1. SEXUAL REPRODUCTION
5AP5

2. Objectives I will understand what is sexual reproduction.
I will be able to differentiate between somatic and germ cells.
I will know where and how somatic and germ cells are formed.

3. sexual reproduction
a type of reproduction in which the genetic materials from two different cells combine, producing an offspring.

4. Gamete The cells that combines to form offspring A reproductive cell
A sex cell
Formed by meiosis
In most organisms meiosis produces 1 of 2 types of gametes

5. 2 types of gametes
Ova (singular-ovum) - female gametes; female sex cell(book calls them eggs)
Sperm - male gametes; male sex cell

6. 2 types of gametes
ovum
sperm

7. Where are gametes formed?
In reproductive organs
Testes – male reproductive organs
Ovaries – female reproductive organs
The female sex cell, an ovum, forms in an ovary.
The male sex cell, a sperm, forms in the testis.

9. Fertilization the formation of a zygote from the union of 2 gametes
The process when a sperm and an ovum join togther.

10. What is sexual reproduction? (cont.)
During a process called fertilization, an ovum cell and a sperm cell join together to create a zygote.

11. Zygote
The new cell that forms from fertilization

12. Diploid cells
Organisms that reproduce sexually form somatic (body) cells and germ (gametes; sex) cells.
In somatic cells of most organisms, similar chromosomes occur in pairs.
Diploid cells are cells that have pairs of homologous chromosomes.

13. Haploid cells
Haploid cells are cells that have only one chromosome from each pair of homologous chromosomes.
haploid
from Greek haploeides, means “single”

14. Meiosis
the process whereby 1 diploid cell forms haploid cells (gametes)
a dividing process during which the # of chromosomes is cut by 1/2 in each resulting cell

15. There are four phases of meiosis I.
The Phases of Meiosis

16. There are four phases of meiosis II.
The Phases of Meiosis

17. Advantages of Sexual Reproduction
Genetic variation occurs in all organisms that reproduce sexually.
Due to genetic variation, individuals within a population have slight differences.

18. Lesson 1 Advantages of Sexual Reproduction (cont.)
Genetic variation may enable one plant to be more disease-resistant than another within the same species.

19. Lesson 1 Advantages of Sexual Reproduction (cont.)
Selective breeding has been used to develop many types of plants and animals with desirable traits.
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