Bellwork Look at the two different populations of organisms below: a.Which one is asexual and which one is sexual? b.Which one has variety and which once does not? AB

Missed work!! If you finish an assignment that was incomplete when I put in homework grades, turn it into the basket! All in class work can be completed for full credit! Find a friend in the class if you are missing a lot of work! Check grades

Vocab Review Chromosome – two chromatids put together, one complete set of information Sister chromatids – make up a chromosome, half of the information Homologous chromosomes – multiple pairs of chromosomes (two chromatids each), some from mom and some from dad

Exploring Meiosis I You will be exploring meiosis I on your own with your NEW lab group today Following the guidelines at each lab bench, model EACH step of meiosis with the colored beads and chalk After each step, YOU MUST GET CHECKED and then draw the step on your worksheet with colored pencils

Your models Chromatid Chromosome Replication  **You will have 4 of these in total, all different colors!

Check your drawings!

Once you are done… Homework if not done in class… – Describe the steps of meiosis using COMPLETE SENTENCES

Bellwork At which stage in meiosis I does the exchange of information on chromosomes occur? 2.How many cells does meiosis I create? 3.Are the products of meiosis I identical or is there variety? *Check grades **Test-make-ups

Meiosis

Meiosis: Unit Vocabulary meiosistetradhaploid diploidsomatic cell homologous pairgametezygote crossing overProphase I and IIMetaphase I and II Anaphase I and IITelophase I and IIgenetic recombination sexual reproductionasexual reproduction independent assortment

Meiosis Video Dfk

How much information? Whole set of DNA = 2n  Diploid Half set = How to remember: Half – Haploid Di = 2 n  haploid

How much information? Talk with your neighbor: Are chromatids haploid or diploid? Are chromosomes (pair of sister chromosomes) haploid or diploid? n – haploid! 2n – diploid!

Pre Interphase! Draw a circle on top of your worksheet and label it pre-interphase What happens to chromatids in pre-interphase to get the results YOU drew in interphase?

Interphase Draw and label the centrioles on your Drawing How much information? 2n!! Diploid DNA replication

Prophase I Tetrads form and crossing over occurs Label the tetrads in your picture & where crossing over happens

Prophase I How much information? n or 2n?? 2n - Diploid!!!

Tetrads & Crossing Over Tetrads – close association of sister chromatids on homologous chromosomes Crossing Over: Homologous chromosomes exchange small pieces, resulting in new chromosomes!

Crossing Over Must Happen Perfectly!!! What do we call the two pairs of chromosomes pictured? Homologous Chromosomes!

20 Homologous Recombination I Where should the circled site on Chromo1 recombine with Chromo2? 1 2 3

Oooops... 2 This is what happens in the mutation that causes color blindness in males! Green opsin gene duplicated and got changed somewhere along the way to sense more in the red region.

22 Short end of the stick

Metaphase I Homologous chromosomes line up at the metaphase plate How much info? 2n – Diploid!

Anaphase I Homologous chromosomes move to opposite ends of the cell Independent assortment occurs creating new combinations! How much info? 2n – Diploid!

Independent Assortment Chromosomes from mom & dad RANDOMLY move to one side or the other

Telophase I Cell walls begin to pinch inwards 2n – Diploid! How much info?

(Cytokinesis I) Two daughter cells pinch off Talk to your neighbor… How do they compare to one another? n (haploid) or 2n (diploid?

Why does genetic recombination matter? Your turn!!! You will get two homologous chromosomes with your partner that look like this… Yellow: White: Red: Green: What traits do each potential individuals have?

Why does genetic recombination matter? Cross over at the indicated positions below Yellow: White: Red: Green: Now what traits do each potential individuals have?

Why does genetic recombination matter? Cross over at the indicated positions below Yellow: White: Red: Green: Now what traits do each potential individuals have?

Bellwork If you missed the drawings for meiosis I, get some colored pencils and copy it from your neighbor. I will stamp it. 2.Get your sentences out from yesterday if I didn’t stamp them yet. 3.Can you find my mistake from yesterday? Extra credit to who figures it out first (hint: it has to do with the amount of information in one step but its not at the end of meiosis I!) 4.Get out your pink sheet and be ready to go through meiosis II!

Announcements Tomorrow we will be walking through the gym to see the science fair boards Test on meiosis next Wednesday Homework is coming on Monday! Don’t get behind! Test make-ups

Once you are done… Write a sentence explaining the steps of meiosis II! One sentence for each step. HOMEWORK IF NOT DONE IN CLASS!

