The new vaccine Gardasil protects against the cancers caused by both HPV types. One ancient louse egg has been found attached to a strand of hair 10, years old.
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The flat, wingless insects are tiny between one and two millimeters long—less than a tenth of an inch , suck on human blood, and cement their eggs, or nits, to our hair. The dominant species in this dental plaque are Streptococcus sanguis and S. Even if you brush diligently, these bacteria will still be there: They arrive soon after your teeth do and stay until they fall out. The bacteria ferment sugars and secrete gluey polymers that form the basis of plaque.
Demodex mites—cigar-shaped, stumpy-legged parasites about 0. They are more likely to infect us as we age, so nearly all elderly people carry them. Stress, aging, or a weakened immune system may reactivate the virus, which can then slink along nerve tracts, causing persistent pain and nasty skin rashes—a condition known as shingles. Research suggests that widespread vaccination against chicken pox, now common in the United States, may lead to a significant increase in shingles among the elderly.
According to epidemiologist Prescott Deininger of Tulane University, these and other parasitical, self-replicating pieces of DNA have evolved with us and can insert copies of themselves into our genome, leading to mutations that may cause new genetic diseases. The most common include staph, Streptococcus , and Corynebacterium , which metabolize sweat to produce body odor. Microbiologist Martin Blaser of the New York University School of Medicine sequenced the DNA of bacteria from the forearms of six people and discovered separate species of bacteria.
Organisms exposed to climate conditions outside their normal range must adapt or migrate, or they will perish. There are 4 more fundamental concepts.
Your Body Is a Planet
The presence of small amounts of heat-trapping greenhouse gases in the atmosphere warms Earth's surface, resulting in a planet that sustains liquid water and life. Changes in climate conditions can affect the health and function of ecosystems and the survival of entire species. The distribution patterns of fossils show evidence of gradual as well as abrupt extinctions related to climate change in the past. A range of natural records shows that the last 10, years have been an unusually stable period in Earth's climate history. Modern human societies developed during this time.
The agricultural, economic, and transportation systems we rely upon are vulnerable if the climate changes significantly. Life—including microbes, plants, animals and humans—is a major driver of the global carbon cycle and can influence global climate by modifying the chemical makeup of the atmosphere. The geologic record shows that life has significantly altered the atmosphere during Earth's history. Life affects the composition of the atmosphere and therefore the climate because different life forms take in and release gases like carbon dioxide, methane and oxygen at different rates.
Climatic conditions help to shape various ecosystems and habitats around the globe. A particular climate can be a boon to one species and a devastation to another. As the climate changes, species and ecosystems respond by adapting, migrating, or reducing their population.
Gradual shifts in the climate are easier to adapt to than abrupt swings, and this is certainly true for humans as well as other species. Studies of Earth's climatic history indicate that climates have changed in the past and resulted in dramatic shifts in ecosystems.
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The most recent geological period the Holocene about last 10, years , however, has been unusually stable. Like much of climate science, these concepts span multiple scientific disciplines. Teaching these ideas is a way to illustrate how scientific thinking benefits from sharing expertise among different types of scientists. This topic can be introduced by brainstorming for conditions that are needed for life to thrive.
Students can explore how life exists in many parts of the earth system, such as in the depths of the oceans or in acidic hot springs. Life is robust and versatile.
3. Climate and Life
Domain Bacteria — prokaryotic , consists of prokaryotic cells possessing primarily diacyl glycerol diester lipids in their membranes and bacterial rRNA, no nuclear membrane, traditionally classified as bacteria. Most of the known pathogenic prokaryotic organisms belong to bacteria see  for exceptions , and are currently studied more extensively than Archaea.
Some examples of bacteria include Cyanobacteria photosynthesizing bacteria that are related to the chloroplasts of eukaryotic plants and algae, Spirochaetes — Gram-negative bacteria that include those causing syphilis and Lyme disease, and Actinobacteria -- Gram-positive bacteria including Bifidobacterium animalis which is present in the human large intestine.
Domain Eukarya — eukaryotes , organisms that contain a membrane-bound nucleus. An inexhaustive list of eukaryotic organisms includes:. Each of the three cell types tends to fit into recurring specialties or roles.
- Outline of life forms.
- Dirty (Mills & Boon Spice).
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- Three-domain system?
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Bacteria tend to be the most prolific reproducers, at least in moderate environments. Archaeans tend to adapt quickly to extreme environments, such as high temperatures, high acids, high sulfur, etc. This includes adapting to use a wide variety of food sources. Eukaryotes are the most flexible with regard to forming cooperative colonies, such as in multi-cellular organisms, including humans.
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In fact, the structure of a Eukaryote is likely to have derived from a joining of different cell types, forming organelles. Parakaryon myojinensis incertae sedis is a single-celled organism known by a unique example. He claims that sequences of features and phylogenies from some highly conserved proteins are inconsistent with the three-domain theory, and that it should be abandoned despite its widespread acceptance.