Introduction to the Fossil Record Flashcards
Who are our ancestors?
- Earliest primates
- Earliest hominins
- Australopithecines
- The genus Homo
- Neanderthals
- Modern humans
What did our ancestors do?
Bipedalism, tool technologies, migrations, social behaviour
What is paleontology and paleoanthropology?
Paleontology: study of prehistoric life, including organisms’ evolution and interactions with each other and their environments
Paleoanthropology: the study of prehistoric human life
Main evidence comes from the fossil record
What is a fossil?
Preserved remains or traces of plants, animals, and other organisms from the past. Preservation quality is highly variable.
What are the types of fossils?
- Bones and teeth
- Trace fossils
- Wood, leaves, etc
- Subfossils (contain organic material (DNA))
Why do continents move?
Plate tectonics
What is continental drift and climate change?
Drift is a major engine of climate change (larger landmasses are colder, orientation of landmasses affect water circulation). This affects vegetation for example.
What are the two fossil dating methods?
- Absolute dating: gives age estimate in years (always has an error)
- Relative dating: gives fossil sequence, and complements absolute dating method (younger than this and older than this)
What is absolute dating in detail?
Elements in nature exist in unstable, radioactive isotopes. The proportion of spontaneous change to another isotope can can tell you the time frame
What is relative dating in detail?
Can tell you which layers are younger based on their position. Supplements absolute dating.
Biostratigraphy: date rocks by looking at the fossils and comparing with other dated sequences
Who has a greater distribution, fossil primates or living primates?
Fossil primates
Describe fossil apes.
- From the oligocene
- Appear first in Africa, then spread to Europe and Asia
- They are declined all around the world by late miocene
- One of these fossil apes must lead to the human lineage
What is a hominin?
Members of the human clade that have evolved since the split with chimpanzees. Basically everything more closely related to us than chimpanzees.
What is a hominid?
All great apes
Who is our closest relative?
Genetic analysis (DNA-DNA hybridization) shows the genus Pan is our closest relative. Molecular clock indicates that the split occurred 6-8 million years ago
What is the common ancestor of both chimps and humans mostly like?
Likely more chimp like. Most parsimonious to think our LCA was Pan like.
- Explains shared features of chimps and gorillas (most simple way)
What are shared derived traits (synapomorphies) of hominins?
- Dental characteristics
- Larger brain/body size ratio
- Slow maturation and development
- Complex symbolic and material culture (including language)
- Habitual bipedalism (anatomical changes from head to toe)
Describe the dental characteristics of hominins.
- Reduction in canine size
- Upper canine no longer hones
- Change in shape of dental arcade from U-shape to parabola
- Enamel gets thicker
Describe slow maturation in hominins.
- Slower life history
- Longer gestation
- Longer juvenile period and growth
- Menopause
Can be measured to some extent in fossils with tooth eruption and bone/enamel development
Describe culture in hominins.
- Increased reliance on technology
- Ability to inhabit almost all environments
- Tools, fire, symbolism, art, and language are major inovations
- Aspects of culture are present but many are not preserved
Describe bipedalism in hominins.
- Most defining feature of hominins
- Recognizable in the fossil record
- Comes first (before big brains)
