Each year I find a way to crossover a bit of my field, vertebrate paleontology, with the Big Ten Conference, two of my favorite things. It’s that time of year again. In 2015 I brought you Dinosaurs, in 2016 you got Not Dinosaurs, and last year I gave you Marine Tetrapods. Another big theme of my field that is connected to, but different from the organisms themselves is time. Scientists who study aspects of geologic time, geologists and paleontologists, have a nifty system of making the vast time that the Earth has existed into more understandable, and identifiable units. Behold, the Geologic Time Scale (GTS), a system of divisions and subdivisions that span the Earth’s formation 4.6 billion years ago to the present day.
How are these subdivisions determined? Well, they are defined by detected major geologic and biologic events, such as major extinctions or drastic environmental changes that mark the end of one of these subdivisions and the start of another. As you move through the strata (layers of the Earth) and you see tons of a certain type of fossil, then suddenly none at all, that usually marks a major extinction. If you move through the strata and see a certain chemical composition, then suddenly a different one, a major environmental change probably happened. These determine distinct time chunks with their own characteristics.
When it comes to determining the actual dates, that would be via chronostratigraphy which often uses isotopes to determine hard, “exact” dates, and then biostratigraphy which uses fossils for relative dating (a rock/fossil in the same strata as T-Rex fossils, for example, is going to be Cretaceous in age).
As you can see in the GTS above, there are subdivisions of these divisions. The biggest divisions are Eons and Eons contain Eras, Eras contain Periods, Periods contain Epochs, Epochs contain Ages. This Power Poll will focus specifically on Geologic Periods because of how many there are and their popularity, many of which I’m sure you’ve heard of.
Disclaimer: This Power Poll reflects my own geologic time period biases. Ask any earth scientist what the best chunk of geologic time is and they’ll give you varied answers. Maybe after today, you’ll have your favorite chunk of time too!
ONTO THE WEEK 3 POWER POLL! (Mya means Million years ago)
1) Ohio State Buckeyes: Jurassic Period (201.3—145 Mya)
Last Week: #1 | High: 1 | Low: 1 | Avg: 1 | First Place Votes: 21
Hard to pick a number one, but in terms of a geologic period which yielded some of the most magnificent evolutionary results, it’s hard to not say the Jurassic. The biggest, most colossal animals to ever live on this planet, the sauropods, dominated the Jurassic landscape. There was a huge diversity of marine reptiles in the oceans and the Jurassic is also where birds first evolved, having evolved from a group of small theropod dinosaurs. As far as flora, gymnosperms, characterized by being tough, pine-needly, and cone bearing were dominant. Like the Jurassic Period, Ohio State stands tall over the rest of the conference.
2) Penn State Nittany Lions: Paleogene Period (66—23.03 Mya)
Last Week: #3 | High: 2 | Low: 3 | Avg: 2.05 | First Place Votes: 0
The Paleogene is the first Period of the Cenozoic, the "Age of Mammals." This period occurred in the wake of the End-Cretaceous extinction that killed the dinosaurs, so there was a lot of recovery to be had still. A lot happened here though. Modern mammal lineages diversify, a lot of others went extinct, the fastest climate change event ever (outside of today’s) occurred, grasses evolved, India was crashing into Asia and the Himalayas were being formed, Australia and Antarctica had broken up. Still though, mammals aren’t looked at as amazingly as dinosaurs, so in spite of all that it had going on, it’s still not a Mesozoic period. It’s great, but most still find it unimpressive or dislike it. Oh hey look, it’s Penn State.
3) Iowa Hawkeyes: Carboniferous Period (358.9—298.9 Mya)
Last Week: #4 | High: 2 | Low: 7 | Avg: 4.19
Carboniferous means “coal bearing” because this happens to be the origin of a ton of modern coal deposits. This coal is derived from the vast swampy forests that took in TONS of atmospheric CO2, incorporated it into themselves, then died without that carbon being re-released by decomposers. The Carboniferous also had the highest ever atmospheric Oxygen content (35% vs the modern 21%) which yielded gigantic terrestrial invertebrates. You think some bugs today are big? Ha. When I think of a giant bug in the Big Ten, it’s definitely Iowa. I look forward to the team they upset this year. They seem to be gearing up for it.
