Download Exploring the Evolution of Horses in Response to Climate Change

Title: Exploring the Evolution of Horses in Response to Climate Change
Introduction
In this performance assessment task, students individually respond to a fictional letter from a paleontologist
requesting their help in the construction of a phylogenetic tree of horses for a museum exhibit. In order to
develop an appropriate and accurate representation they will apply their understanding of the processes that
impact evolution as well as the skills obtained and data recorded through a series of investigations performed as
“field pathologists” to write a scientific explanation answering the question: How do changes in the environment
impact the appearance and disappearance of species over time? The evidence students use to support their
claim will come from direct measurements of horse teeth and from observations collected from photographs of
environmental conditions aligned with the time frames that will be represented on the phylogenetic tree.
Prior to beginning this summative task students will have recorded observations in their science notebooks from
a series of illustrations representing the physical landscape of five geological epochs. Students will make note
of the flora (vegetation) present and use the data collected to make inferences about climate conditions during
these time periods. Students will also use their measurements of fossil teeth HI values (length-width ratio or
hypsodonty index) to create a graph that summarizes the relationship these measurements and fossil age. They
will use the data collected through these investigations to defend a connection between changes in horse teeth
and plant evolution.
Assessable Standards
Next Generation Science Standards (NGSS):
HS-LS4-4
Construct an explanation based on evidence for how natural selection leads to adaptation of populations.
HS-LS4-5
Evaluate the evidence supporting claims that changes in environmental conditions may result in: (1)
increases in the number of individuals of some species, (2) the emergence of new species over time,
and (3) the extinction of other species.
Disciplinary Core Ideas (DCI): LS4.C: Adaptation
 Changes in the physical environment have contributed to the expansion of some species and the
disappearance of others.
 Species become extinct when they can no longer survive and reproduce in their environment.
 If members of a species cannot adjust to change that is far too fast or too drastic, then the opportunity for
the species to evolve is lost.
 Differential survival and reproduction of organisms in a population that have an advantageous heritable
trait leads to an increase in the proportion of individuals in future generations that have that trait and a
decrease in the proportion of individuals that do not.
Cross Cutting Concepts:
Cause and Effect
Empirical evidence is required to differentiate between cause and correlation and make claims about
specific causes and effects.
1
Science and Engineering Practices:
Constructing Explanations and Designing Solutions
Construct an explanation based on valid and reliable evidence obtained from a variety of sources
(including students’ own investigations, models, theories, simulations, peer review) and the assumption
that theories and laws that describe the natural world operate today as they did in the past and will
continue to do so in the future.
Engaging in Argument from Evidence
Engaging in argument from evidence in 9-12 builds on K-8 experiences and progresses to using
appropriate and sufficient evidence and scientific reasoning to defend and critique claims and
explanations about the natural and designed world(s). Arguments may also come from current or
historical episodes in science. Evaluate the evidence behind currently accepted explanations or solutions
to determine the merits of arguments.
Information for Classroom Use
Approximate Duration for the Task:
Each formative assessment component will take one or two class periods on a traditional schedule. The
summative assessment will take approximately three days to complete: one day to generate a possible
phylogenetic tree, one day to present and defend proposed relationships, and one day to finalize. If student
evidence supporting targeted claims does not meet expectations, additional scaffolding and learning experiences
may need to be provided.
Assumptions:
It is assumed that students have:
1. Had the opportunity to learn all content prerequisites prior to engaging in the summative assessment
component of this task.
2. Been assessed through embedded formative assessments during all of the associated learning
experiences and received appropriate support as needed for mastery of the targeted concepts.
3. Experienced grade level appropriate science content related to the NGSS Disciplinary Core Ideas in Life
Science, 4.C band on Adaptation in grades 6-8, in particular the ability to apply an understanding of:
a. The characteristics that define a given species.
b. How reproduction passes traits on to the next generation.
c. The genetic basis of trait expression
d. How fossil records are used to provide evidence of past geological and environmental conditions.
4. Received explicit instruction and practice on grade level appropriate NGSS Science and Engineering
Practices required for successful completion of these formative and summative assessment tasks (See
grade band 3-5 in NGSS Appendix F). Such as:
a. Describe, measure and/or compare quantitative attributes of different phenomena and display the
data on simple charts and/or graphs.
b. Plan and conduct an investigation collaboratively to produce data to serve as the basis for evidence.
c. Use evidence to construct or support a scientific explanation
d. Develop and/or use models to describe and/or predict phenomena.
e. Obtain and combine information from books and/or other reliable media to explain phenomena.
