Hi my name is Sierra Cunningham. I am a student at Olathe North, I am a junior and I am 16 years old. I work at an animal hospital because I love animals and it gives me a great chance to work with them. I also want to be a veterinarian and go to K State to major in animal sciences. I am also athletic and I like running, playing soccer, and exercising.
Many Animals use Camouflage and Mimicry as a way to protect themselves from larger predators and a way to hide themselves from prey making it easier for them to capture it. When an animal uses Camouflage they blend in to their environment by making the color of their body match the color of the object or plant they sit still on. The object most times just looks like a leaf, twig, a rock, when really it has an animal on it.
During Mimicry, animals use their markings on their bodies to look like another animal to protect themselves from predators that might want to eat them and other animals. There are three types of mimicry used by both predator and prey: Batesian mimicry, Muellerian mimicry, and Self-mimicry. The definition of Mimicry just means the similarities between animal species.
The first type of Mimicry is Batesian mimicry which is when to two or more species look alike in appearance, but only one of then has spines or stingers when its obvious look alike does not have these same traits. The second species has no defense other than looking like the other species and has protection from certain predators by its resemblance to the other species, which the predator fears. Examples of Batesian mimicry are the many species of butterflies that mimic other butterflies. Another butterfly mimic is the Papilio. Each female butterfly can produce one or more different female forms which can mimic five other species of the other foul-tasting butterflies. Other examples are the coral, milk, and king snakes of the New World. Both snakes are marked with yellow, red, and black bands causing possible predators to avoid them. The deadly coral snake has bands of red, yellow, and black, while the other harmless species have the pattern of red, black, yellow.
The second type of Mimicry is Muellerian mimicry which is a form of mimicry that means two disagreeing species are mimics of each other with easily seen warning colors. Thus all mimics share the benefits of the colors since the predator will recognize the coloration of an unpleasant group after a few bad experiences. Since several species have the same appearance to the predator, the loss of life will be spread out over all the species, which lessens the impact on each individual species.
The third type of Mimicry is Self-mimicry which is a misleading term for animals that have one body part that mimics another to raise their survival rate during an attack or helps predators appear harmless. For example the butterfly has eye-spots which are large dark markings that when flashed may startle a predator for a second and allow the prey some extra seconds to escape. Eye-spots can also help prey escape predators by giving predators a fake target. It seems less often predators put self-mimicry to use to aid in catching prey by looking less threatening or fooling the prey before the attack. For example, several turtle species have tongue extensions that are used as a lure to attract prey to a position where they become easy to catch. One of the most interesting examples of self-mimicry is two-headed snake which has a tail that resembles a head and a head that resembles a tail. The snake even moves its tail in the way most snakes move their heads. This adaptation takes place to trick prey into believing the attack is taking place from where it is not.
A different type of deception is called camouflage which is where animals seek to look lifeless or not edible to avoid detection by predators and prey. There are many examples of rainforest species which are mysteriously colored to match their surroundings. An amazing group is the katydids, which is a group of grasshopper-like insects found everywhere. Katydids are nocturnal insects which use their various colors to stay unnoticed during the day when they are inactive. They stay still, and they are often in a position that makes them blend in even better. Katydids have changed so their body coloring and shape matches leaves, including half-eaten leaves, dying leaves, and leaves with bird droppings, sticks, twigs, and tree bark. Other well-known camouflage creatures are beetles, caterpillars, snakes, and frogs.
Some species appear to have noticeable colors when they really are not in the right surroundings. For example, the blue Morpho, has rainbow-like upper wings and a seven inch wingspan. But because the under wings are dark, when the Morpho flies through flickering light in the forest or even in daylight, it look like it disappears. Other forest species, especially mammals, have spots or stripes to help break up the animal's outline. In the shade large mammals like leopards and jaguars are difficult to see with their confusing colors.
Sunday, November 18, 2007
Wednesday, November 14, 2007
Natural Selection
About Me.
