Evolution Chapter 15

What are two reasons for focusing on endemic species?

-extinctions are common in such species -it is much easier to study extinction in endemic species because local extinction becomes synonymous with global extinction.

What are the three things paleontologists look for when deciding dig sites?

1. Fossilization likely to happen in that region 2. Other scientist are searching nearby 3. Prediction from phylogenetic reconstructions, rocks analysis etc

How many mass extinctions have there been?

5 mass extinctions

What precentage of species must be lost for a mass extinction to occur?

75%

What sorts of evidence do you think could be used to infer that human hunting was a factor in the extinction of Pleistocene megafauna?

A number of answers would be correct here. For example, we might look for marks on fossil bones that indicate that animals were hunted by humans using weapons that the archeological record shows were produced during this period.

What is carbonization?

A process of fossil formation wherein thin layers of carbon are laid down on sandstone or shale.

This person estimated the relative abundance of major plant taxa on the basis of evidence from the fossil record.

Andrew Knoll

What fungus is to blame for the decline in the amphibian population?

Batrachochytrium dendrobatidis

What are two examples of fossils found in Lagerstatten?

Burgess shale fossils and fossils from the Ediacaran period

This refers to the standard rate of extinction in earth's geological and biological history before humans became a primary contributor to extinctions.

background extinction rate ; normal extinction rate

Signor-Lipps effect is a form of...

backward smearing

The K-Pg boundary denotes the end of the _______ period and the begining of the _____ period.

crestascous / Palegene

Signor-Lipps effect can cause paleontologists to date an extinction _______ than it actually occurred.

earlier (AKA backward smearing)

This is a burst of rapid speciation in a taxon, often associated with entering a new, relatively unoccupied niche.

evolutionary raditation

This is extinction later than it actually occurred

forward smearing

what must an organism have in order to be fossilized?

hard parts

Where is good to study predation?

islands (channel islands)

What is anti-predetor behavior in squirrels?

kick dirt and rocks at snakes in order to defend itself

This is the principle that, barring some kind of disturbance, fossils found lower down in the sediment at a particular locality will be older than those found closer to the surface.

law of superposition

This is the method of estimating fossil dates based on shifts in Earth's magnetic field by measuring the alignment of metal particles in the substrate in which the fossil was found.

paleomagentic dating

This is a technique for dating geological strata by using the decay rate of carbon-14 to nitrogen-14.

radiocarbon dating

If there had not been a mass extinction about 65 million years ago...

reptilian dominance of the land would likely have continued for some amount of time, which in turn might have kept mammals as they were—small, mouse-sized, nocturnal creatures.

the tuatara is a representative of a deep phylogenetic lineage parallel to the _________.

squamate reptiles (lizards and snakes)

The "fossil record" refers to the placement of fossils throughout the ________ of the Earth.

surface layers

What are ways we can date fossils?

the "law of superposition", Signor-Lipps effect, backward smearing, and forward smearing.

A mass extinction typically refers to...

the wholesale loss of many groups of organisms over a broad geographic range.

How do paleontologists minimize forward smearing effect?

they look for burrowing in the strata

When a new taxon arises, it often increases sharply in frequency and drives other taxa...

to lower abundance.

What are the 5 mass extinctions?

Ordovician, Devonian, Permian, Triassic, Cretaceous

This is the lag between the last observed fossil of an extinct species and the actual date of extinction.

Signor-Lipps Effect

What is something that can disrupt the process of fossilization?

When an organism dies in areas conducive to fossilization, predators and scavengers often leave little of the organism behind. Soft tissues rarely remain long enough to fossilize, which is why so much of what we see in the animal fossil record consists of hard substances that were once teeth, bones, shells, exoskeletons, and so on.

What is Lagerstatten?

German for mother lode. Huge site of preservation of soft body parts and soft bodied organisms.

This was a mass extinction of some three-quarters of the plant and animal species on Earth that occurred over a geologically short period of time approximately 66 million years ago.

The Cretaceous-Paleogene (K-Pg) extinction event (AKA: Cretaceous-Tertiary (K-T) extinction)

What is the fossil record?

The history of life on Earth as recorded by fossil evidence

What is megafauna?

The large land animals of a particular region, habitat, or geological period. Mammoths, American Cheetahs, giant bevers.

What population has shown a major decline in the last 30-40 years?

amphibian population

What are some fossils that have been found in the La Brea tar pits of California?

ancient bison, wolves, and extinct camels