Geo Sci 110 Final

Chronological order of the three ERAS of the Phanerozoic

1) Paleozoic
2) Mesozoic
3) Cenozoic
Pay My Children

3 periods of mesozoic era

1. Triassic
2. Jurassic
3. Cretaceous

3 periods of the cenozoic

1. Paleogene
2. Neogene
3. Quaternary

Age of earth

4.6 billion years old

When did the Phanerozoic eon begin?

541 million years ago

When did the paleozoic end? (think permian mass extinction)

252 million years ago

Age of the Cretaceous mass extinction

66 million years ago

Triassic terrestrial vertebrates

Therapsids

1) Despite suffering heavy losses, therapsids (mammal-like reptiles) recovered to dominate terrestrial vertebrate faunas for much of the ensuing Triassic Period
2) Early synapsid reptiles (pelycosaurs) gave rise to therapsids that, in turn, evolved into early mammals during the Triassic

Temporal Fenestrae: synapsid vs. diapsid reptiles

Amniotes possess temporal fenestrae in their skulls that are useful for classification & phylogeny
C) The synapsid has a singular temporal fenestrae - below the postorbital-squamosal contact
D) The diapsid has two temporal fenestra - one above, and one below the postorbital-squamosal contact

Exaptation and evolution of jaw/ear bones during reptile-mammal transition

Quadrate and articular bones are recruited to form inner ear bones.

Lobe fin fish(Hyomandibular became stapes in ear) - Early amphibian(Quadrate becomes incus in ear) - Therapsid(Articular became malleus in ear) - Mammal(Angular become middle ear housing, or auditory bulla)

Morganucodonts - what were they? When did they first appear in fossil record?

earliest mammals - appear in Late Triassic

When did first dinosaurs appear?

Triassic

When did first pterosaurs appear?

Triassic

Dinosaurs: Advanced mesotarsal (AM) joint in ankles of hind legs

Advanced mesotarsal (AM) joint in hind limbs for erect, bipedal posture. Astragalus is larger than calcaneum, and both of these ankle bones are fused to shin. Thus, the main foot hinge is positioned between the first and second row of ankle bones.

Jurassic Terrestrial Vertebrates

Sauropods (largest land animals ever)

Lessons learned from dino trackways

1) Sauropod trackways suggestherd-like social behavior
2) Tell us about the mobility, speed, and position of limbs with respect to body of the animal

Archaeopteryx (anatomical features, something in between dinos and birds

1) The Archaeopteryx specimen has impressions of long feathers. Despite the feathers, it had a skeleton and teeth similar to those of small dinosaurs; Archaeopteryx is about the size of a modern crow.
2) Archaeopteryx evolved from small carnivorous dinosaurs

CRETACEOUS ANIMALS

T-rex, ceratopsians, hadrosaurs

Tyrannosaurus rex

Cretaceous Hadrosaurs

Complex dental battery forming "washboard like" surface for grinding and chewing vegetation before swallowing it

Ceratopsians

Ceratopsians also became one of theprimary herbivorous groups ofdinosaurs during the Cretaceous (K)

In North America, how do Jurassic plant-eating dinosaurs differ from Cretaceous plant-eating dinosaurs?

Jurassic Sauropods have simple "peg like" teeth used for ripping off vegetation and swallowing it whole
Cretaceous
Hadosaurs hace a complex dental battery forming a "Washboard like" surface for grinding and chewing vegetation

Angiosperms - what are they? When do they first appear in fossil record?

A flowering plant which forms seeds inside a protective chamber called an ovary. - first appear in the fossil record during the Cretaceous Period

Lessons learned from dino nests with eggs?

1) Many modern bird species, like these cormorants, nest in large colonies
2) These communal nesting sites are consistent with seasonal breeding, migration, and birthing. This type of behavior is reminiscent of endothermic animal behavior.

How many mass extinctions have occurred over the course of the Phanerozoic Eon?

5

How were marine, terrestrial ecosystems affected by the End-Cretaceous mass extinction

76% of all marine invertebrate animal species went extinct
Bivales, corals, echindoderms hit hard, ammonites and belemnites gone
Marine plankton devastated
Many marine vertebrates eliminated
Peslocsours gone
Icthysosaurs gone
Mosasaurs gone

How were terrestrial ecosystem affected by end Cretaceous mass extinction?

