Evidence on evolution Flashcards
What is punctuated equilibrium?
Rapid changes followed by little change
What is gradualism?
Many small ongoing changes occur
Define genetic drift.
Random change in alleles for a trait in the population
What are stromatolites?
Ancient fossils constructed from anaerobic cyanobacteria
How old are the first known cells from stromatolites?
~3.5 billion years ago
What role did the first known cells play in the atmosphere?
Filled the atmosphere with usable oxygen
What is the half-life of Carbon-14?
5,714 years
What is the half-life of Uranium-234?
80,000 years
What is the half-life of Potassium-40?
1.3 billion years
What is the half-life of Rubidium-87?
50 billion years
How can we determine the age of rocks on Earth?
Using radioactive decay analysis
What are unstable radioisotopes?
Radioisotopes found in rocks and fossils that change over time
What is a bottleneck effect?
Drastic drop in population rebuilt by a limited number of individuals
What does the founder effect lead to?
Decreased variety in the population
What is endosymbiosis?
A single celled organism absorbs and incorporates another organism
What is the process called when organisms are forced to adapt or die?
Natural selection
What is speciation?
The formation of new species
What factors can affect species change?
- Reproductive isolation
- Isolation (locations, mating times)
- Behaviours
- Physical/Genetic incompatibility
What is a phylogenetic tree?
A diagram that shows evolutionary relationships
What is the significance of better-dated fossils?
They show that organisms get more complex over time
What is modern evolutionary synthesis?
Combination of evolutionary theories incorporating different fields of biology
What does Mendelian inheritance refer to?
Inheritance patterns consistent with evolution
How does evolution affect populations?
Evolution affects populations, not individuals
What is the estimated age of the Earth?
About 4.6 billion years old
What is the age range of the oldest rocks on Earth?
3.9 – 4.28 billion years old
What can mutations lead to in a population?
Source of variation
What are the three types of selection that can occur?
- Directional
- Stabilizing
- Disruptive
What is allopatric speciation?
Organisms of a species become separated geographically
What is sympatric speciation?
Organisms in one population develop into two separate species
What is artificial selection?
Favours individuals with traits not necessarily related to survival
What are homologous genes?
Similar genes in different species
What are pseudogenes?
Vestigial genes that no longer serve a useful purpose