Hi my name is Justin, I am a junior at Olathe North. I want to play colege football at any school that wants me. If i dont do that i would want to go to Kansas to major in buisness management. I'm a very athletic person, i love all contact sports. I hope you like my post on Natural Selection.
Natural Selection:
Natural selection is the process by which favorable traits that are heritable become more common in successive generations of a population of reproducing organisms, and unfavorable traits that are heritable become less common.Natural selection acts on an organism's phenotype, or physical characteristics. Phenotype is determined by an organism's genetic make-up (genotype) and the environment in which the organism lives. Often, natural selection acts on specific traits of an individual, and the terms phenotype and genotype are used narrowly to indicate these specific traits.
The term "natural selection" has slightly different definitions in different contexts. In simple terms, "natural selection" is most often defined to operate on heritable traits, but can sometimes refer to the differential reproductive success of phenotypes regardless of whether those phenotypes are heritable. Natural selection is "blind" in the sense that individuals' level of reproductive success is a function of the phenotype and not of whether or to what extent that phenotype is heritable
The concept of fitness is central to natural selection. Although fitness is sometimes colloquially understood as a quality that promotes survival of a particular individual - as illustrated in the well-known phrase survival of the fittest - modern evolutionary theory defines fitness in terms of individual reproduction. The basis of this approach is: if an organism lives half as long as others of its species, but has twice as many offspring surviving to productive adulthood, its genes will become more common in the adult population of the next generation. This is known as differential reproduction.
Natural selection can act on any phenotypic trait, and selective pressure can be produced by any aspect of the environment, including mates and conspecifics, or members of the same species. However, this does not imply that natural selection is always directional and results in adaptive evolution; natural selection often results in the maintenance of the status quo by eliminating less fit variants.
The unit of selection can be the individual or it can be another level within the hierarchy of biological organisation, such as genes, cells, and kin groups. There is still debate about whether natural selection acts at the level of groups or species to produce adaptations that benefit a larger, non-kin group. Selection at a different level such as the gene can result in an increase in fitness for that gene, while at the same time reducing the fitness of the individuals carrying that gene, in a process called intragenomic conflict. Overall, the combined effect of all selection pressures at various levels determines the overall fitness of an individual, and hence the outcome of natural selection.
Natural selection occurs at every life stage of an individual. An individual organism must survive until adulthood before it can reproduce, and selection of those that reach this stage is called viability selection. In many species, adults must compete with each other for mates via sexual selection, and success in this competition determines who will parent the next generation. When individuals can reproduce more than once, a longer survival in the reproductive phase increases the number of offspring, called survival selection. The fecundity of both females and males (for example, giant sperm in certain species of Drosophila[8]) can be limited via fecundity selection. The viability of produced gametes can differ, while intragenomic conflicts such as meiotic drive between the haploid gametes can result in gametic or genic selection. Finally, the union of some combinations of eggs and sperm might be more compatible than others; this is termed compatibility selection.
A well-known example of natural selection in action is the development of antibiotic resistance in microorganisms. Antibiotics have been used to fight bacterial diseases since the discovery of penicillin in 1928 by Alexander Fleming. Natural populations of bacteria contain, among their vast numbers of individual members, considerable variation in their genetic material, primarily as the result of mutations. When exposed to antibiotics, most bacteria die quickly, but some may have mutations that make them slightly less susceptible. If the exposure to antibiotics is short, these individuals will survive the treatment. This selective elimination of maladapted individuals from a population is natural selection.Natural selection by itself is a simple concept, in which fitness differences between phenotypes play a crucial role. It is the union of natural selection as a mechanism with genetic material as a substrate that offers most of the theory's explanatory power
Natural selection results in the reduction of genetic variation through the elimination of maladapted individuals and consequently of the mutations that caused the maladaptation. At the same time, new mutations occur, resulting in a mutation-selection balance. The exact outcome of the two processes depends both on the rate at which new mutations occur and on the strength of the natural selection, which is a function of how unfavorable the mutation proves to be. Consequently, changes in the mutation rate or the selection pressure will result in a different mutation-selection balance.
