Biogeography-1

Pre-Test Characteristics Differentiating Living vs Non-Living:

Study of Life

  • Study of human-environment relationships

  • Species adaptations

  • Species surviving in cold environments (e.g., polar bears, arctic foxes, and certain plants that develop antifreeze proteins)

  • Species surviving in desert environments (e.g., camels, cacti, and various reptiles that can go long periods without water)

Understanding Life

All living organisms share defining characteristics that distinguish them from non-living things (Dubeck et al 2004).

Characteristics of Living Organisms

  1. Cellular Complexity

    • All living things consist of one or more cells, which are the basic units of life.

    • Cells can be prokaryotic (e.g., bacteria) or eukaryotic (e.g., plants and animals) and exhibit complex structures and functions.

  2. Growth and Development

    • Organisms progress through stages from birth to maturity, involving cellular division and differentiation.

    • This includes changes not only in size but in shape and function (e.g., metamorphosis in frogs).

  3. Reproduction

    • Organisms reproduce to ensure the continuation of life and pass genetically inherited traits to the next generations.

    • Reproduction can be sexual (involving the fusion of gametes) or asexual (e.g., budding, fission).

  4. Irritability

    • Organisms respond to stimuli in their environment, which can include light, temperature, and touch.

    • This responsiveness is crucial for survival and adaptation.

  5. Homeostasis

    • Organisms maintain internal balance despite external changes, such as regulating body temperature and pH levels.

    • Homeostatic mechanisms involve feedback systems that help to restore stability when internal conditions deviate from normal.

Geologic Time Scale

  • Relative Time: Subdivisions based on relative age, commonly assessed through stratigraphic position (layers of rock).

  • Absolute Time: Numerical ages in millions of years, obtained through radiometric dating methods.

Evidence of Evolution

Types of Evidence:

  • Direct Evidence: Observable changes in species over time; includes fossil records.

  • Indirect Evidence: Inferred evolution without direct observation; includes genetic studies.

  1. Biogeography Distribution Study

    • Examines the geographical distribution of organisms and their evolutionary history.

    • Historical Biogeography: Examines species distribution through geological time.

    • Ecological Biogeography: Studies species distribution in relation to environmental factors such as climate.

    • Conservation Biogeography: Combines conservation efforts with biogeography to protect biodiversity.

  2. Molecular Biology

    • Similarities between biological molecules (e.g., DNA, proteins) can indicate shared evolutionary ancestry.

    • Genes and Species Relationship: Comparison of related gene sequences helps determine evolutionary relationships.

    • Molecular Clocks: These are used to assess how closely species are related by examining differences in DNA or amino acid sequences.

  3. Comparative Anatomy

    • Homology vs Analogy:

      • Homologous Structures: Similar structures in different species derived from a common ancestor (e.g., forelimbs of humans and bats).

      • Analogous Structures: Similar structures that evolved independently due to adaptation to similar environments (e.g., wings of insects and birds).

    • Embryology Stages of Embryo Development:

      • Sequence of fertilization (union of egg and sperm), cell division forming a blastocyst, implantation in the uterine lining, and further development through fetal stages.

Evolutionary Mechanisms

  1. Mutation: Source of new alleles leading to genetic variation.

  2. Gene Flow: Movement of alleles between populations affecting allele frequencies.

  3. Natural Selection: Process where advantageous traits increase an organism's survival chances and reproductive success.

  4. Genetic Drift: Random changes in allele frequencies due to chance events, which can significantly impact smaller populations.

Evolutionary Relationships

  • Relationships between organisms that share a common ancestor provide insight into the development of traits over time.

  • Phylogenetics: The study of evolutionary relationships helps in tracing lineage and understanding characteristics of descendants.

History of Evolutionary Relationships

  • The first organisms were likely simple microorganisms; later developments led to more complex life forms such as amphibians.

  • Primate evolutionary trees illustrate the branching of species and diversification over millions of years, showing connections among species with common ancestors.

  • Analysis of these relationships assists in understanding similarities and adaptations among various species.

Post-Test Directions

  • Describe evolutionary relationships using evolutionary evidence in 3-5 sentences.

Upcoming Quiz

  • Coverage includes Fossils and Embryology; consisting of 20 items overall.