Chapter 1: Biology and the Tree of Life- pt.1
Biology: Study of all living organisms
Organisms: life form - living entity made up of one or more cells
What is a living organism?
1) Energy- stay alive and reproduce
2) Cells- made up of membrane bound unit (cells)
3) Information- genetic info (genes) respond to info from environment
4) Replication- main goal (reproduction)
5) Evolution- each organism is product of evolution
Nature of science → asking questions???
a) Scientific Theory
- best explanation for a general class of observations supported by a wide body of evidence
- most theories have 2 components
Pattern: observation leads to identifying a pattern in nature
Process: the “how” part of science that makes the pattern make sense
- three unifying theories in biology
Cell theory
Theory of evolution - by natural selection
Chromosome theory of inheritance
b) 2 Methods of reasoning (LOGIC) in science
- INDUCTIVE REASONING
based on observations or experiments, NOT speculations or anecdotal evidence
how hypothesis arise
may lead to a scientific theory
Observation → Pattern → Tentative Hypothesis → Theory
d) Example
Observation/ pattern → honeybees sting, honeybees sting, wasp sting
Hypothesis → yellow and black insect’s sting
-DEDUCTIVE REASONING
used for testing a hypothesis or theory
utilizes IF/THEN statements
requires a large volume of data in order to determine casualty not coincidence
Theory → Hypothesis → Observation → Confirmation
Cell theory: All organisms are made of cells and all cells come from preexisting cells.
Robert Hooke: 1st to make crude microscope in 1665 (30x)
1st thing he sees is cork from preexisting cells.
makes book about cork (cells)
Anton Va Leeuwenhoek: made handheld microscope (300x)
1st to see blood cells, yeast cells, sperm cells, single celled organisms
single celled organisms he called Ina molecules that we now call micro-organisms
microorganisms = bacteria
“scientists”, judge, tradesman, Dutch lens grinder