Chapter 20 Flashcards
What is a phylogenetic tree?
A phylogenetic tree is a diagram that represents the evolutionary relationships among various biological species based on similarities and differences in their physical or genetic characteristics.
True or False: A phylogenetic tree can depict the passage of time in evolution.
True
Fill in the blank: The length of the branches in a phylogenetic tree often represents _______.
time
Multiple Choice: What does a node represent in a phylogenetic tree? A) A species B) A common ancestor C) A time period D) A habitat
B) A common ancestor
How does the arrangement of a phylogenetic tree reflect evolutionary changes over time?
The arrangement shows how species diverged from common ancestors, indicating the sequence and timing of evolutionary events.
True or False: Organisms that appear closely related on a phylogenetic tree always share a recent common ancestor.
False
What is convergent evolution?
Convergent evolution is the process where unrelated organisms independently evolve similar traits due to adapting to similar environments.
Fill in the blank: The similarities between organisms that are not closely related can often be attributed to __________.
homoplasy
Multiple Choice: Which of the following is a reason why organisms may appear closely related despite being distantly related? A) Genetic drift B) Convergent evolution C) Natural selection D) All of the above
D) All of the above
Short Answer: What role does the rate of evolution play in the interpretation of phylogenetic trees?
The rate of evolution can vary significantly among different lineages, leading to discrepancies in the perceived relatedness of organisms on a phylogenetic tree.
What is the primary reason scientists distinguish between homologous and analogous traits when building phylogenetic trees?
To accurately represent evolutionary relationships among organisms.
True or False: Homologous traits arise from a common ancestor, while analogous traits arise independently in different lineages.
True
Fill in the blank: Homologous traits provide __________ evidence for constructing phylogenetic trees.
evolutionary
Which type of trait is misleading when determining evolutionary relationships: homologous or analogous?
Analogous
What is an example of a homologous trait?
The forelimbs of mammals, birds, and reptiles.
What is the highest level of the taxonomic classification system?
Domain
True or False: The taxonomic classification system includes only five levels.
False
Fill in the blank: The second level of the taxonomic classification system is called __________.
Kingdom
List the levels of the taxonomic classification system in order from highest to lowest.
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
Which level of classification comes immediately after ‘Phylum’?
Class
Multiple Choice: What level of classification is ‘Canis’ in the species name ‘Canis lupus’?
Genus
True or False: ‘Species’ is the most specific level of classification.
True
What is the purpose of the taxonomic classification system?
To organize and categorize living organisms based on shared characteristics.
Fill in the blank: The taxonomic level that groups organisms by their evolutionary history is called __________.
Phylogeny
What is the lowest level of the taxonomic classification system?
Species
What term describes traits that are similar due to convergent evolution, such as the body shape of dolphins and fish?
Analogous traits
True or False: The similar body shape of dolphins and fish is an example of homologous traits.
False
Fill in the blank: Dolphins are __________, while fish are __________.
mammals; aquatic animals
What is the main reason dolphins and fish have similar body shapes?
Adaptation to similar aquatic environments
Which of the following best describes homologous traits?
Traits that are similar due to shared ancestry
What is the principle of maximum parsimony in phylogenetics?
The principle of maximum parsimony states that the simplest explanation or tree that requires the least number of evolutionary changes should be preferred.
True or False: Maximum parsimony always provides the correct phylogenetic tree.
False
Fill in the blank: Maximum parsimony is often used to infer __________ relationships among species.
evolutionary
Which of the following methods is commonly associated with maximum parsimony: a) distance matrix, b) neighbor-joining, c) character-state optimization?
c) character-state optimization
Short answer: What is a potential limitation of using maximum parsimony in phylogenetic analysis?
It can be overly simplistic and may not account for complex evolutionary scenarios such as convergent evolution.
What are the three main theories for the evolution of eukaryotic cells?
The three main theories are the endosymbiotic theory, the autogenous theory, and the hybrid hypothesis.
True or False: The endosymbiotic theory suggests that eukaryotic cells originated from a symbiotic relationship between prokaryotic cells.
True
Fill in the blank: The ________ theory posits that eukaryotic cells evolved from the infolding of prokaryotic cell membranes.
autogenous
Which theory combines elements of both the endosymbiotic and autogenous theories?
The hybrid hypothesis
Short Answer: What is a key piece of evidence supporting the endosymbiotic theory?
The presence of double membranes and circular DNA in mitochondria and chloroplasts.
What is the primary reason aphids can change color?
Aphids can change color primarily for camouflage and to avoid predation.
True or False: All aphid species have the ability to change color.
False
Fill in the blank: Aphids acquired color-changing abilities through ________ adaptation.
evolutionary
What environmental factor is known to influence the color change in aphids?
Light exposure and temperature
Which selective pressure contributes to the evolution of color change in aphids?
Predation by visual hunters