4) Michigan Wolverines: Triassic Period (251.9—201.3 Mya)
Last Week: #6 | High: 3 | Low: 7 | Avg: 4.19
The Triassic Period occurred in the wake of the most devastating extinction in Earth history. In this recovery was the start of the diversification of dinosaurs and other archosaurs like crocodylomorphs and pterosaurs. There were tons of super weird reptile lineages in the Triassic, with that weirdness not being being seen ever again. All in all though it was a period marked by ecological recovery, and growth in diversity and growth in size of the animals. Very reflective of this path and overall weirdness is definitely Michigan. Michigan looks good since recovering from Week 1. Harbaugh is still a weirdo though.
5) Wisconsin Badgers: Cretaceous Period (145—66 Mya)
Last Week: #2 | High: 3 | Low: 8 | Avg: 5.52
A warm and lush period that was the temporal home to tons of fan-favorite dinosaurs like Triceratops and T-Rex. This is also where flowering plants first appeared. The Cretaceous Period seemed to have everything going for it. However, this period is well-defined by a major, sudden decline. Towards the end of the Cretaceous, the Earth was being suffocated and further warmed by volcanic gases from heightened volcanic activity and then there was the asteroid that struck the planet 66 million years ago, causing the K-Pg Extinction, which marked the sad end of this period. Oh look, it’s “Gonna totally win the Big Ten this year/look at that stacked senior team. Crap they just lost to BYU at home” Wisconsin.
6) Indiana Hoosiers: Cambrian Period (541—485.4 Mya)
Last Week: #9 | High: 3 | Low: 8 | Avg: 6.19
The Cambrian Explosion is where life went from simple, mostly unicellular and basic multicellular life to complex multicellular and mineralized organisms. Mineralized means they had evolved hard parts that could readily fossilize and be more easily detected (by us). The Cambrian was the first period of the Paleozoic Era and it’s where more recognizable lineages of life started to appear (slightly, they still had a long way to go). Land was barren minus a few possible microbial crusts. Still though, big things were happening! Look at you go, Indiana. (I still hate you)
7) Minnesota Golden Gophers: Devonian Period (419.2—358.9 Mya)
Last Week: #7 | High: 3 | Low: 9 | Avg: 6.52
The Devonian is also know as the “Age of Fishes,” because this is where the first of the modern groups of fish evolved. Gigantic armored fish called placoderms existed here as well as primitive sharks. Additionally, lobe-finned fish (our ancestors) started to dabble in walking. The Devonian was also where the first significant evolution of life on dry land occurred. Plants with real roots and arthropods (bugs) where doing well on the surface. Roots starting to take hold and aquatic life taking off (row) sounds analogous to Minnesota’s progress. Still though, the end of the Devonian was marked by a major marine extinction which killed off tons of lineages of cool marine life that would never been seen again. Minnesota is doing a thing, but against cupcakes. I imagine the extinction is around the corner.
8) Michigan State Spartans: Permian Period (298.9—251.9 Mya)
Last Week: #8 | High: 4 | Low: 10 | Avg: 6.76
The Permian is characterized by the single greatest mass extinction event in the history of life on Earth. Before this, however, the Permian was where modern amniote (animal whose embryo develops in an amnion and chorion and has an allantois— you see all these in your breakfast eggs) groups first diversified— mammals, turtles, lepidosaurs (snakes, lizards & tuataras), and archosaurs (dinosaurs, birds and crocodiles). But whew, at the end of this period, 96% of marine life died out, and 70% of terrestrial life died out. The culprit was likely extreme climate change. The Permian-Triassic Extinction was so bad that it not only divided the Permian and the Triassic Periods, it defined a new era. The ushering in of the Mesozoic Era, the "Age of Reptiles" (dinosaurs) from the Paleozoic Era. Michigan State being compared to the Permian and its decline and making way for the Triassic (Michigan), Jurassic (Ohio State), and Cretaceous (Wisconsin) above works TOO perfectly.
