Chapter 8-Mendel and Heredity List on a piece of paper five characteristics that are passed on in families. Name one characteristic that may be inherited, but influenced by behavior or environment. Look at the following pages of plants, come up with a list of traits that could be inherited in plants.

The origins of Genetics Heredity-The passing of traits from parents to offspring. Gregor Mendel-Discovered basis for genetics. Genetics-Branch of Biology that focuses on heredity. Why Peas????? Look in your book and write this down, ok? Spend a couple minutes on this. Let’s go over table 1.

Monohybrid crosses-Cross that involves one pair of contrasting traits. Open up your books to page 164. Identify and write in your notes the following terms. – True-breeding, P generation, F₁ generation, F₂ generation. What is the results of the crosses. Let’s go over ratios.

Section 2- Do not write this down- A gardener notes that some of the flowers on their plants were white. Previous years they had been purple. What has happened to explain for this difference?

Mendel’s Theory Most people thought offspring was a blend of their parents. Is it? Mendel’s hypotheses – For each inherited trait, two copies of the gene, one from each parent – Alternate versions of genes – One trait may be expressed, the other not – Gametes (oh yes) carry only one allele for trait.

Some key terms-Section 2 Gene-A segment of DNA that is located in a chromosome and codes for a specific hereditary trait. Allele-Different forms of a gene. It explains how Mendel saw both tall and short pea plants. Dominant-Expressed form of a trait or variations that hide other variations. Recessive-Non-expressed form of a trait or hidden trait.

More terms,  Homozygous-If the two alleles are the same. Heterozygous-If the alleles are not the same. Homozygous dominant-DD Homozygous recessive-dd Heterozygous-Dd Genotype-The set of alleles an individual has. – Dd, FF, Ff, GgFF, BBFF, Phenotype-Physical appearance. – Blond, dimples, freckles, ear lobes, hairy knuckles

Laws of Heredity Law of segregation-Two alleles for a trait separate when gametes are formed. Law of independent assortment-The alleles of different genes separate independently. What? This only happens if genes are on other chromosomes. End of section 2-Please read section 3

Studying Heredity Do not write down anything, but I want you to learn how to draw a simple Punnett square. Make it empty.

Let’s do some Punnett Square problems Monohybrid crosses

Dihybrid crosses Let’s figure out ratios on this one!!!!

Human trait activity Read thoroughly before commencing. Groups of 2-4, NO MORE!!!!

Section 2 continued Test cross-An individual whose phenotype is dominant, but whose genotype is not known is crossed with a homozygous recessive individual. Let’s look over the problem on pages 172. Probability-Likelihood that a specific event will occur. – Probability = number of one kind of possible outcomes Total number of all possible outcomes Let’s look at page 174.

Pedigree-A family history that shows how a trait is inherited over several generations. Sex-linked trait-Trait whose allele is located on the X chromosome.

Section 4-Complex Patterns of Heredity Polygenic trait-When several genes influence a trait. – Example-Eye color, height, weight, hair and skin color. Incomplete dominance-An individual displays a trait that is intermediate between two parents. – Snapdragons red crossed with white=pink