BIOLOGY 160 NOTES- GROFF (Ch. 24, and part of 25…to be continued)
BIOLOGY 160 NOTES- GROFF (Ch. 24, and part of 25…to be continued) BIL 160
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This 3 page Class Notes was uploaded by Khrystel Bernard on Saturday January 30, 2016. The Class Notes belongs to BIL 160 at University of Miami taught by Paul Groff in Spring 2016. Since its upload, it has received 94 views. For similar materials see EVOLUTION & BIODIVERSITY in Biology at University of Miami.
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Date Created: 01/30/16
BIOLOGY 160 NOTES GROFF (Ch. 24, and part of 25…to be continued) Microevolution vs. macroevolution Microevolution: Is change BELOW the species level….allele frequency changes over generations and (Variations occurs in a specific individuals of a species). - The changes in species at a molecular, or DNA, level. All species on Earth have very similar DNA sequences that code for all of their characteristics, which supports the belief of a common ancestry. Macroevolution: Change ABOVE the species level…. major evolutionary changes over time at a grand scale, the origin of new types of organisms from previously existing, but different, ancestral types. Emergence of organisms through speciation events, mass extinctions inflicted influencing biodiversity, and the origins of adaptations. the type of evolution that Darwin described Speciation evolutionary process by which reproductively isolated biological populations evolve to become distinct species; basically the origin of new species (natural speciation vs artificial speciation) Biological species concept: reproductive isolation When two groups of animals live close enough to one another to interact, but CANNOT interbreed with one another [prezygotic barriers (before egg fertilization) and postzygotic barriers (after egg is fertilized) prevent interbreeding] Reproductive isolating mechanisms: - Prezygotic: Individuals from different species cannot mate - Postzygotic barriers: Developmental problems in the womb Morphological species concept A more subjective classification. Organisms are classified in the same species if they appear identical by morphological (anatomical) criteria. This is used when species do not reproduce sexually, some are known only from fossils. Overall similarity between species Phylogenetic species species as a group have a shared and unique evolutionary history relies on common ancestry concept and shared evolutionary history Allopatric speciation vs. Sympatric speciation Allopatric speciation: A few members of a species becomes geographically separated and diverge into another group; each group evolves new and distinctive traits. (Example: The northern spotted owl and the Mexican spotted owl are geographically separated and live in different climates and habitats.) Sympatric speciation: A few members of a species form a new group without being geographically separated (Example: Flies of the same species at first eat red apples but then some members begin to only eat green apples) Polyploidy (autopolyploid vs. allopolyploid) Polyploid: A new species emerges because of a mistake during cell division which causes extra sets of chromosomes Autopolyploid: An organism having more than two sets of chromosomes, all of which were derived from the same species Allopolyploid: Having two or more complete sets of chromosomes derived from different species (Example: 3 different species of wheat) Punctuated equilibria vs. Gradualism in evolutionary patterns Hybrid zone: A place where members of different species come to interact with one another and mate Hybrids become reproductively isolated from their parents Hybrids form new species 3 outcomes of hybrid zones Reinforcement: Reproductive barriers become more prominent between the two original species and hybrids stop being formed Fusion: Reproductive barriers are weakened, which causes the two species to form more hybrids and eventually a new species Stability: Small population of hybrids are being formed but the original population of the two species is sustained Punctuated equilibria: Species are generally stable in their populations, and change little by little over millions of years, until an extremely fast and short “spike” period of change causes the creation of a new species and that leaves few fossils behind. (Example: intermediate fossils that link chickens to the TRex). On early Earth, cells were formed in 4 stages: Abiotic synthesis of small organic molecules (amino acids and nitrogenous base These small molecules bond with one another until they form macromolecules (large molecules such as proteins and nucleic acid) Packaging of molecules into “protobionts” or protocells (http://exploringorigins.org/protocells.html) Origin of selfreplicating molecules Conditions on early Earth made the origin of life possible http://www.centralia.edu/academics/bioscience/courses/biol221/outlines/10_history.html
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