The Concept of a Species.

Classification The Concept of a Species. Definition: Species (Collins Dictionary): Said "spee-sheez" NOUN a class of plants or animals whose members have the same characteristics and are able to breed with each other. There is no simple definition for a 'species'. The recently founded idea that species may 'evolve' gradually over time has changed the concept of a species. Before the idea of evolution, it was believed by almost everyone that a God created all species individually, and that they were fixed and unchanging. But later, much evidence such as the fossil record and extensive studies on the adaptations of certain creatures found by scientists, including Charles Darwin, led more and more people to believe that species have evolved very gradually over long periods of time. And because of this, the concept of a species has been modified. Ernst Mayr, one of the founders of modern evolutionary philosophy and theories defined biological species as: "Groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups". This definition is also known as the biological species concept (BSC). Advocates of the BSC say that forms that are only slightly different (for example different geographical forms) may interbreed if they had the opportunity. Therefore they should be considered as the same species. However,

  • Word count: 3263
  • Level: University Degree
  • Subject: Biological Sciences
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An ivestigation into animal foraging.

An ivestigation into animal foraging. Animal foraging refers to the habits and techniques that animals employ when they search for food; it refers to all types of animal, both herbivore and carnivore, as it assumes that all animals are 'predators' (Krebs, 1978). The basic assumption of foraging theories is that animals optimise energy over time in order to find the highest quantity or quality of food. Some terms used in the literature need prior definition: a 'patch' is an area where food is available; 'prey' refers to food, either animal or vegetable; and 'handling time' means the time between finding the food and digesting it. In order to achieve the maximum amount of energy, an animal has to make several decisions about foraging, including patch choice, diet, and moving from patch to patch. These decisions may not be conscious, but recent experiments have shown that they do take place, and theoretical interpretations have been made from them. The first decision animals have to make is where to look for their food - they have to choose a patch. The patch should be plentiful in food supply (net rate of energy), but it is equally important to consider the rate of possible predation - if there is a high density of predators, the patch will probably not be chosen even if it is rich in prey (Pyke, Pulliam and Charnov, 1977). The animal may also consider the possibilities of

  • Word count: 1551
  • Level: University Degree
  • Subject: Biological Sciences
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A Winter’s Night

A Winter's Night As the cold winter sets in for the night the animals wait in apprehension for the icy winds to test their home. For the humans it is all too easy. They have all the comforts of the modern world. Sitting in their houses in their comfy chairs and central heating. While the humans are staring vacantly in to the box in the corner of the room, the animals outside are fighting a losing battle against the cruel natural world. The wind outside is harsh and piercing with its icy claws that take hold of life and rip it from its possessor. This fiendish wind soars around the forest and the impenetrable fortress that is the human's home. This icy wind batters the animal's flimsy shelter and rips it apart as if it were tissue paper. The animals stand by their wrecked homes and look on in awe as the humans begin to make their way to their luxury burrows, where they will drift off in to a heavy slumber dreaming of the warmth oblivious to the scenes of chaos outside. Eventually the wind will die away leaving an aftermath of death and destruction. But not for hours to come. When the wind eventually does die down, the animal receive an illusion of security and calm, but with this calm comes an unseen enemy. This enemy will dance around the forest laying its magnificent blanket of silvery ice. In under an hour the frost has been laid and the animal desperate to find shelter

  • Word count: 482
  • Level: University Degree
  • Subject: Biological Sciences
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Compare and Contrast two of the five main approaches in psychology.

