1. Explain the link between reproduction and heredity.
General Outcome #2:
Explain the link between reproduction and heredity.

2. Topic 3 – Passing It On Can I identify characteristics that are
heritable?
not heritable?
Can I identify characteristics that
heredity and environment may both
play a role?

3. -characteristics that are passed on from the parents (mother and father) to their offspring (child) are said to be inherited or heritable
-these traits are passed down through your genes, the genetic material that makes up your body (much like a map)
e.g. You look similar to both your father and mother; you have inherited traits

4. Reproductive Strategies
Can I describe types of asexual reproduction?
1. Asexual Reproduction
-one parent
-offspring are duplicates of the parent; exact copies (clones!!!)
-they have the same genetic material, therefore the same characteristics

5. Advantage:
There is no need to find a mate.
There are fewer genetic mutations.
Disadvantage:
Since there is little variation between each individual, if one is vulnerable to an environmental change then all will be vulnerable.

6. a) Binary Fission -found normally in one celled organisms
(e.g. bacteria, paramecium)

7. -each new cell is identical to the original
-once the organism reaches a certain size, the organism makes copies of its organelles and nucleus then divides itself in half
-each new cell is identical to the original

9. b) Asexual Spores -found mainly in fungi, such as mushrooms
-spores are single-celled, reproductive structures similar to an egg except that it is an exact copy of the parent

10. -spores can be made by the thousands and can survive in almost any type of environment
-spores found in the arctic that were thousands of years old easily grew when they were placed in suitable habitat
-zoospores are similar to spores except they have flagella (tail-like structures) that move them around (e.g. Chlamydomonas can form zoospores)

11. c) Budding -occurs in smaller animals such as sea sponges and hydra
-occurs in smaller animals such as sea sponges and hydra
-as a hydra grows, one of its cells will form a bud (much like a flower’s bud) and start to grow on its own
-eventually this will detach and form a copy of the original organism

12. d) Asexual Reproduction with Plants
-the growing tips of roots and stems contain areas of rapidly reproducing
cells called meristem
-when a plant is damaged, these meristem cells can create copies of the damaged cells and the plant continues to grow

13. -by taking a cutting of the meristem, you can grow an exact copy of the plant (a CLONE)

14. -plants can also reproduce by runners or stems that lay along the ground and form roots to create a new plant
e.g. strawberry plants

15. -suckering is the process of shoots arising from existing root systems
e.g. poplar trees

16. -bulbs, tubers and corms are also forms of
asexual reproduction in plants
e.g. Potato tubers
e.g. Gladiolus
corms
e.g. Onion bulbs

17. Asexual reproduction that involves a clone being formed from roots, stems or leaves is also known as vegetative reproduction.

18. 2. Sexual Reproduction Can I describe types of sexual reproduction?
Can I describe the formation of zygote and
embryo in plant and animal reproduction?
2. Sexual Reproduction
-two parents
-offspring are combinations of the genetic codes of both parents
-gametes (egg and sperm) are involved in reproduction
-fertilized cell is called a zygote

19. Advantage of Sexual Reproduction:
Recombination of genes allows for more variation therefore promoting natural selection.
Natural selection has no intentions or senses; it cannot sense what a species “needs.” If a population happens to have the genetic variation that allows some individuals to survive a particular challenge better than others, then those individuals will have more offspring in the next generation, and the population will change.

21. Disadvantage of Sexual Reproduction:
A great deal of time and energy is required to find a mate.

22. Forms of Sexual Reproduction
Zygospores
Some organisms such as moulds can reproduce asexually by spores but they can also form spore like zygospores that contain genetic materials from two different sources.

23. Bacterial Conjugation
Genetic material is passed directly from one cell to another but no actual reproduction happens since there is no increase in the number of cells from this process.

24. Sexual Reproduction in Plants
Gymnosperms (“naked seeds”)
conifers such as spruce, pine and fir
do not form flowers
produce seeds inside of cones
the seeds are not covered with a fruit

25. Angiosperms flowering plants dioicious-male and female parts
on separate plants (unisexual)
monoicious—male and female
parts on one plant
produce seeds that are covered
by fruit
seed is formed when the pollen
and the ovule unite during
pollination

26. Sexual Reproduction in Animals
External Fertilization
-in some animals, such as fish and amphibians, fertilization occurs outside the body

27. Advantages Disadvantages
female and male do not have to be there at the same time
can produce a large number of eggs since the female does not need to carry the babies
sperm / egg / zygote can dry out if water is not present
gametes and zygotes unprotected so sensitive to pollutants and temperature change and easy prey
water may wash sperm and egg away from each other

28. 2. Internal Fertilization
-in some animals, such as mammals, birds, and insects, the egg is fertilized inside the body
-when the male sperm enters the female, it travels up toward the egg
-when the sperm fertilizes the egg, a zygote is formed within the female

29. With internal fertilization, the egg is fertilized INSIDE the body, but does not always STAY inside the body.
e.g. Birds use INTERNAL FERTILIZATION but after the zygote forms and the embryo begins to grow inside the mother then a shell will develop and the bird lays the egg. The embryo will finish developing OUTSIDE the mother.

30. Advantages Disadvantages
gametes are kept warm and moist
greater chance of fertilization occurring
sperm / egg / zygote protected within the mother’s body
both male and female must be present
greater time and energy investment is required
Can I describe examples of organisms that reproduce asexually, sexually and those that use both strategies?