1. Sexual and Asexual Reproduction
Methods of
Reproduction
Sexual and Asexual Reproduction

2. Asexual Reproduction:
requires only 1 parent and the offspring are an exact copy of the parent---a clone

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

4. Methods of asexual reproduction:
Binary fission
Budding
Fragmentation
Parthenogenesis
Spores
Regeneration
Vegetative Reproduction

5. Binary fission Bi= 2 Fision= splitting
Binary Fission = asexual reproduction where a single cell splits in two new cells.
The 2 new cells are exact copies of the original cell.
*Single-celled organisms Amoeba, Paramecium, Euglena)

6. When conditions are good, such as plenty of water, food, right temperatures, etc., binary fission is a very effective way of producing many, many offspring.
For example, the cell of a Paramecium can divide, grow, and divide again in the space of 8 hours.

7. Spore Formation Fern Spore Formation
Fungi
Spore Formation
happens in fungi, green algae, moulds and non flowering plants (e.g. ferns)
spores are produced and each spore develops into offspring which are identical to parent

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. Fragmentation
In this form, the body of the parent breaks into distinct pieces, each of which can produce an offspring.
Example: Tape Worm

11. Regeneration
A piece of the organism breaks off – and the organism can regrow from that piece.
Pieces of coral broken off in storms
can grow into new colonies.
A new starfish can grow from
one detached arm.

12. Parthenogenesis
Parthenogenesis is a form of asexual reproduction in which females produce eggs that develop without fertilization.
Parthenogenesis is seen to occur naturally in some invertebrates, along with several fish, amphibians, and reptiles as well as in many plants.
There are no known cases of parthenogenesis in mammals.

13. Vegetative Reproduction
does not involve seeds
some offspring can grow from cuttings (e.g. coleus), runners (e.g. strawberries), tubers (e.g. potatoes) or bulbs (e.g. tulips)… which are part of the parent plant

14. 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

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

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

17. Sexual Reproduction in Plants
pollen (male) + ovule (female) → single-celled zygote → multi-celled embryo (contained in a seed) → new individual

18. 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.

19. 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

20. Sexual Reproduction Summary
Male Gamete
Female Gamete
Type of Union
Result of Union
Final Result
Plants
pollen
ovule (egg)
pollination
single cell zygote
multi-cell embryo
(in seed)
Animals
sperm
egg
fertilization

21. Which is Better? It depends!
Asexual Reproduction
advantages
does not require special cells or a lot of energy
can produce offspring quickly
in a stable environment creates large, thriving population
disadvantages
limited ability to adapt
face massive die-off if environment changes
Sexual Reproduction
advantages
lots of variation within a species
able to live in a variety of environmental settings
able to adapt to changes in the environment
disadvantages
needs time & energy
produce small populations