Unit a biologicaldiversitynotes(asexual-sexual reproduction)

1. z
Asexual
Reproduction

2. z
Asexual Reproduction:
Involves only one parent.
Offspring are identical to the parent.
Types: Binary Fission, Budding,
Spore Production, ​and Vegetative
Reproduction.

3. z
1. Binary Fission:
A one-celled organism splits exactly into 2.
-ex: bacteria, amoeba, some algae.
Paramecium

4. z
2. Budding
The parent produces a small bud that develops
into a ​new but identical individual.
-ex: yeast, hydra, coral
hydra
yellow yeast
asexualbudding-d.wmv
The_Asexual_Reproduction_of_the_Hydra.asf

5. z3. Spores
• Similar to seeds, but are produced by the division
of ​the single parents cells.
• each spore can develop into a new but identical
individual.
-ex: fungi, green algae, some molds, ferns, and other
non-flowering plants.
Fern spores
Green algae spores

6. z4. Vegetative Reproduction
• Reproduction of a plant without seeds, in all cases
the ​offspring are again identical.
• ex: cuttings from a plant, runners
(strawberry ​ plant), tubers (potatoes), bulbs (tulip),
shoots or​ suckers (aspen)
Potato Tuber
Strawberry Runner

7. z
What now? Answer the following questions:
1. Define asexual reproduction. List three examples
of ​asexual reproduction.
2. An individual produced by asexual reproduction may
be identical to one of its parents. Do you agree or
disagree with this statement? Support your answer.

8. z
Sexual
Reproduction

9. z
Sexual Reproduction:
Involves two parents.
Offspring have a mix of ​characteristics from
both ​parents

10. z
-During this process the male gametes (sperm) meet
with female gametes(eggs) in a process called
fertilization; each gamete has only half the DNA of a
normal cell.
- When the two gametes meet they form a zygote that
will then divide rapidly.

11. z
In Animals:

12. z
In Animals:
Sperm Cell: Male sex cell (gamete). In humans it has
23 chromosomes
Egg Cell (Ova): Female sex cell (gamete). In humans it
has 23 chromosomes
Fertilization: Union of a female sex cell and male sex
cell

13. z
In Animals:
Zygote: First cell created by the joining of the gametes,
which then divides. It has 46 chromosomes in humans
(23 from egg, 23 from sperm)
Cleavage: First divisions of a
fertilized egg
Embryo: An undeveloped organism in its early
development (all cells in an embryo have 46 cells)

14. z
1. fertilization occurs when a sperm cell penetrates an egg cell
2. the joining of the male gamete with the female gamete produces
a ​single-celled zygote
3. cell division of the zygote (cleavage) takes place
4. cell division continues
5. a multicellular embryo develops
In Animals:

15. z
In Animals:

16. z
In Plants:

17. z
In Plants (Male Parts):
Stamen: Male part of the flower
Anther: Part of the flower that produces pollen and
stores it
Pollen: Fine yellow powder on the anthers of flowers,
consisting of grains that contain male gametes

18. z
In Plants (Female Parts):
Pistils: Refers to the entire female
reproductive organ of the flower
Stigma: Female part of a flower, which receives pollen
Style: Structure that supports the stigma and connects
it with the ovary of a plant
Ovary: Female reproductive organ in which egg cells
are produced, the structure contains the ovules, and
develops as the fruit of flowering plants
Ovules: Sac containing the female gametes of a plant

19. z
1. Pollination occurs when pollen is transferred from the anther to
the ​stigma.
2. Fertilization occurs when the pollen grain, which encases
the ​sperm nuclei, develops a long tube that grows down the style
and into ​the ovary that contains the ovules (eggs).
3. The joining of the male and female gametes produces a single-
​celled zygote.
4. Cell division occurs.
5. A multi-celled embryo develops inside a seed that offers
it ​protection and food.
6. Unlike animals, the embryo may remain dormant within the
seed ​until growing conditions are favorable.
In Plants:

20. z
In Plants:
Pollination: Transfer of pollen from anther to stigma
Cross Pollination: When the pollen of one plant is
carried to the stigma of another by wind, water, or
animals
A, B = Pollination
C = Cross Pollination

21. z
In Plants:
Cross Fertilization: When a grain of pollen produces a
long tube that eventually grows down the style into the
ovary and the 2 gametes join to form a zygote
• Zygote forms into a an embryo located inside a seed
• Seed provides protection for the embryo and stores
food

22. z
Advantages and
Disadvantages of
Asexual
Reproduction

23. zAdvantages:
• Does not require specialized cells
• Can produce lots of individuals quickly if the
conditions are good
• Does not require a minimum population
Disadvantages:
• If conditions become unfavourable, the entire
population could be wiped out (extinction)
• Limits variation within the species

24. z
Advantages and
Disadvantages of
Sexual
Reproduction

25. z
Advantages:
• Provides lots of variation which helps a species
survive environmental change
• Increases diversity of organisms
Disadvantages:
• Requires a lot of energy and therefore produces a
limited number of offspring
• Requires finding a partner
• Requires specialized sex cells
• Requires a minimum population to reproduce

26. z
Organisms That
Reproduce Both
Asexually and
Sexually

27. z• Many plant organisms reproduce both sexually and
asexually
• Some animals can reproduce both ways ex: Aphids
• Aphids – females produce females without fertilization
during the summer. In the fall, when the temperatures drop,
males and females are produced and they reproduce
sexually
• Corals can reproduce buds, and reproduce sexually
• Some plants develop seeds without the contribution of
sperm cells (ex. Some grasses, sunflowers, etc.)