Lecture 12 Flashcards
Where did heavy elements come from?
Supernovae
When did earth form?
4.5 bya
When did oceans form?
4 bya
What is the time of our first evidence for life?
3.8 bya
What did the first form of life probably look like?
Single ancestors that lived off hydrothermal vents
When did we split from Chimpanzees
7 mya
When we split from chimps what was our lineage called?
Hominins
What were 4 changes from other greater apes that make hominins unique?
- Adaptations for fast running in open habitat
- Alternations to mouth throat, tongue, lips to enable speech
- Hands, for manipulation
- Brain size for body mass
What is a cost of bigger brain size?
Very metabolically costly
What were some adaptations to bigger brain size?
Change in diet (more calorie dense food), fat storage for energy, delayed maturation
WHen did Homo Erectus evolve?
2 mya
What are the waves of hominin leaving Africa?
- 2 mya Homo erectus
- 700 kya Neanderthals –> Neanderthals + Denisovans
- 70 kya Modern Humans
Where did Neanderthals and Denisovans live?
Neanderthals expanded to Europe and Denisovans formed in Asia
When did modern humans evolve?
200 kya
What people were more likely to hybridize with Neanderthals and Denisovans?
People in Europe and Asia have 2-4% of DNA, while people in Africa have little or no DNA
How similar is the human genome across the world?
88%
What are the difference between cultural and biological evolution?
- Intentional vs random
- Horizontal vs strictly vertical
- Traits that decrease fitness by biased transmission
- Is much faster
Are humans still evolving?
Yes, cholesterol and Sexually antagonistic selection of height in the UK
What are some benefits of agriculture?
- Allowed for towns
- Increased calorie consumption
- Triggered population explosion
What were some immediate negative effects of agriculture?
Decline in health due to poor nutrition, tooth decay, new diseases
What is some evidence that there was selection for the negative effects of our new diet?
Changes in allele frequencies to adapt
