evolution in the fossil record. goals an evolutionary biologist’s geology toolkit understand the...
Post on 20-Dec-2015
218 views
TRANSCRIPT
![Page 1: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/1.jpg)
Evolution in the Fossil Record
![Page 2: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/2.jpg)
Goals
• An evolutionary biologist’s geology toolkit• Understand the nature of the rock record• Understand the nature of the fossil record• See what kinds of data fossils can give us
![Page 3: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/3.jpg)
Earth, from outer space
• Some facts about Earth:– Age: ~4.6 billion years– Weight: 6x1024 kg (heavy!)– Hot on the inside, cooler on the outside– Spins on its axis and makes orbits around the…– Sun– Is home to a lot of water
![Page 4: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/4.jpg)
Earth, from outer space
• How do we know that there is life on Earth?• Life has caused planet-scale phenomena• Life and the planet: a give and take
![Page 5: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/5.jpg)
Earth, from inside
![Page 6: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/6.jpg)
Earth, from the ground:Plate tectonics
• Proposed in 1915 but no mechanism suggested• Accepted in 1960 when mechanism proposed• Data supported this mechanism
![Page 7: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/7.jpg)
Earth, from the ground:Plate tectonics
![Page 8: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/8.jpg)
Earth, from the ground:Plate tectonics
![Page 9: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/9.jpg)
Earth, from the ground
This map illustrates the break-up of the supercontinent, Rodinia, which formed 1100 million years ago. The Late Precambrian was an "Ice House"
World, much like the present-day
![Page 10: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/10.jpg)
Earth, from the ground
Animals with hard-shells appeared in great numbers for the first time during the Cambrian. The continents were flooded by shallow seas. The
supercontinent of Gondwana had just formed
![Page 11: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/11.jpg)
Earth, from the ground
Vast deserts covered western Pangea during the Permian as reptiles spread across the face of the supercontinent. 99% of all life perished during the extinction event that
marked the end of the Paleozoic Era
![Page 12: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/12.jpg)
Earth, from the ground
During the Cretaceous the South Atlantic Ocean opened. India separated from Madagascar and raced northward on a collision course with Eurasia.
Notice that North America was connected to Europe, and that Australia was still joined to Antarctica.
![Page 13: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/13.jpg)
Earth, from the ground
We are entering a new phase of continental collision that will ultimately result in the formation of a new Pangea supercontinent in the future
![Page 14: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/14.jpg)
Earth, from the ground
New subduction zones along the eastern coasts of North America and South America will begin to consume the ocean floor separating North America
from Africa
![Page 15: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/15.jpg)
Earth, from the ground
The next Pangea, "Pangea Ultima" will form as a result of the subduction of the ocean floor of the North and South Atlantic beneath eastern North
America and South America. This supercontinent will have a small ocean basin trapped at its center
![Page 16: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/16.jpg)
Rock
Igneous rock
here be no fossils
![Page 17: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/17.jpg)
![Page 18: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/18.jpg)
Rock
Sedimentary rock
here be fossils
![Page 19: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/19.jpg)
Rock
Metamorphic rock
here be damaged fossils
![Page 20: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/20.jpg)
Rock
![Page 21: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/21.jpg)
The Geological time scaleCorrelation of rock: relative ages
• Strata: horizontal bands = a point in time• Older are lower, vertically• Younger are higher, vertically
![Page 22: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/22.jpg)
The Geological time scaleCorrelation of rock: relative ages
• Strata: horizontal bands = a point in time• Older are lower, vertically• Younger are up higher, vertically• Strata often differ in the kinds of fossil
organisms they host
![Page 23: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/23.jpg)
CorrelationFossil organisms can be used to correlate rocks
Many geological time points are defined by the organisms found within
There are, for example, 67 global ammonite zones for the 55 myr long Jurassic
When does the Cretaceous end? When the ammonites disappear
![Page 24: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/24.jpg)
Absolute age of rocks
• Once we have the relative order of stages, how do we assign absolute dates?
Ash beds are used for absolute dates. The rocks they occur in are dated. Fossils are assigned to rocks, not dates.
½ life = 0.7 billion years
![Page 25: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/25.jpg)
![Page 26: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/26.jpg)
Gaps in the rock record
• Why gaps?
• Sea level fluctuates– Imagine a point just offshore right now that is receiving sediment.
Organisms can become trapped in this sediment to form fossils– Now imagine sea level drops. That point will no longer receive sediment – Now imagine sea level rises gain, this time higher than ever. That point
will experience erosion, and all fossils that may have been laid down before will disappear from the rock record
– In any particular rock column, there may be only pulses of sedimentation
![Page 27: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/27.jpg)
Fossils
Issues– How complete is the fossil record? – If we glean patterns from fossil data, can we trust them?
![Page 28: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/28.jpg)
FossilsThe fossil record is incomplete
1. Delicate, they can decay rapidly
2. Sediments formed sporadically
3. Fossil bearing sediments must become rock
• Rock formation
• Rock persist
• Rock found by paleontologists
![Page 29: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/29.jpg)
FossilsThe fossil record is incomplete
![Page 30: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/30.jpg)
FossilsTwo basic questions:
1. Provides evidence for evolutionary change?
2. Evolution is gradual versus the idea that changes are discontinuous
![Page 31: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/31.jpg)
Fossils:missing links
• Are fossils ancestors?
• Probably not.
![Page 32: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/32.jpg)
Evolutionary Change within Species
Changes in the mean number of ribs in eight lineages of trilobites
![Page 33: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/33.jpg)
Evolutionary Change within Species
Changes in the mean values of fin rays in fossil sticklebacks
![Page 34: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/34.jpg)
Evolutionary Change within Species
Changes in the mean values of dorsal spines in fossil sticklebacks
![Page 35: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/35.jpg)
Origins of Higher Taxa
![Page 36: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/36.jpg)
Origin of Amphibia
Eusthenopteron, a member of the group of lobe-finned fishes from which tetrapods arose
![Page 37: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/37.jpg)
Origin of Amphibia
![Page 38: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/38.jpg)
Origin of Birds
![Page 39: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/39.jpg)
Skeletal features of (A) Archaeopteryx, (B) a modern bird, and (C) a theropod dinosaur
Origin of Birds
![Page 40: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/40.jpg)
A phylogeny of some groups of theropod dinosaurs
Origin of Birds
![Page 41: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/41.jpg)
Estimated body weights of fossil hominins
Hominin Fossil Record
![Page 42: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/42.jpg)
Hominin Fossil Record
![Page 43: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/43.jpg)
The approximate temporal extent of named hominin taxa in the fossil record
Hominin Fossil Record
![Page 44: Evolution in the Fossil Record. Goals An evolutionary biologist’s geology toolkit Understand the nature of the rock record Understand the nature of the](https://reader036.vdocuments.site/reader036/viewer/2022062516/56649d475503460f94a22b34/html5/thumbnails/44.jpg)
Frontal and lateral reconstructions of the skulls of a chimpanzee and some fossil hominins
Hominin Fossil Record