... species would start to increase. 3. It is seldom possible to count all the individuals in a given space. Explain one method by which biologists can study population densities without obtaining such data. Scientist barely ever count the amount of individuals in a certain area because it would take too much time. Instead of actually counting the number of individuals in an area they would compare it with other areas where they know the population of individuals. In this way they can roughly estimate the number of individuals in a certain area. 4. What might happen to a rabbit population in an area where there are no predators? If there were a few rabbits in an ar ...
Words: 1414 - Pages: 6
... in crop losses in many South American countries. Although primarily an agricultural pest, this insect on occasion may invade the home for cereals. In the United States, the Texas leaf-cutting ant, Atta texana , occurs in Texas and Louisiana. This ant is believed to cause a total yearly loss of $5 million in the United States (unison services. 1998). There are about 9,500 named species of ants. These ants are divided into 16 sub families and 300 genera, all which belong to the family called Formicidae, the family of ants (Hoyt. 1996). The leaf cutting ant belongs to the genus called Atta. There are fifteen different species of Atta and all are limited to the new ...
Words: 3880 - Pages: 15
... away from each other ever since. Today the universe is still expanding, as astronomers have observed. The Steady State model says that the universe does not evolve or change in time. There was no beginning in the past, nor will there be change in the future. This model assumes the perfect cosmological principle. This principle says that the universe is the same everywhere on the large scale, at all times.2 It maintains the same average density of matter forever. There are observational evidences found that can prove the Big Bang model is more reasonable than the Steady State model. First, the redshifts of distant galaxies. Redshift is a Doppler effect w ...
Words: 1280 - Pages: 5
... of polar wandering revived it. Since then, the modern theory of Plate Tectonics has evolved from and replaced Wegener's original thesis. Plate Tectonics is the theory that deals with the structure, history, and dynamics of the earth's crust. The earth's crust is formed of 13 continental plates. The boundaries of the zones are where tectonic activities occur, and where earthquakes and volcanic eruptions tend to happen. The plate tectonics theory was thought up in the 1960s and 1970s, with ideas taken from Wegener’s earlier thoughts. Earlier, Wegener and other scientists had noted that continental crust grows by additions and that a ridge in the middle of the oc ...
Words: 726 - Pages: 3
... They are dense, granular bodies that disappear at the beginning of cell division and reappear at the end. Then you have the Cytoplasm. This is the watery material lying within the cell between the cell membrane and the nucleus. The Cytoplasm also contains organelles, which have specific functions in the cell metabolism. Then there are the Golgi Bodies, which serve as processing, packaging, and storage for the cell. These organelles package and ship things out. Another parts of the cell, a very important one in fact, are the Lysosomes. These organelles are used to break things down and contain enzymes. First we placed the slide under the simple microscope and observe ...
Words: 491 - Pages: 2
... they seem, and nowhere is this more true than in nature, where dozens of animals (and plants) spend their time masquerading as others. So clever are their disguises that you've probably never known you were being fooled by spiders impersonating ants, squirrels that look like shrews, worms copying sea anemones, and roaches imitating ladybugs. There are even animals that look like themselves, which can also be a form of impersonation. The phenomenon of mimicry, as it's called by biologists, was first noted in the mid-1800s by an English naturalist, Henry W. Bates. Watching butterflies in the forests of Brazil, Bates discovered that many members of the Peridae bu ...
Words: 1457 - Pages: 6
... what physics could teach him. This student, only having a rudimentary knowledge of physics, asks, "Can you give me a definition of physics?" The sage rolls his eyes back, and rubs his temples. He replies, "Big or small?" The student baffled by this, prompts again, "Um, physics?" The teacher noticing the ignorance in the room explains, "Physics is split into two major fields: Relativity (Einstein) and Quantum. Thus, they explain big forces in nature and small forces in nature, respectively. They are not cross- applicable." The student, still baffled, persisted, "But if physics explains nature, how is it that nature can be prejudiced in what applies? I mean ...
Words: 4497 - Pages: 17
... the lamina of the leaf is within less than 15° from the normal to the sun. Many plants that exhibit diaheliotropic movements also show paraheliotropic response as well. Paraheliotropism minimizes water loss by reducing the amount of light absorbed by the leaves; the leaves orient themselves parallel to the sun’s rays. Plants that exhibit paraheliotropic behavior usually do so at midday, when the sun’s rays are perpendicular to the ground. This reorientation takes place only in leaves of plants that are capable of nastic light-driven movements, such as the trifoliate leaf of Erythrina spp. (Herbert 1984). However, this phenomenon has been observed in other ...
Words: 2307 - Pages: 9
... topsoil to the groundwater, due to rainfall or irrigation, can result in a dramatic rise in groundwater pressure and watertable levels. The trees of the open forests are now replaced by shallow-rooted crops and pastures which absorb far less water than the native trees. Those trees had been massive water pumps, sucking up moisture from deep underground and putting it back into the atmosphere through the evaporation from their leaves. With those pumps gone, excess rainfall accumulates underground and watertables rise to the surface, bringing ancient sediments of salt with them, often in heavy concentrations. Once exposed to the air and sun, the salts become even mo ...
Words: 286 - Pages: 2
... yet get little recognition for it. Whenever you take an aspirin, eat some vegetables, or even sleep in the house that was once built, you can thank a botanist for it all. Many people, such as myself, would wonder why someone would want to be a botanist. The main reason anyone can name is that plants have intrigued people for thousands of years. Plants are used for decoration, as well as our basic needs, such as: food, shelter, and even the air we breathe. Today, our world requires new needs for plants. Increasing human population is linked to gigantic environmental problems. Among them is the need for more food to feed the world. Pollution of both air and w ...
Words: 1114 - Pages: 5
