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