Non avian dinosaurs gone
Pterosaurs wiped out
50% of plant species gone
Some mammal groups affected

What is the age of end-Cretaceous mass extinction?

66 million years ago

Walter and Luis Alvarez

Walter Alvarez is a geologist who wanted to know more how much time clay layer of K/Pg boundary represented. Luis Alvarez reasoned that if one could measure iridium concentration one could estimate the time it took to accumulate assuming a steady input

Evidence for Asteroid Impact as Kill Mechanism

1. Iridium (Ir) Anomaly
2."Shocked" quartz grains
3. Tektites
4. Chicxulub Impact Crater in Yucatan Peninsula of Mexico

What was the Cenozoic Era?

Age of mammals

What are hominins?

all species on the "human" side of the family tree after it split from the branch that became modern chimps. To date, roughly 20 types of hominins found in fossil record have been described as separate species

Sahelanthropus

(6-7 million years ago); position of foramen magnum suggests upright biped

• early record fragmentary
• by 6.0 Ma, our ancestors had split from chimp lineage
• skull\=mosaic of ape-like and hominin-like traits

Australopithecines

~4.0-1.8 Ma:"AGE OF AUSTRALOPITHECINES" variety of species with different food niche

small brain and body but definitely bipedal

Skull with endo cranial cast of brain found in limestone quarry near Taungs, South Africa. Brain size considerably larger than that of a chimpanzee.
Skull and brain of juvenile complete with milk teeth and erupting molars.

Where did australopithecines live?

Eastern and Southern Africa - Ethiopia

who is "Lucy"

Australopithecus afarensis: biped, chimp-sized brain, dental arcade, small body size - Ethiopia, Africa (ca. 3.2 Ma)

Australopithecus has many transitional features:

• femurs and pelvis are human-like (bipedal)
• long arms, finger bones slightly curved (some climbing)
• ape-like head with chimp-sized braincase
• except semi-parabolic tooth row and reduced canine teeth (ape-humans)

Laetoli Tuff footprints (3.6 Ma) in Tanzania, Africa showed what

Direct evidence of bipedalism

Nominal cutoff between the hominin genera Australopithecus and Homo is brain size (\>600 cc)

• split to Homo lineage ~2.5 Ma ??
• development of stone tool technology ~2.5 Ma
600 cc brain size, cutoff between australopithecines and the genus Homo

Homo habilis

diverged from Australopithecine lineage circa 2.5 Ma. Development of stone tool technology
600 cc brain size, cutoff between australopithines and the homo genus

Homo erectus (1.8 Ma)

large brain and bidepal
• more carnivorous -\>greater demands on technical abilities & social organization
• skeletal changes -\>long-distance running
• sexually dimorphic
• LARGE BRAINS impose high metabolic cost -\> dietary & behavioral strategies providing high caloric returns
• increased hunting/scavenging impose risks: competition with large carnivores, unreliability of game, long training for skill development
• deal with risks via food sharing, sexual division of labor, gathering plant foods
• social environment in turn selects for larger brains

by 1.8 Ma, someH. erectus left Africa

Homo neanderthalensis (230 - 30 kyr ago)

the species before us homo sapiens; lived form 30,000 to 300,000 years ago; they were stronger and had bigger brains. Heavy built, muscular \--- IDK IF THIS IS RIGHT, I may keep it though slay

Homo neanderthalensis males: 55 females: 51heavily built, muscular

Neanderthals ranged across Europe, W&C Asia, Middle East circa 230 kyr to 30 kyr were cold-adapted (it was the Ice Ages!) modern humans of non-African descent have 1-4% neanderthal DNA

When and where did homo sapiens evolve

Homo sapiens (modern humans) first evolve in Africa sometime around 160 kya, some populations start to disperse to other regions around 55 - 70 kya

Trends in hominin/human anatomical evolution (know them!)

1. Body size
2. Brain size tripled in 3 million years
3. Knuckle walking to obligatory bipedalism
4. Rectangular to parabolic dental arcade with smaller, blunter canine teeth
5. Less body hair

Quaternary Glacial - Interglacial Cycles

began circa 3.2 Ma

What were CO2 levels prior to industrial revolution

varied between 180 ppm (glacial) and 300 ppm (interglacial)

Last Glacial Maximum & Larentide Ice Sheet (North America)

20,000 years ago

North American Mammal Megafauna of last Ice Age

Wooly Rhinos, Mammoths, Mastodons, Giant Ground Sloths, Glyptodonts, Camels, Horses, Short-Faced Bears Dire Wolves, Saber Toothed Cats (Smilodon), American Lion, American Cheetah

La Brea Tar Pits-why so many carnivorous predators?