During the instructional components of this unit the teachers questioning should aim to ensure that students
understand the concept of natural selection. Specifically, students will develop an understanding of how natural
selection involves variation within a population, struggle for survival, variation of fitness/selection, and
reproduction/passing down of best-fit traits.
Materials Needed (per team):
Fossil horse teeth study set (3D printouts and/or photos)
Calipers
Colored pencils
Two types of plant material: soft herbaceous leaf and rough grass samples for grinding
Mortar and pestle
Epoch image cards
Horse species image cards
Chart paper or whiteboards, with markers and/or tape
Supplementary Resources:
Fossils and other materials for this lesson were provided by the University of Florida: “Chewing on Change”
Exploring the Evolution of Horses in Response to Climate Change. PDFs of class materials and teacher notes,
including end of unit assessment, may be obtained from links found at:
http://www.cpet.ufl.edu/resources/curricula/created-by-fellows/evolution/
Instructional Notes:
Implementation of the assessment components described in this document depends upon the use of visible
thinking techniques, such as student whiteboard displays, to present findings. Subsequently, the teacher should
be prepared to facilitate a class discussion in order to reach a class consensus of a concept. See attached
Teacher Background document for suggestions on how to facilitate this type of class discussion.
To learn more about Socratic questioning and view an additional list of question starters, visit the “Changing
Minds” website: http://changingminds.org/techniques/questioning/socratic_questions.htm
Connecting Targets and Evidence
Claim
Evidence
Looks like/sound like
Science and Engineering Practice: Engaging in Argument from Evidence
Make and defend a claim based on evidence
about the natural world (Task #1, 2, 3)
Use evidence collected about horse teeth shape and
size to support claims about the relationship between
environmental conditions and advantages for survival.
Compare and evaluate competing arguments
(Task # 3)
Review compare explanatory models describing horse
evolution developed different teams of students.
Respectfully provide and accept critiques of
scientific arguments
Ask probing questions and provide constructive
feedback to teams of student about their explanatory
model of horse teeth evolution.
Construct, use or present an oral or written
argument based on evidence
Apply the process used by teams to develop an
explanatory model for the evolution of a selected
organism (not the horse)
Uses reasoning and evidence to defend and
critique a claim. (Task 2, 3, 4)
Apply understanding of natural selection to defend
scientific claims made about the relationship between
horse teeth and horse evolution using evidence from
photographs and fossil sample.
Determines the merit/evaluates the strength of
an argument. (Task 3)
Ask probing questions and evaluate response during
team presentations of explanatory models.
Science and Engineering Constructing Explanations and Designing Solutions
Make a quantitative claim regarding the
relationship between phenomena (Task 1, 2)
Use measurement of horse teeth and information
about plant evolution to match a fossil sample with
the appropriate time frame.
Construct and revise an explanation based on
valid and reliable evidence based on a variety
of sources. (Task 2, 3)
Use measurements and other evidence to explain how
horses of the same species could have had different
shape and size teeth.
Apply scientific ideas, principles, and/or
evidence to provide an explanation of
phenomena. (Task 2, 3)
Use evidence collected about changes in horse teeth,
climatic conditions and plant availably to construct
and explanatory model for horse evolution.
Apply scientific reasoning, theory or models to
link evidence to claims. (Task 1, 2, 3)
Apply understanding of genetics and natural selection
to make connections between claims about observed
changes in horse teeth and the evolution of horses
over time.
Knowledge (HSCE/GLCE or DCI): LS4.C – Adaptation
Key concepts:
Evidence of understanding:
Changes in the physical environment have
contributed to the expansion of some species
and the disappearance of others. (Task 2, 3)
Correlates the changes in dentition with chemical
differences in available vegetation.
Differential survival and reproduction of
organisms in a population that have an
advantageous heritable trait leads to an increase
in the proportion of individuals in future
generations that have that trait and a decrease
in the proportion of individuals that do not.
(Task 2, 3)
Infers that tooth shape and size have a genetic
component.
Species become extinct when they can no
longer reproduce in their environment. (Task 3)
Infers that branches that continue to present consist
of populations that not only survived, but also
reproduced.
