Heredity

It’s in the genes!

What is heredity?

Heredity is the passing of traits from parent to offspring.You inherit traits from your parents

What are traits?

Eye ColorHair ColorHeightWeightBody StructureFacial FeaturesSkin Color

http://www.dance-classes.ca/photos/faces/faces_2004W_comp1.jpg

More Traits

What traits did you inherit from your parents?

Complete the genetic scavenger hunt with the people at your table.List any unusual traits that your group members have on the back of the paper.You have 5 minutes to complete this assignment.Be ready to share with the class.

How traits are passed

When organisms reproduce, traits are passed from parent to offspring. These traits are carried in DNA, the genetic material found in a cell’s nucleus. DNA acts like a blueprint.

How are traits passed?

publications.nigms.nih.gov

http://www.healthsystem.virginia.edu/internet/huntdisease/images/DNA.gif

http://www.geocities.com/Heartland/Bluffs/1958/notech1.html

Dominant and Recessive

Each parent has two genes (or letters) for a trait. These letters are called alleles.Capital letters are called Dominant alleles. When these alleles are present, they take over or show. They are the “stronger” allelesLower case letter are recessive alleles and are the “weaker” of the alleles.

http://naturalsciences.sdsu.edu/classes/lab2.4/trait.jpg

Punnett Squares

Using Punnett Squares allow us to show what the offspring could look like

Allows us to calculate probability of certain genotypes and phenotypes to occur

http://www.math.utep.edu/Faculty/mleung/probabilityandstatistics/probapps2.html

Punnett Squares

Gender

Female – XXMale –XYMale determines the sex of the baby

Practice Punnett Squares

10 examplesGuinea Pig Punnett Squares

Dominant/Recessive

Capital letters are called Dominant alleles. When these alleles are present, they take over or show. They are the “stronger” allelesLower case letter are recessive alleles and are the “weaker” of the alleles.

Dominant

B – brown eyesT – tallC – curly hairW – widows peakF – frecklesD – dark skin

Recessive

b – blue eyest – shorts – straight hairw – no widows peakf – no frecklesd – light skin

Genotype and Phenotype

Genotype – the inherited alleles (letters)Phenotype – what the alleles look like when inherited.

http://www.phschool.com/atschool/science_images/human_punnett_square.jpghttp://www.bbc.co.uk/schools/gcsebitesize/img/bigenopheno.gif

Genotype/Phenotype

No FrecklesffFrecklesFfStraight HairccCurly HairCcShortttTallTTBlue EyesbbBrown EyesBbPhenotypeGenotype

Homozygous and Heterozygous

IF the genes are the same, they are homozygous– “homo” means same

IF the genes are different, they are heterozygous– “hetero” means

different

http://discover.edventures.com/images/termlib/h/homozygous/support.gif

Homozygous/Heterozygous

RRRrrrTtttBBBb

Drop and Drag Genetics

http://www.zerobio.com/drag_gr11/mono.htm

Punnett Square Practice

Complete part 2 of the worksheet that we completed yesterday.Complete the other Punnett Square Practice SheetIf you finish either one, put it in the tray.

Class Survey

http://www.phschool.com/atschool/science_activity_library/survey_of_traits.cfm

Assignment

Complete the Alien Genetics activity (2 aliens)After you cut out your aliens, make sure your name is on the back of each and turn in.Complete the Monsters Inc. Heredity worksheet and turn in.

Assignment

Make the 5 door foldable that you see on the board.You will read pages 56-63 in the Cells and Heredity book and complete the Who, What, How, Why foldable about GregorMendel.Due by the end of class.

The study of heredity started with the work of Gregor Mendel and his

pea plant garden

Gregor Mendel is considered to be the father of genetics

Who was Gregor Mendel

Gregor Mendel was born in 1822 in Austria. He grew up on his family’s farm and was able to learn a lot about flowers and fruit trees. After going to college, he joined a monastery. At the monastery, he worked in the garden where he studied how traits were passed form parent to offspring.

Why??

Mendel noticed that some patterns of inheritance made sense and other did not. For example, Mendel noticed that when he crossed a purple flowered pea plant with a white flowered pea plant, that all of the offspring had purple flowers. He then noticed that if he crossed two of these offspring, then one out of every four offspring had white flowers. Mendel wanted to know why.

http://www.mentalfloss.com/store/files/d_219.jpg

WHY???

What did Mendel Do?

Mendel looked at 7 traits of pea plants. Mendel crossed pea plants with two different forms of each trait (for example, smooth/wrinkled peas or yellow/green peas) to determine which traits would appear and how often. Mendel was then able to determine which of the 7 traits were dominant and which were recessive.

What traits do you see?

http://www2.edc.org/weblabs/Mendel/MendelMenu.html

How??

The flowers of pea plants are self pollinating which means that they contain both male and female reproductive structures.Pollen from one flower or plant can fertilize the eggs of the same plant or another plant.

http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20102/Bio%20102%20lectures/Seed%20Plants/Lily_flower.jpg

HOW???

Mendel cut off the anthers of one flower and used the pollen from these anthers to fertilize the stamen on another plant. For example, he used the pollen from a plant that produced wrinkled seeds to fertilize the plant that produced round seeds. The stigma of the flower actually turns into seeds (peas). These seeds/peas are then planted in the ground to produce more pea plants.

Steps of Mendel's

Experiment

Mendel Clip