Bellwork (in spiral) Imagine that you are planning to meet

your pen pal but you two have never met in person.

What traits (distinguishing quality or characteristic) would you use to describe yourself? Make a list.

Which of these traits do you think you inherited? Put a check mark next to these traits on your list.

GeneticsInheriting the good, the bad, and the ugly!The study of heredity and the variation of inherited characteristics.

Why don’t you look like a rhinoceros?

How likely is it that a dog is the parent of a cat?

Why?? Because your parents do not have the traits of

a rhinoceros! Dogs and cats have different DNA. They are

genetically different from one another. Heredity is the passing of traits from

parents to offspring. A trait is a distinguishing quality or

characteristic. Offspring is the descendants of a person,

animal, or plant considered as a group.

My Traits Activity Complete the Inventory of My Traits –

Survey independently Data Table Results, as a class Make a graph of the class results Study the data. What trends do you

observe? What heredity traits are more common among the class?

Inventory Traits Survey Help

Hmmm… But, what if both of your parents have

straight hair, and you have curly? What if both of your parents have brown

eyes, but you have blue?

Hypothesize… With your table group, develop 2-3

possible reasons for how this might happen. Write your hypotheses in your spiral.

Question If a black dog and a white dog

have puppies, what color will those puppies be?

Grey? Black? White? Half black and half white? A different color all together?

Genetics and Heredity The study of genetics and heredity helps

us to answer these puzzling questions. How do we study heredity?

Early Ideas Early studies used plants, rather than

animals. Why? Plants make LOTS of offspring (seeds). Easier to have lots of growing plants in a

lab. Easier to control who breeds with who.

Early Ideas - Blending Prior to the 1850’s, people believed in

the idea of blending. Blending is like mixing two paints

together, you mix black and white, you get…

Gray! But this didn’t make much sense…

eventually everyone would look the same.

Blending With blending, if you crossed red with

white, you’d always get pink.

Red White PinkX =

Gregor Mendel An Austrian monk,

Gregor Mendel, also thought this was quite odd and questioned the idea of blending.

In the mid-1800s, in a series of experiments, Gregor Mendel discovered the rules underlying patterns of inheritance.

Gregor Mendel Used Scientific Method

Question: Does blending occur? Prediction: No, blending does

not occur. Test Hypothesis: Observed

different characteristics in pea plants…some had wrinkled seeds and others had round seeds.

wrinkled round

Bellwork In your spiral… Write a 3-4 sentence summary of what

you learned about genetics yesterday.

Experiment Planted one wrinkled

seed and one round seed. Transferred pollen from

the wrinkled plant to the round plant, called cross-pollination.

If blending were occurring what would you expect to see as a result of this test?

Answer: slightly wrinkled seeds

Parent generation

Results The resulting seeds were ALL round. Therefore, proving Mendel correct that

blending did not occur.

New Experiment This led Mendel to a

second experiment, in which he planted two of the resulting round seeds in 2 other pots.

He cross pollinated the plants again.

This time, the results were different.

What do you think the results were?

First Generation

Conclusion This plant produced 3

round seeds and 1 wrinkled seed.

Mendel tested this many times and with different characteristics of the plants, and got the same pattern of results over and over.

Second Generation

Results of Mendel’s Experiments

Parent Generation

First Generation

Second Generation

Ratio = 3:1

Cause & Effect Map (part 1)

Main Event (middle)

Gregor Mendel’s Experiments

Include a description and drawing of the results of his experiments.

Causes (left side)

Thinking back to what you learned yesterday, add the reasons that led to Mendel’s experiments.

Why did he develop a hypothesis to test?

:

Statistics indicated a pattern.

Discoveries One trait was always present in the first generation,

while the other trait seemed to disappear. Mendel called this trait the dominant trait.

Dominant Trait – the trait observed in the first generation when parents that have different traits are bred. (Stronger trait)

Recessive Trait – the trait that seems to disappear in the first generation, but reappears in the second generation. (weaker trait)

Mendel realized that his results could only be explained if each plant had two sets of instructions for each characteristic.

Instructions First generation plants carried instructions for

both the recessive and dominant trait. Genes are the instructions for an

inherited trait. (wrinkled or round, we often use letters to represent each instruction)

Alleles are the different forms of a gene (recessive or dominant) (R or r, use a capital letter to represent the dominant allele, and the same letter in lower case to represent the recessive allele)

Phenotype Phenotype is an organisms physical

appearance or detectable characteristic. (what you see) For example: round seeds, flower color, blue eyes, blonde hair, freckles etc.

What is the phenotype for the following pictures?

GenotypeGenotype is the combination of

alleles that make up a specific trait. (example: RR or Rr)

Homozygous is a genotype that has two of the same form of the allele. (example: RR or rr)

Heterozygous is a genotype that has two different forms of the allele. (example: Rr)

Genotype versus phenotype.

How does a genotype ratio differ from the phenotype ratio?

Hornimonster Activity

Female - mother

Male - father

Pedigree analysis reveals Mendel’s pattern in human inheritance

PedigreeA diagram that shows the occurrence of a genetic trait in several generations of a family.

Hemophilia is a recessive trait defined by the absence of one or more of the proteins required for blood clotting.

Probability Activity…

Probability Probability is

a mathematical chance that something will happen.

The probability of throwing heads or tails on a coin is 50% (1/2 chances)

PROBABILITYo Helps predict the chance that something will

happen

o Your predictions become more accurate with the more trials you run!

Punnett Squares Punnett

square: a chart used to organize all of the possible combinations of offspring from particular parents.

Make a Punnett Square Look back and Mendel’s first

experiment. What allele should we use for the seed

type? The round seed is dominant over

wrinkled, so use the letters R and r to represent the allele.

The genotype for the round seed is RR. The genotype for the wrinkled seed is rr.

Make a Punnett Square RR x rr

R R

r

r