If members of a species cannot adjust to
change that is far too fast or drastic, then the
opportunity for the species to evolve is lost.
(Task #3)
Infers that dead-end branches represent species that
were unable to evolve in response to change.
Proposes that organisms with traits suited to their
environment will survive and reproduce at greater
rates than individuals who have less advantageous
traits.
Cross Cutting Concepts: Cause and Effect
Suggest cause and effect relationships to
explain past and predict phenomena (Task #2,
3)
Explanations describe cause and effect relationship
between changes in physical characteristics (tooth
shape and size) and environmental conditions (plant
availability)
Use mathematical patterns to make claims
about specific causes and effects (Task #1, 2,
3)
Measurements comparing size and shape or horse
teeth are used to support claims and inferences made
in development of explanatory model.
Explain how changes in systems may have
various causes that may not have equal effects.
(Task #3)
Alternative explanatory models that are supported by
evidence and reasoning are accepted
Assessment Task Overview (Formative and Summative Components)
Core Idea
LS4.C:
Adaptation
Crosscutting
Cause and Effect
Practices
Constructing
Explanations
Purpose
Formative
Target PE
Task Component #1:
Students will use evidence from
observations of photos from
different geological epochs,
representations of fossilized
horse teeth and experience
breaking down different types of
plant material to explain the
relationship between the change
in horse tooth physiology,
climate changes and plant
evolution.
LS4.C:
Adaptation
Cause and Effect
Engaging in
Argument from
Evidence
Formative
Task Component #2
Relate variation in teeth a given
species to potential differences in
health and reproductive success
among members of the same
species.
LS4.C:
Adaptation
Cause and Effect
Constructing
Explanations
Summative
Task Component #3:
Student teams will apply
information gathered during the
unit and from the formative
assessment components of this
task to construct an explanatory
model explaining horse
evolution. Students will
individually write a summary
report explaining how their
team’s model can be used to
explain and make predictions
about another population’s
evolutionary patterns.
Engage in
Argument from
Evidence
Assessment Task Components:
Context:
This assessment task is composed of 3 components (2 formative and 1 summative). The component tasks are
designed to be embedded within a unit on evolution, which is organized according to a constructivist
instructional model such as the 5E Model. The 3 component tasks provide a map for designing the unit’s lesson
sequence. (Explore, Elaborate, and/or Evaluate stages of instructional cycle). Although based on this form of
pedagogy, these assessments should also be applicable to a more traditional instructional style.
Task Components:
After students analyze and interpret data, they use data and patterns that surface to develop scientific
explanations for natural phenomena they are investigating.
Students will compare their explanations to those developed by their peers and use evidence and
questioning to evaluate differing ideas.
After students have had the opportunity to revisit and revise their explanations, they should begin the
summative assessment portion.
Note: It would be helpful for students to keep their work for this unit in a science notebook to document their
work and their thinking.
Formative Assessment Task #1: Matching a Fossil with Past Environmental Conditions
Directions:
In this task, students individually respond writing to the following two prompts:
Prompt 1:
Students are given a sample of a fossilized horse (fossil replica and/or photo) with a HI of 1.9. They are
directed to write a scientific explanation answering the question: During which period would a horse with
this type of teeth be most successful?
Prompt 2:
Students are given a photo of an environment. They are directed to use their observations and what they
have learned about the relationship between horse teeth, environmental conditions and plant growth to
answer the question: What is the ideal HI (or tooth shape) for a horse that might have been successful in
this location?
Note: Prior to this formative assessment task student will have been provided with pictures of a changing
environment over time (i.e. Representative images of five geological epochs: Eocene, Oligocene, Miocene,
Pliocene, Pleistocene). Students use the photos to make observations about climate and plant life and identify
patterns over time. Next, students were given fossils (3-D models or images) from each representative time
period. Students sketch and make observations about relative size and complexity of each fossil (in this case, of
horse teeth). Students will record both qualitative and quantitative data and will use a mathematical process to
identify the “shape” of a tooth with the aid of calipers. Students are then given samples of plant material to
break down with a mortar and pestle (this acts as a model for chewing). Students record observations and make
notes about the differences in the breakdown of two different types of plant matter (leaves, grass). Students are
provided microscopic images of grasses so they can make observations about variations in silica content.
