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Results for: 'living cells'
Cellular slime mold life cycle Animation
By: HWC, Views: 873
Life cycle of Dictyostelium discoideum, a cellular slime mold Animation. Amoeba-like slime mold cells live in the soil, where they feed on bacteria. The free-living cells grow and reproduce by mitosis. When food dwindles, the amoebas stream toward one another in response to a chemical...
Evolutionary tree of life Animation
By: HWC, Views: 286
An evolutionary tree of life that reflects mainstream thinking about the connections among major lineages (bya = billions of years ago, mya = millions of years ago). By about 3.8 billion years ago, chemical and molecular evolution had produced the first living cells. The first major divergenc...
Darwin's Observation (Fossils, Galapagos Islands & Africa ) and Natural Selection (Adaptive Traits)
By: HWC, Views: 6558
Along Darwin's voyage, he made many observations. Each one added to his understanding of how organisms change over time. Darwin was already familiar with fossils and knew that many fossils were very different from living organisms. But, also there were some fossils that were very similar to li...
By: HWC, Views: 6517
An ecosystem is a community of organisms and their environment. The community forms the living component of the ecosystem. These are called the 'biotic' factors, which means all of the living things in the ecosystem. The environment forms the nonliving component of the ecosystem, such as ...
Global warming and its effect on climate change
By: HWC, Views: 6301
Global warming, habitat destruction, and pollution are all hot topics in the news. Environmentalists are concerned that many of these factors will lead to the loss of species. But how will this happen? One way to think about the environment is as a finely-tuned, high performance engine. If one...
By: Administrator, Views: 9646
A wound is an injury to living tissue caused by a cut, blow, or other impact, typically one in which the skin is cut or broken.
Vascular tissues in a corn stem and a buttercup root
By: HWC, Views: 1153
Vascular tissues in a corn stem and a buttercup root. The cells that make up each tissue. Xylem conducts water and dissolved ions. It also helps mechanically support a plant. The cells, called vessel members and tracheids, are dead at maturity. Their lignified walls interconnect and serve as p...
Diversity of Living Creatures - Charles Darwin & the Beagle's Voyage
By: HWC, Views: 6386
As we look around at the living creatures on Earth, we see a great amount of diversity. In some cases, the differences are quite noticeable, like the differences between plants and animals. Some differences are not as easy to see, like the differences between two species of lizard. How did all...
By: HWC, Views: 3786
In the late 1920s, Fred Griffith was attempting to develop a vaccine against a bacterium that causes pneumonia. To find out why two strains of the bacteria differed in their deadliness, he injected mice with four different mixtures. Mice injected with R cells remained healthy. When Griffith ex...
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