Chapter 4: HereditySection1- Genetics

Life Science

Lesson Plan

Inheriting Traits Create a short list of characteristics

about yourself…

HeredityHeredity is the passing of traits

from parents to offspring.

Inherited Traits- Traits that are passed from parents to their offspring (through fertilization)

Genes are passed down… but what are genes?

Genes - Sections of DNA on a chromosome.

Genes on chromosomes control the traits that show up in an organism.– There are hundreds of genes on a

chromosome

Alleles are different forms of a trait that a gene may contain.– There are TWO alleles for every trait

Example: Height– 1 allele is tall (T)– 1 allele is short (t)

Allelesalleles

a gene

GENETICS Genetics- the study of inherited traits.

Gregor Mendel- The Father of

Genetics “The Man”

Mendel’s Experiment Mendel studied the traits of Pea Plants

– Look Page 105

Crossed 2 Plants with different expressions of the trait – Example- Tall (T)& Short (t)– Round (R) & Wrinkled (r)

Mendel’s Experiment When the plants were crossed he

discovered that the new plant formed looked like one of the two parents.

Take a look…

Mendel’s Tall vs. Short Plants

Mendel used pollen from both Tall and Short Plants to pollinate by hand the flowers.

Cross-Pollination- the pollination of two different plants together

http://www2.edc.org/weblabs/Mendel/MendelMenu.html

Hybrid vs. Purebred

3.Purebreds- offspring that receives two of the same alleles for a trait (TT or tt)

Hybrid vs. Purebred

4. Hybrids- offspring that receives two different alleles for a trait (Tt)

OR……

Check out these websites!

http://www.switcheroozoo.com/zoo.htm

http://www.buildyourwildself.com/

2 Types of Allelesa. Dominant allele- covers up or dominates the other trait.

Represented by a CAPITAL

b. Recessive allele- the trait seems to disappear

Represented by a lower case

Homozygous vs. Heterozygous

Homozygous – an organism with 2 alleles for one trait that are the same (written TT)

6 Heterozygous – an organism with 2

alleles for one trait that are different (written Tt)

Phenotype vs. Genotype

Genotype- the genetic-makeup of an organism (types of letters used)

Phenotype vs. Genotype

Phenotype- the way an organism physically looks/behaves as a result of its genotype.

Types of Words used: Tall, Short, Blonde, Brown, etc.

The Use of Punnett Squares

A Punnett Square can help you predict what an offspring will look like.

For example, Male and Female Chromosomes

Check out the Punnett Square

Screencast!

Works Cited www.coolclips.com http://kentsimmons.uwinnipeg.ca/

cm1504/mendel.htm www.classzone.com www.dkimages.com www.virtualsciencefair.org

www.scienceray.com