Catalyst #3: September 12, 2013 (5 minutes)
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Catalyst #3: September 12, 2013(5 minutes) African elephants typically have large tusks. The ivory in the tusks is highly valued by some people, so hunters have hunted and killed elephants to tear out their tusks and sell them (usually illegally) for decades. Some African elephants have a rare trait -- they never develop tusks at all. In 1930, about 1 percent of all elephants had no tusks. Tuskless elephants are not valuable to hunters, so they are not killed. Meanwhile, elephants with tusks were killed off by the hundreds, many of
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Catalyst #3: September 12, 2013 (5 minutes). - PowerPoint PPT Presentation
Transcript of Catalyst #3: September 12, 2013 (5 minutes)
Catalyst #3: September 12, 2013(5 minutes)
African elephants typically have large tusks. The ivory in the tusks is highly valued by some people, so hunters have hunted and killed elephants to tear out their tusks and sell them (usually illegally) for decades. Some African elephants have a rare trait -- they never develop tusks at all. In 1930, about 1 percent of all elephants had no tusks. Tuskless elephants are not valuable to hunters, so they are not killed. Meanwhile, elephants with tusks were killed off by the hundreds, many of them before they ever had a chance to reproduce. Describe how African Elephants are evolving using the four principles of natural selection. (Hint: What are the different traits? Which is better? What will all the elephants have in time?)
Catalyst
. The result: As many as 38 percent of the elephants in some modern populations have no tusks [source: BBC News]. Unfortunately, this isn't really a happy ending for the elephants, since their tusks are used for digging and defense.
Agenda Catalyst: (5 minutes) Natural selection video (5 minutes) Natural Selection Review (5 minutes) Natural Selection Pom Pom Simulation (15
minutes) Adaptation & Natural Selection Review (10
minutes) Homework:
Adaptations & Natural Selection HW Study for Adaptations and Natural Selection
quiz
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Unit 3: Guiding Questions
What determines which organisms survive and which do not?
Do species ever change?How do scientists believe all of the
species that exist today were formed?
What evidence is there to support evolution?
Today’s SPI and Objectives
SPI 3210.5.3 Recognize the relationships among environmental change, genetic variation, natural selection, and the emergence of a new species.
SWBAT explain the idea of evolution by natural selection in their own words
SWBAT describe the role of genetic variation and adaptation in the process of evolution by natural selection
SWBAT identify examples of natural selection and explain how they demonstrate natural selection
Adaptations & Natural Selection Review
BiologyUnit 3Section 15.1
http://app.discoveryeducation.com/search?Ntt=natural+selection
Natural Selection and Adaptations SWAT Adaptation
Genetic Variation
Favorable trait
Camouflage
Mimicry
Natural Selection
What is Evolution?
Evolution is the gradual change in a population of organisms over time
One of the main ways evolution occurs is through natural selection Who developed this concept?
Natural Selection 4 main principles of natural
selection: All organisms have different traits
due to genetic variation Not all organisms can survive, so
organisms with adaptations survive and reproduce
Surviving organisms reproduce and pass on genes for their adaptations
Eventually all organisms inherit the adaptations
Examples
Deer mice in Sandyhill, Nebraska Dark brown light brown
Pesticide-resistant insects Not resistant Resistant
Peppered moths in England Light moths Dark moths
(then back to light
Pom Poms 1. We will be split into two using two
different habitats: Black Forest and RedGrassland .
2. Pompoms come in two colors: black and red. I will scatter an equal number of each color on the Black Forest and on the RedGrassland. Which color pompom do you
think will be more likely to survive in each habitat?
Pom Poms Cont.
You are Pom Pom hunters! There are two different types of feeding structures: forks and spoons.. You will also be given a cup. This cup will serve as your “stomach”. To capture a pompom, you must use only your fork or spoon to lift the pom pom from the habitat and put it into your cup. Which feeding structure do you think will
do better in each habitat?
Your job is to “eat” as many Pom Poms as possible!!
Expectations
Do not shovel Pom Poms into your stomach!
Only start feeding when I say GO and stop IMMEDIATELY when I say stop!
Do not steal other people’s Pom Poms!
Pom Poms
1. Which of the feeding instruments was best at catching Pom Poms?
2. If the only food that the hunters had to eat in their environment were Pom Poms, which type of hunter would be most likely to survive over time?
3. Which Pom Poms were easiest to catch in the Black Forest? In the Red Grassland? Why?
4. Over time, which type of Pom Pom would be most likely to survive in the Black Forest? In the Red Grassland?
Adaptations and Natural Selection Homework Begin working independently on
your homework. This will help you study for your quiz
tomorrow. WRITE ON A SEPARATE SHEET OF
PAPER. DUE TOMORROW!
Exit Ticket
Answer the questions on the back of your bell-work sheet
1. Explain natural selection in 1-2 sentences
2. It is possible that at one time lizards of all different colors lived in the desert. Explain how natural selection resulted in all desert lizards being tan in color.