Evidence Statements:
Students will:
 Support claims with evidence in science notebooks that was collected during unit team investigations and
research
 Use reasoning to link multiple data sources (e.g. climate, tooth shape/size, plant material available and
difference in plant material, variation) to the evidence used for constructing their explanations.
 Use reasoning to relate shape or structure of tooth to function. (Examples: Compares shape of teeth to
different plant food sources. May refer to fiber and silica content of plants: leaves are soft and easy to
break down, whereas grasses contain silica-rich phytoliths or abrasive granules, which are difficult to
break down.)
Formative Assessment Task #2: The evolution of horse teeth
Directions:
In this task teams of students will measure fossils of six teeth from the Oligocene horse population (horse teeth
from one dig site in the Oligocene) and compare variation within that group. They will create a data table to
display the information collected. Lab groups then present their findings and explain a plausible mechanism for
the variation they observed. Students will use the data they team collected construct a scientific explanation
answering the question: How can individual horses of the same species end up with different tooth shapes/sizes.
After completing the investigation individuals will be asked to respond to the following prompt:
“Using a population other than horses, summarize the process of natural selection. Be sure to include a
description of the four key components (i.e. Darwin’s 4 main ideas).
Note: Students will use the data they collect during this investigation in the summative component of this task
where they are expected to connect tooth features to a model the explains the impact of heredity and allele
frequency on potential reproductive success
Evidence Statements:
Team presentation:
 Data presented includes multiple variables: e.g. climate, tooth shape/size, plant material
available, variation.
 Explains the connection between horse tooth shape and genetics
 Explains relationship between tooth shape and survival advantages (ability to use plants
available as food source.)
 Scientific explanation includes:
A claim that is correct (based on evidence collected and understanding of process of
natural selection)
Evidence that is selected from data collected specifically supports claim
Reasoning which includes how the horse population is an example of the concept of
natural selection (organisms with traits suited to their environment will survive and
reproduce at greater rates than individuals who have less advantageous traits.)
Individual:
 Applies data and explanation about horse teeth to another population that has or is evolving
(bacteria, Galapagos finches, Rock Pocket Mouse)
 Uses understanding of Darwin’s theory of natural select to support inferences made about
environmental changes, hereditary changes and changes in trait frequency.
Task #3: Summative Assessment: Developing an Explanatory Model for the Evolution of Horses
(Phylogenetic Tree)
Student teams will apply information gathered during the unit and from the formative assessment components of
this task to construct a phylogenetic tree of horse evolution. This task is framed as a request from a
paleontologist, asking students to generate a more accurate representation of horse evolution to replace a
“flawed” version currently on display in a natural history museum. (Detailed information about this context,
including a rubric, can be found in the supplementary resources section of this document). Upon completion,
individual students will be expected to write a summary report describing the information and process the team
used to construct their model.
Note: This assessment task could target a different another species students have studied and/or researched.
Team Directions:
Part 1: Creation of initial model:
Provide teams of students with images of the 15 species (horses) and with the rubric. Direct students to
construct their initial phylogenetic displays on whiteboards or chart paper using cards, tape, markers, etc.
Part 2: Whole class feedback:
Upon completion of the initial model, provide time for students to present their ideas to the class and engage in
a class discussion about the placement of species on various trees (see supplemental teacher background
information document for a sample script).
Part 3: Creation of final, revised model:
Direct student teams to regroup, discuss possible modifications inspired through the peer review process, and
create a final phylogenetic tree on chart paper for posting/sharing.
Part 4: Individual Reports:
Students will individually write a report to the paleontologist that requested this project. The report will:
 Describe the process used for developing the model
 Provide evidence supporting the models design and structure
 Describe how the model can be used to explain the process of evolution to others
 Explain how the model can be used to make predictions.
Evidence Statements:
 Incorporates multiple pieces of evidence gathered during unit (e.g. climate, tooth shape/size,

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






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plant material available, variation).
Identifies patterns of HI increasing over long time periods.
Applies data to make inferences about environmental change.
Applies data to make inferences about changes in trait frequency in a population.
Uses a model to predict responses to specific environmental changes.
Makes connections to scientific principals of genetics
Includes description of how with traits suited to their environment will survive and reproduce at
greater rates than individuals who have less advantageous traits.
Branches of model are consistent with inference that populations which survived also
reproduced.
