Bio160 - Class Notes Week 1
Bio160 - Class Notes Week 1 BIO 160
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This 5 page Class Notes was uploaded by Aenea Mead on Saturday October 1, 2016. The Class Notes belongs to BIO 160 at California Polytechnic State University San Luis Obispo taught by Jennifer Yost in Fall 2016. Since its upload, it has received 2 views. For similar materials see Diversity and History of Life in Biology at California Polytechnic State University San Luis Obispo.
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Date Created: 10/01/16
Vocabulary F itness: The ability of an individual to produce offspring (more reproduction means higher fitness) Adaptation: A trait that increases the fitness of an individual in a particular environment H eritable: traits that can be passed onto offspring Evolution: the change in heritable characteristics in a population overtime Concepts / Content Five Main Properties of Life: 1. Uses and requires energy 2. Made of cells 3. Ability to reproduce/replicate 4. Ability to process information 5. Ability to evolve Cells: ● Smallest unit of life ● Discovered and named by Robert Hooke Anton Van Leeuwenhoek: ● “Father of Microbiology” ● Created some of the first microscopes ● Used his microscopes to discover the first single celled organisms (1660’s) ● Discovered sperm with his microscopes (1677) Louis Pasteur: ● Disproved theory of spontaneous generation with an experiment. In summary he had two flasks filled with water, both were boiled, so no living organisms remained in the water. One of the flasks was open at the top, the other was closed. After some time organisms began to appear in the open flask, but not the third. This disproved spontaneous generation because if cells simply appeared without having come from other cells, then they would have appeared in the closed flask. Cell Theory: 1. All organisms of made of cells 2. All cells come from preexisting cells Implications of Cell Theory: ● All cells are connected through a common ancestor Theory of Evolution by Natural Selection: ● In 1858, separate from Pasteur, biologists Darwin and Wallace, proposed the idea that all species are related through descent from a common ancestor ● Called it, “Descent with modification” Tieing together the Cell Theory and Natural Selection: 1) All species are related by a common ancestor 2) Species change overtime from natural selection Requirements for Evolutions by Natural Selection: 1. Individuals are different 2. Differences between individuals are heritable 3. Differences in heritable traits affect fitness **Note: Natural Selection acts on an individual, whereas evolution happens to a population Life processes information: 1902 - Sutton and Boveri come up with the Chromosome Theory 1950’s - Watson and Crick discover the structure of DNA How Traits Are Passed On (basic explanation): 1. Each strand of DNA is made up of nucleotides: A, T, C, G 2. Two nucleotides pair up to create base pairs 3. Base pairs line up to form a gene 4. Gene is copied, the copy is called mRNA 5. mRNA travels out of the nucleus to a protein 6. The protein uses the mRNA to synthesize a new protein On an individual level, changes from parents in one’s DNA sequence can increase / decrease fitness. If there is a certain trait that increases fitness, then that trait will be passed on from generation to generation. Ex. Let’s say tall people have better fitness. The first graph shows the average height of one generation of people in a population. The second graph (ignore the text and axis, just look at the curve) shows the average of height of people in a population the next generation. Since height increases fitness, those who are taller reproduce more, which in turn results in more tall people. Number of Species of the Planet: ● Scientists estimate there are 8.7 million species on Earth ● Only 1.4 million species have been cataloged Being that there are so many species on this planet, trying to categorize and define each one of them can get a little tricky. Here are a few ideas scientists have come up with: 1) Biological species concept: considered the same species if they can interbreed 2) Morphological species concept: separate species based on appearance - any obvious differences means two different species 3) Phylogenetic species concept: smallest monophyletic group (do not need to understand what this means yet) Classification and Taxonomy: All life has a latin binomial name. The first word is the genus and the second word is the species. Ex. Homo sapiens (homo is genus, sapien is species) Aristotle’s Model for Classifying Life: Plants Animals Linnaeus’ Model for Classifying Life: In the mid eighteenth century, Carl Linnaeus came up with the system of classification that we use today. - Kingdom - Phylum - Class - Order - Family - Genus - Species **Note: A good mnemonic to remember it by is: Kings Play Chess On Fine Sand Human Classification: animalia, chordata, mammalia, primates, hominidae, homo, sapiens Three Domains of Life: 1) Bacteria 2) Archaea 3) Eukarya Where did the first cell come from? The current theory is that it came from chemical evolution. An input of energy led to the formation of increasingly more complex carbon-containing molecules. This led to molecules that could replicate themselves, which was where the switch from chemical to biological evolution occurred. **Note: Dates from other sources will not match these exactly, if you are in Bio 160 at Cal Poly then remember the ones above! If you are not then that is okay, all of the dates are correct, just not overly accurate, so be sure to keep that in mind. Early Atmosphere Composition: CO, H O, CO , N , H 2 2 2 2 Today Cells are 96% H, C, N, O (important to notice where the elements that make up our cells originated).