What are we made of?
TEKS & NGSSScience TEKS: Organisms and the environments.
7.14A – Define heredity as the passage of genetic instructions from one generation to the next generation
7.14C – Recognize that inherited traits of individuals are governed in the genetic material found in the genes within chromosomes in the nucleus.
Math TEKS: 7.1B – Number, operation, and quantitative reasoning. Convert between
fractions, decimals, whole numbers, and percents mentally, on paper, or with a calculator
7.12A – Probability and statistics. Describe a set of data using mean, median, mode and range.
NGSS: Disciplinary Core Ideas, LS3.A: Inheritance of Traits Cross Cutting Concepts, MS-LS3-2: Cause and Effect Science and Engineering Practices, MS-LS3-1: Develop and use a model to
describe phenomena.
Check yes or no
Do you have the following traits?
Which traits do you have?
Dominant or Recessive?
Why?
Genetics________: passing characteristics from parent to
offspring
________: branch of biology devoted to the study
of heredity
______: segment of DNA or hereditary unit
Heredity
Genetics
Genes
What we know now
Father of Genetics
Mendel’s Theory of Heredity1. For every trait, there are_______copies of the
gene (one from each parent)two
Mendel’s Theory of Heredity2.There are alternative versions of genes (_________)
alleles
Mendel’s Theory of Heredity3. When two different alleles are present, one is expressed (__________) while the other is not visible (_________).
dominantrecessiv
e
Mendel’s Theory of HeredityBy looking at an individuals alleles, we can
describe their
__________________: genetic makeup
__________________: what they look like
GenotypePhenotype
Alleles can be Dominant or Recessive
Dominant: always expresses itself (capital letters are used to represent dominant alleles)
Example: “B”
Recessive: only expressed in absence of a dominant allele
(lowercase letters are used to represent recessive alleles)Example: “b”
More terms
HomozygousHomozygous heterozygous
Heterozygous
homozygous
Explore:Practice: For each genotype below, indicate whether it is heterozygous (He) or homozygous (Ho).
____RR
____Rr
____TT
____pp
____Hh
____BB
____Nn
____Ll
____ll
____ss
____Tt
____aa
Determine the phenotype for each genotype using the information provided
Round head is dominant over oval head
RR _____________________ Rr ______________________ rr ____________________
Dominant vs. Recessive Allelesin Creatures
Triangle eyes are dominant
Star eyes are recessive
T Triangle eyes t Star eyes
By looking at an individuals alleles, we can describe their Genotype: genetic makeupPhenotype: what they look like
Genotype for Star eyes tt
Genotype for Triangle eyes TT
Tt
Phenotype : Triangle eyes
Phenotype: Star eyes
Head shape Round (R) is dominant over Oval (r)
Eye shape Triangles (T) are dominant over Stars (t)
Eye color Purple (P) is dominant over Orange (p)
# of eyes One eye (E) is dominant over three eyes (e)
Nose slits Three nose slits (N) is dominant over two nose slits (n)
Height Tall (H) is dominant over short (h)
# of legs 4 legs (L) are dominant over 5 legs(l)
# of arms 2 arms (A) are dominant over 4 arms (a)
Skin color Red (C) is dominant over green (c)
Hairiness Hair (I) is dominant over hairless (i)
Hair color Blue hair (B) is dominant over yellow hair (b)
Mouth shape Wide mouth (W) is dominant over narrow mouth (w)
Fingers 3 fingers per hand (F) is dominant over 7 fingers per hand (f)
ElaborateObtain 2 allele cards for each trait (no
peeking)Write down your genotypes on the My
Creature handoutWrite down your phenotypes on the My
Creature handoutDraw your creature
Further Elaboration: Punnett Squares
Punnett Squares
Evaluate• Name three recessive traits
in this alien.
• What are the two possible genotypes for this alien’s number of fingers?
• This alien’s genotype for number of legs is Ll. If it married another alien with genotype Ll, what is the probability that their baby would have five legs? Express as a fraction and percent.
Math Extension Number as
fractionNumber as decimal
Number as percent
Oval head shape
Star eye shape
Orange eye color
Three eyes
Two nose slits
Short height
Five legs
Four arms
Green skin
Hairless
Yellow hair
Narrow shape
Seven fingers
1. What is the mean percent of recessive traits?_________
2. What is the median percent of recessive traits?_______
3. What is the range in percent of recessive traits?_______