A prerequisite for natural selection to result in adaptive evolution, novel traits and speciation, is the presence of heritable genetic variation that results in fitness differences. Genetic variation is the result of mutations, recombinations and alterations in the karyotype (the number, shape, size and internal arrangement of the chromosomes). Any of these changes might have an effect that is highly advantageous or highly disadvantageous, but large effects are very rare. In the past, most changes in the genetic material were considered neutral or close to neutral because they occurred in noncoding DNA or resulted in a synonymous substitution. However, recent research suggests that many mutations in non-coding DNA do have slight deleterious effects. Although both mutation rates and average fitness effects of mutations are dependent on the organism, estimates from data in humans have found that a majority of mutations are slightly deleterious
The exuberant tail of the peacock is thought to be the result of sexual selection by females. This peacock is an albino - it carries a mutation that makes it unable to produce melanin. Selection against albinos in nature is intense because they are easily spotted by predators or are unsuccessful in competition for mates, and so these mutations are usually rapidly eliminated by natural selectionBy the definition of fitness, individuals with greater fitness are more likely to contribute offspring to the next generation, while individuals with lesser fitness are more likely to die early or fail to reproduce. As a result, alleles which on average result in greater fitness become more abundant in the next generation, while alleles which generally reduce fitness become rarer. If the selection forces remain the same for many generations, beneficial alleles become more and more abundant, until they dominate the population, while alleles with a lesser fitness disappear. In every generation, new mutations and recombinations arise spontaneously, producing a new spectrum of phenotypes. Therefore, each new generation will be enriched by the increasing abundance of alleles that contribute to those traits that were favored by selection, enhancing these traits over successive generations.
Friday, November 9, 2007
.·:*¨¨*:·. Genetic Drift & Speciation .·:*¨¨*:·.
About Me ~
My name is Mollie. I'm a junior at Olathe North. I have the coolest boots you will ever see. I love my chinchillas, my dogs (a corgi and lab), my quarter horse, rubber ducks, heavy metal, movies, reading, and everything Jhonen Vasquez and Tim Burton. My favorite naturalist buddies are Tank, the leopard gecko, the savanna monitor, and I guess the hedgehog too, because I know I'm probably his favorite person to pee on. I love going to my uncle's farm and riding horses and just spending time with the horses and goats, which is a very rare opportunity for me. But, I enjoy every moment when I do.
All You Will Ever Probably Want, Or Need, To Know About Genetic Drift! ~
Genetic drift, also known as allelic drift, is when a species splits into two groups. Genetic drift usually happens as a result of a geographical factor that makes it difficult for these two groups to come in contact. With this separation and different environments, natural selection will favor different genes in each of the groups. These genes will vary for the groups because the natural selection will be favoring those needed in the new environment. After a period of time, the difference in the gene pools of the groups can become quite dramatic.
Such examples of genetic drift in human history can be explained in the Toba
Catastrophe Theory. According to this theory, a volcano severely reduced the human population around 70,000 to 75,000 years ago. Supposedly, the Toba Caldera in Indonesia underwent a category 8 eruption. This was a "mega-colossal" and reduced the global temperature by 5 degrees Celsius for several of years which may have caused an ice age. This ended up killing off all the human species, also known as a bottleneck, except for what branches that became Neanderthals and modern humans. With computer models and some geological evidence support the plausibility of this happening. This suggests that all humans today came from a small group, around 1,000 and 10,000 breeding pairs.
Another example of genetic drift and a bottleneck is the cheetah. There is very little genetic variation in the cheetah population because of a population bottleneck that probably happend around 10,000 years ago or less. Even today, the cheetah population, as large as it is, hasn't been able to recover it's genetic diversity.
