Download Heredity - Githens Jaguars

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
Color
‹ Hair Color
‹ Height
‹ Weight
‹ Body Structure
‹ Facial Features
‹ Skin 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/i
mages/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”
alleles
‹ Lower 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
– XX
‹ Male –XY
‹ Male determines the sex of the baby
Practice Punnett Squares
‹ 10
examples
‹ Guinea 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”
alleles
‹ Lower case letter are recessive alleles and
are the “weaker” of the alleles.
Dominant
‹B
– brown eyes
‹ T – tall
‹ C – curly hair
‹ W – widows peak
‹ F – freckles
‹ D – dark skin
Recessive
‹b
– blue eyes
‹ t – short
‹ s – straight hair
‹ w – no widows peak
‹ f – no freckles
‹ d – 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.jpg
http://www.bbc.co.uk/schools/gcsebitesize/img/bigenopheno.gif
Genotype/Phenotype
Genotype
Bb
bb
TT
tt
Cc
cc
Ff
ff
Phenotype
Brown Eyes
Blue Eyes
Tall
Short
Curly Hair
Straight Hair
Freckles
No Freckles
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
‹ RR
‹ Rr
‹ rr
‹ Tt
‹ tt
‹ BB
‹ Bb
Drop and Drag Genetics
‹ http://www.zerobio.com/drag_gr11/mono.ht
m
Punnett Square Practice
‹ Complete
part 2 of the worksheet that we
completed yesterday.
‹ Complete the other Punnett Square Practice
Sheet
‹ If 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 Gregor
Mendel.
‹ 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/Mend
elMenu.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