Evolution Test Study Guide Part 2

Embryology & Evolution Scientists can look at embryos of different vertebrate species and see that they have many similar features. Similarities in embryos suggest an evolutionary relationship. For example chicken and rabbit embryos both have gill slits and tails.

Vestigial Structures & Evolution Some species have structures on their bodies that seem to have no function. Scientists hypothesize that vestigial structures are body parts that once functioned in an ancestor. For example snakes have pelvic bones but they don’t use them, indicating that their ancestors may have had legs which would have used the pelvic bone.

Homologous Structures & Evolution When looking at some structures in different species, you can see significant similarities even though those structures may not be used for the same thing. Homologous structures often indicate that two or more species share common ancestors. For example a human arm and a whale have the same number and arrangement of bones indicating that there may have been a common ancestor between the two.

DNA & Evolution DNA is the genetic material of an organism. If you have two species have similar DNA it may mean that they are closely related or have a common ancestor. For example a human and a chimpanzee have about 98% of the same DNA indicating that they are closely related.

Fossils & Evolution Fossils are the remains, imprint, or trace of a prehistoric organism. Scientists use fossils to compare species and determine how a species has changed over time. For example, by looking at fossils of the bones of the forefoot of horses scientists can show the evolution of a 5 toed horse to the horse that we have today.

4 layers of the Earth Crust Mantle Outer Core Inner Core

Divergent Boundary A plate boundary where two plates move away from each other.

Convergent Boundary A plate boundary where two plates move toward each other.

Transform Boundary A plate boundary where two plates move past each other in opposite directions.

Subduction The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary.

Convection The transfer of thermal energy by the movement of a fluid. Convection currents in the mantle drive the movement of the tectonic plates.

Pangaea The name of the single landmass that broke apart 200 million years ago and gave rise to today’s continents

What is the greenhouse effect & how does it impact our global climate? The greenhouse effect is the trapping of heat near the Earth’s surface. Without the greenhouse effect, Earth would be much colder. If we continue to add to the greenhouse gases in the atmosphere, the Earth will continue to get warmer.

How will global warming, over many thousands of years, affect the way primate species will have to adapt and evolve to survive? Primates will need to migrate to cooler climates. Primates may need to lose body hair. Primates may need to evolve to be able to drink salt water because fresh water will be scarce. Primates such as Monkeys and Apes will need to find new shelters because there will be few trees to use because of less rain. Primates may need to adapt to eating new foods because plants will be scarce.

What evolutionary changes might be linked to climate changes over millions of years? Climate change will cause the earths temperature to rise causing changes in weather patterns, flooding, and loss of organisms. Loss of body hair Ability to drink and process salt water. Lower body temperatures for mammals due to increase in temperature. Creating new foods due to plant decrease. Migrating underground to find cooler temperatures.