A strange example of genetic drift being resisted was in a
remote sheep population on Haute Island in the Indian Ocean. The mouflon had been put there to establish a group for sport hunting. After being bred over a dozen generation from a single male and female pair, scientists were surprised to find the sheep had maintained the genetic diversity of the founding parents. As genetic drift goes, with an inbred population, genes should have been lost, not maintained. Evolutionary geneticist Dr. David Coltman believes the harsh environment of Haute Island, with its cold winters, scarce resources and grass-borne parasites, has "kept the mouflon on their genetic toes, so to speak." He believes that the extreme conditions of the island have prevented genetic drift due to the premium advantage the more genetically diverse mouflon on the island hold over their less genetically diverse cousins. Mouflon are a hardy and fecund species of sheep, with the ewes able to produce an average of more than five offspring in a four-year lifespan. The Haute Island mouflon population peaked around 700 in the 1970s and since then has bounced between 200 and 600. The geneticists were able to trace the DNA from the original pair on the island using teeth, fur, and bone from the zoo in France they originally came from in the 1950s. Samples from the generations after were taken from "trophies" that hunters had, and in the 70s scientists began taking their own samples.
All You Will Ever Probably Want, Or Need, To Know About Speciation! ~
Speciation, on the other hand, is when genetic drift in a species becomes so great that a brand new species occurs. It is considered a new species because the organisms who are capable of reproducing but can't with a member of the same species, are considered a different species. It is one of the key evolutionary processes and is responsible for the diversity of life that exists on Earth.
One example would be how the domestic dog came about. The earliest dogs came about when humans began keeping wolves, separating the wild wolves from the ones humans were keeping. This was the barrier which created the genetic drift between the domestic wolves and dogs, and with time and inbreeding, the domestic dog was born. As breeding continued, people began breeding dogs for certain qualities, which resulted with the mass number of different dogs we have today.
Another more dramatic example of speciation would be the continent of Australia. Millions of years ago the earth existed as one giant continent, Pangaea. When the continent began to split, the genetic ancestor of all of Australia’s marsupial mammals was caught on what would become Australia. With time, that common ancestor became what we know today as the kangaroo, wallaby, and kola. Kangaroos adapted to living on the ground, with their long, powerful hind feet for moving quickly over large areas. More closely related to the kangaroo, wallabies are smaller version of the kangaroo. The wallaby’s smaller size comes from living in rocky areas where their smaller size makes them more agile. Kolas on the other hand, adapted to living in the trees and feeding on a diet of eucalyptus leaves. Due to the isolation from all the other mammals in their ancestral line, they've become so different from members of their line on other continents. The main difference between them and other mammals of their line is that they bear their young inside a pouch, while all the other mammals are placental.
However, it is occasionally possible to produce a hybrid between two different
species. The down side is, is that the offspring is infertile, due to genetic disorders that arise when mating takes place between distinct species, and even this imperfect product is possible only by mating two species that are very closely related. Animals in which this is common are horses and mules, lions and tigers, and wolves and dogs. For example, these happy face spiders look different, but since they can interbreed, they are considered the same species: Theridion grallator. 
Links ~
My name is Mollie. I'm a junior at Olathe North. I have the coolest boots you will ever see. I love my chinchillas, my dogs (a corgi and lab), my quarter horse, rubber ducks, heavy metal, movies, reading, and everything Jhonen Vasquez and Tim Burton. My favorite naturalist buddies are Tank, the leopard gecko, the savanna monitor, and I guess the hedgehog too, because I know I'm probably his favorite person to pee on. I love going to my uncle's farm and riding horses and just spending time with the horses and goats, which is a very rare opportunity for me. But, I enjoy every moment when I do.
All You Will Ever Probably Want, Or Need, To Know About Genetic Drift! ~
Genetic drift, also known as allelic drift, is when a species splits into two groups. Genetic drift usually happens as a result of a geographical factor that makes it difficult for these two groups to come in contact. With this separation and different environments, natural selection will favor different genes in each of the groups. These genes will vary for the groups because the natural selection will be favoring those needed in the new environment. After a period of time, the difference in the gene pools of the groups can become quite dramatic.
