Meiosis And Variation (Potato Head)

1- How does DNA work? 1- How does DNA work?

2- How is a persons DNA passed on to their children?

3- What is the difference between how cells divide and humans reproduce?

There are 46 pieces of There are 46 pieces of DNADNA or or CHROMOSOMESCHROMOSOMES in human beings in human beings

((diploiddiploid number) number)

X Y

23 pairs of chromosomes. One of each pair is from MOM, other from DAD!

-Understand why sexual reproduction is -Understand why sexual reproduction is advantageous to individuals of a specific advantageous to individuals of a specific species. species. -Given a diagram of male and female cells, each -Given a diagram of male and female cells, each having two pairs of chromosomes, the student having two pairs of chromosomes, the student will:will:

diagram the four possible gametes from diagram the four possible gametes from the male and female cells. the male and female cells.explain why it is necessary for the explain why it is necessary for the number of chromosomes in the gametes number of chromosomes in the gametes

to be half that of the parent cell. to be half that of the parent cell. explain how meiosis promotes genetic explain how meiosis promotes genetic diversity in the offspring at fertilization. diversity in the offspring at fertilization.

-meiosis-meiosis--chromosomechromosome-chromatid-chromatid-haploid-haploid-diploid-diploid-variation-variation-random segregation / -random segregation / independent assortmentindependent assortment-random fertillization-random fertillization-crossing over-crossing over-natural selection-natural selection

Why is it an advantage/adaptation Why is it an advantage/adaptation for a species to reproduce sexually for a species to reproduce sexually

versus asexually?versus asexually?

A human egg surrounded by sperm - one A human egg surrounded by sperm - one of which will fertilize itof which will fertilize it

http://www.bbc.co.uk/schools/gcsebitesize/biology/variationandinheritance/1reproductionandgenderrev5.shtml

Step 3.Step 3.

“Hitting a moving target…”

EvolutionEvolution: “The Advantage of Sex”: “The Advantage of Sex”

Use the analogy of the “Red Queen” to explain why sexual reproduction is advantageous.

EvolutionEvolution: “The Advantage of Sex”: “The Advantage of Sex”

A study of human geneticsA study of human genetics

--In this activity you will perform In this activity you will perform a a simulation to study how facial simulation to study how facial characteristics are inherited.characteristics are inherited.

--You will follow the basic You will follow the basic Mendelian Laws of Inheritance to Mendelian Laws of Inheritance to detemine your childs detemine your childs genotypegenotype and and

then draw their then draw their phenotypephenotype..

VocabularyVocabulary

genegene alleleallele

genotypegenotype phenotypephenotype

dominant dominant recessiverecessive

sex chromosomessex chromosomes

Inheritance PatternsInheritance PatternsDominantDominant

RecessiveRecessive

Incomplete DominanceIncomplete Dominance

CodominanceCodominance

PolygenicPolygenic

Sex-linked TraitsSex-linked Traits

General General GenotypeGenotype Rules Rules1- Genes come in pairs. 1- Genes come in pairs. (one from each (one from each parent)parent)

2- Use letters to represent genes.2- Use letters to represent genes.

3- Dominant vs Recessive3- Dominant vs Recessive

4- Homozygous vs Heterozygous4- Homozygous vs Heterozygous

Genotype Data TableGenotype Data Table

Checklist for PhenotypesChecklist for Phenotypes

Phenotype IllustrationsPhenotype Illustrations

THE ASSIGNMENT: make a 30 second commercial which explains and “sells” the answer to the question or topic you were assigned. You will perform tomorrow.

HINTS: commercial can be a jingle, you can act out a scene, use propts / signs.

MANDATORY: You must use the bold words in the question and you must correctly explain the concept – “sell it!”  

Group 1: Explain why sexual reproduction is better than asexual reproduction in terms of survival and natural selection. (variation)

Group 2: Why is meiosis necessary for organisms that reproduce sexually? (Explain how meiosis creates gametes or sex cells with half the normal number of chromosomes)

Group 3: In meiosis, independent assortment of chromosomes, is a source of variation. Explain how this works and when it happens in meiosis

Group 4: Crossing over of chromosomes is another source of variation. Explain what crossing over is and how it happens. (talk about the exchange of genes between homologous chromosomes)

Group 5: Random fertilization is also a source of variation in sexually reproducing organisms. Explain why this is a source of

variation.

Group 6: Meiosis is really complicated explain how it is similar and different from mitosis. (include info about chromosome number (diploid / haploid))

Group 1: Explain why sexual reproduction is better than asexual reproduction in terms of survival and natural selection. (variation)

 Group 2: Why is meiosis necessary for organisms that reproduce sexually? (Explain how meiosis creates gametes or sex cells with half the normal number of chromosomes)

Group 3: In meiosis, independent assortment of chromosomes, is a source of variation. Explain how this works and when it happens in meiosis

Group 4: Crossing over of chromosomes is another source of variation. Explain what crossing over is and how it happens. (talk about the exchange of genes between homologous chromosomes)

Group 5: Random fertilization is also a source of variation in sexually reproducing organisms. Explain why this is a source of variation. 

Group 6: Meiosis is really complicated explain how it is similar and different from mitosis. (include info about chromosome number (diploid / haploid))

3 persons per group / Numbered 1-3 / Each person answers a question and 3 persons per group / Numbered 1-3 / Each person answers a question and passes the note to the next person who answers the next one, until all are passes the note to the next person who answers the next one, until all are done.done.

1- How does DNA work?

2- How is a persons DNA passed on to their children?

3- What is the difference between how cells divide and humans reproduce?