Life on Earth (Parts 1 and 2)
What is the big scorpion called from the carboniferous period?
Pulmonoscorpius
What is meant by the term "Cambrian Explosion"?
"Cambrian Explosion": Rapid diversification · Faunal diversity exploded in the Early Cambrian · Mollusks, brachiopods, nautiloids etc. · Some animals appear then very rapidly disappear o Natural Selection a possibility
What happened at the end of the Proterozoic eon?
"Snowball Earth" -- a major cold snap
What does life need to exist?
(all life needs water and some form of energy)
Why did the "Snowball Earth" occur? How did the whole Earth freeze?
- Greenhouse gases = lower (carbon dioxide and methane levels were much lower) - we need these things to trap heat in - Global climate becomes colder, creating larger areas of ice and snow - Ice and snow reflect more solar radiation (more ice you have, the more sun's energy is not getting absorbed by the earth's surface and heating it up. Instead it is being reflected back) ^^called a positive feedback loop - Volcanic activity pumped more carbon dioxide into atmosphere (heating up air temp = warmer conditions)
How did "The Great American Biotic Interchange" effect North America?
- Majorly affect ecosystems - Predators in particular from South America 1) Terror Bird (Phorusrhacos) from South America no longer hunted the same way. With predators from North America (smilodons) beginning to hunt and leave leftovers, they became scavengers and eventually went extinct from competition w/ animals like these that migrated into SA. 2) Smilodon (North America's most dominant predator effected ecosystems, changing the way birds hunted and competing with other animals for food) 3) Doedicurus (armadillo like creature that went extinct maybe bc it wasn't as good at moving around and didn't have same way of protecting itself as the armadillo)
How do banded iron formations form?
- Photosynthesis creates oxygen - Iron weathering erosion -> released into oceans - Oxygen combines with Fe to form magnetite (iron oxide) - Too many organisms would then grow --> oxygen levels too high, becomes toxic for this lifeforms (if there is no iron left to scrub levels of Oxygen, the organisms die) Dark areas represent when these organisms died off - Mass die offs of algae --> settles on seafloor and converted into silica rich rock chert - Population then rebounds and creates more oxygen that reacts with oxygen - Cycle continues (growth, death, growth, death)
What animals were able to survive the mass extinction of the cretaceous?
- Smaller animals were able to survive and birds
How do we know the T-Rex could chew through bone?
- coprolite = dinosaur droppings (show evidence of bone in droppings)
What ended the Phanerozoic era? What is the era that was entered after the Phanerozoic?
- ended with a mass extinction that left 90% of marine species extinct. next era = Mesozoic Era
What is Indricotheres? What is the closest modern day relative?
- it is basically an early rhino
What were the titanosaurs?
A group of dinosaurs discovered in south America and Africa. included: - Argentinosaurus - Dreadnoughtus - Paralititan Notable: size - Possibly grew to 30+ meters in length - Evolved to grow larger than predators
Do we know what T-Rex used its forelimbs for?
Forelimbs not really used (question over what they were for; maybe just not necessary bc of huge skull) - 2 claws in the front that were very short (don't really know the purpose of them)
What is the big millipede called from the carboniferous period?
Arthropleura
Why were there more forest fires in the carboniferous period?
Bc plants have colonized, they are pumping a ton of oxygen into the atmosphere (probably double what we have now) fires were more severe bc there was more oxygen to feed forest fires)
Why was the emergence of flowers so important during the cretaceous period?
Flowers contain pollen. Insects were adapted to get nutrients from plants, unwittingly carrying pollen and causing germination (angiosperms) *changes the way ecosystems function - insects have different role* ^see the development of bees, butterflies, etc. that rebuild the ecosystems and the way they functioned^
What epoch are we in now? What is notable about it?
Holocene Epoch We continually go from warmer to colder climates. · Glacial periods driven species to change (wholly rhinos, wholly mammoths) (Combo of climate and human factors led to extinction of these creatures)
What is notable about the T-Rex as a predator?
Large skull with huge bite · Skull shape: - open jaw up very wide. Jaw muscles were very strong (downward bite ten times stronger than an alligator. - puncture and pull feeding strategy (pulled away the muscle and bone - capable of cutting through bone as well as flesh - ambush predator (hid and then ran into attack and then clamped down on prey) - jaw can resist moving back and forth (shearing), this proved that it could keep animal in its mouth and clamp down.
How do we divide eras?
Major geologic events are how we divide the eras. (ex mass extinction)
What is the big dragonfly called from the carboniferous period?
Meganeura
How can we tell that there was a "Snowball Earth"?
Paleomagnetism plus rock record shows that there was ice close to the equator + evidence of glacial deposits.
What is a period vs an epoch?
Periods = overarching (Epochs are "series" within a period)
What eon are we currently living in?
Phanerozoic Eon
What are the eras?
Precambrian Time: Paleozoic Era: Mesozoic Era: Cenozoic Era:
What was the Dimetrodon reptile from the permian period?
Predatory with large sail on it's back
What is meant by the term "The Great American Biotic Interchange"?
Refers to the connection of North and South America and the sharing of species that eventually happened. North and South America only became connected w/in last 7-10 million years. Each were originally unique ecosystems that formed on their own with their own species.
What are carbon films?
Small, dark compressions, most resembling circles, ribbons, or leaves (Form when dead organisms are squeezed btwn layers of rock. This leaves behind the organism's carbon imprint in the rock)
What is the Anthropocene epoch?
The Anthropocene Epoch is an unofficial unit of geologic time, used to describe the most recent period in Earth's history when human activity started to have a significant impact on the planet's climate and ecosystems. (would start about · 1 minute, 22 seconds before midnight in Year of Earth's history) Proliferation of humans (dramatic increase in #s)... · Humans are making an impact on the geologic enviro · Nuclear explosions have left traces in soil and rock layers · Humans have fundamentally altered geologic timeline by altering environment.
what is the Cenezoic era?
The era we are currently living in. it is considered to be the age of mammals (Dec 26 - Dec 31) in our year of Earth history
What is the Precambrian era?
The majority of time in our Earth's history
What is the quaternary period? What is notable about this period?
The period we are in now, under the cenozoic era. (dec 31 8:51 PM to midnight) in year of Earth History. · Apelike primates: ~12-16 Ma ago · Humanlike primates: ~4 Ma ago · Glacial cycles · Human evolution
What was the Jurassic period? What era is this period under?
Under Mesozoic era Characterized by: · Pangea starting to break apart · Dinosaurs morph into different body types · The Jurassic Period was a *dinosaur renaissance* · Abundant dinosaurs · Air, land, sea o Flying reptiles o NOT birds § Pteranodon (low bone density; they were large and light) · Then came the first birds o Archaeopteryx (arguably one of most important arch. discovery of all time. Trace fossils showed that this bird had feathers) Pointed skull more like a bird, but had rows of teeth inside it. Missing link btwn birds and dinosaurs. · Sauropods (largest land animals of all time; hard for predators to even touch them) o Evolved from Plateosaurus o Typified by their long necks and tails o Designed depending on the type of vegetation that they ate - dinosaur renaissance in the oceans as well...
What was the Triassic period? What era is this under?
Under Mesozoic era · First true dinosaurs (We don't know a lot about Triassic dinosaurs, but they existed) o Coelophysis (one of first ones we knew about - small bipedal reptiles); Pro-sauropods o Plateosaurus (prosauropod, this group eventually turn into the group of largest land creatures of all time) · First mammals · Small, rat-like creatures · Ezostrodon (looks like a possum) · Land vertebrates became abundant during the Triassic Period · Swimming reptiles · Large scale deserts (formation of Pangea cutting off moisture)
What was the Cretaceous Period? What era was this under?
Under Mesozoic era · Last period of dinosaurs :( · Pangea continues breaking apart · Extensive swamps (coal) · Flowering plants evolved for the first time. · A time of significant/greatest dinosaur diversity (even though they originally came from small lizards)...Various different types of species & time where dinosaurs got to their largest sizes (including very large predators!)
What was the the Carboniferous Period? What era was this part of?
Under Paleozoic era.. Characterized by: · Mississippian (359-323 Ma) + Pennsylvanian (323-299 Ma) Epochs · Reptiles (Laid eggs) ·colonization of plants · Giant Insects · Extensive swamps (associated with Pennsylvania) · Mississippian Epoch - much of North America was covered by warm, shallow seas · Continents start moving together again during the end of this pd · Development of limestone · The Carboniferous Period was a time of extensive organic carbon deposition
What was the permian period? What era was this part of?
Under Paleozoic era.. Characterized by: · Supercontinent of Pangea formed · Continued development of land and marine life · Ended with a major extinction · Known as the age of Reptiles (they have started to lay eggs, evolve into various forms that can survive) · Mass extinction at the end · Volcanic activity on a massive scale in what is now Siberia
What were the Devonian and Silurian periods? What era were these under?
Under Paleozoic era... Characterized by: (recovery of life from late Ordovician period) · Vascular plants arose (tissues within them that allow them to move minerals and water through their systems) o Mosses, ferns o Have the internal structures to move water, minerals, and the products of photosynthesis throughout the plant · Spiders, scorpions, insects, crustaceans · Jawed fish o E.g., sharks (stethacanthus - shark with horn) · Silurian the first clear evidence of life on land o Armored fish such as Dunkelosteus (armor plated head, jaw was one massive tooth on the bottom... apex predator... hunted sharks) - End of Devonian = first amphibians o Vertibrates... walked on land and breathed air o Transition from aquatic to land based organisms § Eusthenopteron Icthyostega (evolution... crawled out of water and breathe air... see the fin become a limb with toes and the joint can rotate)
What is the Ordovician period? What era is this under?
Under Paleozoic era... Ordovician period characterized by: · First marine (ocean) vertebrate animals · Internal skeleton o Jawless fish § Ostracoderm · Devastating mass extinction of organisms at the end of the Ordovician · Major glaciation centered in Africa --> severe drop in sea level · 85% of species were lost
What was the Cambrian period? What era was this under?
Under Paleozoic era... · The Cambrian Period marks the first preservation of animal shells etc. · First animals with mineralized exoskeletons · Invertebrates o e.g., trilobite · Size, muscle support · Predator protection and support for soft tissue found within it · Start to see evolution of eyes (organisms being able to see and sense things in their enviro)
Are the ancestors of dinosaurs still alive today?
Yes, their ancestors are birds
What evidence do we have of photosynthetic organisms from the Archean eon?
banded iron formations - To help us look at cycles of growth and death - Tells us how life has come and gone in the oceans during this time pd.
What was the Phanerozoic eon?
eon after the proterozoic and after the precambrian era ended. Things that characterized this eon: - The Paleozoic Era was one of amazing diversity o Shelled organisms, vertebrates o Beginnings of life on land o Start to see animals protect themselves (hard shells, etc) o Start to see land going animals § Pre-dinosaur
What was the Lystrosaurus reptile from the permian period?
formed large herds (evidence of continental drift)
Types of species of dinosaurs during the Cretaceous period: Ceratopsians.
horned dinosaurs with crests (developed molars)
What is notable about Giganotosaurus: (carchardontosaurus) as predators?
larger than T-Rex, but bite = weaker. - Biting force several tims weaker than that of a T rex, couldn't really just eat anything... like bone (could still open its mouth incredibly wide) - More of a slicing action (shearing and slicing rather than having the power to clamp down) - suggested that it might have just taken a bite of a dinosaur and then just go on its way without actually killing the dinosaur. - Possible pack hunter to take down titanosaurs (couldn't have taken down this prey on its own)
What is notable about the Spinosaurus as a predator?
largest predatory animal massive sail on the back of it - Unnown jaw gape (has been based on what we know about similar dinosaurs) - Narrower teeth, teeth orientated differently (the other 2 dinosaurs have curved teeth, spinosaurs had straight teeth) - Nostrils way farther back on its face than the other 2 (bc it had high nostrils we can hypothesize that it stuck its long snout in rivers and waited for fish to swim in its mouth) - Spinosaurus' size helped it in competition with other large dinosaurs (ie carcharodontosaurus - they lived in the same area) - More alligator like - Ambush from above
Types of species of dinosaurs during the Cretaceous period: Ankylosaurids.
literal tanks; armor plated with a club tail (predators would all run away from - no predator could chew through and tail could easily fracture bones and damage internal organs) - start to see evolution of armoring creatures.
What is the proven nail in the coffin for dinosaurs? What evidence do we have of this?
meteorite impact 1) we know where on Earth this meteorite hit (hit Yucatán peninsula which would have been near Mexico) 2) Global signal at K-T boundary (there is a thin band of rock in the geologic layer all over the world -- suggesting worldwide event-- that contains more iridium than other bands that could only be explained by coming from a meteor) 3) Shocked quartz (type of metamorphic rock that forms in evidence of a major impact found near Yucatán) 4) Tektites - glass beads that form by melting and cooling material very quickly 5) Tsunami (found many tsunami deposits around Yucatán. 6) ash 7) dust in stratosphere -- global cooling that stopped photosynthesis (all vegetation caught fire when the impact happened and then the sun was blocked out by all the dust)
Types of species of dinosaurs during the Cretaceous period: Hadrosaurs.
mid-sized herbivores capable of walking on two or four limbs
Is there such thing as a sabor tooth tiger?
no such thing as a "sabor tooth tiger". The correct name for the animal that this name has been given to is a Smilodon or a sabor-tooth cat)
What was the Postosuchus reptile from the permian period?
o Ambush predator; Thought to be bipedal, unusual compared to other reptiles (needed to find a way to heat up.. thought spines on its back had bloodflow to heat it up)
What is arguably the most important animal discovery in geologic history?
o Archaeopteryx (arguably one of most important arch. discovery of all time. Trace fossils showed that this bird had feathers) Pointed skull more like a bird, but had rows of teeth inside it. Missing link btwn birds and dinosaurs.
What evidence do we have of human evolution?
o Australopithecus (first evidence that apes started to walk upright) - one of most important finds. o Homo erectus o Homo sapiens (us) (our brain is developed for higher order functions (social interaction) so we survived) o Neanderthals (stalkier, more resistant, larger eyes, developed more in Euro where things were darker, higher order functions were not well developed. Went extinct) o ^ evidence that these two interbred (small set of human pop that has small trace of Neanderthals w/in it
How was there a dinosaur renaissance in the oceans as well as on land?
o Icthyosaurs § Opthalmosaurus § Large eye cavities - sensitive sight for hunting (could see easily in dark oceans, maybe hunting fast moving prey like squid) § Dolphin like reptiles o Pliosaurs (apex predator of ocean?) o Giant Ammonites (spiraled shelled organisms) floated around in ocean and could recoil into shell to protect themselves § Some smaller than a fingernail, some over 2 meters wide
What reasons could there be for the mass extinction at the end of the permian period?
o Pangea? o Ocean overturn? o Meteorite? o Global anoxia?
What was the Archean eon? What era is it part of
part of precambrian time... · End of major bombardment · "Late Heavy Bombardment" · Impact cratering has decreased over time · The Archean Eon records Earth's earliest life
What moved the Earth on from the Precambrian era to the Palaeozoic era?
the "Snowball Earth" event
What eon is there true evidence of early life in?
the Archean eon
What is the Proterozoic Eon? What era is it under?
under precambrian era - era where Eukaryotes evolved (more complicated with different internal organelles) o Include a cell nucleus · Complex life forms arose in the Proterozoic Eon · Multicellular organisms evolve · Soft-bodied - hard to preserve - Can see these in trace fossils (ex of a trace fossil = footprint) We can see multicellular organisms via trace fossils · Carbon films - Small, dark compressions, most resembling circles, ribbons, or leaves The Proterozoic Eon featured a major cold snap
What were Apatosaurus and Brachiosaurus designed to feed on?
§ Apatosaurus (Probably moved around horizontally. Bone structure didn't allow its neck to reach up high into trees) - fed on plants low to the ground. § Brachiosaurus (bone structure exclusively allowed it to eat from the tops of trees) § ^ plants. We can tell this bc of the way their teeth are, could clamp down on plant. Back jaw of brachiosaurus no molars in the back means they didn't actually chew up their food.
What were the main events of the hadean eon?
· Earth differentiated (core, mantle, primitive crust) Iron nickel sink into core; silicate material making up crust · Hellish time (lot of volcanic stuff, magma ocean world, probably completely liquid) ^^Partially to completely molten during this process. · The Moon formed during the Hadean Eon (would be about Jan 4th) · Likely by a giant impact o Mars-sized planet, Theia, crashed into Earth o Iron core sank into Earth and combined with our own o Some of the mantle of Theia and of our planet combined to form the Moon - Time of major impacts · Primitive atmosphere started to form o Derived from "outgassing" volcanoes (earth hold on to gaseous molecules via gravity) o Consisted of N2, O2, NH3, CH4, H2O, CO, CO2, SOx · Comets brought some of the material that is on our planet such as some of our ocean water · Also the first hydrosphere formed at this time · Evidence for earliest ocean
What kind of elephants did we see (3 variations of modern elephant)
· Elephants Moerotherium (earliest relative to elephant?) Deinotherium (weird version of the elephant with tusks pointing downward - might have used for stripping bark off trees) · Mammoth = elephant that adapted to being in the cold (many of these skeletons = perfectly preserved from tar or ice)
How did the Cretaceous Period end?
· Ended with a large extinction · 90% of plankton · 75% of plant species · All of dinosaurs
What is the evidence for the earliest life in the Archean eon?
· Evidence for earliest life: biomarkers (single cellular and incredibly basic) o Stromatolites (bacterial mounds that form colonies; dif layers of biologic material with other sediment on top; colonies of bacteria and basic organisms called prokaryotes) *evidence of these = fossils* o Cyanobacteria o Blue-green algae o Prokaryotes - Single cells - Don't have individual parts (organelles)
What is the evidence for the earliest ocean forming in the hadean eon? Does this suggest life?
· Evidence for earliest ocean o Magma contains water o Ancient Zircon crystals formed at really low temperatures (relatively, compared to certain magmas) o Implies lots of water mixed in · Possible early life . . . (all life needs water and some form of energy) o But the record has been wiped out o Along with any Hadean life that may have existed
Why did insects get so big in the carboniferous period?
