AP Biology Flashcards: Common Ancestry

What this deck covers

This deck focuses on Common Ancestry, giving you a quick way to review the definitions, rules, and examples that matter most for AP Biology.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: Identify the term for a branching point in a phylogenetic tree.

Answer: Node. Each branching point shows where lineages split from ancestors.

Flashcard 2: What is the founder effect?

Answer: When a new colony is started by a few members. Small founding population creates genetic drift in new location.

Flashcard 3: Which type of evolution results in similar traits across unrelated species?

Answer: Convergent evolution. Independent evolution produces similar solutions to environmental challenges.

Flashcard 4: What is an analogous structure?

Answer: Structures with similar function but different origins. Result of convergent evolution, not common ancestry.

Flashcard 5: How do vestigial structures support common ancestry?

Answer: Remnants of structures from common ancestors. These useless structures indicate inheritance from functional ancestral forms.

Flashcard 6: What evidence supports the idea of a universal common ancestor?

Answer: Universal genetic code. Same code in all life suggests all organisms share one ancestor.

Flashcard 7: Which type of molecule is used to infer evolutionary relationships?

Answer: DNA or protein sequences. Molecular sequences reveal evolutionary distances and relationships.

Flashcard 8: Which term describes a trait inherited from a common ancestor?

Answer: Homologous trait. Shows direct inheritance from a shared ancestor.

Flashcard 9: Which term describes the evolutionary history of a species?

Answer: Phylogeny. The complete evolutionary history and relationships of a lineage.

Flashcard 10: What evidence supports the idea of a universal common ancestor?

Answer: Universal genetic code. Same code in all life suggests all organisms share one ancestor.

Flashcard 11: Which molecular evidence supports common ancestry?

Answer: DNA and protein sequence similarities. These molecules show evolutionary relationships through sequence conservation.

Flashcard 12: Which evidence from biogeography supports common ancestry?

Answer: Species distribution correlates with geological history. Geographic patterns match evolutionary divergence from common ancestors.

Flashcard 13: What is the bottleneck effect?

Answer: Reduction in genetic diversity due to population reduction. Severe population decline randomly eliminates genetic variants.

Flashcard 14: Define co-evolution.

Answer: Reciprocal evolutionary changes in interacting species. Species evolve together, each influencing the other's evolution.

Flashcard 15: What is convergent evolution?

Answer: Different species evolve similar traits independently. Creates analogous structures through similar environmental pressures.

Flashcard 16: Define co-evolution.

Answer: Reciprocal evolutionary changes in interacting species. Species evolve together, each influencing the other's evolution.

Flashcard 17: What does a polyphyletic group lack?

Answer: A common ancestor. Polyphyletic groups incorrectly combine unrelated lineages.

Flashcard 18: Which molecule's universality supports common ancestry?

Answer: DNA. All life uses the same genetic code, indicating common origin.

Flashcard 19: What does a sister group in phylogenetics represent?

Answer: Two lineages that are each other's closest relatives. Shows the closest evolutionary relationship possible between lineages.

Flashcard 20: What is the significance of the Galapagos finches in evolution?

Answer: Example of adaptive radiation. Darwin's finches show how one species diversified into many.

Flashcard 21: What is the role of genetic drift in evolution?

Answer: Random changes in allele frequencies. Causes random evolutionary changes independent of natural selection.

Flashcard 22: What is the significance of fossil records in common ancestry?

Answer: They show transitional forms and evolutionary history. Fossils provide direct evidence of evolutionary changes over time.

Flashcard 23: What is adaptive radiation?

Answer: Diversification of a species into various forms. Shows rapid evolution from a common ancestor into new niches.

Flashcard 24: Which is an example of a transitional fossil?

Answer: Tiktaalik. Shows transition between fish and tetrapods with intermediate features.

Flashcard 25: What is the definition of common ancestry?

Answer: Organisms share a common ancestor if they descend from a shared species. This defines the fundamental concept of shared evolutionary origin.

Flashcard 26: What is an analogous structure?

Answer: Structures with similar function but different origins. Result of convergent evolution, not common ancestry.

Flashcard 27: Identify the common ancestor in a simple phylogenetic tree.

Answer: The root of the tree. The base of the tree represents the original common ancestor.

Flashcard 28: Which structure indicates common ancestry: homologous or analogous?

Answer: Homologous. Homologous structures share ancestry; analogous structures do not.

Flashcard 29: Identify a vestigial structure in humans.

Answer: The appendix. A reduced organ that once served a function in ancestors.

Flashcard 30: What is the definition of common ancestry?

Answer: Organisms share a common ancestor if they descend from a shared species. This defines the fundamental concept of shared evolutionary origin.

Flashcard 31: Define monophyletic group.

Answer: A group that includes a common ancestor and all its descendants. Represents a complete evolutionary unit with no missing lineages.

Flashcard 32: Identify a molecular clock's role in phylogenetics.

Answer: Estimating divergence times based on mutation rates. Uses constant mutation rates to calculate when species diverged.

Flashcard 33: What is horizontal gene transfer?

Answer: Transfer of genes between organisms in a manner other than reproduction. Allows rapid spread of advantageous genes between species.

Flashcard 34: What is convergent evolution?

Answer: Different species evolve similar traits independently. Creates analogous structures through similar environmental pressures.

Flashcard 35: Which molecular evidence supports common ancestry?

Answer: DNA and protein sequence similarities. These molecules show evolutionary relationships through sequence conservation.

