-organisms in pond water:
Many species from bacteria to animals can be found in pond water. We will divide the species by kingdom and state general differences in their classification.

17. Kingdom Monera:
Monera are unicellular and prokaryotic (no nucleus or membrane-bound organelles)
Ex. Bacteria
VERY tiny under microscope

18. Kingdom Protista:
Protists are unicellular and eukaryotic (have a true nucleus and membrane-bound organelles)
Some are “animal-like”=eat and some are “plant-like”=photosynthesis
Ex. Amoeba, Paramecium, Euglena, Algae

19. Kingdom Animalia
Animals are multicellular, eukaryotic, and heterotrophic.
Ex. Hydra, Daphnia, Rotifers

20. Practice: draw the following organisms in detail on high power (100x)
Amoeba
Paramecium
Euglena
Stentor
Spirogyra
Volvox
Hydra
Radiolaria

21. Amoeba

22. Paramecium

23. Euglena

24. Stentor

25. Spirogyra

26. Volvox

27. Hydra

28. Radiolaria

29. What is sexual reproduction?
Requiring 2 parents
male and female (egg & sperm)
The egg and sperm join (zygote) to form an entirely new organism
Offspring are different from the parent organism because

30. Sexual Reproduction: Requiring 2 parents (egg & sperm)
Combining different genetic material

31. Methods of sexual reproduction:
Pollination
External Fertilization
Internal Fertilization

32. Sexual Reproduction in Flowering Plants
Pollen is produced in the male organs of the flowers - anthers. Pollination occurs when pollen is transferred from the anthers to the female organs by wind or by animals. If the female stigma is receptive to a pollen grain, the pollen produces a pollen tube, which grows through the female tissue to the egg, where fertilization takes place by the sperm nucleus.
Sexual Reproduction in Flowering Plants

33. External Fertilization
External fertilization usually requires a medium such as water, which the sperms can use to swim towards the egg cell. External fertilization usually occur in fish and amphibians.
The females lay the eggs in the water and the male squirts the sperm in the same area.

34. Internal Fertilization
Fertilization occurs within the female.
Internal fertilization occurs in mammals, insects, birds, reptiles.
Mammals (gorillas, lions, elephants, rats, zebras, and dolphins have live births)
Insects, birds, reptiles lay eggs

35. Sexual Reproduction
Sexual reproduction produces a greater chance of variation within a species than asexual reproduction would.
This variation improves the chances that a species will adapt to his environment and survive.

36. Sexual vs. Asexual Reproduction
Asexual reproduction results in offspring that are genetically identical to the parent organism.
Sexual reproduction results in offspring that are genetically different from the parent organisms.