Historical Geology Exam #2

Which of the following likely facilitated the earliest forms of life?

RNA

Radiometric Dating

*Most sedimentary rocks are unsuitable for radiometric dating.

Fossils generally form only under specific conditions

- Organism had a durable Skeleton - Lived where burial in sediment was likely - Avoided decay, scavenging and metamorphism (quick burial)

Which observations led Wallace to understand how species change over time? List all the statements that apply. _________________

- The traits in a population vary from one individual to the next. - Populations tend to produce more offspring in each generation than will survive. - Individuals with traits that give them a slight advantage over other individuals in a population will survive, and over time individuals with those traits will outnumber other individuals.

The image below is the famous "I think" sketch that appears in one of Darwin's notebooks. Which observations from the list below support the ideas presented in Darwin's sketch? List all the statements that apply. _______________

- Tortoises from different islands of the Galápagos have different shells. - Fossils of extinct animals resemble animals living today. - Mockingbirds on different islands of the Galápagos have different markings.

Biozones

- defined by fossils

Lithostratigraphy

- uses rock types without the consideration of age or mode of origin Basic Unit is called formation

4 principles of stratigraphy:

1) original horizontality 2) lateral continuity 3) superposition 4) cross-cutting relationships

Precambrian time accounts for about ________ percent of Earth history.

88

Unconformity

A break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time.

Walther's Law

A concept holding that the facies in a conformable vertical sequence will be found laterally to one another.

Principle of Inclusions

A rock must exist in order for it to be included in another rock

Disconformity

A type of unconformity in which the beds above and below are parallel.

Body Fossils consist of _____________________________.

Actual skeletal parts of animals

Nonconformity

An erosion surface cut into plutonic rocks or metamorphic rocks that is overlain by sedimentary rocks.

The Principle of Inclusions

Any clasts contained within a rock are older than the rock that contains them.

Which observation led Wallace to conclude that all species are connected in a tree of life? ________

Around the globe, the more similar two species are, the closer to each other they tend to live.

What is the name of the "explosion" that gave rise to the Ediacaran fauna?

Avalon

What sign of life may be found in the Hadean?

Biogenic Carbon

Which pair of characteristics (similarity and difference) are both correct comparisons of Darwin and Wallace?

Both Darwin's and Wallace's ideas about natural selection were revealed to the scientific community at the same time. Darwin's ideas about natural selection were inspired by what he observed on the Galápagos Islands, while Wallace's ideas about natural selection were inspired by what he observed on the Malay Archipelago.

Unaltered remains have not undergone any change in ______________ or _______________ of the organism.

Composition or Structure

Altered remains have undergone some amount change in _____________________ and/or _____________________________ of the original material.

Composition or Structure.

Chronostratigraphy

Correlates using time but requires radiometric ages or single identifiable events.

Where could the primordial energy necessary for life have come from?

Deep Sea Hydrothermal Vents

Cratons consist of buried pairs of platforms

False

Oxygen levels have remained relatively stable throughout Earth history.

False

The oldest rocks on Earth are from the Hadean eon.

False

Index Fossils

Indicative of a certain period of time.

The Principle of Faunal Succession

Layers with older fossils were deposited before layers with younger fossils.

Geologist use a combination of all three approaches (Chronostratigraphy , Biostratigraphy, and Lithostratigraphy) depending on ________________.

Location

Inclusions

Magma moves up through pre-existing layer, pieces of those layers break off and form clasts.

Trace Fossils

Not actual remains but an indication of organic activity such as tracks, trails, burrows, and nests.

Angular Unconformities

Occur when lower beds are deposited,tilted, the eroded. Upper beds are deposited flat.

Superposition

Oldest on bottom; youngest on top

Sedimentary Rocks

Preserve evidence of surface processes and evolution of life.

Comformable

Rock layers that are stacked without interruption.

Lateral continuity

Rock layers will continue across and opening, river channel,etc

Which supercontinents existed during the Proterozoic?

Rodinia and Pannotia

Original Horizontality

Sediments settle in nearly horizontal layers

Vast areas of exposed ancient rocks are found on continental ________ .

