Evolution PDF

Key principles of Evolution Descent with modification- a process that is used by natural selection as traits that are passed through generations, there is modification. Modifications are the difference that natural selection will either get rid of / will increase. Fitness- success at surviving and r...

Key principles of Evolution Descent with modification- a process that is used by natural selection as traits that are passed through generations, there is modification. Modifications are the difference that natural selection will either get rid of / will increase. Fitness- success at surviving and reproducing (how well a species does this in their environment.) Struggle for existence- the automatic competition of members for a natural population for limited vital resources. Processes of Evolution Natural selection- the mechanism by which advantageous traits become more common. Genetic drift- random changes in allele frequencies, especially in small populations. selective breeding- artificial selection in agriculture and domestication. LUCA Last universal common ancestor. Cladograms and phylogenetic trees Cladograms- shows relationships between organisms based on shared characteristics. (non-genetics) Phylogenetic trees- represent specific evolutionary history (DNA) over time. How to read cladograms: ​ Locate the starting point of the cladogram. ​ Move up the main line of the cladogram to move forward through time ​ Determine differences in animals based on where they branch off from the main line How to read phylogenetic trees ​ Locate the starting point of the cladogram ​ Move up the main line of the cladogram to move forward through time ​ Use the position of the nodes to determine which characteristics evolved first ​ Determine differences in animals based on where they branch off from the main line. Scientific contributions Darwin- Darwin proposed that species can change over time, that new species come from pre-existing species, and that all species share a common ancestor (finches) Lamarche-physical changes in organisms during their lifetime—such as greater development of an organ or a part through increased use—could be transmitted to their offspring Malthus- the human population grows more rapidly than the food supply until famines, war or disease reduces the population Wallace- natural selection can contribute to reproductive isolation of incipient species by creating barriers and speciation Wegener- continental drift Dobzhansky- all species are related and slowly change over time Margulis- developed the endosymbiotic theory Gould- punctuated equilibrium Wilson - evolution drives the differences in animal populations through genes Theory of natural selection the process through which populations of living organisms adapt and change. Competition- the rivalry between or among living things for territory, resources, goods, mates Predation-where one organism, the predator, kills and eats another organism, its prey Climate change- changes in the average weather patterns etc affecting Earth’s health parasitism - the parasite, lives on or inside another organism, the host, causing it some harm Pollution- when chemicals, particles, or other materials are released into the environment, harming the organisms there Selective pressure- when a specific organism is favored in the environment (causing genes to pass down) geographic isolation- the physical separation of populations of organisms from one another due to geographical barriers Temporal isolation- isolated in time Behavioral isolation- when species are reproductively isolated from others due to differences in behavior Gradualism equilibrium- evolution occurs slowly and over time Punctuated equilibrium- evolution occurs in long periods of stability interrupted by rapid change Convergent evolution- distantly related organisms independently evolve similar traits to adapt to similar necessities Divergent evolution- different organisms having common ancestors develop different traits or characteristics Coevolution- mutual evolutionary influence between two species Adaptive radiation- rapid diversification of a species into a variety of forms to adapt to different environments Mass extinction- significant loss of biodiversity in a relatively short period Evolutionary arms race- continuous adaptations and counter adaptations between competing species Fossil records-shows us when specific types of organisms appeared, went extinct, or changed Radioactive dating- a method of dating rocks and minerals using radioactive isotopes Comparative embryology- the branch of embryology that compares and contrasts embryos of different species Homologous structure- an organ, system, or body part that shares a common ancestry in multiple organisms (hands) Analogous structure- common traits found in different groups of species which are anatomically different, serve the same function, but evolved independently in the different groups of species Out of africa hypothesis and agricultural revolution Out of africa- a model for the origin and dispersal of modern humans Agricultural revolution- when farming techniques drastically improve within a relatively short period of time