Such examples of genetic drift in human history can be explained in the Toba
Catastrophe Theory. According to this theory, a volcano severely reduced the human population around 70,000 to 75,000 years ago. Supposedly, the Toba Caldera in Indonesia underwent a category 8 eruption. This was a "mega-colossal" and reduced the global temperature by 5 degrees Celsius for several of years which may have caused an ice age. This ended up killing off all the human species, also known as a bottleneck, except for what branches that became Neanderthals and modern humans. With computer models and some geological evidence support the plausibility of this happening. This suggests that all humans today came from a small group, around 1,000 and 10,000 breeding pairs.
Another example of genetic drift and a bottleneck is the cheetah. There is very little genetic variation in the cheetah population because of a population bottleneck that probably happend around 10,000 years ago or less. Even today, the cheetah population, as large as it is, hasn't been able to recover it's genetic diversity. A strange example of genetic drift being resisted was in a
remote sheep population on Haute Island in the Indian Ocean. The mouflon had been put there to establish a group for sport hunting. After being bred over a dozen generation from a single male and female pair, scientists were surprised to find the sheep had maintained the genetic diversity of the founding parents. As genetic drift goes, with an inbred population, genes should have been lost, not maintained. Evolutionary geneticist Dr. David Coltman believes the harsh environment of Haute Island, with its cold winters, scarce resources and grass-borne parasites, has "kept the mouflon on their genetic toes, so to speak." He believes that the extreme conditions of the island have prevented genetic drift due to the premium advantage the more genetically diverse mouflon on the island hold over their less genetically diverse cousins. Mouflon are a hardy and fecund species of sheep, with the ewes able to produce an average of more than five offspring in a four-year lifespan. The Haute Island mouflon population peaked around 700 in the 1970s and since then has bounced between 200 and 600. The geneticists were able to trace the DNA from the original pair on the island using teeth, fur, and bone from the zoo in France they originally came from in the 1950s. Samples from the generations after were taken from "trophies" that hunters had, and in the 70s scientists began taking their own samples.All You Will Ever Probably Want, Or Need, To Know About Speciation! ~
Speciation, on the other hand, is when genetic drift in a species becomes so great that a brand new species occurs. It is considered a new species because the organisms who are capable of reproducing but can't with a member of the same species, are considered a different species. It is one of the key evolutionary processes and is responsible for the diversity of life that exists on Earth.
One example would be how the domestic dog came about. The earliest dogs came about when humans began keeping wolves, separating the wild wolves from the ones humans were keeping. This was the barrier which created the genetic drift between the domestic wolves and dogs, and with time and inbreeding, the domestic dog was born. As breeding continued, people began breeding dogs for certain qualities, which resulted with the mass number of different dogs we have today.
Another more dramatic example of speciation would be the continent of Australia. Millions of years ago the earth existed as one giant continent, Pangaea. When the continent began to split, the genetic ancestor of all of Australia’s marsupial mammals was caught on what would become Australia. With time, that common ancestor became what we know today as the kangaroo, wallaby, and kola. Kangaroos adapted to living on the ground, with their long, powerful hind feet for moving quickly over large areas. More closely related to the kangaroo, wallabies are smaller version of the kangaroo. The wallaby’s smaller size comes from living in rocky areas where their smaller size makes them more agile. Kolas on the other hand, adapted to living in the trees and feeding on a diet of eucalyptus leaves. Due to the isolation from all the other mammals in their ancestral line, they've become so different from members of their line on other continents. The main difference between them and other mammals of their line is that they bear their young inside a pouch, while all the other mammals are placental.
However, it is occasionally possible to produce a hybrid between two different
species. The down side is, is that the offspring is infertile, due to genetic disorders that arise when mating takes place between distinct species, and even this imperfect product is possible only by mating two species that are very closely related. Animals in which this is common are horses and mules, lions and tigers, and wolves and dogs. For example, these happy face spiders look different, but since they can interbreed, they are considered the same species: Theridion grallator. 
