Feedback mechanism
Allows biological processes to self-regulate
Negative Feedback
As more of a product accumulates, the process that creates it slows and less of the product is produced
Leads to balance
- Regulating body temperature
- Regulating metabolic proceses
Positive Feedback
As more of a product accumulates, the process that created it speeds up and more of the product is produced
- Blood clots
- Milk production
- Child birth
A striking unity underlies the diversity of life
- DNA is the universal genetic language common to all organisms
- Unity is evident in many features of cell structure
Charles Darwin
published “On the origin of species by means of natural selection” in 1859
- Species showed evidence of “ descent with modification” from common ancestors
- Natural selection is the mechanism behind “descent with modification”
Darwin’s theory explained the duality of unity and diversity
Individuals in a population vary in their trains, many of which are heritable
More offspring are produced than survive and competition is inevitable
Species generally suit their environment
Individuals that are best suited to their environment are more likely to survive and reproduce
Over time, more individuals in a population have the advantageous traits
Evolution occurs as the unequal reproductive success of individuals
Earth
Fossils and other evidence document the evolution of life on Earth over billions of years
Accepted age of Earth is 4.55 billion years
Fossil
Trace of previous life
- Dinosaur bones
- Clam or snail shell
- Footprints
- Dung
Data
Rcorded observations or items of info
Qualitative data = Descriptions rather than measurements
ex. Jane Goodall's observations of chimp behavior. ex. color
Quantitative data = Recorded measurements which are sometimes organized into tables and graphs
Hypothesis
Tentative answer to a well-framed question
Scientific hypothesis leads to predictions that can be tested by observation or experimentation
Must be testable and falsifiable
Scientific method
Idealized process of inquiry
Hypothesis-based science is based on the “textbook” scientific method but rarely follows all ordered steps in order
Observations and experimental results must be repeatable
Theory
Broader in scope and more well-defined than a hypothesis
Can lead to new testable hypotheses
Supported by a large body of evidence in comparison to a hypothesis