Compare and Contrast two of the five main approaches in psychology Written By Mark Costa The two approaches I will be looking at in this essay are 'behavourism' and 'humanism'. Apart from the fact that one of them is scientific and the other is not, I have chosen these two as they have very different aspects of studying and interperatation that interests me. Psychology evolved through three subjects philosophy, biology and physics. It developed through stages and views, firstly with Psychoanalysis, behaviarism, cognitive, humanistic and lastly biological. Behaviourists believed that we are shaped by the way our behaviours are rewarded. Behaviourists want results, by which they can check measure and observe on the stimulus and the reacted response. Humanists believe that every human being in the world is unique and also that there will never be any two people whom are identical. This relates to the belief on genetics and the experiences we go through in life are different from each other. Through 'ethics' there is a rule that no mental or physical harm should come to a participant of an experiment carried out on a psychological basis. Although in Behaviourism it is believed that animals are practically and ethically more convenient to test. The behaviourists believed that the laws of learning were crucial and as there was only a small difference between animals and

  • Word count: 1616
  • Level: University Degree
  • Subject: Biological Sciences
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Aristotle (384-322 B.C.E.)

Aristotle (384-322 B.C.E.) Mine is the first step and therefore a small one, though worked out with much thought and hard labour. You, my readers or hearers of my lectures, if you think I have done as much as can fairly be expected of an initial start . . . will acknowledge what I have achieved and will pardon what I have left for others to accomplish. Aristotle was born in Stagira in north Greece, the son of Nichomachus, the court physician to the Macedonian royal family. He was trained first in medicine, and then in 367 he was sent to Athens to study philosophy with Plato. He stayed at Plato's Academy until about 347 -- the picture at the top of this page, taken from Raphael's fresco The School of Athens, shows Aristotle and Plato (Aristotle is on the. right). Though a brilliant pupil, Aristotle opposed some of Plato's teachings, and when Plato died, Aristotle was not appointed head of the Academy. After leaving Athens, Aristotle spent some time travelling, and possibly studying biology, in Asia Minor (now Turkey) and its islands. He returned to Macedonia in 338 to tutor Alexander the Great; after Alexander conquered Athens, Aristotle returned to Athens and set up a school of his own, known as the Lyceum. After Alexander's death, Athens rebelled against Macedonian rule, and Aristotle's political situation became precarious. To avoid being put to death, he fled to the

  • Word count: 1252
  • Level: University Degree
  • Subject: Biological Sciences
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Charles Darwin and his Theory of Natural Selection

Charles Darwin & his theory of Natural Selection On modern day Earth, there are over four million different life forms. Because we live in such a diverse environment it is not rare nor difficult to discover an unknown plant or animal species. Spend a day in the tropical rainforests of South America, turning over logs, looking beneath bark, sifting through the moist litter of leaves, followed by an evening shining a mercury lamp on a white screen, and one way or another you will collect hundreds of different kinds of small creatures. Moths, caterpillars, spiders, long-nosed bugs, luminous beetles, harmless butterflies disguised as wasps, wasps shaped like ants, sticks that walk, leaves that open wings and fly- the variety will be enormous and one of the creatures you come across will almost certainly be undescribed by science. Often the difficulty we face in identification of a new species is finding specialists who know enough about the group concerned to be able to single out a new one. No one can say just how many species of animals there are in these greenhouse- humid dimly lit jungles. They contain the richest and most varied assemblage of animal and plant life to be found anywhere on earth. Not only are there many major categories of creatures - monkeys, rodents, spiders, hummingbirds, butterflies - but most of these types exist in many different forms. There are over

  • Word count: 1652
  • Level: University Degree
  • Subject: Biological Sciences
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The role of Zoos.

The Role of Zoos The main role of zoos is the conservation of endangered and rare species. This is done in four main ways: captive breeding programs; research; funding and resources; and education. Captive breeding - These programs are meant to serve as "savings banks" for animals that are declining in numbers. This ensures that the genetic diversity if the species is conserved. The breeding is carefully planned and closely recorded. The data is used to decide which pairs are should breed together so all animals produce offspring which prevents the increase of homozygousity within the species. Animals from many different zoos participate in the schemes so the number if animals and therefore amount of genetic information is as large as possible. This all helps to prevent inbreeding and preserve the gene pool. Some animals are bred in captivity for release into the wild. Hopefully this way the new animals can breed with wild animals and increase the population in the wild. The drawback of this is that if the habitat is not large enough or of sufficient quality to support a larger amount of animals the numbers will decline again, so the release of captive bred animals alone will have no effect on the overall natural population. This is why habitat conservation is also necessary. Research - The research carried out by zoos is vital in the conservation of endangered

  • Word count: 933
  • Level: University Degree
  • Subject: Biological Sciences
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Discursive essay on evolution.

