BIOLOGY Unit 6 Cycle Practice

1. Using the dendrogram or cladogram to the left, which species is more closely related to the sea lions, bears or seals? Explain your answer. Seals because they share the same evolutionary branch. 2. If an organism has genes that improve their ability to survive and reproduce then what will most likely increase? The frequency of that gene within the population.

3. Why does a pesticide used to kill insects lose its effectiveness over time?

The insects become resistant & pass that gene for resistance onto their offspring.

4. Present day whales evolved from ancestors that had four legs. What would the fossils look like to support this theory? The older fossils will have four limbs and the more recent fossils will have flipper-like appendages.

Species 1 ATGTAGC Species 2 ATCTGAC Species 3 AGGTACC Species 4 AGGCGGC 5. Four species with a homologous section of DNA have the following nucleotide sequences. According to the information, which 2 species are more closely related? Explain why. Species 1 and 3 because they only have two differences in their DNA.

6. What type of structure is depicted in the picture below?

HOMOLOGOUS

7. If you and a different species shared the structure illustrated in question #6, what could you say about your evolutionary history? They have a common ancestor 8. Label the speciation diagrams on the right and explain the difference between the two.

Gradualism – adaptations occur slowly (gradually)

Punctuated – adaptations occur quickly/rapidly & there is a distinct change in the species

GRADUALISM PUNCTUATED

9. Wolves that live in snowy climates often prey on rabbits. Some rabbits can move quickly across deep snow because they have large feet that don’t sink into the snow. Rabbits without this adaptation move more slowly across the snow. Explain how natural selection might cause a rabbit population to change over time & how would the rabbits look as a result of the changes. The population would change over time because rabbits without the adaptation (small feet) would frequently be preyed on, lowering their reproductive success and limiting their alleles in the population. The larger footed rabbits (the fittest for their environment) would then be able to reproduce, increasing the frequency of the large foot alleles until a majority of the rabbit population exhibited the trait.

10. The fossils found in layer D resemble those found in layer C. This similarity suggests that – may have evolved from earlier forms of life

11. What major change in the environment occurred after layers D and E? A large sudden change in the environment that removed the source of water. 12. Two species of Antelope squirrels are on opposite sides of the Grand Canyon. What mechanism of evolution led to the speciation of these animals? Geographical Isolation which will lead to greater genetic variety.

13. Scientists studying the moth population in the woods of east Texas found the distribution of moth wing color shown in the graph to the right. The woods contained trees with bark that was mostly black. Two years later a fungus attacked nearly all of the trees in the woods and the tree bark changed from black to patches of gray & white. Which graph shows the probable distribution of moth wing color within the next several years?

Bonus: Define denatured and inhibited. Denatured is to change the properties or alter the quality of something. Inhibit means to prevent/stop.