Evolutionary Biology Concepts Quiz

Founder Effect

• A small group separates from a larger group.

Darwin's Theory of Evolution

• Species today are descended from ancestral species, called "descent with modification".
• Natural selection is a mechanism for evolution.

Wallace's Theory of Evolution

• Natural selection of inherited traits over generations can create new species.

Fossil Record

• Chronological record of life's remains in sedimentary rock layers.

Biogeography

• Study of the distribution of organisms, past and present.

Convergent Evolution

• Unrelated organisms evolve similar traits when adapting to similar environments.

Direct Observations

• Using the five senses to observe phenomena; capturing information by watching.

Natural Selection

• Individuals with inheritable traits better suited for survival and reproduction pass those traits.

Artificial Selection

• Breeding organisms with desired traits to produce offspring with those same traits.

Homologies

• Similarities in organisms due to common ancestry.

Mechanism of Natural Selection

• Mutations introduce genetic variation. Organisms with higher fitness survive. Descent with modification leads to better adaptation.

Descent with Modification

• Species change over time.

Homology (general)

• Similarity due to shared ancestry.

Homologous Structure

• Similar structure, different function in different organisms, due to shared ancestry.

Analogous Structure

• Similar function, different structure in different organisms, due to similar environmental pressures, not shared ancestry.

Fossils

• Preserved traces or remains of ancient organisms.

Vestigial Structure

• Remnants of structures useful in ancestors, but not useful today.

Evolutionary Tree

• Diagram reflecting hypotheses on evolutionary relationships.

Adaptation

• Trait that increases survival and reproduction in a particular environment.

Evolution

• Gradual change in species over time.

Population as the Smallest Unit of Evolution

• Evolutionary change happens in allele frequencies within interbreeding groups over generations.

Genetic Variation in Populations

• Changes in allele frequencies.

Genetic Variation's Role in Natural Selection

• Provides the diversity of traits that is necessary for selection to act.

Hardy-Weinberg Equilibrium

• p² + 2pq + q² = 1
• p + q = 1

Hardy-Weinberg Equilibrium Conditions

• No selection
• No mutations
• No migration
• Large population
• Random mating

Directional Selection

• Natural selection favors one extreme variation of a trait.

Disruptive Selection

• Natural selection favors both extreme variations of a trait.

Stabilizing Selection

• Natural selection favors intermediate variations, against extremes.

Balancing Selection

• Natural selection maintains multiple phenotypic forms.

Natural Selection is Not Goal-Oriented

• Natural selection cannot create perfect organisms.

Genetic Drift's Effect on Small Populations

• Faster and more impactful in smaller populations.

Gene Pool

• Combined genetic information of a population's members.

Population

• Group of individuals of the same species in the same area.

Microevolution

• Evolutionary change within a species or small group over a short period.

Macroevolution

• Large-scale evolutionary changes over long periods.

Bottleneck Effect

• Reduction in genetic diversity due to a population size reduction (usually random, environmental).

Genetic Drift

• Random change in allele frequencies in smaller populations.

Gene Flow

• Movement of genes between populations.

Migration (genetic perspective)

• Gene movement between populations.

Fitness

• Ability of an organism to survive and reproduce.

Mutation

• Change in DNA sequence.

Horizontal Gene Transfer

• Genes transferred between genomes.

Biological Species

• Groups of populations with potential for interbreeding and producing fertile offspring.

Morphological Species

• Species defined by body shape and structural features.
• Limitation: Degree of dissimilarity is subjective.

Ecological Species

• Species defined by ecological niche.
• Limitation: Similar ecology doesn't always mean species relationship.

Speciation: Single Species Becoming Two

• Reproductive isolation.

Reproductive Isolation's Role in Population Divergence

• Prevents gene flow, allows genetic differences to accumulate.

