1. Heredity and Reproduction
MYP 2

2. What is Sexual Reproduction?
Sexual Reproduction is a type of reproduction in which the genetic materials from two different cells combine, producing an offspring.
It’s a combination of sex cells, an egg and a sperm, that comes from the sex organs.
Fertilization is when these cells come together.
The new Cell that forms is a zygote

3. Diploid Cells The zygote goes through mitosis and cell division.
Mitosis is cell reproduction that takes place in body cells and makes nearly all of the cells in a multicellular organism aka YOU!
Organisms that produce sexually have 2 types of cells: Body Cells and Sex Cells.
All cells carry Chromosomes, Body Cells carry all of the Chromosomes, sex cells carry only half

4. Different Cells Body Cells Sex Cells
Diploid: Carry both copies of a chromosome
For example Humans have 46 chromosomes
Haploid: Carries only one copy of each Chromosome
Human Sperm has 23 Chromosomes
Human Egg Cells 23 Chromosomes

5. Body Cells vs Sex Cells
Diploid CELLS
Haploid Cells

6. What are Chromosomes? Chromosomes Carry all of your genetic material.
Homologous Chromosomes are pairs of chromosomes that have genes for the same traits arranged in the same order.
The genes maybe for the same trait but not be exactly the same
You get from an Egg and from a sperm (Blue eyes; Brown Eyes)
They are located at the same place but code for different variations

7. Chromosomes

8. Chromosomes

9. Mitosis and Meiosis Mitosis takes place in the body cells
Meiosis takes place in the sex cells
Mitosis has 4 stages: Prophase, Metaphase, Anaphase, and Telophase
Then it goes through cytokinesis to split the cell
Mitosis leaves you with Identical 2 daughter cells that have a Diploid number of Chromosomes
Meiosis has Prophase 1, Metaphase 1, Anaphase 1, Telophase 1, Prophase 2, Metaphase 2, Anaphase 2, Telophase 2
Meiosis leaves you with 4 Non-Identical Cells with A haploid Number of Cells

10. Mitosis
Prophase : Duplicated chromosomes condense and thicken. Homologous Chromosomes come together and form pairs.
Metaphase : Chromosome pairs lineup along the middle of the cell. A spindle Fiber attaches to each chromosome.
Anaphase : Chromosome Pairs separate and are pulled toward the opposite ends of the cell.
Telophase : A nuclear membrane forms around each group of duplicated chromosomes. Cytoplasm divides through Cytokinesis and 2 Identical daughter cells Form.

11. Mitosis

12. Meiosis
Prophase 1: Duplicated chromosomes condense and thicken. Homologous Chromosomes come together and form pairs.
Metaphase 1: Chromosome pairs lineup along the middle of the cell. A spindle Fiber attaches to each chromosome.
Anaphase 1: Chromosome Pairs separate and are pulled toward the opposite ends of the cell.
Telophase 1: A nuclear membrane forms around each group of duplicated chromosomes. Cytoplasm divides through Cytokinesis and 2 daughter cells Form.

13. Meiosis
Prophase 2: Chromosomes are not copied again. They remain as condensed, thickened sister chromatids.
Metaphase 2: The pairs of sister chromatids line up along the middle of the cell in single file.
Anaphase 2: The sister Chromatids of each duplicated chromosome are pulled away from each other and move toward opposite ends of the cells.
Telophase 2: During the Final phase of meiosis a nuclear membrane forms around each set of chromatids, which are again called chromosomes.
The cytoplasm divides through cytokinesis and four non-identical haploid cells.

14. Meiosis

15. Mitosis vs Meiosis

16. Why is Meiosis Important?
Without Meiosis There would be no way for us to remain the species that we are
Meiosis gives us half of the chromosomes so when sexual reproduction takes place we have the correct number of chromosomes.
In some cases Meiosis does not occur properly and it results in genetic defects like Trisomy 21 and 13.
This means that an error may occur during anaphase 2.

17. Advantages of Sexual Reproduction
Main advantage is that we inherit half of our DNA from the Sperm and half of the DNA From the Egg.
Genetic Variation is what takes place because of this.
The inheritance of one trait does not influence the inheritance of another and this is called independent assortment.
This can give some organisms and advantage or disadvantage if the environment around them changes.
Selective breeding can take place aka artificial Selection

18. Selective Breeding

19. Disadvantages of Sexual REproduciton
IT takes time and energy
Searching for mates can expose them to predators, disease, or harsh environments
Reproduciton is limited due to pregnancy
Fertilization can’t happen when an animal is pregnant
Some mammals are pregnant for 2 years

20. What is Asexual Reproduction?
One parent organism produces offspring without meiosis and fertilization.
That means that the parent and the offspring have the exact same genetics.

21. Types of Asexual Reproduction
Fission is one form
It’s a cell dvision that takes palce in prokaryotes and causes two genetically identical cells.
The DNA is copied and attaches to the cell membrane and then the cell expands until it makes two cells.

22. Types of Asexual Reproduction
Budding is when a new organism grows by mitosis and cell division on the body of its parents.

23. Types of Asexual Reproduction
Animal Regeneration occurs when an offspring grows from a piece of its parent.

24. Types of Asexual Reproduction
Vegetative Reproduction- the offspring grows from a part of the parent plant.

25. Cloning
A type of asexual reproduction performed in a laboratory that produces identical individuals from a cell or from a cluster of cells taken from a multicellual organism.
Can be done in plants and Animals
Plant clonig is done to get desireable traits for plants and fruits
Animal clonig being done to try and save endangered species

26. Cloning

27. Asexual Reproduction Advantages Disadvantages Reproduce without a mate
Rapidly produce offspring
No genetic variation
Mutations will be passed on