All flashcards
Flashcard 1: What is a phylogenetic tree (cladogram) used to show?
Answer: Hypothesized evolutionary relationships and common ancestors. Diagrams branching patterns of evolution from shared ancestors.
Flashcard 2: What is the fossil record?
Answer: Preserved remains or traces showing life over time. Fossils document evolutionary changes through geological time.
Flashcard 3: Choose the correct inference: two species have very similar embryos early in development.
Answer: They likely share a common ancestor. Similar embryos indicate shared developmental programs.
Flashcard 4: Identify the correct conclusion: Species A and B have fewer DNA differences than A and C.
Answer: Species A and B are more closely related than A and C. Fewer differences mean more recent common ancestor.
Flashcard 5: Which observation most strongly indicates convergent evolution: homologous bones or analogous wings?
Answer: Analogous wings. Similar function without shared structure shows convergence.
Flashcard 6: Which type of evidence is being used when comparing amino acid sequences in proteins?
Answer: Molecular (biochemical) evidence. Proteins are molecular evidence like DNA sequences.
Flashcard 7: What is a homologous structure, and what does it indicate about ancestry?
Answer: Similar structure from common ancestor; may have different functions. Same basic structure evolved once in shared ancestor.
Flashcard 8: On a cladogram, which organisms are most closely related: the two sharing the most recent node or the root?
Answer: The two sharing the most recent node. Recent nodes show more recent divergence from common ancestor.
Flashcard 9: What is common ancestry in evolutionary biology?
Answer: Shared descent from the same ancestral species. All organisms evolved from earlier life forms through branching lineages.
Flashcard 10: Which part of a cladogram represents the most recent common ancestor of two species?
Answer: The node (branch point) where their lineages meet. Nodes show where one ancestral species split into two.
Flashcard 11: What does it mean when two species are "sister taxa" on a cladogram?
Answer: They share an immediate common ancestor not shared by others shown. Closest relatives that split from same recent ancestor.
Flashcard 12: Identify the stronger evidence for common ancestry: homologous structures or analogous structures?
Answer: Homologous structures. Shared structure indicates common descent, not convergence.
Flashcard 13: Which evidence best supports common ancestry: same bone pattern in forelimbs or same habitat use?
Answer: Same bone pattern in forelimbs (homologous structure). Structural similarity shows shared ancestry, not ecology.
Flashcard 14: What is an analogous structure, and what does it indicate about ancestry?
Answer: Similar function, different origin; indicates convergent evolution. Different ancestors evolved similar solutions independently.
Flashcard 15: What is a vestigial structure, and what does it suggest about evolution?
Answer: Reduced or unused trait; inherited from ancestors where it was useful. Evidence of evolutionary history when structures lose function.
Flashcard 16: What is comparative anatomy used for when inferring common ancestry?
Answer: Comparing body structures to identify shared evolutionary origins. Reveals homologous structures that indicate common descent.
Flashcard 17: What is comparative embryology evidence for in evolutionary biology?
Answer: Similar early development patterns suggest common ancestry. Shared developmental stages reveal evolutionary relationships.
Flashcard 18: What is molecular evidence for common ancestry?
Answer: Similar DNA or protein sequences indicate relatedness. Genetic similarities reflect shared evolutionary history.
Flashcard 19: What does it mean if two species share many DNA sequence similarities?
Answer: They likely share a more recent common ancestor. Less time since divergence means fewer genetic differences.
Flashcard 20: What does a fossil record provide as evidence for common ancestry?
Answer: Shows changes over time and transitional forms linking groups. Preserves evidence of evolutionary transitions between groups.
Flashcard 21: What is a phylogenetic tree (cladogram) used to show?
Answer: Hypothesized evolutionary relationships and common ancestors. Visual diagram mapping evolutionary relationships.
Flashcard 22: What is molecular evidence of common ancestry based on?
Answer: Similarities in DNA or amino acid sequences. Genetic code similarities reflect shared evolutionary history.
Flashcard 23: What does comparative embryology study to infer relatedness?
Answer: Similarities in early developmental stages. Related species show similar patterns during embryonic development.
Flashcard 24: Which type of structure is stronger evidence of common ancestry: homologous or analogous?
Answer: Homologous structures. Same structure from inheritance shows direct evolutionary connection.
Flashcard 25: Identify the best overall conclusion if fossils, DNA, and homologous structures all agree.
Answer: The organisms share a common ancestor. Multiple independent evidence types confirm evolutionary relationship.
Flashcard 26: Which pair is more closely related if pair 1 differs by 2 DNA bases and pair 2 differs by 12?
Answer: Pair 1 (2 base differences). Fewer mutations indicate less time since divergence.
Flashcard 27: Identify the evidence type: whale pelvis bones that no longer support walking.
Answer: Vestigial structures. Remnants from land-dwelling ancestors that walked on legs.
Flashcard 28: Identify the evidence type: wings of bats and insects share function but different structure.
Answer: Analogous structures. Independent evolution created similar solutions for flight.
Flashcard 29: Identify the best evidence type for common ancestry: same bone pattern in forelimbs across mammals.
Answer: Homologous structures. Same skeletal pattern inherited from common mammalian ancestor.
Flashcard 30: Which option best indicates closer relatedness: more DNA differences or fewer DNA differences?
Answer: Fewer DNA differences. Less evolutionary time means fewer accumulated genetic changes.