GENETICS &

CLASSIFICATION

GENETICS &

CLASSIFICATION

http://youtu.be/Mehz7tCxjSE?t=13s

Heredity

• Gregor Mendel

• Austrian Monk

• studied garden pea plants to unveil patterns of heredity

• Developed the Laws of Inheritance

• Mendel noticed that traits from the pea plant parents didn’t always show up in their offspring

Heredity• 2 types of traits were identified:

– Dominant trait – trait that appears in the offspring, offspring only needs one dominant allele from the parent to show up

– Recessive trait – trait that fades in the background or may not show up in the offspring, only shows up if the offspring gets two recessive alleles from their parents

– Mendel noticed that certain traits would reappear in later generations

GenesMendel discovered that each

individual carries 2 sets of characteristics (genes)

Each offspring has two forms of a gene (one from each parent)

Genes - carry information that determines your traits.

GenesGenes

Where are They?

• Genes hang out all lined up on thread-like things called Chromosomes.

– The chromosomes and genes are made of DNA which is short for deoxyribonucleic acid.

• Chromosomes are found inside cells–Specifically in the nucleus of the cell. (the

nucleus is sort of like the brain of the cell)

Where are They?

• Genes hang out all lined up on thread-like things called Chromosomes.

– The chromosomes and genes are made of DNA which is short for deoxyribonucleic acid.

• Chromosomes are found inside cells–Specifically in the nucleus of the cell. (the

nucleus is sort of like the brain of the cell)

Genes

Alleles

Allele - different form(s) of a gene, responsible for hereditary variation.

– Dominant trait – appears if it inherits the gene for that trait from either parent; will always be expressed and will “mask” a recessive trait. Shown by capital letter(s).

– Recessive trait – appears only if it inherits that trait from both parents and can only be expressed if there are no dominant alleles present; shown by lower case letters.

Alleles• Genotype –The alleles present in an organism.

inherits from its parents, the actual gene makeup represented by letters.

• (Example: BB, Bb, or bb)

“Purebred”, also called Homozygous consists of gene pairs with genes that are the same. (Example: “RR” -or- “rr”)

“Hybrid”, also called Heterozygous and consists of gene pairs that are different. (Example: “Rr”) • Note: The capital letter always is written first.

This is the "internally coded, inheritable information" carried by all living organisms.is

.

BB Bb bb

• Phenotype – is the physical appearance of a trait.What it looks like…

– Example: blue eyes or brown hair

• These are the physical parts, anything that is part of the observable structure, function or behavior of a living organism.

Alleles

Red Red WhitePhenotype---------

Punnett SquarePunnett Square

Punnett Square - a diagram used to predict outcomes of genetic combinations. The Punnett square is a summary of every possible combination of one maternal allele with one paternal allele for each gene being studied in the cross.

Steps for Using the Punnett square:

– One parent’s alleles (genotype)(genotype) go along the top– The other parent’s alleles go down the side.– You fill in the squares like doing the communicative

property of multiplication.

Punnett Square - a diagram used to predict outcomes of genetic combinations. The Punnett square is a summary of every possible combination of one maternal allele with one paternal allele for each gene being studied in the cross.

Steps for Using the Punnett square:

– One parent’s alleles (genotype)(genotype) go along the top– The other parent’s alleles go down the side.– You fill in the squares like doing the communicative

property of multiplication.

Punnett SquarePunnett SquarePractice: Both parents have the same genotype (Bb)B= brown hair color b= blond hair color

Fill out the Punnett square on the right to help answer the following questions.

This organism has ________% or __________chance of receiving brown hair.

This organism has ________% or ____________ chance of receiving blonde hair.

The possible genotypes are:

The possible phenotypes are:

F

M

ReproductionReproduction

• Asexual Reproduction – only need one parent to produce an offspring, offspring are exact copies of the parent. The genetic information passed to offspring is identical to that of the parent. – Produces uniform offspring– Most single-celled organisms reproduce this way

ReproductionReproduction

• Sexual Reproduction – requires 2 parents to reproduce, offspring share characteristics from both parents and are not exactly like either parent– Produces more diverse offspring

Survival and Reproduction

Charles Darwin first presented his theory of evolution by natural selection in his book called On the Origin of Species in 1859.

Natural Selection – organisms with favorable hereditary traits are more likely to survive and reproduce than other organisms; these organisms gradually increase their proportion of a species.

Charles Darwin first presented his theory of evolution by natural selection in his book called On the Origin of Species in 1859.

Natural Selection – organisms with favorable hereditary traits are more likely to survive and reproduce than other organisms; these organisms gradually increase their proportion of a species.

Survival and ReproductionNatural Selection in 4 Steps:

– Overproduction – more individuals are born than will survive to adulthood

– Genetic variation – each individual in the species has different traits, some traits make an individual more likely to survive and reproduce.

– Struggle to survive – only some of the individuals in a population become adults and reproduce.

– Successful reproduction – individuals have traits that make them better adapted to their environment are more likely to reproduce.

• Example: Peacocks with dull feathers won’t survive, eventually all die off

Survival and ReproductionExample:

Peacocks with dull feathers won’t survive to pass on trait, eventually all dull feathered peacocks will die off

Overproduction

Genetic Variation

In the wild

Struggle to Survive

To find food

Successful ReproductionModern Peahen, adapted to the

environment looks for Mr. Right.

Mr. Right

Mr. Right,shiny feathers..good hunter…

great traits

Darwin visited the Galapagos Islands off the coast of South America. There he made many observations. One of the most famous, was the Finch.