Download Ch. 3 Section 1: Genetics

• On your paper, record as many physical features as
you can for each organism.
• Today’s Schedule
• 1. Question of the Day
• 2. Reproductive Strategies Review
• 2. Ch. 3 Section 1: Genetics
Question of the Day
• Migration and hibernation are two different types
of behavioral adaptations.
• What do both of these processes have in common?
• A. They help the organism produce food.
• B. They help the organism produce energy.
• C. They help the organism change the environment.
• D. They help the organism adjust to changes in the
environment.
Question of the Day
• Both paramecia and fish live in a shallow pond. The
paramecia usually reproduce asexually. The fish reproduce
sexually. Suppose the environmental conditions in the
lagoon change. What advantage will the sexually
reproducing fish have?
• A. sexual reproduction decreases the genetic variability in
the fish populations.
• B. Sexually reproducing fish produce offspring that are
identical to the parents.
• C. Sexual reproduction limits the spread of harmful
characteristics in fish populations.
• D. Sexual reproduction in fish allows populations to adapt
to new conditions over fewer generations.
Why do organisms look like that?
Traits- the physical characteristics that make up an
organism .
Heredity- the passing of traits from parents to
offspring.
Genetics- the scientific study of heredity.
Organisms inherit their traits from their parents.
Who was Mendel?
• The “Father” of Genetics
• Studied peas and observed how peas passed on
their traits to offspring.
Mendel’s Experiments
• Purebred- an organism that always produces
offspring with the same form of a trait as the
parent.
• Remember, Mendel wanted
to know why pea plants
had certain traits!!!
• Mendel crossed purebred
tall pea plants with
purebred short pea plants.
So, why do organisms show certain traits
over others?
• In sexual reproduction a female contributes 1 factor
and male contributes 1 factor.
• The dominant factor will mask the other factor.
So, why do organisms show certain traits over others?
• Genes- the factors that control traits.
• Alleles- different form of a gene.
• Example: (Gene = height)
(Alleles= tall & short)
(Gene = hair color) (Alleles= dark & light)
The dominant allele controls the inheritance of traits.
The recessive allele will be masked or covered up.
Hybrids
• Hybrid- is the crossing of two things to make one.
• For hybrid organisms the dominant allele will
always mask or cover up the recessive allele.
A closer look.
• Heredity and Traits
• dominant human traits
• more human traits
• Answer both Questions of the Day on your paper.
• One of the most beautiful and common butterflies in our area is the
monarch butterfly. Due to the diet of monarch caterpillars, the
butterflies develop a taste that is unpleasant. Another species, called
the viceroy butterfly, does not produce an unpleasant taste, but has
evolved a color pattern similar to the monarch. Both species have
different adaptations that help them survive.
1. Which type of adaptation probably help the monarch survive?
A. Migration
B. camouflage
C. unpleasant taste
D. imitating another species
2. Which type of adaptation probably helps the viceroy survive?
A. Migration
B. camouflage
C. unpleasant taste
D. imitating another species
Skills Lab
• Open your book to page 86-87
• Objective: Explore how greatly traits can vary in a
group of people—your classmates.
• Problem: Are traits controlled by dominant alleles
more common than traits controlled by recessive
alleles?
• 1. Follow the procedure.
• 2. Complete the entire lab sheet.
• 3. Lab due at the end of class.
Skills Lab Part 1
• Problem:Are traits controlled by dominant alleles
more common than traits controlled by recessive
alleles?
• Write down your hypothesis now.
Skills Lab Part 2
• Work with a partner to determine which traits you
have. Circle your traits in the data table.
Total Number Surveyed: 8
Trait 1
Number
Trait 2
Free ear lobes
Attached ear lobes
Hair on fingers
No hair on fingers
Widow’s peak
No widow’s peak
Curly hair
Straight hair
Cleft chin
Smooth chin
Smile dimples
No smile dimples
A
B
C
D
E
F
Number
Skills Lab Part 3
• You will now survey 7 more students in your class
and record your findings in the data table below.
Total Number Surveyed: 8
Trait 1
Number
Trait 2
Free ear lobes
Attached ear lobes
Hair on fingers
No hair on fingers
Widow’s peak
No widow’s peak
Curly hair
Straight hair
Cleft chin
Smooth chin
Smile dimples
No smile dimples
A
B
C
D
E
F
Number
Skills Lab Part 4
• Look at the circle of traits on page 87. All the traits
listed in your data table appear in the circle. Place
the eraser end of your pencil on the trait in the
central circle that applies to you-either free ear
lobes or attached ear lobes.
• 6. Look at the two traits touching the space your
eraser is on. Move your eraser onto the next
description that applies to you. Continue using your
eraser to trace your traits until you reach a number
on the outside rim of the circle. Write that number
in the box.
Skills Lab Part 5
• Answer the analyze and conclude questions.