Bio 200 Lab Quizzes with Accurate
Solutions
Describe the scientific method
& if reject... - ANSWER--Make observations
-Ask questions
-Check accumulated scientific data
-Formulate hypothesis
-run multiple controlled experiments
-make conclusions and accept of reject orig hypothesis
-report findings
**if reject.. formulate new hypothesis
Generally a hypothesis leads to very specific --- - ANSWER-scientific predictions
the prediction made with initial hypothesis is --- - ANSWER-testable
There are several factors to keep in mind when designing a scientific experiment: (3) -
ANSWER--variables (need to be tested,measured and held constant)
-controls (to be run)
-replicate (how many times to replicate and experiment)
Independent variables - ANSWER-variables that cause changes in dependent variables
What is the big question facing a systematist who is interested in traits that indicate
shared ancestry? - ANSWER-How do you determine which traits are from a common
ancestor?
Homologies - ANSWER-are traits that appear in different organisms because they were
inherited by a common ancestor
ex) lizards, birds, and bears have the same functional types of bones in their forelimbs -
passed along from ancestor
Homologous traits - ANSWER-can have similar functions, they do not have to have
similar functions in the modern organisms
Phylogenies - ANSWER-tree diagrams based on homologous traits
, ---> only trees considered to show the path of evolution
homoplasies - ANSWER-similar structures that have evolved independently.
homoplasies can develop due to (2) - ANSWER--Covergent evolution (covergence)
-Reverse evolution (reversal)
Covergent evolution - ANSWER-when a derived trait evolves independently in two
lineages
**usually appears via diff pathways in the two species and close examination of the trait
will show that covergence is at work
Reversals - ANSWER-lead to homoplasies when a group of organisms develops a
derived trait, but a member of that group reverts to the ancestral trait
Triangle represents - ANSWER-Covergent evolution
Circle represents - ANSWER-trait evolves
square represents - ANSWER-reversal
***look at page 16 the tree - ANSWER-----
In cases of reversal, the organisms that shows the reverted trait --- - ANSWER-does not
share it with other organisms bc the common ancestor had the trait
While ---- can only be made using homologous traits, ---- can be made using either
homologies or homoplasies - ANSWER-While phylogenies can only be made using
homologous traits, phenograms can be made using either homologies or homoplasies
While all ---- are ----, all --- are not ---- - ANSWER-While all phylogenies are
phenograms, all phenograms are not phylogenies
Do homoplasies help systematists make natural classifications? - ANSWER-no
homoplasious structures can be very similar and evolutionary trees can be incorrect,
leading to --- - ANSWER-erroneous conclusions
The safest way to determine if structures are homologous is through --- - ANSWER-
genetic comparisons
Why does anyone ever make phenograms? - ANSWER-genetic data may not be
avaliable
Solutions
Describe the scientific method
& if reject... - ANSWER--Make observations
-Ask questions
-Check accumulated scientific data
-Formulate hypothesis
-run multiple controlled experiments
-make conclusions and accept of reject orig hypothesis
-report findings
**if reject.. formulate new hypothesis
Generally a hypothesis leads to very specific --- - ANSWER-scientific predictions
the prediction made with initial hypothesis is --- - ANSWER-testable
There are several factors to keep in mind when designing a scientific experiment: (3) -
ANSWER--variables (need to be tested,measured and held constant)
-controls (to be run)
-replicate (how many times to replicate and experiment)
Independent variables - ANSWER-variables that cause changes in dependent variables
What is the big question facing a systematist who is interested in traits that indicate
shared ancestry? - ANSWER-How do you determine which traits are from a common
ancestor?
Homologies - ANSWER-are traits that appear in different organisms because they were
inherited by a common ancestor
ex) lizards, birds, and bears have the same functional types of bones in their forelimbs -
passed along from ancestor
Homologous traits - ANSWER-can have similar functions, they do not have to have
similar functions in the modern organisms
Phylogenies - ANSWER-tree diagrams based on homologous traits
, ---> only trees considered to show the path of evolution
homoplasies - ANSWER-similar structures that have evolved independently.
homoplasies can develop due to (2) - ANSWER--Covergent evolution (covergence)
-Reverse evolution (reversal)
Covergent evolution - ANSWER-when a derived trait evolves independently in two
lineages
**usually appears via diff pathways in the two species and close examination of the trait
will show that covergence is at work
Reversals - ANSWER-lead to homoplasies when a group of organisms develops a
derived trait, but a member of that group reverts to the ancestral trait
Triangle represents - ANSWER-Covergent evolution
Circle represents - ANSWER-trait evolves
square represents - ANSWER-reversal
***look at page 16 the tree - ANSWER-----
In cases of reversal, the organisms that shows the reverted trait --- - ANSWER-does not
share it with other organisms bc the common ancestor had the trait
While ---- can only be made using homologous traits, ---- can be made using either
homologies or homoplasies - ANSWER-While phylogenies can only be made using
homologous traits, phenograms can be made using either homologies or homoplasies
While all ---- are ----, all --- are not ---- - ANSWER-While all phylogenies are
phenograms, all phenograms are not phylogenies
Do homoplasies help systematists make natural classifications? - ANSWER-no
homoplasious structures can be very similar and evolutionary trees can be incorrect,
leading to --- - ANSWER-erroneous conclusions
The safest way to determine if structures are homologous is through --- - ANSWER-
genetic comparisons
Why does anyone ever make phenograms? - ANSWER-genetic data may not be
avaliable
