Lecture One: Geologic History Flashcards
January 23
Roughly, how long did it take from animals in the aquatic environment to be able to walk on land?
300-350 million years.
Are animals with more complicated body plans better than those with simpler body plans?
No.
They have simply evolved to suite different niches. If they were better, they would be the only animals left alive. This is not the case.
Is the blue whale the largest animal on the planet?
No.
What is allowing us to rapidly discover more about dinosaurs?
Population growth –> more excavation for building –> more fossils found.
What period and era do vertebrates first appear in?
Cambrian period.
Paleozoic era.
What is the order of the geologic time periods from oldest to youngest? What eras are they in?
- Precambrian
Paleozoic
2. Cambrian
3. Ordovician
4. Silurian
5. Devonian
6. Carboniferous
7. Permian
Mesozoic
8. Triassic
9. Jurassic
10. Cretaceous
Cenozoic
11. Tertiary
12. Quaternary
What is considered the “age of fish”? Why?
The Devonian period.
This was when the greatest diversification of fish occurred.
Non-avian dinosaurs went extinct in what geologic period?
Cretaceous.
Why did non-avian dinosaurs go extinct?
Geologic changes on Earth (ex. volcanic activity).
Meteor strike.
Why did the Pangea cause a massive extinction event?
Water is largely responsible for weather and climate. The continent was so large that no water made it to the more inland parts. As a result, it became a massive desert and did not support life.
What caused the largest mass extinction event? When?
Photosynthesis.
Cyanobacteria produced O2 as a waste product. O2 was toxic to these anaerobic organisms, and increasing levels of O2 caused them to die. 90% of organisms killed.
2 billion years ago.
What qualifies an extinction event?
80-85% of all species going extinct.
Describe the relationship between mass extinctions and species diversity.
There is an increase in species families and diversity after major extinction events.
Picture a forest fire. It takes out the major dominant organisms (trees), allowing grasses, flowers, weeds, and more to grow, increasing the number of species, until dominance is established again. More trees come in, create a canopy, and decrease the species below them.
Extinct:
A species/group/family of organisms has no living members left. No longer exist.
Extant:
Still in existence, surviving.
In geologic time, atmospheric CO2 is very low compares to what it has been in the past. So, what is significant about anthropogenic CO2 emissions?
Climate change is happening at a rate faster than we have ever seen, not greater than ever seen.
