1. Passing it On
Unit A: Topic 3

2. Living organisms display a wide variety of methods or reproductive strategies for passing on their genetic information to their offspring.

3. Asexual Reproduction Involves only one parent
Offspring are identical to the parent
Four main types of asexual reproduction are:
Binary fission
Budding
Spore Production
Vegetative Reproduction

4. Binary Fission Occurs in unicellular organisms
Cell splits in two producing identical offspring
Examples: Bacteria and protists

6. Budding
Parent produces a small, attached (identical) version of itself.
The offspring can stay connected or detached
Examples: Coral, yeast, hydra.

8. Spore Production Similar to seeds
Produced by the division of parent cells.
Examples: Fungi, ferns, moulds, and algae.
Many spores are produced to ensure some survival.
Some fungi and algae produce zoospores which move with a tail-like flagella

9. Vegetative Reproduction
There are many different types including runners, tubers and suckers.
Examples: Strawberry plants, potatoes, and aspen trees.

10. Asexual Reproduction
Asexual reproduction can also happen without special cells.
In the meristem of plants, found in the tips of roots and stems, cells rapidly divide.
Cutting from a parent stem
may be used to produce new
plants that clones (exact copies)
if that stem is planted.

11. p. 29

12. pollen grains
pedicel

13. Go through the Structure of Plant
Bill Nye

14. Sexual Reproduction in plants

15. Sexual Reproduction in plants
Most plants will produce both male and female gametes in one plant, but some only produce male or female gametes.
Pollen, which is found on the stamen, has the male gametes in it.
Ovules, which are found on the pistil, contain the female gametes.

16. Pollen
Self-Pollination: when the pollen from the anther is transferred to the stigma.
Cross-pollination: when the pollen from one plant is carried to a different plant.
THE BEAUTY OF POLLINATION (4 MIN)
How can pollination occur?
Wind, water, animals/birds

17. Fertilization
Fertilization: When the gametes in the pollen join with the gametes in the ovum (on the same plant).
Cross-fertilization: When the pollen from one plant fertilizes another plant.

18. Sexual Reproduction in plants http://www. teachersdomain
Pollen grains, each of which contains a sperm nucleus, are brought to the female eggs in the ovaries.
The pollen grain grows an extension called a pollen tube. This pollen tube grows until it reaches the ovule.
The sperm nucleus travels down the tube to fertilize the egg.
A zygote is formed and contains the genetic information from both parents.
It then goes through many cell divisions to form a multicellular embryo containing miniature leaf, root, and stem.
The embryo is protected by a seed and can stay dormant for a long time.

19. Sexual Reproduction in animals
Involves specialized sex cells called gametes
Fertilization – the union of sperm and egg

20. Sexual Reproduction in animals http://www. youtube. com/watch
Fertilization can occur internally or externally.
Internal fertilization occurs in insects, reptiles, birds, mammals, some fish and amphibians.
Results in a high rate of success because egg cells are protected.
External fertilization occurs in sponges, most worms, many fish and amphibians.
Results in a low rate of success because egg cells are exposed to harsh climates and predators.

21. Sexual Reproduction in Bacteria
Bacterial Conjugation
A connection forms between two cells. Genetic material is transferred directly from one cell to another
Cells will then go through binary fission to create more cells

22. Comparing Asexual to Sexual

23. Asexual Reproduction Advantages Disadvantages Only need one organism
Doesn’t require any specialized cells to bring gametes together
Can produce lots very quickly
If conditions are unfavourable, the entire population could be wiped out.

24. Sexual Reproduction Advantages Disadvantages
Provides lots of variation which helps species survive environmental change
Perfect timing and conditions are required
Two partners are needed
Takes lots of energy
Only produces limited offspring

25. What are some organisms that reproduce both sexually and asexually?
Some species of grasses
Sunflowers
Roses
Aphids
Sponges
Fungi – some types of fungi can produce asexually by using spores, but they can also produce sexually by using zygospores. Zygospores contain genetic information from two different sources.

26. Bill Nye
Genetic Diversity

27. Review Assignment What is a zygote and how is it formed?
List three examples of asexual reproduction.
List three ways pollination can occur.
What is similar about sperm and egg cells? What is different?
List the steps of fertilization and embryo development in animal sexual reproduction.
List the steps of fertilization and embryo development in plant sexual reproduction.