Bellwork Have your sentences from meiosis I out if they have not been stamped yet as well as meiosis II sentences 2.Have pink sheet with drawings out for meiosis I and II to be stamped 3.Work on the questions at the end of your pink meiosis packet for bellwork. This will be stamped WHEN YOUR DONE!

Bellwork What is the difference between a homologous chromosome pair and a chromosome? 2.What is a tetrad? 3.Have sentences from meiosis II out to be stamped 4.Have green science fair sheet out to be stamped if I didn’t stamp it Friday

Announcements Meiosis quiz Wednesday Essential question Drawing and binder check TODAY!

PRE - INTERPHASE INTERPHASE

PROPHASE Crossing over occurs between homologous pairs Tetrad= 2 homologous chromosome pairs (one from mom in each, one from dad in each): 4 chromatids

METAPHASE 1 (middle) ANAPHASE 1 (apart) Homologous chromosome pairs line up Spindles attach to chromosomes

TELOPHASE 1CYTOKINESIS Almost two cells

PROPHASE IIMETAPHASE II Spindles attach to chromatids

ANAPHASE IITELEPHASE II & CYTOKINESIS Chromatids separate

Prophase II Beginning with the end products of meiosis II Chromosomes are condensed and prepare for another division No crossing over!! n or 2n? 2n - Diploid!!

Metaphase II Chromosomes line up at the metaphase plate More similar to mitosis this time Not homologous pairs any longer n or 2n? 2n - Diploid!!

Anaphase II Chromatids move to either end of the cell n or 2n? 2n - Diploid!!

Telophase II Chromatids separate to individual cells n or 2n? n - haploid!!

(Cytokinesis) Individual cells form n or 2n? Talk with your neighbor: How do the cells compare to each other? How do they compare to the products of meiosis I?

What do we call these cells? These cells are called gametes  they can be Eggs (from females) or Sperm (from males) n or 2n? They are haploid!!! Get half of information from mom, half from dad

Fertilization – Making babies! Sperm + Egg = Zygote

Human Chromosomes! How many pairs? How many chromosomes? How many sex chromosomes? How many undergo meiosis? All of them!

Chromosome vs. Chromatid and how they are used

Meiosis I vs. Meiosis II Products : What is divided : Crossing over? Amount of info: Spindles attach to:

Funny Meiosis Video Kt8 Kt8

Vocab activity You and a partner will get a sheet of card stock to draw a stage of meiosis I or II. You MUST label all parts of your drawing (homologous chromosomes, centrioles, cell pinching, metaphase plate etc.) When you and your partner/s are done, present to the class

Binder Check Bellwork (4 stamps) Notes Meiosis I and meiosis II notes (hand written) Homework/worksheets/labs Green variation activity with colors Pink meiosis packet with all drawings and stamps Green science fair worksheet Meiosis I and II sentences (handwritten)

Homework Orange meiosis worksheet – due tomorrow! Tuesday Put homework and notes packet together and take home to study!

Bellwork What is being separated in meiosis I? a.Chromosomes b.Homologous chromosomes 2.What is being separated in meiosis II? a.Chromosomes b.Homologous chromosomes 3.What is the difference in the amount of information from meiosis I to meiosis II?

Presentations Present your stage of meiosis I or II

Slate Quiz! Look at the pictures on the following slides & name the stage of meiosis!

????

Charades!

Unit Packet Notes on top (meiosis I and meiosis II) Homework/worksheets/labs on bottom – Green variation activity – Pink meiosis packet – Green science fair worksheet – Meiosis I and II sentences (handwritten) – Orange homework multiple choice worksheet – Yellow questions packet  add tomorrow!

Work on yellow sheet Last 10 minutes… Finish the first page (front and back) of the yellow sheet as your ticket out the door.

Bellwork Grab an article by the door, read it for bellwork and answer the following questions… a.What was the main point the article was trying to make? b.Hypothesize how this might be possible given what we have learned so far.

Work on yellow sheet Work on the second sheet (front and back) of the yellow sheet You have 10 minutes

Turn in unit packets and bellwork Add yellow sheet to unit packet and turn into basket Add up bellworks (6 stamps) and write at the top

Unit Packet Notes on top (meiosis I and meiosis II) Homework/worksheets/labs on bottom – Green variation activity – Pink meiosis packet – Green science fair worksheet – Meiosis I and II sentences (handwritten) – Orange homework multiple choice worksheet – Yellow questions packet