Get a learning target sheet from up front 3/9

• I can describe how growth and development are related to cell division, growth, and signaling

• I can describe how cells become specialized for specific functions

Agenda

• Ch 13 Notes 1 • Short Video & Practice activity• Finish Notes 1• Short video & Practice activity

CH 13 Notes #1 Growth & Development

• Multicellular organisms are formed bycell growth, division, and differentiation

Sexual reproduction

• Fertilization: sperm and egg coming together

• When sperm and egg come together they form a zygote

• After fertilization, cell division starts

• Embryo: organism once its made of more than one cell

Cell cycle

• Interphase (90% of the time): cell is not dividingG1 (cell gets bigger)S (DNA replication)G2 (More organelles made, getting ready to

divide)

• Mitosis: cell division

New CellCell division(mitosis)

Cell grows

DNA replication

Cell gets ready to divide

• The cells keep dividing until they make a hollow ball called a blastula

• Gastrulation: cells on the outside start to push in

• Gastrula: hollow ball of cells when cells on the outside start to push inward

• The outside cells start to form the nervous system (brain, nerves, spinal cord)

• After the nervous system starts to form we call it a neurula

Gastrulation Animation

• http://www.youtube.com/watch?v=8v6cXkzlEQA

Foldable

• Label the organism in each of the stages we’ve talked about– Zygote– Embryo– Blastula– Gastrula– Neurula

Developmental stages quiz!

How do cells become specialized (get a specific job)?

• Differentiation: cells becoming specialized (ready to perform a specific job)

• Differentiation happens when cells send chemical signals to each other

• If you move a cell it will become the same type of cell as its new “neighbors” because of these chemical signals

Becomes a nerve cell

Becomes a stomach cell

Becomes a skin cell

Stem Cells

• Stem cells: cells that have not become specialized yet

• Scientists are interested in stem cells because they can be turned into many types of other cells

Uses of stem cells

1. Healing damagedtissues

2. Gene therapy3. Drug research

Stem cell controversy

• One method of researching embryonic stem cells will kill the embryo

• BUT researchers are working to change this

A special case of development

• Metamorphosis: When an organism dramatically changes after birth

Video: Metamorphosis Examples

• Metamorphosis• http://www.teachersdomain.org/asset/tdc02_

vid_metamorph/