Ap Human Geography Chapter 25 Summary
Chapter 25
Process of fossilization
· Moving water can suspend sediment – inorganic particles
· Moving water fills into still body of water o Sediment flats to the bottom o Forms a layer o More layers form with different compositions on the bottom of the lake or ocean
· Living things in the ocean die and get buried in the sediments in the ocean
· A lot of weight and pressure pushing down
· The organic material is replaced by rocks – mineralization resulting in fossils
· Fossils: representations of living things that used to exist
· Ocean is not the only possibility for fossils to form o Wind can move a lot of sediments as well o Water is ideal but not only possibility
· Places …show more content…
o A yardstick for measuring the absolute time of evolutionary change based on the observation that some genes and other regions of genomes appear to evolve a constant rates o The number of nucleotide substitutions in orthologous genes is proportional to the time since the genes became duplicated o Rate of the clock may vary greatly between genes
· Neutral theory o Possible that many of the genetic changes result from genetic drift or are neutral (neither detrimental or adaptive) o Neutral theory: much evolutionary change in genes and proteins has no effect on fitness and therefore is not influences by Darwinian selection o If most are neutral, then the rate of molecular change should indeed be like a clock o Differences in a clock rate are a function of how important it is o More important = less neutral change, most harmful changes, change slowly o Less important = less harmful, more neutral, change quickly
· Difficulties with molecular clocks o Natural selection causes many irregularities o Have been used to date past the fossil record – highly uncertain o Problems may be avoided by using many genes
26.6 New information continues to revise our understanding of the tree of life
· Three domains are a level higher than the
Process of fossilization
· Moving water can suspend sediment – inorganic particles
· Moving water fills into still body of water o Sediment flats to the bottom o Forms a layer o More layers form with different compositions on the bottom of the lake or ocean
· Living things in the ocean die and get buried in the sediments in the ocean
· A lot of weight and pressure pushing down
· The organic material is replaced by rocks – mineralization resulting in fossils
· Fossils: representations of living things that used to exist
· Ocean is not the only possibility for fossils to form o Wind can move a lot of sediments as well o Water is ideal but not only possibility
· Places …show more content…
o A yardstick for measuring the absolute time of evolutionary change based on the observation that some genes and other regions of genomes appear to evolve a constant rates o The number of nucleotide substitutions in orthologous genes is proportional to the time since the genes became duplicated o Rate of the clock may vary greatly between genes
· Neutral theory o Possible that many of the genetic changes result from genetic drift or are neutral (neither detrimental or adaptive) o Neutral theory: much evolutionary change in genes and proteins has no effect on fitness and therefore is not influences by Darwinian selection o If most are neutral, then the rate of molecular change should indeed be like a clock o Differences in a clock rate are a function of how important it is o More important = less neutral change, most harmful changes, change slowly o Less important = less harmful, more neutral, change quickly
· Difficulties with molecular clocks o Natural selection causes many irregularities o Have been used to date past the fossil record – highly uncertain o Problems may be avoided by using many genes
26.6 New information continues to revise our understanding of the tree of life
· Three domains are a level higher than the