1. Asexual and Sexual Reproduction
Mitosis and Meiosis
Asexual and Sexual Reproduction
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2. Why Do Cells Divide? Cell division takes place for different reasons.
Cell division is important for asexual reproduction, which involves only one parent organism.
Most growth in a multi-cellular organism happens because cell division produces new cells.
Cell division produces cells for repair.

3. DNA The genetic material in cells is called DNA.
In eukaryotic cells, DNA is found in the nucleus.
A DNA molecule contains the information that determines the traits that a living thing inherits and needs to live.
Before cell division, DNA is duplicated.

4. Mitosis There are four phases of mitosis:
prophase, metaphase, anaphase, and telophase.
By the end of the four phases, the cell will have two identical nuclei.

5. Mitosis cont…
Mitosis results in two nuclei that are identical to the original nucleus.
When mitosis is complete, the cell has two identical sets of chromosomes in two separate nuclei.
Body Cells

6. Meiosis
Before sexual reproduction can take place, each parent produces sex cells.
Sex cells have half of the genetic information that body cells have.
When genetic information from two parents combines, the offspring will have one full set of genetic information.

7. Meiosis cont… Normal human body cells contain 46 chromosomes.
Sex cells are also known as gametes. Gametes have only half of the usual number of chromosomes.
How many chromosome are located in sex cells?

8. Sex cells
Sex cells are needed so that in sexual reproduction offspring receive a total of 46 chromosomes.
male
female 23 + 23 = 46

9. How do they compare?
Only sex cells undergo meiosis. All other cells divide by mitosis.
In meiosis, chromosomes are copied once, and the nucleus divides twice.
In mitosis, the chromosomes are copied once, and the nucleus divides once.

10. REPRODUCTION
The organism that produces the new organism or organisms is called a parent.
Each new organism is called an offspring.
The offspring produced by asexual reproduction are genetically identical to their parents.

11. ASEXUAL REPRODUCTION Most single-celled organisms and some
multi-cellular organisms reproduce asexually.
Example: Body Cells
In asexual reproduction, one organism produces one or more new organisms that are identical to itself (clones).

12. ASEXUAL ADVANTAGES It allows an organism to reproduce very quickly.
Favorable traits from the parent are passed on to the offspring.
Reproduction can occur without a partner, and all offspring can reproduce.
Large number of offspring.

13. ASEXUAL disADVANTAGES
No Genetic Variation.
Passes unfavorable/ damaged traits.

14. SEXUAL REPRODUCTION
Most multi-cellular organisms can reproduce sexually.
In sexual reproduction, two parents each contribute a sex cell to the new organism.
Half the genes in the offspring come from each parent.

15. SEXUAL ADVANTAGES
It increases genetic variation. Offspring have different traits, which improves the chance that at least some will survive.
Easier to adapt to changes in the environment as well.

16. SEXUAL DISADVANTAGES Fewer egg/sperm cells may be produced.
Takes longer amount of time
Organisms may care for their young/ vulnerable to predators
High death rate off offspring before they can reproduce.

17. ASEXUAL VS. SEXUAL REPRODUCTION
ASEXUAL REPRODUCTION
ONE parent copies itself, making the offspring have the exact same traits as the parent.
SEXUAL REPRODUCTION
TWO parents provide sex cells that combine to make an offspring with traits of both parents.

18. ASEXUAL VS. SEXUAL REPRODUCTION
ASEXUAL REPRODUCTION
BENEFITS
Population reproduces very quickly.
DRAWBACKS
“Weakspots” are common since all are the same.
SEXUAL REPRODUCTION
BENEFITS
Mixture of genes helps give strength to offspring.
DRAWBACKS
Slow to reproduce, takes a lot of energy to find a mate.