Shields

Stratigraphy

Study of geological record and primarily focused on the study of sedimentary rocks.

Which statement about the Hadean is accurate?

The Moon formed.

Fossil Record

The record of ancient life

Fossils

The remains or traces of prehistoric organisms preserved in rocks, are most common in sedimentary rocks, but they may also be found in volcanic ash and volcanic mudflows.

Cross-cutting relationships

The structure is younger than the rocks it cuts acrosse.g. The great canyon: the rocks had to be there before the running water could cut through it, so the Colorado river is younger than the rocks

The diagrams here illustrate the bones in the forelimbs of four different organisms. Although these limbs all look different, they share some common patterns. These common patterns suggest that ________

These organisms share a common ancestor.

One of Alfred Russel Wallace's motivations to travel to South America and the Malay Archipelago collecting plants and animals was to sell his specimens to museums and collectors. What was Wallace's other major motivation? ________

To understand the origin of species.

Trace fossils include indications of organic activity including ____________________________________________________________________________________.

Tracks, trails, burrows, nests or feces called coprolites.

Although plate tectonics was present in the Archean, the style of plate tectonic activity was different due to higher Earth temperatures at the core.

True

Archean rocks are typically granite-gneiss complexes and greenstone belts.

True

During the Hadean, Earth was a hot, barren, planet without large pools of water, bombarded by comets and meteorites.

True

Life was almost wiped out by an increase in oxygen content in the atmosphere.

True

The image shows the bones found within the flippers of manatees. Similar bones are found in the flippers of whales. True or false? Based on his observations of these seemingly useless structures and others like them, Wallace concluded that every species is a modified form of an older species.

True

True or false? Wallace concluded that the islands west of the line were at one time connected to the continent of Asia, while the islands to the east of the line had been connected to Australia, but that the western and eastern islands had never been connected to each other.

True

If there is a long period of geologic time without a rock record it is called an ____________________.

Unconformity

Hutton's Unconformity was one of the first things he noticed that led to the development of _____________.

Uniformitarianism

Range Zones

Zones over which a particular fossil group is found.

Concurrent Range Zone

Zones over which several fossils are all found together

Sedimentary Facies

a body of sediment with distinctive physical, chemical, and biological attributes

For abiogenesis to occur, what must be present?

an energy source

When Charles Darwin set sail on his five-year journey on the HMS Beagle, both he and most of his contemporary scientists thought that ____________________.

each species was specially created by God in its present form and did not change over time.

Darwin and Wallace both gathered a large number of observations and facts on which they based their theories. Which of the following types of evidence was NOT part of the evidence they gathered? ________

fossil evidence

Nonconformities

generally occur when sedimentary rocks are deposited on igneous or metamorphic rocks.

Disconformities

indicative of long pauses in sedimentary deposition with some erosion before deposition begins again.

Marine Transgression

invasion of a coastal area or much of a continent by the sea as sea level rises, resulting in a landward migration of the shoreline

Surface water on Earth likely came from which two sources?

outgassing and comet bombardment

The first organisms on Earth such as bacteria consist of ________ cells, and ________ contain an internal, membrane-bounded nucleus.

prokaryotic; do not

geological record

record of geological activity as appearing in the layers of rocks and sediment over geological time

Lithostratigraphic Correlation

relates geologic formations to one another based on rock type alone.

Marine Regression

sea level falls, exposing former sea floor as a land area

Biostratigraphy

uses fossil content without regard to rock type or time of origin *Biozones

angular unconformity

where horizontally parallel strata of sedimentary rock are deposited on tilted and eroded layers, producing an angular discordance with the overlying horizontal layers

Select all the rules for life:

~A living thing must work to avoid decay and disorder ~A living thing has to create a closed system ~They have some molecule that can carry information ~This info must evolve by natural selection

Select all the accurate statements about RNA & DNA.

~RNA can fold and do things in a way similar to proteins ~A "U" replaces "T" in the coding for RNA ~DNA has a double helix structure