Biology Study Guide C17, 18, and 20

v What are Index Fossils? How are they used?

Index fossils are distinctive fossils used to establish and compare the relative age of rock layers and the fossils they contain

v What is Archaeopteryx? Why is it significant to the study of evolution?

It is an example of a fossil which is an intermediary stage between reptiles and birds. And It indicates that birds evolved from reptiles

v List environmental requirements for natural selection to occur in a population.

It occurs in any situation in which more individuals are born than can survive, natural heritable variation affects the ability to survive and reproduce, and fitness varies among individuals. Environmental Pressure - (Change)

v What is the endosymbiotic theory?

It proposes that organelles in eukaryotic cells were formed when different types of prokaryotic cells joined in a kind of merger.

v What is the difference between background extinction and mass extinction?

Background extinction Is a extinction caused by slow and steady progress of natural selection and Mass extinction is a event in which many species become extinct during a relatively short period of time Correct. Extinction is natural and does regularly happen (I.e. so many species every 100 or 1000 years). BTW: this is why we are calling the Anthropocene that SIXTH mass extinction. The rate of extinction today is 100x to 1000x that of normal "background" extinction.

What don't fossils provide a complete record of all the extinct species that have lived on Earth?

Because not all fossils survive. . .they get destroyed by water, human cause, nature causes and more. And they are very fragile

v Why is the long bill of the hummingbird illustrated here and example of an adaptation?

Co-Evolution

v In a population of land snails, both light-colored and brown-colored snails are better able to blend with their marshy everglades environments. In this case, the light-colored and brown shell colors are favored by natural selection over the intermediate tan color. Which type of natural selection is illustrated by this example?

DISRUPTIVE SELECTION

During the Industrial Revolution in Britain, many new factories were built which released dark clouds of smoke into the atmosphere. Dark grey moths survived attacks by birds more often than the salt and pepper colored moths. Over time, salt and pepper moths disappeared from the area. This change in the population is an example of

Directional Selection

What is a fossil? Provide examples.

Fossils are preserved remains or traces of ancient organisms Some examples are dinosaur bones and footprints

v Define species.

Group of similar organisms that can be breed and produce fertile offspring

v Compare / contrast analogous and homologous structures.

Homologous structures are structures that are similar in different species of common ancestors and Analogous structures are body parts that share a common function, but not a evolutionary history

v Human birth weight is typically between 6 and 9 pounds. Larger babies have trouble passing through the birth canal and thus present higher complications for both mother and themselves. Lighter birth weights have trouble keeping warm and may be more prone to infections. Which type of natural selection is illustrated by this example?

STABILIZING SELECTION

v Give an example of fitness using wolves as an example.

So "unfit" wolves would be slow or not have enough stamina or have not so good a sense of smell... etc.

v Why are a variety of genotypes and phenotypes in a population useful in ensuring the survival of the species?

So the variety in the genome allows for the species to survive when environmental pressure changes

v A scientist detects a certain amount of radio-active isotope in a sample artifact. This isotope has a half-life of 5700 years. If only 1/8th of the C-14 that should be present is detectable; what is 'ball-park' age of the fossil?

So, given the half-life of C14; in 5700 years, there will only be ½ the original C14 remaining. In 11,400 years ¼; in 17,100 years, 1/8 ... and so on.

v Why is the appendix in the alimentary canal of Homo sapiens a vestigial structure?

The appendix is a vestigial structure because we don't need It and use it anymore.

v What about early Earth's atmosphere supported the emergence of life that today's atmosphere lacks?

There was not enough oxygen in the atmosphere and taking one breath there might have killed you.

The idea that continents are not fixed, but instead, their position and position of the oceans have changed over time is referred to as

plate tectonics

Charles Darwin was a... ?

son of clergy who worked with natural history and hired on as ship's naruralist on the Beagle's voyage around the world. From those observations, Darwin formulated his premise of Natural Selection.

v What is the Law of Superposition?

the oldest layer is at the base and that the layers are progressively younger

v What is implied by the finding of similar fossils in the limestone layers of two mountains on different continents separated by an ocean? What other evidence might support this supposition?

they were connected in the supercontinent or "Pangea" and were together. In other words, they evolved PRIOR to the separation of the continenets. E.g. it is how we know that cats evolved AFTER the breakup of Pangea (separation of Australia).

Write the equation for the Hardy-Weinberg law. What is indicated if, after counting numbers of alleles in a population, the equation balances?

v IF the equation is equal to 1 that means that no evolution is occurring. P^2 + 2pq + q^2=1 and p+q=1