Processes of Evolution & Genetics Part 2

Learning Objectives 1.Describe the importance of DNA replication 2.Describe the mechanisms of inheritance at a cellular level 1.Explain the link between meiosis and Mendelian genetics 2.Explain the evolutionary significance of meiosis 3.Illustrate an understanding of terms associated with evolutionary biology and genetics through defining and/or describing the terms 4.Distinguish between different forms of gene expression 1.Illustrate an understanding of different forms of gene expression through trait examples and visual diagrams

DNA Structure  DNA = Deoxyribonucleic Acid  ________________  ____________________ Discovered by: James Watson & Francis Crick unlocked structure and Function of DNA  Revolutionized science

DNA Structure DNA composed of chains of nucleotides. Each nucleotide, in turn, is made of : Double helix is a _____________________ DNA Bases: ___________________________

DNA Replication Why Replicate?

Chromosomes Chromosomes: ___________________________ Contain hereditary genetic information

Chromosomes Two Basic Forms: 1. ___________ 2. ___________ X Chromosome Y Chromosome

Chromosomes  Somatic cells: __________________  Each pair - same genes  _______________________________  Locus (pl., loci):  Allele:

Chromosomes

Mutation Changes to the _______________ _____________________________________ Is one of the _________________________ Is the only source of __________________ When does a mutation occur? _________________________

Mutation - Demonstration

Cell Division Source of Genetic Diversity  Cell division and differences in division have evolutionary significance Only two types of cell in our bodies: Somatic cells: such as hair, skin, liver, heart, muscle tissue, etc Sex cells (gametes): egg, sperm

Mitosis: Somatic Cell Division DNA replicates; Parent cell now has full set of chromosomes (23 pairs = 46 chromosomes Replicated DNA lines up in middle of cell During division DNA separates. One complete complement goes into one new cell, and the other into the second new cell Each new cell has full set of DNA

Meiosis Meiosis: development of ________________ Only occurs in the testes and ovaries  produce __________ Sex cell division – daughter cells contain _______ ___________________________ Meiosis involves __________________

Meiosis Parent cell is diploid Begins like mitosis; DNA replicated DNA lines up at middle of cell Cell divides & DNA separates, creating two diploid daughter cells 2 nd cell division: each daughter cell splits into two more cells, and paired chromosomes are split Each new cell has 23 chromosomes BUT NO PAIRS

Differences Make sure that you can not only names these differences but can also describe them

Evolutionary Significance of Meiosis Meiosis – greatly increases genetic variation in a _____________ ____________________________ (can) produce upwards of 10 billion unique combinations multiplied by the # of possible combinations for any random mating

Evolutionary Significance of Meiosis

Linkage Inheritance pattern in which _________________ ______________________ Why?  ___________________________________ Geneticists calculate linkage percentages This is an ____________ to Mendel’s principle of independent assortment

Genes & the Genome Gene Genome

Genes & the Genome Polygenic Inheritance Cumulative effects of ________________ __________________ contribute Not ______________________ Expression on a _____________________ (continuous variation) – bell shaped curve – _________________________ Examples: Gene Trait

Genes & the Genome Pleiotropy ___________________________________ Primary and secondary results Gene Trait

Norm of Reaction Table or graph illustrating the possible range of phenotypic expression for a given genotype Fruit Fly Example Gene & the Genome

Environmental Context Niche construction ____________________________________ Why is this important for biologists, and biological anthropologists, to consider? Why should cultural anthropologists and archaeologists pay attention to niche construction?