Bed Bugs on the Rise
Saturday January 10, 2009
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Bed bug |
Instances of bed bug infestations have been on the rise in all types of residences in urban areas. That includes homes, hotels, and apartments. What are bed bugs? They are parasitic insects that feed on the blood of humans and other warm-blooded organisms.
Researchers believe that this rise is due to the development of resistance in certain bed bugs to pyrethroid insecticides. These insecticides work by attacking the nervous system of the bugs causing paralysis and death. It seems that certain bed bug populations, in particular those in urban areas, have developed mutations in their nerve cells that have allowed them to become immune to these insecticides.
Learn more about this study, see:
Saturday January 10, 2009
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Endangered Florida Panther USFWS photo by John & Karen Hollingsworth |
Endangered species are animals and plants that are on the verge of vanishing from the earth. These species have become endangered due to habitat loss, exploitation, or habitat disturbance.
It is important for us to preserve these plants and animals not only because of their intrinsic beauty, but because they provide valuable services in nature. These organisms clean air, regulate our weather and water conditions, provide control for crop pests and diseases, and offer a vast genetic source from which we can develop many useful items.
Some organisms that are on the U.S. Threatened and Endangered Species List include the grizzly bear, gray wolf, black lace cactus, and green sea turtle.
Thursday January 8, 2009
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Onion cell in anaphase. © The Entangled Bank |
Mitosis, a form of cell division, enables organisms to grow and reproduce. Dividing cells go through an ordered series of events called the cell cycle.
In anaphase, the paired chromosomes (
sister chromatids) separate and begin moving to opposite ends (poles) of the cell. Spindle fibers not connected to chromatids lengthen and elongate the cell.
Once the paired sister chromatids separate from one another, each is considered a full
chromosome. They are referred to as
daughter chromosomes.
In preparation for the next stage of mitosis,
telophase, the two cell poles also move further apart during the course of anaphase. At the end of anaphase, each pole contains a complete compilation of chromosomes.
Learn more about mitosis:
Saturday January 3, 2009
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Photo: USFWS |
Temperate forests are areas with high levels of precipitation and humidity. These forests also contain a variety of deciduous trees. Deciduous trees lose their leaves in winter.
Due to abundant rainfall and thick soil humus, temperate forests are able to support a wide variety of vegetation. These forests are also home to a wide variety of animals.
Temperate forest animals have many different ways to deal with the cold and lack of food in winter. Some animals hibernate during the winter and arise in spring when food is more plentiful. Other animals store food and burrow underground to escape the cold.
Temperate forests can be found in several locations around the globe including eastern Asia, central and western Europe, and the eastern United States.
Learn about other biomes: