Evolution Flashcards
Scientific Theory
a description of the natural world that scientists have proven through rigorous testing
A theory explains how nature behaves under specific conditions
theories tend to be as broad as their supporting scientific evidence will permit
serve as a definitive explanation of some aspect of the natural world
describe how phenomenon happens
Theories begin as….
a hypothesis, proposed explanation for a natural phenomenon
how do scientists turn a hypothesis into a proven theory?
-researchers design science experiments to challenge their ideas under conditions of the natural world
adhere to scientific method allows scientists to accumulate enough evidence to prove their hypothesis, making it a theory with predictive power
Scientific law
describes phenomena that the scientific community has found to be provably true
develop from scientific discoveries and rigorously tested hypothesis + new theories
uphold + expand laws, not held to be true
Scientific laws v. theorys
scientific laws differ from theories in that they tend to describe a narrower set of conditions. Theories are typically more expansive and they focus on the how and why of natural phenomena
both scientific laws and theories are considered scientific facts –> both can be disproven when new evidence emerges
Theory of Evolution
- created by Darwin
-explains many aspects of what we observe about biological phenomena, such as the origin of species and the relatedness of living things
-has been tested repeatedly + hold up to scrutiny
-useful in making predictions
How does evolution happen
-the environment is in a constant state of change
-living things need to accommodate these changes both in order to survive and reproduce (both are needed for a species to be successful
-populations evolve, not individuals –> Driving force = environment: natural selection
How does natural selection work
- a population can be looked at as a collection of genetic traits (allelels) which we collectively call a gene pool
-generally there is variety of alleles among individuals within a population
-some of these variations give advantage to the individual possessing them, giving their environmental conditions.
-those individuals are more likely to be successful and their traits are more likely to be passed to their offspring
- overtime generations/the population changes in response to the environment and ultimately new species develop
-populations change because of environmental pressure –> natural selection
Evolution in a nutshell
- populations = variations in allels (characteristics) among individuals
- some variations = heritable
- some are more advantageous than others given the environment
-populations = immigration + emigration
-over time more advantageous traits will persist in the population, those less so will not, and the species will evolve