Because an animal would get stuck and cry out, attracting the predators, so tar pits have more fossils or predators and scavengers compared to prey animals

What is megafauna?

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

When did Megafauna Extinction happen in North America?

11,000 years ago

Who were victims of Megafauna Extinction?

Mammoths, Mastodons, Horses, Camels, Ground Sloths, Glyptodonts, saber-toothed cats, short-faced bears, dire wolves, NA lions, NA cheetah

When did humans first arrive in North America?

Expansion of the continental ice sheet caused sea level to fall by 120 meters that made a land bridge. Clovis spearhead 14,000 years ago

Evidence for Overkill Hypothesis as cause of Megafauna Extinction in North America

- Extinction peaked at a time when human arrived in North America.
- opposition

hat makes large-bodied mammals more susceptible to extinction?

1. Greater individual longevity(lifespan)
2. Longer time to reach sexual maturity
3. Longer pregnancies
4. Birth fewer offspring

When and where were the last mammoths?

4000 years ago on Wrangel Island in the Siberian Arctic

What is present day atmospheric CO 2 level?

421 ppm

Relative timing of current sharp rise in CO 2 and beginning of Industrial Revolution (i.e. burning fossil fuels)

1880 ish - Rose with the start of the Industrial REvolution

Model forecasts for future atmospheric CO 2 levels

800 by 2100

Albedo Effect

reflectivity of a material

L and ocean have low albedo because they absorb more radiative energy. Clouds, ice and snow have a high albedo because they absorb less radiative energy.

Arctic Amplification of Global Warming

As the planet warms, more ice melts, exposing more land and water that have lower albedos and so absorb more heat, amplifying the warming. In other words, "the hotter it gets, the hotter it gets"

Relationship between melting continental glaciers and rising sea level

As the ice melts sea level increases

Environmental Impacts\= CO2 induced global warming, ocean deoxygenation, ocean acidification

1. Warming ocean means less oxygen
2. Created dead zones through top-down temperature gradient
3. Eutrophication- increased runoff of agriculture and human wastes

What is ph?

It is the NEGATIVE log of hydrogen ion concentration-log[H+],expresses the free hydrogen ion concentration in a solution (i.e. seawater).
pH values decrease then seawater [H+] increases\= ocean acidification

Ocean acidification

Dynamic relationship between rising CO 2 levels and lowering of ocean pH.

Rising CO 2 levels is acidifying our oceans, which is causing a drop in carbonate ion concentrations. Carbonate under-saturation will inhibit skeletal growth in many marine organisms (e.g.,corals, coccolithophorids, pteropods, foraminifera,clams, oysters, crabs)

carbonic acid (H 2CO 3)

CO 2 bonds with H 2O to make a weak acid

Do you think we are presently experiencing the 6 th Mass Extinction of the Phanerozoic Eon?

no currently - but that if we continue at this rate of destruction we are on today, that we are trending closer and closer to a mass extinction.

Do large population sizes always protect species from extinction?

no - ex passenger pigeon

classic causes: overhunting, loss of habitat

How are Frogs as environmental indicators-"canaries in the coal mine"

Cause(s) for current loss of amphibian biodiversity

All relate to human impact on the environment
1. Habitat modification/ loss
2. Fungal disease
3. Pollution of various types (amphibians sensitive because: eat lots of insects (pesticides), permeable skin, naked eggs)

Frogs are good environmental indicators

Shifting Baseline Syndrome

This is the idea that each generation inherits an increasingly degraded ecosystem, but because most people lack long-term perspective they accept current conditions as normal or even natural.

EXAM 1 TOPICS

What is a scientific hypothesis and theory?

Hypothesis: A proposed explanation for an observed phenomenon. A scientific hypothesis must be testable

Theory: A hypothesis that has withstood extensive testing by a variety of methods, and in which a higher degree of certainty may be placed.

