20. How are new species of organisms formed? An organism is considered a new if it cannot with other organisms that are like it If a population is from other populations (of the same species) for long enough, the separated population may develop enough differences to make impossible with the original population 21. What are the 4 major types of isolation that can cause a new species to form? isolation – mating dances, calls, or scents (pheromones) change prevent mating isolation – mountains, rivers, dried lake beds cause physical barriers that prevent mating isolation – reproductive patterns in seasons or time of day may change to prevent mating isolation – members of the same species from different populations cannot mate with one another
22. What is the difference between microevolution and macroevolution? How do scientists get evidence for macroevolution? is the genetic change observed in a population is the -scale change over all time Scientists get evidence for macroevolution from of the record
23. What types of evidence does the fossil record provide? diversity – the fossil record shows a vast amount of different living things in the history of life Mass – the fossil record shows large groups of organisms going extinct right before each new era the Precambrian, Paleozoic, Mesozoic, and Cenozoic eras Episodic – the fossil record shows that new characteristics in new species (speciation) show up in organisms right after mass extinction events.
24. What are the 5 factors that can lead to evolution? Genetic – random changes in allele frequencies cause different species to form Gene – movement of alleles to new populations cause changes – mutations can cause new alleles, which make new traits for nature to “select” selection – traits that improve mating are more likely to get passed on in offspring selection – nature “selects” traits that are more likely to lead to survival and reproduction