Flashcard 36: Define monophyletic group.

Answer: A group that includes a common ancestor and all its descendants. Represents a complete evolutionary unit with no missing lineages.

Flashcard 37: What is horizontal gene transfer?

Answer: Transfer of genes between organisms in a manner other than reproduction. Allows rapid spread of advantageous genes between species.

Flashcard 38: Which is an example of a transitional fossil?

Answer: Tiktaalik. Shows transition between fish and tetrapods with intermediate features.

Flashcard 39: What is the bottleneck effect?

Answer: Reduction in genetic diversity due to population reduction. Severe population decline randomly eliminates genetic variants.

Flashcard 40: What is a homologous structure?

Answer: Structures in different species with a common origin. Despite different functions, they share the same evolutionary blueprint.

Flashcard 41: What is a synapomorphy?

Answer: A shared derived trait in a clade. A defining characteristic that unites a group of related species.

Flashcard 42: How do vestigial structures support common ancestry?

Answer: Remnants of structures from common ancestors. These useless structures indicate inheritance from functional ancestral forms.

Flashcard 43: What is the significance of gene duplication in evolution?

Answer: Provides material for evolutionary innovation. Extra gene copies can evolve new functions without losing originals.

Flashcard 44: What is the principle of parsimony in phylogenetics?

Answer: Simplest explanation with fewest evolutionary changes. Minimizes assumptions by choosing the most economical evolutionary pathway.

Flashcard 45: What is a cladogram?

Answer: Diagram showing evolutionary relationships. Uses branching patterns to show evolutionary relationships.

Flashcard 46: Which molecule's universality supports common ancestry?

Answer: DNA. All life uses the same genetic code, indicating common origin.

Flashcard 47: Which evidence from biogeography supports common ancestry?

Answer: Species distribution correlates with geological history. Geographic patterns match evolutionary divergence from common ancestors.

Flashcard 48: What is the significance of gene duplication in evolution?

Answer: Provides material for evolutionary innovation. Extra gene copies can evolve new functions without losing originals.

Flashcard 49: What is the significance of fossil records in common ancestry?

Answer: They show transitional forms and evolutionary history. Fossils provide direct evidence of evolutionary changes over time.

Flashcard 50: Identify the term for a branching point in a phylogenetic tree.

Answer: Node. Each branching point shows where lineages split from ancestors.

Flashcard 51: Which theory explains the origin of mitochondria?

Answer: Endosymbiotic theory. Explains how bacteria became organelles through symbiosis.

Flashcard 52: Which term describes the evolutionary history of a species?

Answer: Phylogeny. The complete evolutionary history and relationships of a lineage.

Flashcard 53: Identify the common ancestor in a simple phylogenetic tree.

Answer: The root of the tree. The base of the tree represents the original common ancestor.

Flashcard 54: What does a sister group in phylogenetics represent?

Answer: Two lineages that are each other's closest relatives. Shows the closest evolutionary relationship possible between lineages.

Flashcard 55: What is the role of genetic drift in evolution?

Answer: Random changes in allele frequencies. Causes random evolutionary changes independent of natural selection.

Flashcard 56: Identify a molecular clock's role in phylogenetics.

Answer: Estimating divergence times based on mutation rates. Uses constant mutation rates to calculate when species diverged.

Flashcard 57: What does a phylogenetic tree represent?

Answer: Evolutionary relationships among species. Shows how species diverged from common ancestors over time.

Flashcard 58: Identify a type of evidence for common ancestry from embryology.

Answer: Similar embryonic development stages. Early developmental similarities reveal shared evolutionary history.

Flashcard 59: Which type of DNA is often used to study maternal lineage?

Answer: Mitochondrial DNA. Inherited maternally, useful for tracing female ancestry lines.

Flashcard 60: What is the principle of parsimony in phylogenetics?

Answer: Simplest explanation with fewest evolutionary changes. Minimizes assumptions by choosing the most economical evolutionary pathway.

Flashcard 61: Which process results in gene flow between populations?

Answer: Migration. Movement of individuals transfers alleles between populations.

Flashcard 62: Which structure indicates common ancestry: homologous or analogous?

Answer: Homologous. Homologous structures share ancestry; analogous structures do not.

Flashcard 63: Which type of selection favors intermediate traits?

Answer: Stabilizing selection. Reduces extreme variations by favoring average characteristics.

Flashcard 64: Which type of selection favors intermediate traits?

Answer: Stabilizing selection. Reduces extreme variations by favoring average characteristics.

Flashcard 65: Which process results in gene flow between populations?

Answer: Migration. Movement of individuals transfers alleles between populations.

Flashcard 66: What does a polyphyletic group lack?

Answer: A common ancestor. Polyphyletic groups incorrectly combine unrelated lineages.

Flashcard 67: Which theory explains the origin of mitochondria?

Answer: Endosymbiotic theory. Explains how bacteria became organelles through symbiosis.

Flashcard 68: What is adaptive radiation?

Answer: Diversification of a species into various forms. Shows rapid evolution from a common ancestor into new niches.

Flashcard 69: Which type of evolution results in similar traits across unrelated species?

Answer: Convergent evolution. Independent evolution produces similar solutions to environmental challenges.

Flashcard 70: What does a phylogenetic tree represent?

Answer: Evolutionary relationships among species. Shows how species diverged from common ancestors over time.

Flashcard 71: Which term describes a trait inherited from a common ancestor?

Answer: Homologous trait. Shows direct inheritance from a shared ancestor.