The Scientific Method. The Scientific Method For centuries, people based their beliefs on their interpretations of what they saw going on in the world around them without testing their ideas to determine the validity of these theories — in other words, they didn’t use the scientific method to arrive at answers to their questions. Rather, their conclusions were based on untested observations. Among these ideas, since at least the time of Aristotle (4th Century BC), people (including scientists) believed that simple living organisms could come into being by spontaneous generation. This was the idea that non-living objects can give rise to living organisms. Observation: Every year in the spring, the Nile River flooded areas of Egypt along the river, leaving behind nutrient-rich mud that enabled the people to grow that year’s crop of food.
Observation: In many parts of Europe, medieval farmers stored grain in barns with thatched roofs (like Shakespeare’s house). Question: Hypothesis: Prediction: Testing: Data: The real process of science. The process of science, as represented here, is the opposite of "cookbook" (to see the full complexity of the process, roll your mouse over each element). In contrast to the linear steps of the simplified scientific method, this process is non-linear: The process of science is iterative.Science circles back on itself so that useful ideas are built upon and used to learn even more about the natural world.
This often means that successive investigations of a topic lead back to the same question, but at deeper and deeper levels. Let's begin with the basic question of how biological inheritance works. At first this process might seem overwhelming. Experimental Designs. Living Things: Habitats & Ecosystems. Mbl. Trending Publications Schmitz, OJ; Raymond, PA; Estes, JA; Kurz, WA; Holtgrieve, GW; Ritchie, ME; Schindler, DE; Spivak, AC; Wilson, RW; Bradford, MA; Christensen, V; Deegan, L; Smetacek, V; Vanni, MJ; Wilmers, CC. 2013. Animating the Carbon Cycle. Ecosystems 1-16, doi: 10.1007/s10021-013-9715-7. Cardon, ZG; Stark, JM; Herron, PM; Rasmussen, JA. 2013.
Sagebrush Carrying Out Hydraulic Lift Enhances Surface Soil Nitrogen Cycling and Nitrogen Uptake into Inflorescences. Clark, JS; Melillo, JM; Mohan, J; Salk, C. 2014. Ocean Ecosystems, Ocean Animals, Ocean Life -- Smithsonian Institution | Ocean Portal | Smithsonian. The Antarctic Ecosystem. Evolution: Survival: Coral Reef Connections. World Population | POPULATION. Disclaimer Due to their size, the following countries and territories are not represented on the map: Faro Island, Denmark; Gibraltar; Hong Kong SAR; Liechtenstein; Maldives; Monaco; San Marino; Seychelles; St.
Helena Island; and Vatican City. Notes The Data Sheet lists all geopolitical entities with populations of 150,000 or more and all members of the UN. Sub-Saharan Africa: All countries of Africa except the northern African countries of Algeria, Egypt, Libya, Morocco, Tunisia, and Western Sahara. World and Regional Totals: Regional population totals are independently rounded and include small countries or areas not shown. World Population Data Sheets from different years should not be used as a time series.
Sources. The Habitable Planet - Demographics Lab - Overview. 2010 Census Interactive Population Map. Human Numbers Through Time. By Susan K. Lewis Posted 04.20.04 NOVA For most of human existence our ancestors led precarious lives as scavengers, hunters, and gatherers, and there were fewer than 10 million human beings on Earth at any one time. Today, many cities have more than 10 million inhabitants each, and populations continue to skyrocket. Trace the dramatic growth of human populations over recent centuries on our global map, and see where on Earth as many as three billion more people may live by 2050.
Note on Graphics The global map was adapted from World Population: A Graphic Simulation of the History of Human Population Growth, a 2003 video produced by Population Connection (www.populationconnection.org). In the map, each dot represents a million people. When areas become super-populated, as they begin to do in certain parts of the world in the 20th century, the dots merge and spread outward like a stain. Illustrations (all) Cofrin Center for Biodiversity. Next NAS Seminar is Friday, April 11, 2014 How do scientists study how molten rock intrusionsgrows? Dr. Ryan Currier, geologist and Associate Professor of Geosciences in the NAS department, will be discussing his work modeling these systems in "The Flowering of Magma Bodies in the Crust".
Social @ 3:15 pm in ES 317 -- Lecture @ 3:45 pm in ES 301, note time change. Save the Date for the Heirloom Plant Sale Seed catalogs have arrived and we are busy planning for this year's sale to be held on May 17th 9-3 in the Lab Sciences Greenhouse. Visit our Heirloom pages for more information and to find out what will be for sale and to get email updates and plant lists. A new tool for measuring forest health! Biodiversity data manager Erin Giese, along with NAS faculty, and TNC staff have developed a a new rigorous, transparent tool for measuring forest health in northern mesic forests of the western Great Lakes region based on local breeding bird assemblages.
Traits of Life: Exhibits: Cell Explorer. Microscope Imaging Station. Stem Cells: Cells with Potential. What are stem cells? Your body contains over 200 types of cells, each with a specific job: blood cells carry oxygen; muscle cells contract so that you can move; nerve cells transmit chemical signals. The job of a stem cell is to make new cells. It does this by undergoing an amazing process—differentiating, or changing into another type of cell. Each time a stem cell divides, one of the new cells might remain a stem cell while the other turns into a heart, blood, brain, or other type of cell.
In fact, stem cells are able to divide to replenish themselves and other cells without any apparent limit. Stem cells are the source, or “stem,” for all of the specialized cells that form our organs and tissues. Next: Why invest so much in studying stem cells? Concepts in Biochemistry - Interactive Animations. Cell Models: An Interactive Animation. Nucleolus: The prominent structure in the nucleus is the nucleolus. The nucleolus produces ribosomes, which move out of the nucleus and take positions on the rough endoplasmic reticulum where they are critical in protein synthesis.
Cytosol: The cytosol is the "soup" within which all the other cell organelles reside and where most of the cellular metabolism occurs. Though mostly water, the cytosol is full of proteins that control cell metabolism including signal transduction pathways, glycolysis, intracellular receptors, and transcription factors. Cytoplasm: This is a collective term for the cytosol plus the organelles suspended within the cytosol. Centrosome: The centrosome, or MICROTUBULE ORGANIZING CENTER (MTOC), is an area in the cell where microtubules are produced.
During animal cell division, the centrioles replicate (make new copies) and the centrosome divides. Centriole (animal cells only): Each centriole is a ring of nine groups of fused microtubules. Welcome to Evolution 101! Evolution.