Unit 7 Day 3 – Evolution + Ecology Name: __________________________________________________Standard: 5.4 Date: _______________________________ Period: ___________

Fossils, Biodiversity & Extinction GUIDED PRACTICE1. In the cross section of the Earth shown below, which

rocks are the oldest? How do you know?

2. If you found a fossil in layer B and were looking for organisms that lived more recently than this fossil, what layer of the Earth would you look at first? WHY?

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5. The diagram to the right shows the homologous bones in the forelimbs of three different organisms. Differences in the bone arrangements support the hypothesis that these organisms…

6. Similarities in the bone arrangements support the hypothesis that these organisms…

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8. Which population of fungus would you expect to have more biodiversity and survive in changing environments? Population A, composed of organisms that reproduce asexually, or Population B, composed of organisms that reproduce sexually? WHY?

9. Genetic variability in a population is often measured by the proportion of genes that are heterozygous (percent heterozygosity). Based on this information, which lizard species is most vulnerable to extinction? WHY?

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14. Researchers arriving at an uninhabited island accidently introduced field mice, a species not previously living on the island. Which organisms could become extinct because of the introduction?A. organisms that prey on field mice B. organisms that require less water than field

mice

C. organisms that eat the same food as field mice D. organisms that reproduce more quickly than field mice

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16. Salamanders can be found in many of the same mountain ranges of California but have different physical appearances, particularly in coloration. What is the best explanation for this observed biodiversity?

a. migration of animals into the environmentb. a lack of environmental change

c. genetic variation in ancestorsd. random changes in animals over time

17. Lake 1 has many different genetically diverse species of phytoplankton that provide oxygen for the fish living in the lake through photosynthesis. Lake 2 has only one species of phytoplankton with little genetic variation. Due to a chemical spill, there was a sudden decrease in pH levels, which made the lake water more acidic.

I. Which lake would you expect to contain more phytoplankton after this event? Why?

II. What would you expect to happen to the fish in each lake as a result? Why?

18. Hermit crabs are often found living inside the discarded shells of mollusks, such as periwinkles and whelks, in intertidal zones. As the crab grows larger, it must find a bigger shell in which to live. In one area, harvesters prefer to take only the largest periwinkles and whelks. These mollusks have begun to limit their growth in response.How is the response of the periwinkles and whelks likely to affect the

population of hermit crabs?A. The population of hermit crabs is likely to decrease in biomass and number.B. The population of hermit crabs is likely to increase in biomass and number.C. The population of hermit crabs is not likely to be affected by the response of the mollusks.D. The population of hermit crabs is likely to move onto land in search of other mollusks.

19. European settlers introduced rabbits into the wild ecosystems of Australia. After a few decades the rabbit population increased from two dozen to more than 10 million because the rabbits had few natural predators and were good at finding seeds and small plants to eat.How did the introduction of rabbits affect wild ecosystems in Australia?A. Rabbits kept farmers from cultivating wild Australian ecosystems.B. Rabbits restored the abiotic resources in wild Australian ecosystems.C. Rabbits reduced the amount of biodiversity in wild Australian ecosystems.D. Rabbits raised the number of native species in wild Australian ecosystems.

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