Lamarck's Theory Of Evolution 1 example essay topic

I. The Evidence of Fossils. (28-1) The Formation of Fossils 1. Fossil: The actual remains or any trace of an organism that lived at some time in the past. 2. Petrifaction: The process by which the body of a dead organism is slowly replaced by dissolved minerals. 3.

Mold: A rock as a hollow form; Cast: A copy of the external form of the original organism. 4. Imprint: A type of fossil formed when an impression made in mud by living thing is preserved when the mud is transformed into rock. B. (28-2) Sedimentary rocks: 1. Sedimentary Rock: A type of rock formed from layers of particles that is settled to the bottom of a body of water, often containing fossils. 2. Water flowing into these body's of water carry fine particles of rock called sediments.

3. The size and mineral composition of sediments being deposited by the rivers will usually change from time to time. Therefore, the sedimentary rock acquires a layered structure. 4.

Geologists have concluded that the crust of the earth is constantly changing and shifting. C. (28-3) Hormones 1. Relative Dating: Any method of determining the order in which events occurred. 2. Correlation: The process of matching by which geologists determine the relative ages of rock layers 3. A study of fossils from many regions have shown that certain types of organisms seem to appeared, flourished for a time over wide regions of the earth, and then disappeared. 4.

Transitional forms: Missing links D. (28-4) Absolute Dating 1. Relative dating allows us to say that one type of organism lived earlier than another, but it does not tell us how much earlier. 2. Absolute dating: Any method that does enable us to find out how long ago an event occurred. 3. The crate at which a radioactive element decays is fixed and unchangeable.

4. Radioactive dating methods cannot be applied to sedimentary rocks. E. (28-5) The Geologic Time Scale 1. Through a combination of absolute and relative dating of rocks, geologists have constructed a timetable of earth's history, which is known as the geologic time scale. 2. Each era is subdivided into periods and epoch. 3.

Radioactivity: The property of emitting radiation. 4. Igneous Rocks: rocks that formed when molten material in the crust cooled and harden. II. Other Evidence of EvolutionA. (28-6) Evidence from Comparative Anatomy 1.

Comparative Anatomy: Is the study of structural similarities and differences among living things. 2. Homologous structures: Parts of different organisms that have similar structures and similar embryonic development, but different forms and functions. 3. Analog us structures: Structures that have similar external forms and functions but quite different internal structure.

4. Vestigial Structures: A nonfunctional structure in an organism that is a remnant of a structure that was functional in some ancestral form of the organism. B. (28-7) Evidence from Comparative Embryology 1. Comparison of the patterns of development of the embryos of different types of organisms can provide evidence of evolutionary evidence. 2.

Embryos of organisms believed to be closely related show similar patterns of development. 3. In these vertebrates, there are many similarities during the early stages of embryonic development. 4. The more closely related the animals, the longer they resemble each other during development. C. (28-8) Evidence from Comparative Biochemistry and Immunology 1. Scientists have discovered that the closer the evolutionary relationship between organisms, the more alike the structure of their DNA and protein molecules.

2. The hemoglobin's of humans and gorillas are the same except for one amino acid. 3. The amount of precipitation is an indication of the similarity in protein structure between each of these animals and humans. 4. The greater the amount of precipitate, the greater the similarity in protein structure, and the more closely the animal is related to humans..

Early Theories of EvolutionA. (28-9) Lamarck's theory of Evolution 1. One of the first theories of evolution was presented by the French Biologist Jean Baptiste de Lamarck in 1809.2. According to Lamarck's theory, evolution involved two principles...

3. The first one of his principles were the Law of use and disuse which means the more an animal uses a particular part of its body, the stronger and better developed that part becomes. 4. The second part of Lamarck theory was the Inheritance of acquired characteristics. Lamarck made and assumption that the characteristics an organism developed through the use and disuse of various parts of its body could be passed onto its offspring. B. (28-10) Weismann's Experiment 1.

From modern genetics it is known that traits are passed from one generation to the next by genes in an individual's gametes. 2. There is no way that these genes could be affected by the individual's life experiences or activitys. 3. Many experiments have been performed to look for evidence of such an effect, and all have failed. 4.

Weismann cut the tails off mice 22 generations, in each generation, the mice were born with tails of normal length. The acquired characteristic of shortened tails was not inherited. C. (16-11) Darwin 1. The name most closely connected with the theory of evolution is that of Charles Darwin, he was the son of a prosperous physician. 2. During those years Darwin collected large numbers of specimens and made detailed observations of the regions through which he travels. 3.

Affects glucose metabolism in several ways. 4. The condition of which the concentration of glucose in the blood increases, and the excess sugar is excreted in the urine. D. (28-12) Natural Selection 1. Shortly after he returned to England, Darwin read An Essay on the principle of population, by Thomas Malthus. This essay greatly influenced Darwins thinking and was to serve as the basis for his explanation of evolution.

2. Darwin realized that all organisms have the same potential for excess population growth. 3. Natural Selection: Organisms with favorable variations would be better able to survive and reproduce than organisms with unfavorable variations. 4. Darwins theory of evolution was eventually accepted by most of the leading scientists of his time. E. (16-14) Applying Darwins Theory 1.

The original giraffe population had short necks and ate grass. However, some giraffes had longer necks than others. 2. Those with longer necks could eat the lower leaves of trees as well as the grass. 3. In times when grass was scarce, the longer-necked animals could obtain more food than the others and would therefore be more likely to survive and reproduce.

Their offspring would inherit the favorable variation of a longer neck. The longer the neck of the giraffe, the higher it could reach for leaves on the trees. 4. Therefore, as a result of natural selection, giraffe necks were slightly longer on the average in each succeeding generation. The modern long necked animal is the result of this gradual process of evolution. F. (16-15) Pineal Gland 1. Pineal Gland: A pea-sized structure attached to the base of the brain.

2. It produces a hormone called Melatonin. 3. Melatonin may inhibit sexual development in human males. 4. Melatonin may also inhibit sexual development in human females. G. (16-16) Prostaglandins 1.

Prostaglandins: Are "local hormones" that produce their effects on the cells in which they are synthesized without ever entering the bloodstream. 2. They are thought to influence a wide variety of metabolic activities, including heart beat blood pressure, excretion or urine, and contraction of the uterus at childbirth. 3. Prostaglandins are bi end studied for possible use in the treatment of such diverse diseases as high blood pressure, stroke, asthma, and ulcers. H. (16-16) Prostaglandins 1. Prostaglandins are bi end studied for possible use in the treatment of such diverse diseases as high blood pressure, stroke, asthma, and ulcers. I. (16-16) Prostaglandins 1.

Prostaglandins are bi end studied for possible use in the treatment of such diverse diseases as high blood pressure, stroke, asthma, and ulcers.