The Precambrian Earth to the present.

4.5 Billions years in 2 weeks!

PowerPoint Notes created by S. KoziolDate : 12/30/2013 Revised : ?/?/??

Objectives Slides 2-21

DescribeDescribe the evidence used to determine the age of the Earth

UnderstandUnderstand why scientist theorize that the early Earth was hot.

ExplainExplain the origins of Earth Crust.

DescribeDescribe the formation of the Archean and Proterozoic continents.

DescribeDescribe the formations of Earth’s atmosphere and oceans.

IdentifyIdentify the origins of oxygen in the atmosphere.

ExplainExplain the evidence that oxygen existed in the atmosphere during the Proterozoic.

DescribeDescribe the experimental evidence of how life developed on Earth.

DistinguishDistinguish between prokaryotes and eukaryotes.

IdentifyIdentify when the first multicellular animals appeared in geological time.

Earth & our Solar SystemMost astronomers agree that the solar system, including

Earth, formed all at once, and therefore Earth and meteorites should be about the same age.

Earth’s Crust

Earth’s earliest crust likely formed as a result of the cooling of the uppermost mantle.

Oldest MineralThe oldest known mineral on Earth is zircon.

Laurentia (North American Craton)

Ancient continent that contained core of modern-day North America

Precambrian shield

Continental core of Archean and Proterozoic rock. aka Canadian shield - The Precambrian shield in N.A.

Craton is an old and stable core of the continental crust - the buried and exposed parts of a continental shield together compose it.

Precambrian shield vs. Canadian shield

A Precambrian shield is a continental core of Archean and Proterozoic rock

The Canadian Shield is the Precambrian shield of North America.

Orogens

Orogens are seams where microcontinents were joined together. These seams are belts of deformed rocks that form mountain ranges.

Ozone & O2

The ozone layer that filters ultraviolet radiation originated from oxygen produced by stromatolites.

OutgassingThe process by which volcanoes vent water

vapor, carbon dioxide, nitrogen, and other substances is called outgassing.

PhotosynthesisCyanobacteria use the process of photosynthesis

to produce energy, and oxygen is given off as a waste product.

Banded iron formationThese are deposits consisting of alternating bands of chert

and iron oxide.

Red beds

Sedimentary rocks younger than 1.8 billion years that are colored by the iron oxides in them.

Start of lifeAmino acids have been found in the waters of

hydrothermal vents, suggesting that proteins and nucleic acids could have formed there during the Archean.

Miller and Urey

Miller and Urey demonstrated that the basic building blocks of life were most likely present on Earth during the Archean.

Miller and Urey (continued)

Heat, cyanide, and certain clay minerals can cause amino acids to join together in chains.

Prokaryote.An organism composed of a

single cell that does not contain a nucleus and is the simplest kind of cell is a prokaryote. Prokaryotes belong to the Kingdom Monera.

Prokaryote vs. EukaryoteA prokaryote is a simple

organism composed of a single cell, which does not contain a nucleus.

A eukaryote is an organism that is composed of multiple cells, which contain nuclei and are more complex and larger than those of prokaryotes.

ExtinctionsA major extinction of acritarchs occurred near

the end of the Proterozoic, in which widespread glaciations may have played a critical role.

Objectives Slides 23-38 DescribeDescribe the paleogeography of Laurentia.

DiscussDiscuss the concept of a passive margin.

DescribeDescribe the Cambrian fauna.

DescribeDescribe the Middle Paleozoic paleogeography.

ExplainExplain the concept of an active margin and the formation of a clastic wedge.

DescribeDescribe the Middle Paleozoic fauna.

DefineDefine the concept of mass extinction.

DescribeDescribe the formation of Pangaea.

ExplainExplain how cyclotherms formed.IdentifyIdentify the importance of

amniote eggs.DiscussDiscuss the causes of the Late

Permian mass extinction.

Paleogeography

Ancient geographic setting of an area.

LaurentiaDuring the Cambrian, Laurentia was covered by

a sea.

Laurentia - PrecambrianOn Laurentia, large, sandy beaches formed when sand-sized

fragments of quartz were weathered from the rocks of the Precambrian Shield and transported to the shoreline.

Passive MarginWhen there is no tectonic activity along the

edge of a continent, the edge is referred to as a passive margin.

