Evolution Quiz: Evidence and Theories

Theory of Evolution

• Evolution proposes all living species are modified descendants of earlier species with a common ancestor.

Evidence of Evolution

• Anatomy: Comparative anatomy reveals relationships among diverse organisms; e.g., similarities in arm bone structures.
• Biochemical: Core metabolic molecules, like ATP, have remained unchanged, demonstrating evolutionary conservatism.
• Development: Embryonic development stages across species show similarities not evident in adult forms.
• DNA and Genes: Conservation of the gene Sonic hedgehog across fish, birds, and mammals indicates shared genetic heritage.

Homologous vs. Analogous Traits

• Homologous Traits: Traits with similar embryonic origins; e.g., limbs of tetrapods.
• Analogous Traits: Traits serving the same function but differing in origin; e.g., wings of birds and bats.
• Both traits can exist simultaneously; e.g., bird and bat wings serve flight yet evolved independently.

Evolutionary Change

• Evolution defined as changes in genetic material over time through adaptive and random processes.

Mechanisms of Evolution

• Natural Selection:
  • Variation, Inheritance, Differential survival/Reproduction, and Adaptation (VIDA) drive population adaptation.
• Gene Flow: Migration affecting gene pools; e.g., red birds entering a blue bird population.
• Genetic Drift: Drastic population size loss affecting gene representation; e.g., post-volcanic eruption survivors.
• Mutation: Random gene changes leading to new traits; e.g., a mutation altering fur color.
• Non-Random Mating: Mate selection based on traits, influencing genetic outcomes; e.g., female birds choosing mates by song.

Speciation

• A species is defined by the ability to interbreed naturally.
• Speciation Process: Resulting from natural selection acting on heritable traits.
• Criteria for species differentiation include hybrid reproduction, physical appearance, dietary habits, and behavior.

Reproductive Isolation

• Mechanisms preventing interbreeding, leading to species evolution:
  • Behavioral Isolation: Specific behaviors essential for reproduction; e.g., unique bird songs.
  • Geographic Isolation: Physical barriers separating populations.
  • Temporal Isolation: Different reproductive timings; e.g., orchid pollination on distinct days.

Types of Cells

• Prokaryotic Cells: Lack a nucleus; DNA in loops/plasmids; unicellular.
• Eukaryotic Cells: Contain membrane-bound organelles; linear DNA; can be unicellular or multicellular.
• Both cell types share cytoplasm, cell membrane, and ribosomes.

Taxonomy and Classification

• Taxonomy: Identifying and classifying organisms based on traits.
• Phylogeny: Studying evolutionary relationships among species.
• Limiting Factors: Environmental factors restricting population growth, e.g., food scarcity.
• Selective Pressure: Influences reproductive success; e.g., presence of predators.

The Linnaean System

• Developed by Carl Linnaeus, organizing life into hierarchical taxonomic groups based on trait similarity.

Phylogenetic Trees

• Visual representations of evolutionary relationships; nodes signify common ancestors, and clades include all descendants.

Six Kingdoms of Life

• Bacteria: Unicellular, asexual reproduction, vital for nutrient cycling across diverse habitats.
• Archaea: Unicellular, thrive in extreme environments, gain energy from various molecules.
• Protists: Primarily unicellular, a mix of asexual/sexual reproduction, diverse energy sources.
• Fungi: Mostly multicellular, decompose organic matter, cell walls of chitin, symbiotic relationships.
• Plants: Multicellular, primarily photosynthetic, with cell walls made of cellulose.
• Animals: Multicellular, heterotrophic, mostly invertebrates, collagen-protein structure.

Test your knowledge on the theory of evolution and the evidence that supports it. Explore concepts related to anatomy and biochemistry that illustrate the connections between current species and their ancestors. Discover how our understanding of evolution shapes our perspective on life.