sci mass extinction

• the fluctuation of temperature glaciation (decline in CO2) and heating events (440MYA)

  Ordovician extinction
• considered the deadliest because 96% of life back then was lost due to massive volcanic activity in Siberia- Acid rain, ocean acidification and global warming


  Permian Extinction
• Tons of CO2 were in the atmosphere due to volcanic eruption (ocean acidification and global warming) - 80% of life was lost


  Triassic extinction
• asteroid hit eart in the Yucatan Peninsula. Mexico and wiped out all dinosaurs along with roughly 60% of life on Earth - superheating and rapid cooling


  Cretaceous extinction
• Microevolution happens when the frequencies of alleles in a group undergo changes.
• Natural selection is a process wherein different environmental pressures lead to different ways of survival and reproduction, which can influence the frequency of alleles in a group
• Directional selection shifts allele frequencies caused by the change in the condition of the environment.
• Stabilizing selection happens when a middle form of the trait is chosen and the extreme forms are eliminated.
• Disruptive selection occurs if the extreme irms of traits are favored more than others.
• Genetic drift is a change in the gene pool of a group.
• A gene pool is the total collection of genes in a population.
• bottleneck effect will result in a drastic reduction of the population size, which can be causer by earthquakes, flash floods, and fires. This may cause the death of large numbers of randor organisms, resulting in a small surviving population. It will also reduce genetic diversity.
• founder effect happens after a small group of organisms form a new group, where their alle frequencies differ from the original group or original population.
• Alleles are different forms of a gene
• Mutation is present when there is a change in the DNA of an organism, resulting in the formation of a new allele
• Mutation is the cause of genetic variation
• Gene flow is also called gene migration
• Gene flow is the movement of alleles in a group of organisms.
• Who are the people who proposed the Genetic Equilibrium?

  Godfrey Hardy and Wilhelm Weinberg
• when was the Genetic equilibrium proposed?

  1908
• Give the 4 conditions to attain equilibrium

  1. Organism must be isolated
  2. There should be no Mutation in the gene pool
  3. mating from the population must be random
  4. There is no natural selection
• Macroevolution refers to the large scale changes that lead to an evolution of organism from simple to complex
• Geological time scale shows how the macroevolution happens for a ling period of time
• Adaptive radiation refers to the evolution of organism into several new ones that are living differently from the original population
• Divergent evolution happens when two isolated populations evolve seperately
• Isolated population is a population that could no longer interveeed witb the original population because it has become geographically seperated
• Speciation is a process where new species will be created
• Geographic isolation happens when the population is separated by a geographic batried
• Convergent evolution happens when the unrelated organisms seem ti look like each other
• what do u call the similarities in convergent evolution?

  Analogy
• Coevolution happens when two different interacting organisms evolve jointly due to the changes in each other
• what do you call the result in where each organism cant live without the other?

  interdependence
• land plants developed deep roots that released nutrients in the ocean. This caused the algae in the ocean to flourish - depleted the oxygen. Global cooling and sea level falling

  Devonian