Download Traits and Inheritance

Have you wondered why you resemble the other
people in your family?
Reproduction Rewind
Type of
Reproduction
No. of Parents
Asexual
Sexual
1
2
Offspring
Identical to
parents
Contains traits of
both parents
Complexity
Simple
Diverse
Example
Algae, protist
Human, tree
http://www.youtube.com/watch?feature=play
er_embedded&v=B_PQ8qYtUL0
1. Heredity-the study of
passing characteristics called
“traits” onto offspring.
• Some examples of traits
include eye color, hair color,
shape of nose, etc.
a. Genetics is the study of
heredity
2. The study of heredity started
with the work of Gregor Mendel
and his pea plant garden
Mendel was an Austrian Monk that
lived in the mid 1800’s. He is
considered the “Father of Genetics”
a. Genes contain DNA , are
found on CHROMOSOMES
and determine our TRAITS.
b. Genes are inherited in
PAIRS (2); you get one from
your MOM & one from your
DAD.
c. Different forms of genes are
called alleles
b. Called a double helix and
looks like a ladder that
has been twisted
Tells the cell what proteins to
make which are important because
they have a role in Creating
All the Traits of an
Individual Organism
a. They are made of DNA
and are found in the
NUCLEUS
is to carry genetic
information that is
passed on from parent to
offspring.
a. A dominant trait is a
strong form of a trait. Upper
case letters represent them.
It will show up but isn’t
necessarily better.
b. A recessive gene is a weak
form of a trait. Lower case
letters represent these traits.
It will only show up if the
dominant form is not present.
is the pair of letters
that represent a trait
Is the physical
trait. The
way something
looks.
When both of the letters (genes)
are the same for a trait
When the letters (genes) are
different for a trait
e. Homozygous – Having two identical alleles for
a trait.
f. Heterozygous – Having two different alleles
for a trait.
g. Incomplete dominance Genes work together to
produce a third trait
where the alleles are
blended
– Like a red flower crossed
with a white flower
produces a pink flower
h. Codominant - Genes work
together and both alleles are
visible
– Like a red flower crossed with a
white flower produces a red and
white flower
combining of gametes (sex
cells) from parents with
different traits
1. PUNNETT SQUARE-a
graphic organizer used to predict
the occurrence of traits. It
shows all possible combinations of
offspring from parents.
2. Probability -the possibility that
something could happen. Punnett
Squares show probability.
The probability that a single coin flip
will come up heads is…
• a. 100 percent
• b. 75 percent
• c. 50 percent
• d. 25 percent
The probability that a single
coin flip will come up heads
is….
• a. 100 percent
• b. 75 percent
• c. 50 percent
• d. 25 percent
3. Types of Crosses
a. Monohybrid Cross – a cross in
which only one trait is paired.
Homozygous or heterozygous
pairings can be used.
-some are purebred crosses and
others are hybrid
PUREBRED MONOHYBRID
CROSSES
Purebred
homozygous
dominant
Purebred
homozygous
recessive
Hybrid monohybrid Cross
• Yields:
– Homozygous dominant
TT
– Homozygous recessive
tt
– Heterozygous dominant
Tt
a.
Others are pairings of one trait that result in blended or
combinations of traits that are neither recessive or
dominant.
Co-Dominance
Incomplete Dominance
b. Dihybrid Cross - crossing parents who
differ in two traits (AABB with aabb)