Mechanisms of Reproductive Isolation

• Habitat isolation
• Temporal isolation
• Behavioral isolation
• Mechanical isolation
• Gametic isolation
• Reduced hybrid viability
• Reduced hybrid fertility
• Hybrid breakdown

Sympatric Speciation

• Speciation within a population without geographic isolation.
• (Polyploidy, habitat differentiation, sexual selection)

Allopatric Speciation

• Geographic isolation leads to speciation.
  • Most common mode of speciation.

Speciation

• Formation of new species.

Reproductive Isolation (general)

• Separation preventing interbreeding and fertile offspring.

Biological Species Concept

• Species defined by interbreeding potential.

Hybrid Zone

• Region where species meet and interbreed.

Polyploidy

• Extra chromosome sets in an organism.

Hybrid

• Offspring from crosses between different species.

Intraspecific

• Variation within a single species.

Interspecific

• Competition between different species.

Adaptive Radiation

• Single species evolving into many descendants.

Eukaryotic Cell Evolution from Prokaryotic Cells

• Endosymbiosis (one prokaryotic cell engulfing another).

Biases in the Fossil Record

• [Information omitted as per instructions]

Steps in Life's Evolution

• Nucleotide/amino acid production
• Polymerization (into larger molecules)
• Protocell formation (containing polymers)
• Self-replicating molecules

Age of Earth

• 4.6 billion years.

Appearance of Prokaryotes

• 3.5 billion years ago.

Appearance of Eukaryotes

• 1.8 billion years ago.

Appearance of Multicellular Eukaryotes

• 1 billion years ago.

Appearance of Animals

• ~0.8 billion years ago.

Appearance of Humans

• 2.5 million years ago.

Appearance of Land Plants

• ~0.5 billion years ago.

Effects of Environmental Change on Organisms

• Climate/temperature, atmosphere, landmasses, floods, glaciation, volcanism, meteorites affect organisms through genetic changes.

Radiometric Dating

• Determining absolute age of rock material using radioactive isotopes.

Fossil's Depth and Relative Age

• Deeper strata contain older fossils.

First Living Cells: Location

• Oceans.

Spatial Gene Expression and Pattern Formation

• Affects phenotypes.

Early Development and Evolutionary Relationships

• Reveals shared embryonic features and processes, reflecting common ancestry.

Protocells

• Simple vesicle-like structures.

Hydrothermal Vents

• Heated mineral-rich water openings in the sea floor.

Alkaline Vents

• Deep sea vents with high pH and warm water.

Ribozymes

• Catalytic RNA molecules.

Endosymbiont

• Cell living within a host cell.

Cambrian Explosion

• Rapid diversification of animal species.

Unicellular

• One-celled organisms.

Multicellular

• Organisms with many cells.

Prokaryote

• Cell without a nucleus.

Eukaryote

• Cell with a nucleus and membrane-bound organelles.

Half-Life

• Time for half of a radioisotope to decay.

Monophyletic Group

• Group containing a common ancestor and all descendants.

Neutral Mutations and Population Spread

• Genetic drift can increase the frequency of neutral mutations in populations, even if not affecting organismal fitness.

Principle of Parsimony

• Favors the simplest explanation.

Molecular Clock

• Model estimating evolutionary divergence time using DNA comparisons.

Horizontal Gene Transfer and Phylogenetic Trees

• Complicate drawing phylogenetic trees.

Binomial Nomenclature

• Two-part scientific naming system.

Taxonomic Hierarchy

• Kingdom, Phylum, Class, Order, Family, Genus, Species.

Taxon

• Group of organisms in a classification system.

Sister Taxa

• Groups sharing an immediate common ancestor.

Analogy

• Similarity of function, not shared ancestry.

Homology (repeated)

• Similarity due to shared ancestry.

Clade

• Group of species with a common ancestor and all its descendants.

Paraphyletic Group

• Group with common ancestor but not all its descendants (some are excluded).

Polyphyletic Group

• Group derived from two or more different ancestors.