About This Chapter
Biological Evolution & Natural Selection - Chapter Summary
The video lessons in this chapter explore the theory of evolution and various types of evidence for evolution. Our instructors look at several hypotheses for rates of evolution and examine the Hardy Weinburg equilibrium in detail. Other lessons examine adaptation and natural selection.
You will review information on speciation, genetic variability and random mutation, and explore an example of rapid adaptation in animals. By the time you've watched these lessons, you should be prepared to:
- Describe evolutionary theory
- Show evidence for evolution found in paleontology, biogeography, embryology, comparative anatomy and molecular biology
- Explain punctuated equilibrium and the molecular clock hypothesis
- State the equation for the Hardy Weinberg equilibrium
- Describe natural selection and adaptation, including rapid adaptation; also describe artificial selection
- Name types of natural selection
- Talk about allopatric and sympatric speciation, as well as prezygotic and postzygotic barriers
- Explore genetic variability and random mutation
Our instructors have developed brief, engaging lessons, filled with real world examples that will aid you in your studies. You may re-discover material that you last studied in high school, and some of the information will probably be brand new to you. The quizzes that are included with the lessons offer a chance to assess your knowledge and see if you need to devote more study time to any particular area.
1. Theories of Evolution: Lamarck vs. Darwin
We'll look at the interplay between population genetics and environment. Are traits individually acquired or do entire populations evolve? The flying hamsters and a few other notable experiments will provide the answers.
2. Evidence for Evolution: Paleontology, Biogeography, Embryology, Comparative Anatomy & Molecular Biology
There is much support for the theory of evolution. This evidence comes from a variety of scientific fields and provides information that helps us trace changes in species over time. In this lesson, we'll look at this evidence and explore how it supports the theory of evolution.
3. Rates of Evolution: Punctuated Equilibrium & Molecular Clock Hypothesis
In general, evolution is a very long process. But rates of evolution can be different for different organisms. In this video lesson, you will identify how scientists study rates of evolution and fill in some of the missing 'steps' in the fossil record.
4. Hardy-Weinberg Equilibrium I: Overview
In this lesson, we'll examine population genetics in greater detail. We'll also explore notions of Hardy-Weinberg equilibrium for large, stable populations. Is the genetic makeup of our flying hamster population changing? The Hardy-Weinberg equilibrium can serve as a reference point as we try to answer population genetics questions.
5. Hardy-Weinberg Equilibrium II: The Equation
The Hardy-Weinberg equilibrium equation is represented by a polynomial, so we'll have to do some calculations. Don't be intimidated; a few coin tosses can help us make sense of allelic frequencies in a given gene pool.
6. Hardy-Weinberg Equilibrium III: Evolutionary Agents
In this lesson, you'll learn how the Hardy-Weinberg equation relates to different evolutionary agents and population changes. Discover how the equation may be used to discover populations that are not in equilibrium.
7. Natural Selection & Adaptation: Definition, Theory & Examples
How does natural selection help shape the amazing types of animals we witness around us? In this lesson, we'll explore adaptations and what they can tell us about a species' past evolution.
8. Natural Selection: Definition, Types & Examples
We'll take a look at the types of natural selection that can occur. From flying hamsters to moths, you'll start to grasp the different paths organisms can take as they respond to their changing environments over time.
9. Speciation: Allopatric and Sympatric Speciation
Discover the definition of a species and learn more about how species split. Find out common terms related to the splitting of species and study what role polyploidy plays in the development of a species.
10. Prezygotic Reproductive Barriers & Speciation: Definition & Examples
We may take for granted why animals choose to mate with other animals of similar appearance, but it's not that simple. There are actually biological barriers to reproduction that can prevent even seemingly closely related species from reproducing. This lesson looks at one such category of hindrances, prezygotic barriers, which make fertilization impossible.
11. Postzygotic Reproductive Barriers: Definition & Examples
Do flying hamsters represent a separate species from your run-of-the-mill hamsters? We'll get to the bottom of this by performing crosses between the two hamster types. You'll explore postzygotic reproductive barriers and their possibly tragic consequences.
12. Genetic Variability and Random Mutation
Evolution is driven by variation among populations. The amount of variability determines how well a population can adapt to environmental changes, while random mutations can provide new variations that help a population adapt to unexpected changes.
13. An Example of Rapid Adaptation: The Peppered Moths
Normally, adaptations occur over thousands or millions of years. However, drastic changes in the environment can shorten the time period in which a change comes about. In such cases, we can learn a lot about the evolutionary process and how natural selection drives it forward.
14. Artificial Selection in Evolution
Humans have been selectively breeding for desirable traits in plants and animals for a long time. This artificial selection allows for a lot of control in the breeding process but can also lead to unintended mutations within a population of organisms.
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Other chapters within the Ohio Assessments for Educators - Middle Grades Science: Practice & Study Guide course
- Principles and Procedures of Scientific Inquiry
- Safety Procedures and Hazards in Scientific Research
- The History and Nature of Science
- Interdisciplinary Relationships in Science
- Introduction to Matter
- Atomic Structure in Chemistry
- Properties of Liquids & Solids
- Trends of the Periodic Table
- Nuclear Processes
- Chemical Bonding & Compounds
- Gas Laws
- Elements, Compounds & Mixtures
- Overview of Stoichiometry
- Types of Reactions in Chemistry
- Equilibrium in Chemistry
- Reaction Rates in Chemistry
- Thermochemistry & the Laws of Thermodynamics
- Electrical Forces and Fields in Physics
- Potential and Capacitance in Physics
- Direct Current Circuits in Physics
- Magnetism in Physics
- Force and the Laws of Motion
- OAE Middle Grades Science: Fluids in Physics
- Work, Energy, & Power in Physics
- Waves, Sound, and Light
- Cell Biology
- Basics of Metabolic Biochemistry
- Overview of Cell Division
- Animal Reproduction and Development
- Male Reproductive System
- Female Reproductive System
- Physiology I: The Circulatory, Respiratory, Digestive, Excretory, and Musculoskeletal Systems
- Physiology II: The Nervous, Immune, and Endocrine Systems
- Organism Classification & Phylogenesis
- Plant Biology
- Plant Reproduction and Growth
- Requirements of Biological Systems
- Biology of Genetics
- Basics of Gene Mutations
- Basics of DNA & RNA
- Process of DNA Replication
- The Transcription and Translation Process
- The Origin and History of Life On Earth
- Populations and Biological Communities
- Overview of Animal Behavior
- Ecosystems and Biomes
- Human Activity and the Biosphere
- Understanding Earth's Spheres & Internal Structure
- Time & Dating in Geology
- Biochemical Cycles
- The Lithosphere
- Rocks & Minerals
- Weathering, Erosion & Wasting
- Geological Forms
- OAE Middle Grades Science: Water Balance
- Flowing Water
- Ground Water Systems
- Life Cycle of Glaciers
- Oceanic Systems & Characteristics
- The Atmosphere
- Weather and Storms
- The Solar System and Universe