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    One of the most important ideas of science, as described in our textbook, is evolution. The general belief in the modern scientific community is that macro evolution certainly exists; what some do not realize is that there are logical and … Keep Reading

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    Northern Leopard Frog Tadpole (Lithobates pipiens)Image from Wikimedia Commons

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    Though genetic engineering had helped many plants become pest-resistant on the field, the same could not be said for crops in storage units. This was a concern for Maarten Chrispeel, T.J. Higgins, and Larry Murdock, who knew that the problem … Keep Reading

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    Philippine Tarsier (Tarsius syrichta)Image from Wikimedia Commons Read more about this species here.

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    At BVNW there are many science courses to take. Last year I took anatomy and I remember Ritu, Caleb and other people who were seniors already knew a lot of the difficult concepts we were learning in anatomy. At that … Keep Reading

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  • 10/10/17--05:01: Stay Thirsty My Friends
  • Many people know that water is considered the molecule of life and that every organism needs water to survive. There is a saying that “there is no such thing as too much of a good thing.” However drinking excess amounts … Keep Reading

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    Blue-fronted Amazon (Amazona aestiva)Image from Wikimedia Commons

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    What is cell suicide? At the cellular level, death is important and vital for life. We have discussed in class about the lipids and the proteins that make up the membranes in cells; and there is one of the membrane … Keep Reading

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    Chapter Nine: Cellular Respiration and Fermentation, although touched upon during Honors Biology in ninth grade, continues to leave mixed emotions within me. Cellular respiration is a metabolic pathway used by plants, animals, and humans to create usable energy called ATP. … Keep Reading

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    One of the biggest concepts in biology is evolution, as shown in the textbook, and it all started when Charles Darwin published The Origin of Species over 150 years ago. There is compelling evidence that individuals with favorable traits are … Keep Reading

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    Dusky Torrent Frog (Micrixalus fuscus)Image from Wikimedia Commons

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    One important topic that we have studied this year in AP Biology is cellular respiration, the process by which living cells create energy, in the form of Adenine Triphosphate (ATP), for their own use. Damage or abnormalities in the mitochondria, … Keep Reading

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    Hippopotamus (Hippopotamus amphibius)Image from flickr Hippos may be cute, but don’t let that fool you, they can be very dangerous to humans. They use their large teeth which can be up to twenty inches long and their tusks to fight … Keep Reading

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  • 10/17/17--05:01: Don’t Stress TOO Much
  • You wake up on Monday morning and remember you have a math test that you didn’t study for. Conjointly, you also realize you had an essay to write but you completely forgot to write it in your planner. You’re extremely … Keep Reading

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    Brown Boobies (Sula leucogaster)Image from Wikimedia Commons

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  • 10/18/17--05:01: Reality, What’s That?
  • Schizophrenia is a chronic mental illness that begins to show its symptoms during early adulthood and lasts the rest of the patient’s life. The term ‘schizo’ in Greek means ‘splitting’ and the term ‘phrenia’ means ‘of the mind’, which accurately … Keep Reading

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    Image from Science Daily

    It’s fall! That means shorter days and cooler nights. And, in many parts of the United States, it means that trees are about to shed their leaves after a final colorful salute to summer.

    Did you know that a tree’s leaves are orange and yellow — even in summer? Most leaves include the pigments of all three colors. It’s just that the pigment chlorophyll (the pigment that makes the leaves green) is a much stronger pigment than the others. It covers the yellow (xanthophyll) and orange (carotene) pigments that are natural to a tree’s leaves. But, come fall, a tree’s leaves produce less chlorophyll. Now the other colors can show through in brilliant explosions of color!

    Another pigment (anthocyanin), which produces reds and purples, isn’t present all year long in most green leaves. It only shows up as the nights get cooler. In fall when trees are breaking down and reabsorbing important nutrients from their leaves, their photosynthetic tissues are especially unstable and vulnerable to too much light and other stresses. Yet trees need the energy from photosynthesis to drive the processes that allow them to recapture as many of those nutrients as possible. Just as this process begins, leaves start producing large amounts of anthocyanins near the leaf surface. Anthocyanin pigments protect the leaves’ dwindling ability to generate energy during this period.

    But why do leaves fall off the tree? The roots and branches of most trees are tough enough to endure freezing temperatures, but leaves are more susceptible to damage when the water inside them solidifies and expands. This kind of damage to living tissues can expose a tree’s internal plumbing system to the open air, increasing the chances of infection and speeding up water loss. To ensure the tree’s survival, any part of the plant that is unable to live through the winter must be sealed off and shed before freezing temperatures set in. As the days get shorter and the amount of available sunlight decreases, the vessels that carry water to and from the leaves gradually close off. A “separation layer” of cells forms at the base of each leaf stem. When the separation layer is completely formed, the connection to the branch is weakened and the leaf soon falls off the tree. (Interestingly, evergreen trees do not lose their needles in the winter because they are covered with a heavy wax coating and contain fluids inside that resist freezing.)

    Fall is a great time of year for learning about the process that gives life to trees and most other plants. As you know, this process is called photosynthesis, which literally means “putting together with light.” As winter nears, less sunlight and less water — elements essential to the process of photosynthesis — will be available to trees. That means less food for deciduous (leaf-shedding) trees! Soon the trees’ photosynthesis “factories” will shut down, the trees will recapture nutrients from their leaves, the leaves will drop to the ground, and the tree will rest until spring when water and light return and awaken the process.


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