Do now activity Why is it important to have variation within a species? Give 2 examples of variation within ONE species. Name 5 possible genes found in the human gene pool. List 5 different species of living things.

Essential Question: Section 7-1: variation Why does an advantageous trait increase in proportion within a species over time? Learning Target Justify why an advantageous trait will increase in proportion from one generation to another when provided statistical evidence. Section 7-1: variation

Critical Readings must be stamped and turned in by Wednesday (2/8/17). announcements Biology Tutoring this week: Lunch B (Tuesday & Thursday) 7:00AM (Monday – Friday) After school Biology Tutoring: Tuesday Critical Readings must be stamped and turned in by Wednesday (2/8/17).

announcements Available Extra Credit: Tissue Box = 2 Points 6.6oz bag of Goldfish (Pretzel/Cheddar) = 5 Points

Don’t forget to chunk your notes!

Variation = differences within a species overview Variation = differences within a species

Variation is needed for Natural Selection overview Variation is needed for Natural Selection

overview Genetic Variation Gregor Mendel Charles Darwin

Population Evolution A _____ is a group of organisms of the same species that can breed and produce fertile offspring. Population Individuals provide the variations But… Populations, not individuals evolve Population: a group of individuals of the same species that can breed with each other We study the genetic make up of a population to see if it changes

Population Evolution A population is a group of organisms of the same species that can breed and produce fertile offspring. Population Individuals provide the variations But… Populations, not individuals evolve Population: a group of individuals of the same species that can breed with each other We study the genetic make up of a population to see if it changes

All the genes in a population is called a ___ ______ . Population Evolution All the genes in a population is called a ___ ______ . Gene pool We study the genetic make up of a population to see if it changes gene pool: all the genes in a population Because populations breed together they have the same gene pool

All the genes in a population is called a gene pool . Population Evolution All the genes in a population is called a gene pool . Gene pool We study the genetic make up of a population to see if it changes gene pool: all the genes in a population Because populations breed together they have the same gene pool

____ _____ is the number of times an allele occurs in a gene pool. Population Evolution ____ _____ is the number of times an allele occurs in a gene pool. Relative Frequency Evolution (genetic terms): any change in the relative frequency of alleles in a population

Population Evolution Relative (gene) frequency is the number of times an allele occurs in a gene pool. Gene/Relative Frequency Evolution (genetic terms): any change in the relative frequency of alleles in a population

Population Evolution What is an allele? cyclins

Alleles are different forms of a gene. Population Evolution Alleles are different forms of a gene. cyclins

_____ are different forms of a trait in a population. Genetic variation _____ are different forms of a trait in a population. Alleles Each gene has at least two alleles Ex. brown or white fur

Alleles are different forms of a trait in a population. Genetic variation Alleles are different forms of a trait in a population. Alleles Each gene has at least two alleles Ex. brown or white fur

There are 2 sources of genetic variation. cyclins

Genetic variation Change (mistake) in DNA code Source #1: Mutations

Source #2: Gene Shuffling Genetic variation Gene shuffling Meiosis followed by sexual reproduction Most genetic variations are due to gene shuffling In humans this produces 8.4 million different combinations of genes Does not change the relative frequency of alleles in a population Source #2: Gene Shuffling

Single gene & polygenic traits # of phenotypes depends on # of genes

Single gene & polygenic traits Frequency of Phenotype (%) Phenotype Single-gene traits have 2 phenotypes Freckles No Freckles

Single gene & polygenic traits Frequency of Phenotype (%) Phenotype Single-gene traits have 2 phenotypes Free Earlobe Attached Earlobes

Single gene & polygenic traits Frequency of Phenotype (%) Phenotype Dominant phenotypes may be less frequent in a population No Widows Peak Widows Peak

Single gene & polygenic traits Most traits are polygenic. Frequency of Phenotype Phenotype (height)

Single gene & polygenic traits Most traits are polygenic. Frequency of Phenotype Phenotype (height)

Single gene & polygenic traits Most traits are polygenic. Examples: Human hair color Human height Human eye color Frequency of Phenotype Phenotype (height)

Single gene & polygenic traits Polygenic traits have more than 2 genes. Frequency of Phenotype Phenotype (height)

Single gene & polygenic traits When there are many variations, they are grouped in a symmetrical bell-curve Frequency of Phenotype Phenotype (height)

Do now activity #1 What type of Natural Selection is selecting brown rabbits? What type of Natural Selection is selecting for black AND white rabbits? What type of Natural Selection is selecting for ONLY black rabbits?