heredity - wcsgithensjaguarsteam.weebly.com/.../heredity_20bw.pdf · the study of heredity started...
TRANSCRIPT
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