Links ~
Survival of the Fittest
About me: I like pina coladas, and getting caught in the rain, im not into yoga, and i have half a brain, i like making love at midnight, im not much into health food, im into champagne. My name is Ethan.
OCEAN-
In my opinion the animal that is best fit for suvival in the ocean is the dolphin. They are the one of the smartest animals in the world. It is immpossible to figure out exactaly how smart they are but they are very fast learners and are able to understand and learn complicated commands. Dolphins are also very efficiant hunters. They always hunt in pods (which is like a group of dolphins). They will use their eco locator and follow it to a group of fish. Then they surround the fish on all sides except the top then they take turns getting fish. Dolphins have even fugured out how to sleep under water. They can't really shut down and sleep like we do. Dolphins turn of half their brain at a time and either sleep at the surface with their blow hole above the surface. Or they sleep in shallow water and come up for air every so often. Total they get about eight hours of sleep. They also have the ability to retain water like an animal that lives in the desert. Since they can't drink the salt water they have to get water from their food. And their kidneys are made to hold as much water as possible. And one of the things about dolphins that most makes me think they are the fittest for survival is the fact that they are able to scare away and have even been known to kill a shark. They also have protected humans from sharks and saved lives. That is why they are they are the most fit for survival in the ocean.
http://www.dolphinear.com/data/dolphins.htm
DESERT-
Vultures are the world trash men. Now while the vulture may not look that nice, with out them our world would suffer. They clean up the planet by eating the carcuses of dead animals. They are desiged to eat dead animals. Vultures have a bald head so that the can when they are done stuff won't get caught in their fethers which would harvest bacteria and give them other diseases. Then after they eat they go sit in the sun and get whatever is stuck to them baked off. Because the vulture eats the carcuses it rids the planet of desease carrying bugs, like maggots. it also make the world look better. Their stomach is made to handle what ever decayed food they put in their body. Vulture stomachs contain and acid that kill virtully any bacteria. its poop is like a sanitizer and when it is done eating an animal it poops on its legs to clean off any diseases. And just because you see a vulture flying above does not mean there is a dead animal around. Vulture have wings that allow them to soar for hours. They are very smart creatures and soaring in warm pockets of air is fun for them.
JUNGLE-
Tigers are built to hunt. They are the largest of the cat species. A tigers stripes helps to keep it hidden by making it look as though it is broken up, so acts as camoflage. A tiger hunts by stelth to get as close as possible to its prey before it pounces on it. The tigers hind limbs are longer than its forelimbs to help it jump better. But the forelegs are able to twist inward so it can grab and hold onto its prey. And if need be a tiger has strong legs and a flexible backbone to help case prey over a short distance. Tigers paws are also padded to keep noise to a minimum. They also walk on their toes. The front paws have 5 claws but the back feet have 4 claws. Its claws are retractable so as to not damage them from over use. Its head is also an important part of the hunting process. The largest premolar on the top and bottom jaw are used for cutting up the meat before chewing. Tiger on average live to be 15 years old in the wild.
ARTIC-
Polar Bears are one of the largest predators in the world. Polar Bears are also very good swimmers. They have a long neck and narrow head with large flat feet for better swimming. They can swim for hours and over long distances. They can close their nostrils while under water. They can stay under water for up to two minutes. The bears also are perfectly made for cold weather. They have thick fur that covers all of their feet, for better traction on the slick ice. Polar Bears also have a thick layer of blubber which provides insulation from the cold and buoyancy for the water. Polar Bears keep them selves so well insulated that they can over heat themselves. They do not hibernate for winter, since its like winter all year round. But they are less active in the summer. When a polar bear hunts for seals and such it will sit by a hole in the ice and wait for the animal to come up and breathe, then they will stab it in the head with its large teeth and claws, and scoop it out of the water.
http://www.defenders.org/wildlife_and_habitat/wildlife/polar_bear.php
Subscribe to:
Posts (Atom)