Group items tagged

CK-12 Biology I is a textbook for high school students covering cell biology, genetics, ev....

The Tree of Life Web Project (ToL) is a collaborative effort of biologists and nature enthusiasts from around the world. On more than 10,000 World Wide Web pages, the project provides information about biodiversity, the characteristics of different groups of organisms, and their evolutionary history (phylogeny).

Comparing ribosomal RNA base sequences, Woese and his colleagues also showed that organisms belonging to Eukarya are more similar to Archaea than they are to Bacteria. Figure 6 is a phylogenetic tree based on their analysis. This tree places Archaea and Eukarya in the same clade (see Lesson 2). It represents the hypothesis that Archaea and Eukarya shared a more recent common ancestor with each other than with Bacteria.

A SYNAPSE is a minute gap between nerve cells which transmits crucial information through the nervous system. The goal of this network is to perform a similar "synaptic" function between biology instructors of all levels and locations. Step one in participation within The Synapse: read & explore. Step two: share. Be a resource. Help to create a synapse that communicates in both directions!

Pedagogiskt godis

Nu när kunskapsområdet är avslutat följ: Wikipedia artiklarnas historik - hur ändras det eleverna skrev? Zomma in över platserna i Google Earth och se bilder ev. någon film som beskriver naturreservatet. Obs troligtvis finns inte bilder och filmer i Google Earth förrän ca 10/6. Läs om kunskapsområdet här i wikispaces

Tools: The Fossil Record, Aging the Ages, and Molecular Clocks By age three, you probably knew that dinosaurs are part of the history of life. Our understanding of where they belong in the tale is relatively recent, but “dragon bones” have been known for thousands of years in China and Europe. Fossils are preserved remains or traces of organisms that provide extremely rare but vivid windows to the past. Because most parts of organisms decompose rapidly following death, fossilization is an exceptionally uncommon occurrence, and usually preserves only hard body parts, shown in Figure below. Remains must be covered by sediment almost immediately. Buried organisms may experience mineralization (occasionally even within cells), or they may decay, leaving a space within the sediment later replaced with rock. Alternative pathways to fossilization include freezing, drying, trapping in resin (amber) or burial in anoxic (oxygen-free) environments. Trace fossils preserve footprints, burrows, droppings, eggs, nests, and other types of impressions. Overall, a great variety of types of fossils reveal the history of life, shown in Figure below.

A Geologic Time Scale Measures the Evolution of Life

Patterns and Processes of Macroevolution