BIO 212 Exam 2 Questions and Answers Already Passed Latest Update 2025-2026
Phylogeny - Answers branching evolutionary history of species or other groups of orgaisms
phylogenetic tree - Answers simplified diagram of phylogeny
Systematics - Answers discipline of biology that characterizes and classifies the relationships
among all organisms on Earth, piecing together the tree of life
tree of life - Answers most universal of all phylogenic trees
Taxonomy - Answers help describe, name, and classify individual species and higher-level
groups
taxa - Answers group or level of organization into which organisms are classified
branches - Answers A line representing a species or other taxon through time
Root - Answers The most ancestral branch in the tree
tip - Answers endpoint of a branch; represents a living or extinct species or other taxon
outgroup - Answers a taxon that diverged prior to the taxa that are the focus of the study; helps
to root the tree
Node (fork) - Answers a point within the tree where a branch splits into two or more branches.
the node represents the most recent common ancestor of the descendant groups
polytomy - Answers A node that depicts an ancestral branch dividing into three or more (rather
than two) descendant branches; usually indicates that insufficient data were available to resolve
which taxa are more closely related
sister groups - Answers two descendants that split from the same node
character or trait - Answers any heritable genetic, morphological, physiological, developmental,
or behavioral characteristic that varies among the taxa to be studied.
ancestral trait - Answers characteristic that existed in an ancestor
derived trait - Answers one that is a modified form of the ancestral trait, found in a descendant
Synapomorphy - Answers a trait found in two or more taxa that is present in their most recent
common ancestor but is missing in more distant ancestors
clades or lineages - Answers monophyletic groups
monophyletic group - Answers evolutionary unit that includes an ancestral population and all of
its descendants but no others
,Homology - Answers similarity resulting from common ancestry
Homoplasy - Answers when traits evolved independently in two or more different lineages and
thus are similar for reasons other than common ancestry.
parisomy - Answers the most likely explanation or pattern is the one that implies the least
amount of change
convergent evolution - Answers independent evolution of similar traits in distantly related
organisms due to adaptation to similar environments and lifestyles.
Palentologist - Answers A scientist who studies fossils
fossils - Answers pieces of physical evidence from an organism that lived in the past.
fossil record - Answers the total collection of fossils that paleontologists and amateur
collectors have found throughout the world and archived in thousands of private and public
collections.
Percambrian - Answers The interval between the formation of Earth, about 4.6 billion years ago,
and the appearance of most animal groups about 541 million years ago. it is divided into the
Hadean, Archaean, and Proterozoic eons.
Paleozic - Answers The "ancient" time period that is marked with the presence of the super-
continent Gondwana.
meszoic - Answers age of dinosaurs
Cenozoic - Answers recent life
Anthropocene - Answers the human epoch
adaptive radiation - Answers A single ancestral species diverges into several different forms
adapted to slightly different environments.
Cambrian explosion - Answers adaptive radiation of animals
fauna - Answers collection of animal species
mass extinction - Answers rapid extinction of a large number of diverse organisms around the
world
background extinction - Answers the lower, average rate of extinction observed when a mass
extinction is not occurring.
impact hypothesis - Answers
1. Predict how flying reptiles called pterosaurs went extinct 66 million years ago. Were they
, poorly adapted to their environment? - Answers
Assess whether the current dramatic decline in sharks is more likely the effect of background
extinction or a mass extinction. (Some shark populations have dropped to just 5 percent of their
former abundance in just a few decades due to overfishing.) - Answers
The null hypothesis for the sixth mass extinction is that current extinction rates represent
background extinctions. How would the graph in (a) look if the data supported the null
hypothesis? - Answers
1. Choose the best definition of a fossil.
a. a rock that contains information about an organism
b. a bone, tooth, shell, or other hard part of an organism that has been preserved
c. any trace of an organism that lived in the past
d. any part of a dead organism - Answers c. any trace of an organism that lived in the past
Critique the following statement: The absence of a trait cannot be used as a synapomorphy in
phylogenetic analysis; only shared derived traits that are present in the clade can be used. -
Answers The statement is false; the loss of a trait, such as the loss of legs in snakes or whales,
can be a valuable synapomorphy for a clade.
Which of the following best characterizes an adaptive radiation?
a. Descendant species occupy a large geographic area.
b. A single lineage diversifies rapidly, and descendant species occupy many habitats and
ecological roles.
c. Natural selection is particularly intense, because disruptive selection occurs.
d. Species recover after a mass extinction. - Answers b. A single lineage diversifies rapidly, and
descendant species occupy many habitats and ecological roles.
