Captain Andrew Jaggery —GUILTY of Murder

REPRODUCTIONREPRODUCTION2 Kinds of Reproduction2 Kinds of Reproduction

Asexual --

One parent Sexual

--Two parents

Specifically-- Sperm and

Egg

Chromosomes and Cell DivisionChromosomes and Cell Division ChromosomesChromosomes – – Structures in a Structures in a

cell’s cell’s nucleus that contain genes.nucleus that contain genes.

Genes – Found on chromosome in cell. Gives living thing a certain trait and tells a cell how to grow/develop.

How do all forms of How do all forms of asexual reproduction end asexual reproduction end

in an organism?in an organism?Through the process ofThrough the process of

MITOSIS!

(Form of reproduction requiring only one parent.)1. Grow2. Repair3. Replacem

ent

Why do organisms go

through asexual reproduction??

Cell Division — 6 phasesCell Division — 6 phasesMitosisMitosis — 4 phases — 4 phases

1. Interphase —normal life functionsToward the end—

chromosomes duplicateHuman

s-46

Once duplicated-

92Sister chromatids held

together-centromere2.

Prophase--Mitosis beginsNuclear membrane

breaks downCentrioles begin to move &

Spindle forms between3.

Metaphase-

Centromeres line up in the MIDDLE4.

Anaphase--Centromeres split—move to opposite sides

Nuclear membrane appearsCytoplasm divides

End result==2 NEW DAUGHTER CELLS

Is this a problem?? Why?

5. Telophase--

Mitosis is complete!

6. Cytokinesis-- Exactly like the parent

cell!

Cell Division/MITOSIS!!Cell Division/MITOSIS!!IIPaintedMyAunt’sToesCrimson!

InterphaseProphaseMetaphaseAnaphaseTelophaseCytokinesis

Actual “Mitosis” only happens in phases 2-5!

Sexual ReproductionSexual Reproduction

Process calledProcess called MEIOSISResults in the formation of 4

daughter cells called GAMETES (sex cells)Gametes—reproductive cells that have

only half the number of chromosomes as the parent cell

What is the name of the gametes in humans?SPERM & EGG

Production of new organism from 2 parents, Production of new organism from 2 parents, a male and a female.a male and a female.

23 23

46

chromosomes

chromosomes

chromosomes

- New person not exactly like each parent.2 complete cells join, new baby has twice the chromosomes as

each parent.

Prophase 1—chromosome number is doubled

Metaphase 1--line up in the middle

Anaphase 1—sister chromatids begin pulling apart

Telophase/Cytokinesis 1--Two new daughter cells

NO PROPHASE!!!!Metaphase 2—Line up in the middle

Anaphase 2 & Telophase 2—Pulls apart and separates

End Result—4 new cells with

half of the number of

chromosomes as the parents

Let’s Compare!!Let’s Compare!!Asexual Asexual

ReproductioReproductionn

Sexual Sexual ReproductioReproductio

nnNumber of Number of parentsparentsType of cell Type of cell divisiondivisionNumber of Number of daughter daughter cells cells producedproducedGenetic Genetic Makeup of Makeup of offspringoffspring

21

Mitosis

Meiosis

2 4 (gametes)Identical to

the parentUnique;

different from parents

MeiosisMeiosis(Process that produces sex cells with ½ (Process that produces sex cells with ½

number of number of chromosomes of parent cell.)chromosomes of parent cell.)

46 chromosomes

Sperm or Egg Cell

2446

46

23

23

23

23

Sperm or Egg Cells

Let’s watch Let’s watch meiosismeiosis in in action!action!

Advantages/Disadvantages of Advantages/Disadvantages of Asexual/Sexual ReproductionAsexual/Sexual Reproduction

Asexual Reproduction

Advantage

Organism does notneed a mate to produce offspring.Disadvantage

Offspring exactlylike parents.

Sexual Reproduction

Advantage

Gives species variation.

Disadvantage

2 parents neededfor reproduction.

SpeciesSpecies(Group of similar organisms that can (Group of similar organisms that can mate with one another and produce mate with one another and produce

fertile offspring.)fertile offspring.)

Why Why mitosismitosis and and meiosismeiosis??