Scientist Study: Gregor Mendel – Simple Genetics

IGCSE BIOLOGY GENETICS

Who is Gregor Mendel?

Gregor Mendel is regarded as the first ever geneticist.  He overcame poverty and the death of his father, funded his own education and finally joined the abbot to continue with his studies.

He spent much of his adult life trying to answer the following question:

How do mothers and fathers – whether they are apple trees, sheep, or humans – pass down traits to their children?

From growing, mating and observing multiple generations of pea plants, Mendel put together his Theory of Heredity.

Gregor Mendel: The Friar Who Grew Peas

gregor mendel

This is a really lovely book, which tells the story of the boy scientist who grew into a man scientist.  I always love the story behind the science and his is a good one.

He spent his whole life growing hundreds upon hundreds of generations of pea plants.  His passion for his subject knew no end until he was finally able to answer the above question he had asked himself his whole life.

Starting exercise

I photocopied this pdf about family traits.  The children had to make a note of which traits they had compared with Gary and I.  The traits included things like the ability to roll your tongue; your hair shape; the presence of dimples, or chin cleft.  It was interesting to work out those traits which may have been dominant and those which were probably recessive.  Whatever the case it allowed the children to see that part of them was made up of part of Gary and part of myself.

 YouTube Videos about Mendelian Genetics

The following video is a biographical one about Mendel’s life:

The next video is a plastocene animation specifically about Mendelian genetics.  It basically retells what is in the book above.  I like to expose the children to as many varieties of information that I can so this was a great addition to our study on Mendel.

The final video is probably the best of the three and so well done:

Biography Page

I had the children fill out a very quick biographical sheet, which helped me check they had understood the basic concepts:

DSC_0485gregormendel

Design an Apple-head

Let the fun begin!  I was so looking forward to this lesson.  I just knew my children would love it but more than that I was excited at the potential for discussion and learning in-built into the building and creating of our own family.

  • First we chose six traits and the gene

The children chose six traits to give to our Mr Apple-head- eyes, nose, hair, mouth, ears, tail.  They took it in turns to decide on the dominant and recessive phenotype (physical trait).  For example C chose green and orange eyes.  Green was the dominant phenotype whilst orange was the recessive.  She chose a capital I for the dominant gene for green eyes and a small i for the recessive gene orange.  She then jotted down each of the possible gene combinations to discover the genotypes which would create either the orange or green genotypes.  It will be from this pool of genotypes that the children will choose from.  Here are all their chosen traits, phenotypes and genotypes:

DSC_0456appleheads

  • Next we decided which features to give Father Apple-head and Mother Apple-head

I drew up a chart on our white board.  For each trait one child chose the phenotype (the physical feature of the trait) and then, from the appropriate genotype pool they chose a specific genotype that would give rise to their chosen phenotype.  Here is the completed chart for both mother and father for all the chosen traits:

DSC_0455apple heads

  • Next we made up Father and Mother Apple-head

I gave the children a stack of Liquorice, jelly tots and a large apple each.  Using their completed chart above, C12 made the Mr Apple-head:

Ribbet collageappleheads1

whilst L12 made Mrs Apple-head:

Ribbet collageapplehead2

Here are the happy couple:

Ribbet collageapplehead4

T13 loves science and I wanted to make it a little harder.  I asked him to create an alternative Mr Apple-head, one which had a genetic mutation to its eye allele and its tail allele.  He needed to decide what feature would change in these two traits and the genotype for these changes.  He jotted down the mutations he wanted onto a mini white board and then created his alternative Mr Apple-head:

Ribbet collageapplehead3The eye gene mutation caused a recessive yellow eye colour.  We chatted about the fact that the mutation could have already been present in his own father and mother but as the gene for yellow eye colour was recessive, in order for the yellow phenotype to show, both parents would have needed to be a carrier of the gene.

Here is a photo with both the Mr Apple-heads showing the second with a mutation which caused yellow eyes and and a second mutation which caused Mr Apple-head to grow three tails instead of tw0:

Ribbet collageapplehead5

Ribbet collageapplehead6

We ate the mutated version and then married off the two remaining Apple-heads:

DSC_0449applehead

Tomorrow I will be posting about newly weds, Mr and Mrs Apple-head, and their new born Applettes.

Homeschooling the Middle & High School Years

17 comments

  1. Fantastic idea, Claire! That has to be one of the best lessons on genetics I have seen. I will make sure the children see this one as a follow-up to their study on genetics. I’m looking forward to tomorrow’s post.
    Have a lovely day!

  2. Wonderful videos – thank you so much for finding and sharing them. You know, this post made me think about one of the (many) reasons I am so excited about homeschooling starting next year. My younger kids will be exposed early to so many concepts that then there will be prior knowledge to scaffold on top of when the concept gets revisited again at a later date. Love this!

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