Sexual vs. Asexual Reproduction vs Asexual...How does Sexual Reproduction work? Meiosis –process that makes sex cells (“gametes”) –cells that only have half the chromosomes

Sexual vs. Asexual

Reproduction

What to take notes on?

When you see something that is underlined and in a different color…you

should take notes on it.

Don’t take notes on something that looks like this – this is stuff that you

should read and think about, but it’s not stuff you will need to retain or

remember for future lessons or assessments

This is what notes you should write down look like – this is stuff you will need to

copy and make sure you look over on your own time

You will use this for future lessons and assessments

DNA – what is it and how does it work?

Every cell in your body has a job – there are over 200 cell types in the human body…that means over 200 jobs!

How does each of these cells know exactly what job to do?

DNA

Set of instructions or a blueprint for each cell

Made up of 4 bases (A, G, T, C)

T <-> A

G <-> C

DNA coding

Two sides to DNA double helix – match to each other

Side one - ATG CGT GGT CAG TCG ATA TAT GGC CCC

Side two - TAC GCA CCA GTC AGC TAT ATA CCG GGG

Chromosomes hold all of your DNA

DNA is packaged tightly and organized into

chromosomes

Chromosomes hold the needed codes for

characteristics like hair color, eye color, height

All cells in an organism have the same set of

chromosomes

Chromosomes exist in pairs

One from mother, one from father

Humans have 23 pairs

Each chromosome pair codes for characteristics

Codes interact with each other – some dominant, some recessive

Purpose of Reproduction

Produces offspring

Continues genetic line

Increases population of the species

Types of Reproduction

Asexual

Offspring arise from a single organism

offspring are genetic copies of the parent

Sexual

Offspring arise from two parent organisms

offspring are a genetic mix of half the mother’s DNA and half the father’s DNA

Asexual Reproduction

Organisms that reproduce asexually:

Single-cell Organisms

Bacteria

Protists

Amoebas

Some multi-cellular Organisms

Starfish

Fungi

Sea anemones

Coral

How does Asexual Reproduction work?

Mitosis – process makes exact copy of DNA

Cell copies its chromosomes and splits

Creates a cell exactly like the original

Parent = Offspring

PARENT CELL

COPIES CHROMOSOMES SPLITTING APART

TWO

IDENTICAL

CELLS

Video on Asexual Reproduction/Mitosis

Be amazed and enriched by the carefully selected and very important video!

Advantages vs. Disadvantages

ADVANTAGES DISADVANTAGES

• FAST PROCESS

• POPULATION GROWS QUICKLY

• ONLY ONE PARENT NEEDED

• no need to find mate

• LITTLE ENERGY REQUIRED

• LACK OF GENETIC VARIATION

• VULNERABLE TO EXTINCTION IF ENVIRONMENT

CHANGES

• IF PARENT HAS ISSUE (BAD TRAIT) – OFFSPRING

HAS ISSUE

Sexual Reproduction

Organisms the reproduce sexually:

Most:

Mammals

Fish

Reptiles

Birds

Insects

How does Sexual Reproduction work?

Meiosis – process that makes sex cells (“gametes”) – cells that only have half the chromosomes of the cells of the parents

Cell copies its chromosomes and splits

Cells then split AGAIN

Creates 4 cells that have half

the chromosomes of the

original cell

These 4 cells are called GAMETES

Sex cells – eggs or sperm

Egg and Sperm come together

½ + ½ = whole cell ORIGINAL CELL

FIRST SPLIT

SECOND SPLITCOPIES CHROMOSOMES

Video on Sexual Reproduction/Meiosis

Be amazed and enriched by the carefully selected and very important video!

Advantages vs. Disadvantages

ADVANTAGES DISADVANTAGES

• GENETIC VARIATION WITHIN SPECIES

• combination of sperm and egg

creates variety

• LESS LIKELY TO GO EXTINCT

• more likely to have traits that allow for

adaptation

• ALLOWS FOR EVOLUTION AND SURVIVAL OF

SPECIES

• REQUIRES A LOT OF ENERGY AND TIME

• HAVE TO FIND/ATTRACT A MATE

• POPULATION GROWS SLOWLY

Test yourself!

http://learn.genetics.utah.edu/content/variation/reproduction/