9) Maryland Terrapins: Quaternary Period (2.58 Mya— Present)
Last Week: #5 | High: 7 | Low: 11 | Avg: 9.0
The Quaternary Period is what we currently live in. It’s defined by cyclic growth and decline of continental ice sheets. Because of this, shorelines have varied throughout the course of the Quaternary and responsible for the closing off and emergence of straits and land bridges and all the biotic shuffling that came with that (hi there, conference realignment). The Quaternary Period gave us... us. Now, one could argue that this makes the Quaternary a great period, or a terrible one. Given that humans are directly responsible for the extinction of various woolly and large prehistoric megafauna I lean towards the latter. On the same basis of possibly good, but probably bad, I assign Maryland to the Quaternary.
10) Northwestern Wildcats: Ordovician (485.4—443.8 Mya)
Last Week: #10 | High: 9 | Low: 13 | Avg: 10.71
During the Ordovician there was an event called “The Great Ordovician Biodiversification Event” which piggy-backed off of the Cambrian Explosion where molluscs, starfish and relatives, trilobites, and arthropods diversified as did “fish.” Now these fish were very different from what we consider fish, but these organisms were the first true vertebrates. This diversification event led to the evolution of all modern lineages of the animals that we know. Also during the Ordovician, the continents in the Northern Hemisphere were underwater and the supercontinent Gondwana (Africa, Australia, South America, and Antarctica) was moving south and... also submerging underwater. Sinking... Northwestern being 1-2 with a loss to Akron... sinking.
11) Illinois Fighting Illini: Silurian Period (443.8—419.2 Mya)
Last Week: #12 | High: 8 | Low: 14 | Avg: 11.24 | Last Place Votes: 2
Life in the Silurian Period was trying so hard to be greater. On land, small moss-like forests of vascular (tissues for conducting water and minerals throughout the plant) plants lived near shorelines. In the water brachipods, molluscs and trilobites were diverse and things called eurypterids (sea scorpions— which could be several meters long) existed. Also, bony fishes with actual jaws appeared for the first time. But the Silurian wasn’t the Devonian which followed, nor did it have the diversity explosion of the Cambrian, nor the diversification event of the previous Ordovician. Sounds like Illinois. Flickers of things, but still lacking so much needed to be great.
12) Nebraska Cornhuskers: Neogene Period (23.03—2.58 Mya)
Last Week: #11 | High: 10 | Low: 14 | Avg: 11.38 | Last Place Votes: 1
The Neogene landscape looked similar to what it is today. Something major that happened geologically is that North America and South America became connected via what is now Central America. This would allow some neat animal exchange back and forth between the continents, but it also cut off the exchange of warm water between the Pacific and Atlantic Oceans, so the Arctic Ocean would then only exclusively be warmed by the Gulf Stream thus bringing down the temperature of the Earth. You know what is helping to bring down the quality of the Big Ten (unexpectedly)? Nebraska.
13) Purdue Boilermakers: Ediacaran Period (635—541 Mya)
Last Week: #13 | High: 11 | Low: 14 | Avg: 12.48 | Last Place Votes: 1
Ediacaran fossils are rare, but there is evidence of multicellular organisms with specialized tissues. Life during the Ediacaran is very, very different from the more recognizable type of life that came after in the Cambrian Period, and the evolution that occurred between the two periods is highly studied because of how confounding it is. How did life get from the Ediacaran to what we saw later? How did Purdue go from the potential they had last year to 0-3? Truly fascinating.
14) Rutgers Scarlet Knights: Cryogenian Period (720—635 Mya)
Last Week: #14 | High: 12 | Low: 14 | Avg: 13.76 | Last Place Votes: 17
Snowball Earth. The greatest Ice ages/glaciation events to ever occur on this planet. It was cold... and sad... This is the oldest period of the 14 mentioned in this Power Poll (yes, there were older ones I didn’t mention). The oldest known fossils of sponges, which are animals, are from the Cryogenian Period. This means that modern animal life (CFB Birthplace analogy) started here, but the period itself was... bleak. The Cryogenian is literally Rutgers is Geologic Time form.
So this was fun. Did you learn anything today that you didn’t expect to? Let us know in the comments!