Science Re-Focus Lesson
Grade: 8
Goal/Objective(s): 5.01
Directions:
The teacher will begin the lesson by asking students what a species is. Answers will vary, but students should be able to say that a species is a group of organisms that share similar characteristics and are able to produce viable young together. The teacher will ask students to list some common species (humans, dogs, cats, goldfish, live oak trees, azaleas, etc.).
Next, the teacher will write the key terms for today’s lesson on the board (species, extinction and evolution). If the students know the definitions of any of these terms already, they can be
discussed as a class.
The teacher will then have the students silently read the outline on the Student Handout. The students will circle or highlight
important terms as they read. When the students have finished, the teacher will re-read the outline out loud and review the meaning of each bold-faced term.
The teacher will then have the students complete a “Three Way Tie” for the terms species, extinction and evolution (see Teacher Guide).
Extension: The students will participate in the “Extinction Demonstration” activity (see Teacher Guide).
Essential learning(s):
How does extinction of a species lead to evolution?
Attachments included:
Student Handout Teacher GuideEquipment/Supplies
needed:
PencilNote cards (1 per student)
Assessment Directions:
On a note card, the students will write down two things they learned from today’s lesson and two questions they still have about today’s lesson. They will give their note cards to the teacher before they leave class.Evolution – Student Handout
I.
Species
– A group of organisms that are able to produce offspring that are healthy
and capable of reproducing together.
a.
Examples of different species:
i.
_______________________
ii.
_______________________
II.
Evolution
– A change in the inherited traits of a species from one generation to the
next.
a.
Because every organism has unique DNA, some organisms within a species are
better suited for certain environmental changes than others.
b.
Organisms within a species that are not well suited for a certain environment
will not survive.
c.
The result is that the characteristics of a species will change when the
environment changes.
d.
If all of the organisms within a species are unable to adapt to an
environmental change, the species will become
extinct
.
i.
Extinction
– When all of the organisms within a species die.
III.
Scientists who studied evolution
a.
Gregor Mendel (“Father of Genetics”) – Studied how traits were passed from
one generation to the next in pea plants.
b.
Charles Darwin – Studied how organisms within a species change when they
move to new environments.
IV.
Proof that organisms change over time
a.
Fossils – prove that the types of organisms on Earth have changed throughout
history (example – dinosaurs)
b.
Rocks – prove that the Earth’s plates have moved over time, which impacts
the environments in which organisms live (example – there are sea shell fossils
in the rocks on Mt. Everest)
Three-way Tie
– In the graphic organizer below, write the definition for the terms in the
boxes provided. On the lines connecting the terms, describe how the terms are related.
Species ‐ ____________________
___________________________
___________________________
Extinction ‐ __________________
___________________________
___________________________
Evolution ‐ __________________
___________________________
Evolution – Teacher Guide
I. Species – A group of organisms that are able to produce offspring that are healthy and capable of reproducing together.
a. Examples of different species:
i. humans, blue whales, dogs, dogwood trees ii. grey squirrels, white tailed deer
II. Evolution – A change in the inherited traits of a species from one generation to the next. a. Because every organism has unique DNA, some organisms within a species are better
suited for certain environmental changes than others.
b. Organisms within a species that are not well suited for a certain environment will not survive.
c. The result is that the characteristics of a species will change when the environment changes.
d. If all of the organisms within a species are unable to adapt to an environmental change, the species will become extinct.
i. Extinction – When all of the organisms within a species die.
III. Scientists who studied evolution
a. Gregor Mendel (“Father of Genetics”) – Studied how traits were passed from one generation to the next in pea plants.
b. Charles Darwin – Studied how organisms within a species change when they move to new environments.
IV.Proof that organisms change over time
a. Fossils – prove that the types of organisms on Earth have changed throughout history (example – dinosaurs)
b. Rocks – prove that the Earth’s plates have moved over time, which impacts the environments in which organisms live (example – there are sea shell fossils in the rocks on Mt. Everest)
c. Ice cores – when scientists drill into polar ice caps, there is evidence that the climate has changed throughout Earth’s history. Climate change impacts the
Three-way Tie – In the graphic organizer below, write the definition for the terms in the boxes provided. On the lines connecting the terms, describe how the terms are related.
1) Relationship between species and evolution – Evolution is a process that describes how a species changes over time.
2) Relationship between species and extinction – Extinction is when a species completely disappears.
3) Relationship between extinction and evolution – Extinction is what happens when an organism doesn’t evolve.
Species – A group of organisms
that are able to produce offspring that are healthy and capable of reproducing
Extinction ‐ When all of the
organisms within a species die
Evolution – A change in the
Extension: Evolution Demonstration
The teacher will tape 10 red circles and 10 blue circles on the board. She will also tape 5 red flowers and 5 blue flowers on the board. A bird image should be drawn on the board near the flowers and circles.
The teacher will tell the students that each circle represents a Dot Bug. Dot bugs are found in tropical regions of the world. Within the Dot Bug species there is a color variation which leads to some Dot Bugs having a blue pigment and some having a red pigment. Half of the species is red and half of the species is blue.
Blue pigmented Dot Bugs live in the flowers of Blue Bell plants and Red Dot Bugs live in flowers of Royal Red plants. The teacher will emphasize this by placing the red Dot Bugs on the red flowers and the blue Dot Bugs on the blue flowers. The teacher will ask how this arrangement may benefit the Dot Bugs. The teacher will also explain that the bird eats both red and blue Dot Bugs. (The benefit is that red and blue Dot Bugs are camouflaged when on their respective flowers).
The teacher will then explain that a recent climate change has caused the Blue Bell plants to become less plentiful. She will demonstrate this by removing three of the blue flowers. The blue Dot Bugs that had been on those flowers will be displaced. Some can be put on the red flowers and some can be taped on the board. The teacher will ask students how this will affect the blue Dot Bugs.