Niels Stenson (Steno): three principles of stratigraphy

Hard core empiricist. Established the three principles of stratigraphy:

three principles of stratigraphy

1) superposition - strata are arranged in a temporal order,with oldest at bottom, youngest at top
2) original horizontality - strata originally deposited horizontally, or nearly so; departures indicate strata have been moved and titled after they formed
3) original lateral continuity - strata originally deposited continuously across an area unless interrupted by solid object; gaps in the same layer of strata indicate rocks have been removed after they formed

William "Strata" Smith: Faunal Succession

created the first geologic map of England and first recognized the importance of fossils for correlating strata. Credited for establishing the Principle of Faunal Succession. Advanced catastrophism.

Faunal Succession

Within any layer of rock (stratum), different types of fossils succeed one another in the same relative order - Temporal Order

Three key properties of an Index Fossil

1. Easy to identify
2. Geographically and environmentally widespread
3. Geographically short-lived

Georges Cuvier

(1769-1832) Largely developed paleontology, the study of fossils. Advocated catastrophism.

Proved extinction but opposed to idea of evolution; instead, life moved progressively toward its "perfect" modern state with the passing of each extinction (i.e. catastrophe).
• Advocated catastrophism, the principle that events in the past occurred suddenly and by different mechanisms than those occurring today.
• Invoked catastrophes to explain breaks in rock record(unconformities) and extinctions.
• Believed that catastrophes were separated by long periods of stability, and that the Earth was many millions of years old.

James Hutton - Father of modern geology

Father of modern geology. Believed in the divine creation of the earth, but also the power of empiricism. Used modern processes to understand how rocks formed(uniformitarianism). Realized the temporal cycle: the earth is old. Plutonism

Uniformitarianism

Used modern processes to understand how rocks formed
- The present is key to the past. Given enough time, small-scale processes can add up to large-scale change.

Plutonism

(igneous rocks derived from molten magma & lava)
igneous rocks, like granite, are molten derivatives of ancient magma bodies that were forcibly intruded into Earth's crust. Noted how previously deposited strata have been upturned/folded and cut by intrusive igneous body (magma chamber) and dikes.

principle of cross-cutting relationships

the geologic feature which cuts another is the younger of the two features

Significance of Unconformities (breaks) in the Rock Record

represents missing time.

Principles of Enclosing Relationships & Inclusion

any rock represented by eroded fragments is older than the rock enclosing it

Rock Cycle & Antiquity of Earth

an idealized cycle of processes undergone by rocks in the earth's crust, involving igneous intrusion, uplift, erosion, transportation, deposition as sedimentary rock, metamorphism, remelting, and further igneous intrusion.

• Rock Cycle: destruction of older rocks balanced by formation of new rocks
• Realized the temporal implications of the rock cycle and record (antiquity of Earth

Actualism

Assumes only a uniformity of kinds of natural causes - that the principles, or laws, of nature, have been constant over time. It also recognizes that intensities and rates of change have varied greatly and that some natural processes active in the past may not be operating today.

Alfred Russell Wallace

Went to the Malay archipelago. Found that the faunas are different from island to island. Father of biogeography. Independently arrived at the principle of natural selection.

- what is Wallace Line?

separates flora and fauna of islands as associated with mainland Asia or mainland Australia. Lombok Straight. Australia has marsupials and Asian fauna are placenta mammals

Thomas Malthus - Essay on the Principle of Population (checks on population size

Population growth would always exceed food production, leading to famine, pestilence and war. So need checks like disease and famine

Three Requirements for Natural Selection

variation, heritability, differential reproductive - and sometimes overproduction of offspring

Biological Species Concept

A group of inter-breeding natural populations that are reproductively isolated from other such groups

Hybrids may thrive where parent species fear to tread (example).

Lonicera fly a hybrid between snowberry maggot and blueberry maggot. When they interacted on invasive honey suckle

What does it take for a hybrid to be successful in the wild?

1) is capable of producing viable (fertile) offspring, and
(2) exploits a niche that differs from that preferred by the parent species.

What is "artificial" selection?

The process by which a species is modified via human intervention to encourage the breeding of individuals with certain traits. Natural selection takes to long

Three reasons why did Darwin focused so much attention on artificial selection.

1. Natural selection is to slow
2. Because artificial selection has resulted in dramatic changes
3. Because Artificial selection demonstrates inheritance

Exam 2 material

What does DNA stand for?

Deoxyribose Nucleic Acid

What are nucleotides?

Composed of a sugar-phosphate backbone, and a nitrogenous base.
Guanine pairs with Cytosine. Thymine with Atamine.