Diversity of Eukaryotic Life: Geologic History

geological time scale

Divides up the history of the earth based on life-forms that have existed during specific time periods

geochronologic units

These divisions are called _____________ _________ (geo rock, chronology time).

Fossils

Geochronologic units are often based on life forms that are found as _________.

Fossils

What are the preserved remains or traces of an organism from the geologic past called?

sedimentary

Fossils are most often found in ____________ rocks.

structure, function, environmental conditions

fossils provide information about organisms such as their __________, ______________, and ____________ conditions over geologic time.

low O2 environment

Why does sediment preserves the fossils better?

mold, cast, petrified, carbonized, trace

What are the fossil types?

mold fossil

when sediments bury an organism and the sediment hardens into rock - BURIES AND HARDENS

• the organism slowly decays inside the rock leaving a cavity filled mold of the organism

cast fossil

when sediment fills an organism which decays it takes ton the shape of the organism

petrified fossil

minerals such as calcium penetrate the buried remains of an organism —→ minerals replace the decayed organics and this becomes rock

carbonized fossil

when organism parts pressed between layer of sediment that hardens over time, organism decays and leaves a carbon imprint in the rock

trace fossil

when sediment hardens into rock after a footprint, trail burrow, or contents of gut was left behind.

evolution

fossil record is useful for understanding _______ of life over geologic time.

morphorological similarities

fossils can also show _________ _______ and differences in organisms over time revealing chaining in species diversity.

relative age

“______ ___” dating relies on methods to estimate the age of one object compared to the age pf another. not an exact age

index fossils

relative age often relies on ______ _______.

novel traits

index fossils are widespread, are abundant throughout their geographic and geologic ranges, and are easily recognized by _____ _______.

trilobites

_________ are commonly used index fossils because they are easy to recognize

absolute ages

________ ______ of rocks can be assigned to geologic time scale on the basis of properties of atoms that make up the minerals of a rock.

isotope

the number of neutrons in a nucleus of am atom determines the ________ of the element just like the number of protons determines the identity of an element.

radioactive decay

what is the process called when some isotopes are unstable and break down into other isotopes?

precambrian

what is the oldest and earliest Eon?

Paleozoic, Mesozoic, Cenozoic

What are the 3 eras of the Proterozoic Eon?

cyanobacteria

_________________ (Domain bacteria) began prodicuong oxygen in the oceans by photosynthesis.

Precambrian and proterozoic

• time period of formation of earth

• no life possible as the earth initially forms 4.6 billion years ago

• life formed in oceans

• simple, single celled forms of life appear in fossil record ~3.8 billion years ago

• first prokaryotes evolve followed by eukaryotic

Early Paleozoic

541-252 mya

• age of fish

• contents one large land mass

• life evolves in oceans as concentrations of O2 increased = increased diversity (b/c of cyanobacteria)

• earliest land plants appear on land (mosses and ferns followed by seed plants (only gymnosperms — angiosperms appear later)

• all existing animal phyla also appear ( Cambrian explosion)

• abundance of trilobites (extinct arthropods) & brachiopods (extinct organisms with a two part shell)

Mid Paleozoic

• lycopods and ferns (monilophytes) are dominant plants

• jawless fish are comon

• invertebrates are also common

• winged insects appear and diversify ( insects are largest species groups today b/c of it becoming winged)

Late Paleozoic

• arthropods (trilobites) common

• echinoderms (crinoids) common

• fish with jaws appear

• Appalachians rise

• end of era marked by mass extinction

limestone

in tennesseee most ares are _________ (Paleozoic origin)

Crinoids

Fossil common in TN. ___________ (sea lilies) were related to starfish were very abundant curing mid Paleozoic.

ammonites, corals

Fossils common in TN. ________ (cephalopods), _____- ( cnidarians) and were abundant during Paleozoic.

Mesozoic

65 - 251 mya

• age of reptiles

• gymnosperms were dominant by mid ________ when conditions were dryer and cooler.

• angiosperms replace conifers as dominant plant in late _______ during warmer and wetter conditions

• most similar to present day climate

early mesozoic

• replies were dominant land animals

• first dinosaurs appear

• first mammals (small rodents)

mid mesozoic

• dinosaurs were abundant

• first bird appear

• American contents moved westward (Atlantic Ocean)

• as continental rifts formed, volcanic activity generated high CO2 concentrations (>1000ppm) creating a green house effect

late mesozoic

• first primates appear

• end of era marked by mass extinction with the demise of all flightless dinosaurs

cenozoic

66 mya - present “age of mammals”

• agio sperms are dominant plant life

• mammals are dominant animal life

• formation of many mountain ranges: rockies, cascades

• a lot of diversitification

early-mid Cenozoic

• tropical plants are common

• large mammals appear (whales, elephants etc.)

mid-late Cenozoic

• hominids appear ~7 mya (other mammals were dominant)

• during late _________ Homo sapiens spreads across the globe (~70,000 years ago)

Mass Extinction

The demise/loss of species

5

How many mass extinctions have we had?

increases

What happens to diversity after mass extinction?

late mesozoic

what is earth’s warmest period?

climate change

__________ _________ is the long term change in the average weather pattern that have come to define earth’s local, regional, and global climates

late cenozoic

what is earth’s coldest period?

extinction

__________ likely at norther latitudes. Polar bears snow leopards, puffins, alaskan caribou, snowshoe hares, narwhals, and moose are examples of animals at risk of extinction due to climate change.