Discursive essay on evolution The argument of whether or not evolution has occurred and still is occurring is a very controversial issue. Those who don't believe in it tend to take a religious perspective and believe that the world and everything in it was made by a "Creator", and those who believe in the theory of evolution generally do so upon grounds of scientific evidence. Evolution is a very complicated issue. There is what is known as micro-evolution, which is known as adaptation, there are slight variations in the species, but at any stage during the process it is still a member of the same family and species. This is known to be true, what the argument is about is macro-evolution. Macro-evolution is on a much bigger scale, For example, from a fish to a dog. Evolutionists believe that if micro-evolution can occur why can't it go further and change the species altogether. The "father" of evolution was a man called Charles Darwin. Around 150 years ago, he shocked the world when he wrote a book suggesting that humans were related to animals. Today, Darwin's idea still forms the basis of what is known as "The Theory of Evolution". The word "evolution", is used to describe the way in which living thing evolve or change, given time. The theory is comprised of three major sections. The first of which is called variation. All living things vary in size, shape, strength and

  • Word count: 1420
  • Level: University Degree
  • Subject: Biological Sciences
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Charles Darwin.

Charles Darwin British scientist, who laid the foundation of modern evolutionary theory with his concept of the development of all forms of life through the slow-working process of natural selection. His work has been of major influence on the life and Earth sciences and on modern thought in general. Born in Shrewsbury, Shropshire, on February 12, 1809, Darwin was the fifth child of a wealthy and sophisticated family. His maternal grandfather was the successful china and pottery entrepreneur Josiah Wedgwood; his paternal grandfather was the well-known 18th-century doctor, poet, and savant Erasmus Darwin. His father was a successful provincial physician with a dominant personality; his mother died when Charles was only eight, after which time he was looked after by his elder sisters. Known as a rather ordinary student, Darwin left Shrewsbury School in 1825 and went to the University of Edinburgh to study medicine. Finding himself squeamish at the sight of human blood and suffering, Darwin left Edinburgh and went to the University of Cambridge, in preparation for a life as a Church of England clergyman, which he thought would best allow him to pursue his increasing interest in natural history. At Cambridge he came under the influence of two figures: Adam Sedgwick, a geologist, and John Stevens Henslow, a botanist. Henslow not only helped build Darwin's self-confidence but also

  • Word count: 2761
  • Level: University Degree
  • Subject: Biological Sciences
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Captive breeding

The role of a modern zoo The role of zoos has evolved from being centers dedicated to the collection of animals and the recreation of the public. The duty of a modern zoo is to promote the conservation of species. To accomplish this is it is necessary to do scientific research, introduce captive breeding programs, and educate the public. By creating the zoo a place for recreation, they aim to raise money for the conservation from the public while still aiming to balance the interests of the animals. They achieve this by giving the public a 'good day out'. Chester Zoo as an example from a recent visit provided the public with an imaginative trip on a monorail and waterbus. Up to £10 of donation price is required to go on the trip and the peak period is between March and November. (1) Monorail at Chester Zoo (2) However in order to balance all of this, a 'good zoo' needs the aid of scientific research on all the species. The need for scientific knowledge is growing every year as more and more habitat continues to change. This knowledge is necessary to feed, house and care for the animals to achieve the educational potential of the zoos. A SOCIAL issue is that it is very crucial that the public are taught the importance of not disturbing the animals in the nearby habitat. This would aid their survival after being re introduced into the wild. Chester is involved in a

  • Word count: 2200
  • Level: University Degree
  • Subject: Biological Sciences
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