Cambrian explosion

During the Cambrian explosion, all but one of the major marine phyla appeared.

Cambrian explosion (continued)

The Cambrian explosion was marked by great diversity of life, including the development of animals with skeletons.

Burgess Shale

Burgess Shale - Contains fossils of soft-bodied Cambrian organisms

Evidence of past lagoons

Fragile organisms can live in a lagoon, which is the calm area behind a reef.

Reefs

An organic reef is a structure composed of carbonate skeletons made by living organisms, such as coral.

Taconic Orogeny

Taconic Orogeny - Mountain-building event named for the mountains of eastern New York State

Clastic Wedge OriginsA triangular-shaped deposit composed of

sediment eroded from adjacent mountains is called a clastic wedge.

The following provides evidence of the Taconic Orogeny:

• angular unconformities• clastic wedges• igneous intrusions

Vascular PlantsThe ability to transfer water through stems and

stalks characterizes vascular plants.

Ancestral Rockies

Mountain range in present-day Colorado formed by inland uplift.

Mountain Building

The Late Paleozoic was a time of active mountain building.

Cyclothems

The series of transgressions and regressions that produce cyclothems were likely produced by glaciations.

Objectives Slides 40-59 ExplainExplain the breakup of

Pangaea.DistinguishDistinguish between the

different characteristics of Mesozoic Orogenies.

Describe Describe how paleontologists distinguish among reptile, dinosaur and mammal fossils.

DescribeDescribe the type of tectonism that characterized the Cenozoic orogeny.

Understand Understand the extent of glaciation that occurred in N.A..

DiscussDiscuss the changes in animals in N.A. during the Cenozoic.

IdentifyIdentify the characteristics of primates.

ExplainExplain what separates hominids from the other hominoids.

200 MYAAs North America rifted from Europe and Africa, a

continuous rift system called the Mid-Atlantic ridge was formed.

New OceansAs Pangaea split apart, the rifts flooded to form

new oceans.

Pangaea break-up

Pangaea probably broke apart because it held heat beneath it, which caused the continent to expand and then fracture and break apart.

Mesozoic orogeniesAs a result of the earliest of the Mesozoic orogenies

in North America, large bodies of granite called batholiths exist throughout the Cordillera.

Mesozoic orogenies (continued)

Orogenic events at the end of the Mesozoic uplifted massive blocks of crust to form the Rocky Mountains.

First Angiosperms

Angiosperms - Seed-bearing plants that have flowers

Archaefructaceae

PhytoplanktonTiny, ocean-dwelling organisms called

phytoplankton made up the base of the food chain during the Mesozoic.

Vertebrates and Invertebrates from among the modern fauna.

Vertebrates: bony fishes, sharks, aquatic reptiles, and aquatic mammals

Invertebrates: crabs, lobsters, shrimps, sponges, sea urchins, modern corals, snails, and clams.

Mesozoic ammonitesFossils of ammonites are often used as index

fossils because these marine animals were widespread and abundant during the Mesozoic.

Early Mammals

Early mammals with a single jawbone arose from mammal-like reptiles.

SauropodThe largest land animals that ever lived were the

quadrupedal, plant-eating sauropods.

S.W. U.S. tectonism

The subduction of the East Pacific Rise coincides with pull-apart tectonism in the southwestern United States.

Pliocene ice ageAs the Pliocene ice age began, great savannas

became arid land and many savanna mammals became extinct.

Pliocene ice age (continued)

The change of climate caused many of the savanna mammals to become extinct. New animals came to populate the land, including sabre-toothed cats, mammoths, giant vultures, giant ground sloths, and huge wolves.

Pliocene ice age (continued)

During the Pliocene, the water of the Arctic Ocean began to freeze to form an arctic ice cap. Glaciers from the arctic advanced and retreated in at least four stages over North America. Glaciers extended as far south as the present-day Ohio and Missouri Rivers.

Pliocene ice age (continued)

The southernmost point to which glaciers advanced in North America is marked by the paths of the Ohio River and the Missouri River.

Eocene Mammals

Most of the currently living groups of mammals had appeared by the Eocene.

Primate Traits

Primates - Mammal possessing specialized traits related to arboreal lifestyle

Primate Traits (continued)

Two important anatomical traits of all primates are an opposable thumb and forward-facing eyes.

Us (you & I)Homo sapiens - Modern human species