Dead-end branches of the model represent species that were unable to evolve in response to
change.
Links changes in environment and/or another population to the appearance or extinction of a
species.
Describes how feedback was used to refine model
CheckBric for Exploring Evolution Performance Assessment Task:
Constructs Scientific Explanations
1 2
3 4
Comments

Use quantitative and qualitative evidence about horse
teeth and environmental conditions to match fossil
samples with the appropriate time frame.
 Use measurements and other evidence to explain how
horses of the same species could have had different
shape and size teeth.
 Use evidence collected about changes in horse teeth,
climatic conditions and plant availably to construct and
explanatory and predictive model for horse evolution.
 Apply understanding of genetics and natural selection to
make connections between claims about observed
changes in horse teeth and the evolution of horses over
time.
Demonstrates an understanding of phylogeny.
1
2
3
4
Comments
1
2
3
4
Comments

Correlates the changes in dentition with chemical
differences in available vegetation.
 Infers that tooth shape and size have a genetic
component.
 Proposes that organisms with traits suited to their
environment will survive and reproduce at greater rates
than individuals who have less advantageous traits.
 Infers that branches that continue to present consist of
populations that not only survived, but also reproduced.
 Infers that dead-end branches represent species that
were unable to evolve in response to change.
Applies cause effect relationships.




Explanations describe cause and effect relationship
between changes in physical characteristics (tooth
shape and size) and environmental conditions (plant
availability and climate)
Measurements comparing size and shape or horse teeth
are used to support claims and inferences made in
development of explanatory model.
Alternative explanatory models that are supported by
evidence and reasoning are accepted
Uses data to propose a cause and effect relationship
between physical variations and fitness.
4 Exemplary
3 Proficient
2 Developing
Work at this level is of exceptional quality. It is both thorough and accurate. It exceeds the
standard. It shows a sophisticated application of knowledge and skills.
Work at this level meets the standard. It is acceptable work that demonstrates application of
essential knowledge and skills. Minor errors or omissions do not detract from the overall
quality.
Work at this level does not meet the standard. It shows basic, but inconsistent application of
knowledge and skills. Minor errors or omissions detract from the overall quality. Your work
1 Emerging
needs further development.
Work at this level shows a partial application of knowledge and skills. It is superficial (lacks
depth), fragmented or incomplete and needs considerable development. Your work contains
errors or omissions.
Teacher Background Information:
In the horse fossil example, the changing climate and subsequent changing vegetation types created
conditions that favored different dentition (e.g. large HI, or “longer” tooth which is more durable for
grinding grasses). Individuals with more favorable dentition are more likely to live longer and therefore
produce more offspring, which may lead to an increase in the frequency of “fit” alleles in the overall
population.
As part of the ongoing unit (before or between formative tasks and summative task) the teacher should
provide additional examples of other populations that have undergone natural selection (through direct
instruction and/or through student research.) These could include:
 Reading selections about the Galapagos finches
 A video about a population such as the Rock Pocket Mouse
(http://www.hhmi.org/biointeractive/making-fittest-natural-selection-and-adaptation)
 Articles about resistant populations such as bacteria or pests
During class discussions teachers should use “Talk Moves” such as the ones below to surface student
thinking rather that provide information directly.
Sample Script:
Suggested guiding questions for teacher to use during peer review and class discussion of initial
versions of model created as part of Task Component #3 (Summative Component):
Direct students to do a gallery walk (listen carefully to team presentations.) prior to the class
discussion and to compare the models their classmates to the one they created and to each other. Ask:
 “What are some similarities? What are some differences? What is the most striking
difference between ___ and ___?”
 “Why did you choose to put this species here?”
 “Why did this branch end?”
 “These species lived during the same time period. Why did you place them in separate
lines?”
 “How did you use teeth measurements in your placement of the species?”
 “Did all teams link the type of plants to the species type in the same way? Explain.”
 “[___], how does your tree compare to [__]’s groups? Do you have the same number of
branches?”
 “When the environment changed, what happened to the horse teeth? What was the cause
of this? How did you show when you displayed your data?”
 “What changed between [this time period] and [this time period]? What else changed?
Did this impact anything else? What/how?
Authors:
Andrea Brook, Lake Orion High School; Rebecca Brewer, Troy High School
Anne Jeannette Lasovage, Southfield High School