Biology- On the origin of species and modern theory of evolution Flashcards
Natural Selection
when the environment favors the reproductive success of some individual within a population over others
Example: When female peacocks are picking their mate they look for the male that displays their feathers the best, has the best colors, and don’t have any issues (feathers aren’t eaten away by disease, matted etc)
Radiometric Dating
used to estimate the age of materials by comparing the amount of naturally occurring radioactive isotopes with the amount of their decay products
Radioisotopes
atom with unstable nucleus that undergoes radioactive decay, where the unstable nuclei release particles and energy, changing from parent isotope into daughter isotope
E.g. carbon-14 to nitrogen-14
Half-Life
time it takes for half of the parent radioactive element to decay to a daughter product; the time is CONSTANT
E.g. carbon-14’s half-life is 5730 years (useful for dating up to 70,000 years, after there is too little C-14 left)
Homologous Genes
genes, inherited from a common ancestor, that have mutated and evolved over time more closely related species should have more similar sequence of bases
E.g. Pax-6 gene for eye development (mammals, birds, fish, insects)
Pseudogenes
genes that are like normal, functioning genes (similar gene sequence), but have mutated to become non-functional (no longer produce a protein)
E.g. dolphins have genes for olfactory receptors (smell), but many are non-functional evolved from land mammals, but have no need for smell in water (genes no longer of value), so if gene became mutated it wouldn’t have been selected against
Paleontology
Helps understand distribution of fossils – fossils found are like current day species in same region (e.g. Darwin’s giant fossils like present day sloth and armadillo), odd locations of fossils (e.g. same species in Africa, India and Antarctica, but nowhere else, or aquatic species in deserts or high on mountains)
Plate Tectonics
theory that describes the large-scale movements and features of Earth’s crust (e.g. mountains, volcanoes, earthquakes)
What did Darwin do in 1844?
wrote an outline of his theory, but was concerned about controversy and challenge, so continued to gather evidence and look for faults in his theory
what happened in 1858?
Alfred Russell Wallace wrote Darwin a letter outlining his theory of evolution (nearly identical to Darwin’s)
Both Wallace and Darwin submitted their papers at a meeting (1858), and Darwin published his book in 1859
KEY OBSERVATIONS and INFERENCES:
Populations produce more offspring than there are adults, do not continue to grow in size, and resources are limited Individuals within a population compete for resources
- Individuals within all populations vary, and some variations are heritable Some individuals will inherit variations that improve their chances of surviving and reproducing
- OVER TIME, advantageous heritable characteristics become increasingly common in each generation
ADAPTATIONS –
characteristics or features of a species that makes it well suited for survival or reproductive success in its environment (specific to enviro)
- E.g. white fur of polar bear in snow/ice covered environment ONLY
3 basic requirements of a good theory
- EXPLANATORY POWER – ability to explain the subject
- PREDICTIVE POWER – offers details about what we may expect to see
- TESTING AND FALSIFICATION – can’t be proven wrong (no falsifying evidence)
Natural Selection: Peppered Moth Example
- Originally most were light coloured (camouflaged against light coloured trees or lichens)
- Due to pollution during industrial revolution, lichens died out and soot covered trees dark coloured moths flourished and light coloured moths died off
- As pollution improved, light moths population increased
Age of Earth
Universe is 13 billion years old, and Earth and the solar system are over 4.5 billion years old (evidence from modern science)
