First Life

• The first life forms on Earth did not need oxygen.

Who or what were these organisms?How about _________!!!!!!!!!!!!!!!!_________ are not complete organisms.

They need other organisms to provide nutrients to live

SO!!!!!!!!!!!!!!!!!

2.5 b.y.a.

• Oxygen build up primarily due to organisms that perform photosynthesis.

• These photosynthetic organisms are called _________.

• Today cyanobacteria live in all green plants and are called?

_________

• Most of the first oxygen reacted with iron forming _________(rust).

• Once the available iron finished reacting, oxygen began to accumulate in the atmosphere.

• _________ began to accumulate in the atmosphere about 2.5 billion years ago.

• Ocean dwelling organism appeared in the fossil record about 540 million years ago (m.y.a.).

Precambrian Fossils

_________ – are layered mounts of calcium carbonate, which are the remains of material deposited by algae.

Paleozoic Era: Life Explodes

The Paleozoic ear is made of several periods including:

• Permian – youngest period• Pennsylvanian• Mississippian• Devonian • Silurian• Ordovician • Cambrian – oldest period

Early Paleozoic History

During the Cambrian, Ordovician, and Silurian periods, the vast southern continent of _________ included:

• South America• Africa• Australia• Antarctica• India• And perhaps China

North America

• was most likely on or near the equator.

• had no living things, plant or animal.

• Later on North America collides with Africa beginning the formation of the Appalachian Mountains and continues for 200 million years.

• By the Silurian period, shallow seas or epicontinental seas covered much of North America.

• Many barrier reefs prevented circulation between the shallow marine basins and the open ocean.

• As the water evaporated salt and gypsum deposits formed.

_________ 2.7 b.y.a

• We now have the basic part to make all forms of life

• We just need to make things more and more complex

• _________ must adjust to do different kinds of jobs

What is the name of the 1 celled life form in the oceans?

• _________

•represents all animal life to come

• _________

•represents all plant life to come

Plankton – 1.8 b.y.a.

Colonial organisms

• _________ critters that are not very specialized

_________ _________ -

(polyps)_________

Early Paleozoic Life

Life at this time is restricted to the oceans. All forms of life were invertebrates.

1- _________ – bottom dwelling scavengers. They occurred in more than 600 types. They were the _________ form of life at this time.

Paleozoic Era - Cambrian period

Dominant form of life is the trilobite

A. Body segmentsB. Head shieldC. Tail shield

2 – _________ – these shelled organisms replace trilobites as the dominant form of life. Except for one species, brachiopods are extinct today.

• Their larvae were free swimming, but like oysters and clams, these shelled animals were attached to the ocean floor.

Paleozoic Era - Cambrian period

•brachiopods are present [ forerunner to the _________]

3 – _________ – cousin to the octopus and squid. These highly mobile _________ were the major predator of the time.

• Cephalopods were the first large animal on Earth.

• By the end of the Ordovician many organism were able to secret material to form hard parts such as an exoskeleton.

Paleozoic Era –Ordovician505 – 440 m.y.a.

•cephalopods (_________)

oldest one is the _________

Late Paleozoic

The tectonic reorganization of Earth’s landmasses into one supercontinent called _________.

Late Paleozoic History

• North America collides with Africa closing the narrow sea that separated them.

• As this collision continues the rest of the Northern Hemisphere continents join them.

• This resulted in the formation of the northern continent of _________.

• By the Permian, Gondwana has traveled north and collides with Laurasia.

• By the end of the Paleozoic _________ is formed.

Late Paleozoic Life

• Plants living at the water’s edge move onto the land.

• These plants were leafless vertical spikes about the size of your index finger.

• By the end of the Devonian Period (40 million years later) there were forests.

• The first forests were in _________ …..

_________

First primitive fish_________

Paleozoic Era – Silurian440 – 410 m.y.a.

• Appearance of _________ water fish.• 1st land critters appear and

were????? _________

Including: _____________________________________________

Paleozoic Era - Devonian Known as the AGE OF FISHES

• _________

_________ __________________

• _________

all modern fish

• Amphibians diversified on land because they had no major competitors.

• By the Pennsylvanian period large tropical swamps extended across North America, Europe, and Siberia.

• Coal deposits today resulted from these swamps.

Lobe fin became the ancestor of

_________