Which of the following is an example of homoplasy?
a. hair in humans and fur in mice
b. astragalus ankle bones in hippos and deer
c. Hox genes in humans and flies
d. streamlined bodies in dolphins and ichthyosaurs - Answers d. streamlined bodies in dolphins
and ichthyosaurs
Phylogeny - Answers branching evolutionary history of species or other groups of orgaisms
phylogenetic tree - Answers simplified diagram of phylogeny
Systematics - Answers discipline of biology that characterizes and classifies the relationships
among all organisms on Earth, piecing together the tree of life
tree of life - Answers most universal of all phylogenic trees
Taxonomy - Answers help describe, name, and classify individual species and higher-level
groups
taxa - Answers group or level of organization into which organisms are classified
branches - Answers A line representing a species or other taxon through time
Root - Answers The most ancestral branch in the tree
tip - Answers endpoint of a branch; represents a living or extinct species or other taxon
outgroup - Answers a taxon that diverged prior to the taxa that are the focus of the study; helps
to root the tree
Node (fork) - Answers a point within the tree where a branch splits into two or more branches.
the node represents the most recent common ancestor of the descendant groups
polytomy - Answers A node that depicts an ancestral branch dividing into three or more (rather
than two) descendant branches; usually indicates that insufficient data were available to resolve
which taxa are more closely related
sister groups - Answers two descendants that split from the same node
character or trait - Answers any heritable genetic, morphological, physiological, developmental,
or behavioral characteristic that varies among the taxa to be studied.
ancestral trait - Answers characteristic that existed in an ancestor
derived trait - Answers one that is a modified form of the ancestral trait, found in a descendant
Synapomorphy - Answers a trait found in two or more taxa that is present in their most recent
common ancestor but is missing in more distant ancestors
clades or lineages - Answers monophyletic groups
monophyletic group - Answers evolutionary unit that includes an ancestral population and all of
its descendants but no others
,Homology - Answers similarity resulting from common ancestry
Homoplasy - Answers when traits evolved independently in two or more different lineages and
thus are similar for reasons other than common ancestry.
parisomy - Answers the most likely explanation or pattern is the one that implies the least
amount of change
convergent evolution - Answers independent evolution of similar traits in distantly related
organisms due to adaptation to similar environments and lifestyles.
Palentologist - Answers A scientist who studies fossils
fossils - Answers pieces of physical evidence from an organism that lived in the past.
fossil record - Answers the total collection of fossils that paleontologists and amateur
collectors have found throughout the world and archived in thousands of private and public
collections.
Percambrian - Answers The interval between the formation of Earth, about 4.6 billion years ago,
and the appearance of most animal groups about 541 million years ago. it is divided into the
Hadean, Archaean, and Proterozoic eons.
Paleozic - Answers The "ancient" time period that is marked with the presence of the super-
continent Gondwana.
meszoic - Answers age of dinosaurs
Cenozoic - Answers recent life
Anthropocene - Answers the human epoch
adaptive radiation - Answers A single ancestral species diverges into several different forms
adapted to slightly different environments.
Cambrian explosion - Answers adaptive radiation of animals
fauna - Answers collection of animal species
mass extinction - Answers rapid extinction of a large number of diverse organisms around the
world
background extinction - Answers the lower, average rate of extinction observed when a mass
extinction is not occurring.
impact hypothesis - Answers
1. Predict how flying reptiles called pterosaurs went extinct 66 million years ago. Were they
, poorly adapted to their environment? - Answers
Assess whether the current dramatic decline in sharks is more likely the effect of background
extinction or a mass extinction. (Some shark populations have dropped to just 5 percent of their
former abundance in just a few decades due to overfishing.) - Answers
The null hypothesis for the sixth mass extinction is that current extinction rates represent
background extinctions. How would the graph in (a) look if the data supported the null
hypothesis? - Answers
1. Choose the best definition of a fossil.
a. a rock that contains information about an organism
b. a bone, tooth, shell, or other hard part of an organism that has been preserved
c. any trace of an organism that lived in the past
d. any part of a dead organism - Answers c. any trace of an organism that lived in the past
Critique the following statement: The absence of a trait cannot be used as a synapomorphy in
phylogenetic analysis; only shared derived traits that are present in the clade can be used. -
Answers The statement is false; the loss of a trait, such as the loss of legs in snakes or whales,
can be a valuable synapomorphy for a clade.
Which of the following best characterizes an adaptive radiation?
a. Descendant species occupy a large geographic area.
b. A single lineage diversifies rapidly, and descendant species occupy many habitats and
ecological roles.
c. Natural selection is particularly intense, because disruptive selection occurs.
d. Species recover after a mass extinction. - Answers b. A single lineage diversifies rapidly, and
descendant species occupy many habitats and ecological roles.
Which of the following is an example of homoplasy?
a. hair in humans and fur in mice
b. astragalus ankle bones in hippos and deer
c. Hox genes in humans and flies
d. streamlined bodies in dolphins and ichthyosaurs - Answers d. streamlined bodies in dolphins
and ichthyosaurs
