10- Darwin's Theory of Natural Selection Flashcards
What was Charles Darwin the first person to do?
Collect evidence and propose a sound theory for how animals evolve
What does Darwin’s struggle for existence assume?
Potential population vastly outstrips environmental means for support
3 places that the ‘struggle for existence’ occurs
- Between individuals within species
- Between species
- With the environment
What does the principle of ‘natural selection’ suggest?
Favorable variations and characteristics lead to those which are not so favorable
3 essential conditions for natural selection
- Variation
- Selection
- Inheritance
Which evolution family tree are humans in?
Family tree of great apes
What are chimps genetically closer to than what?
Chimps closer to humans than chimps are with gorillas
4 lines of evidence for species mutability
Fossil records, common features of embryological development across species, physiological and cognitive similarities between animals, changes through selective breeding
3 approaches to dating fossils
Relative dating, numerical aging, magnetism
What is relative dating?
Putting geological events in order without knowing exact data
What did discovery of ‘Lucy’ tell us?
That our ancestors started walking on 2 legs about 3 million years ago
What is numerical aging?
Using an estimated date of a geological event to find a precise date of when a fossil lived
What is an isotope?
Atoms of the same element with a different number of neutrons
How does radioactive decay of elements occur in an isotope?
At a constant rate
What happens in radioactive decay?
A change in number of protons and/or neutrons
What is the atomic nucleus that decays called?
The parent isotope
What is the product of decay called?
The daughter isotope
How is exact age determined in numerical aging?
By the ratio of parent and daughter isotopes in a rock sample
What does magnetism use?
Knowledge of changes in Earth’s magnetic field over time in order to date a fossil
What has happened to Earth’s magnetic field in history?
It has reversed many times
Where do small magnetic minerals point to in rocks?
Magnetic north
What do changes in brain structure across vertebrates show?
Same brain parts become enlarged when overall brain size increases
What are adaptations?
Characteristics of living organisms enable them to survive and reproduce successfully in environments where they live
4 lines of evidence for adaptations
- Making use of existing genetic variations
- Using artificially produced variation
- Comparative method
- Adaptation through design
2 examples of existing genetic variations
Light and dark forms of peppered moths, gull colonies and nesting locations
What is lactose?
A protein found in milk
When does lactose intolerance begin?
After weaning
Why does lactose intolerance occur?
Due to decreasing levels of the enzyme lactase-phlorizin hydrolase
Where did lactose tolerance emerge as an adaptation?
In ‘pastoralist populations’