· Extensive forests lead to much higher concentration of O2 in the atmosphere o 35% of the atmosphere, compared to 20% today o Insects grew well in these conditions
What is notable about Marsupials and placentals during the early Cenozoic?
· Giant mammals - Giant Sloths; Indricotheres
What life forms started to form later in the Archean eon?
· Late Archean: photosynthetic organisms o H2O + CO2 --> CH2O + O2 · Beginning of free oxygen (O2) in the atmosphere o Evidence: banded iron formations (BIFs)
What is Megatherium? What is its closest modern day relative?
· Megatherium - had armor plating embedded in skin (related to modern day sloths)
What are the theories about why the dinosaurs went extinct?
· Possible causes of extinction o Climate change o Plate tectonics (created a larger amount of volcanos and CO2 build up) § i.e., continental configuration o Disease o Competition with mammals for food o Volcanic eruptions o Meteorite impact
What are the possible causes of the "Cambrian Explosion"?
· Possible external causes of this explosion of life o Preservation (ocean warmup?) o Global warming o Supercontinent breakup - Gondwana § When you break apart a continent you create an ocean basin § Increased the area of continental shelf § Produced shallow seas (big reasons why we saw animals explode into different forms. Animals can thrive underwater close to the sun) § Expanding the diversity of environmental niches
When did we start to see variations of modern mammals like elephants in the Cenozoic era?
· Start to see early forms of modern mammals in Eocene & Oligocene
What are the Deccan Traps, India? What are they evidence of?
· Suggests that dinosaurs were maybe already on the way out before the meteor impact... · Deccan Traps started the climate shift, but the meteorite polished them off · Deccan Traps (huge outpourings of lava erupting over thousands of years... this changed the climate, putting more CO2 in the climate and heating it up, getting in the water and making oceans more acidic) · Life on earth was already quite stressed bc of climate change before the meteorite finished them off.
We have had many supercontinents form in Earth's history. Why do they all eventually break apart?
· Supercontinents have formed many times throughout history (this is not stable over time, so they don't last long before they start to break apart) Magma formed in what we now know as Iceland which started breaking this apart.
How do we know that the hadean eon was a time of major impacts?
· The Hadean Eon was a time of major impacts (moon is very cratered and doesn't have plate tectonics, we can see the original crust of the moon by looking at the light gray parts; impact craters have been dated via bringing rocks back from the moon... we can tell that a lot of objects experienced a lot of impacts by looking at what happened to and has been preserved on the moon)
What characterized the Mesozoic era?
· The Mesozoic Era is generally considered to be the "Age of Dinosaurs" · Ended with a bang
What is the hadean eon? What era is this under?
· The first time period of our planet (within the precambrian era) Jan 1 - Feb 13th in year of earth history
What did Apatosaurus and Brachiosaurus evolve from?
· Under general group, Sauropods (largest land animals of all time; hard for predators to even touch them) o Evolved directly from Plateosaurus.
How may have volcanic activity caused the mass extinction at the end of the permian period?
· Volcanic activity on a massive scale in what is now Siberia (Produced carbon dioxide) · Global warming that followed may have increased average ocean water temperatures by as much as 8°C · Much of the carbon dioxide released by the eruptions would have been absorbed by the oceans. · High levels of dissolved carbon dioxide in seawater are toxic to many marine invertebrates. · Also would have produced changes in seawater chemistry that may have made it difficult for some marine invertebrates, such as corals, to grow shells or skeletons. · Evidence that the amount of oxygen dissolved in sea water (which invertebrates and fish breathe with their gills) was reduced, probably as a result of changes in ocean circulation. In words explained by prof: ^huge amounts of very hot magma creates massive lava flows over the magma (low viscosity magma means gas can escape easily) CO2 warms up the planet and goes into the ocean. If you put too much CO2 in the ocean, the water starts to become more acidic (when shelled organisms build their shells out of this they die off) also decreased Oxygen available in the oceans. As a result of volcanic activity that was related to the coming together of the continents.
What is so interesting about the evolution of whales? What are 2 whales that are examples of this evolutionary feature? What did they likely eat?
· Whales probably came from shrew like creatures that spent time on land and on trees evidence of whales that walked and evolved from walking (changes in their limbs and size) · Ambulocetus (name literally means walking whale; probably ate smaller mammals) · Basilosaurus (whale that they originally thought was a dinosaur - forearms turned into flippers; probably largest predator in the ocean at this time; could probably hunt sharks and other whales - large skull and teeth)