New Mexico SBA Science
Nature of Science
Physical Science
Life Science
Earth Science
Science and Society
Scientific Method
• You will need to design an experiment.
“Why is that plant bigger than the others?” The Problem
1. Create a possible solution. Hypothesis
That plant gets more water. If I gave the other plants more water they would grow
bigger. A Prediction
2. Design a test. The Experiment.
Get several plants, (must be the same kind of plant.)
Provide the same soil and water and temperature to every plant.
Every plant is treated the same. The Controls
Provide some plants with more light than the other plants and measure the growth.
The Variable.
3. Measure the size of the plants. The Data
4. Determine if the amount of light made a difference in plant growth. The Analysis
Natural Selection, how species change and new species arise.
• Organisms create too many offspring because…
• There are limited resources (food, water, space), this causes competition…
• In a species there are variations, they are not identical…
• The organisms that have the “best” traits survive
• They reproduce, have babies..
– These babies are like their parents.
Differences from year to year can build up so that eventually an organism is
different from it’s ancestors. A new species
Peppered Moth
•
Peppered moths have colors from light to
dark. Variations.
•
The trees were light so dark moths were
easier to see by the predators.
•
The industrial revolution stained the trees
dark, soot from burning coal. Light moths
were easier to see by the predators.
•
The population became dark with few light
moths.
•
Today the trees are returning to their light
appearance and the population is changing.
Roundup resistant weeds, natural selection
Roundup is a herbicide, plant killer. When
it first was used it killed all plants.
The company made corn resistant to
roundup. Spray a field, no weeds only
corn.
Today there are plants that roundup does
not kill, these are new kinds of plants.
Variation in weeds.
Spray chemicals that kill weeds. Selection
Survival of resistant types, new plant
Artificial Selection, dairy cows
• Cattle were domesticated by man long ago.
• Some cows made more milk than other cows. Variation
• Man kept the “good” milk cow and used it to make more
“good” milk cows. Selection
• Different types of cattle created by artificial selection