Unit+7+Teacher

Unit Overview

• Unit 7: Natural Selection

  • Lesson 1: Natural Selection

  • Lesson 2: Population Genetics

  • Lesson 3: Hardy Weinberg Equilibrium

  • Lesson 4: Evidence of Evolution & Common Ancestry

  • Lesson 5: Phylogeny

  • Lesson 6: Speciation & Extinction

  • Lesson 7: Origins of Life on Earth

Lesson 1: Natural Selection

Aim

• What causes natural selection and how does it affect populations?

Key Concepts

1. Variation

   • Genetic variation exists within populations and can be inherited.

2. Competition

   • Overproduction of offspring leads to competition for resources and survival.

3. Selection

   • Individuals with beneficial adaptations are more likely to survive and pass on their genes.

   • Over generations, allele frequencies change leading to evolution.

Lesson 2: Population Genetics

Aim

• What are the different mechanisms of evolution?

Population Genetics Basics

• Population: A group of individuals of the same species in a specific area that interbreed.

• Gene Pool: The total genetic diversity within a population which includes all alleles.

• Allele Frequency Changes: Changes occur due to:

  • Mutations: Source of genetic variation.

  • Genetic Drift: Random changes in allele frequency, especially significant in small populations.

  • Gene Flow: Transfer of alleles due to migration.

  • Natural Selection: Favorable traits increase in frequency.

Lesson 3: Hardy-Weinberg Equilibrium

Aim

• What is Hardy-Weinberg equilibrium?

Hardy-Weinberg Basics

• Equilibrium Equation:

  • P + q = 1 (frequency of dominant + recessive alleles)

  • p² + 2pq + q² = 1 (Genotype frequencies)

Conditions for Hardy-Weinberg Equilibrium

1. No mutations

2. Random mating (no sexual selection)

3. No natural selection

4. No genetic drift

5. No gene flow

• Failure to meet conditions results in microevolution.

Lesson 4: Evidence of Evolution & Common Ancestry

Aim

• What evidence supports evolution and common ancestry?

Types of Evidence

1. Fossil Record: Visual representation of evolutionary changes over time.

2. Comparative Morphology: Study of structure similarity across species.

   • Homologous Structures: Similar origins but different functions.

   • Vestigial Structures: Remnants without function (e.g., human appendices).

3. Biogeography: Species distribution patterns indicate evolutionary relationships.

Lesson 5: Phylogeny

Aim

• How do phylogenetic trees and cladograms display evolutionary relationships?

Phylogenetic Relationships

• Systematics: Classification based on evolutionary relationships.

• Use of fossil records, DNA, and homologous structures to determine relations.

Lesson 6: Speciation & Extinction

Aim

• What causes new species to arise and what may cause extinction?

Speciation Process

• Species: Group able to interbreed.

• Allopatric Speciation: Geographic isolation due to barriers.

• Sympatric Speciation: New species arise without geographic separation.

Extinction Factors

• Environmental changes can rapidly increase extinction rates.

Lesson 7: Origins of Life on Earth

Aim

• What scientific models explain the origin of life?

Hypotheses on the Origin of Life

1. Miller-Urey Experiment: Demonstrated organic compounds can form under early Earth conditions.

2. RNA World Hypothesis: Suggests RNA as the first genetic material capable of self-replication.

3. Evolution of Complex Life: Simple organic molecules combined to form complex structures leading to life.