Since bogs are wet, the presence of small, hard leaves in bog plants is harder to explain. For each hypothesis, draw a phylogeny of plants that would support the hypothesis. Include bog plants with small hard leaves, desert plants with small hard leaves, and large leafed plants that do not occur in bogs or deserts in both phylogenies. L if the species has large leaves and does not occur in deserts or bogs, B if the species has small hard leaves and occurs in bogs, D if the species has small hard leaves and occurs in deserts. During their development, dogs initially have rounded, floppy ears.
Some dog breeds retain rounded, floppy ears throughout life.
Still other breeds go through the two previously described stages and then develop ears that are pointy and fully erect. Give an explanation for the evolution of sexual reproduction based on the impact of parasites on their hosts. Clearly explain why. Researchers attempting to use DNA based phylogenies to date the movement of human populations from Africa use the molecular clock hypothesis. To do this, they must have some way of determining the rate at which the DNA they are studying evolves.