bio103 lect 3

types of observation

qualitative & quantitative

what is qualitative

observation that involves descriptive data and characteristics rather than numerical measurements. (in words)

define quantitative

observation that involves numerical measurements and data analysis (in numbers)

important points about observation

• must be completed and detailed

• must avoid value judgement

• must not confuse observation with interpretation

limitation of observation

• we are biased toward sight

• our sense limited

why do we classify

• identifies organisms

• shows evolutionary relationships

• allows global communication

• prevents confusion with common names

modern classification based on:

• DNA evidence

• evolutionary relationships

Draw hierarchy diagram

as you go up groups become smaller, organisms become more similar

scientific method steps to prediction

1. observation

2. question

3. hypothesis

4. prediction

5. test

6. support or reject hypothesis

difference between hypothesis and prediction

H: explanation

P: if… then statement

what happens if prediction fails

hypothesis may be wrong

what happens if hypothesis survives many tests

may become part of a theory

what is independent

factor you change

what is dependent

what’s measured

what is treatment group

receives independent variable

replication in bio

• experiment must be repeated

• replication reduce random error

adequate replication depends on:

• variation in organism

• complexity of system

• statistical analysis

Lamark’s proposed idea on acquired characteristics

is the theory that organisms can pass on traits acquired during their lifetime to their offspring.

example: giraffe stretch necks—> offspring have longer necks

weissmann proposed idea on acquired characteristics

is the theory that organisms cannot pass on traits acquired during their lifetime to their offspring, emphasizing genetic inheritance over acquired traits.

example: chop tail off of rats, the children won’t change and have no tails bc it doesn’t change their traits

Van Helmont belief on spontaneous generation

is the idea that living organisms can spontaneously arise from nonliving matter, such as how grains of wheat were thought to produce mice.

red (1668) belief on spontaneous generation

showed that maggots arise from flies attracted to decaying meat, not from spontaneous generation.

needham (1745) belief on spontaneous generation

is the belief that microorganisms could arise from nonliving matter, demonstrated in his experiments with boiled broth that later became cloudy with microbial life.

spallanzani (1765) belief of spontaneous generation

is the belief that microorganisms do not arise from spontaneous generation, demonstrated through his sealed experiments that showed no microbial growth in sealed boiled broth.

pasteur (1862) belief on spontaneous generation

is the belief that microorganisms arise from other microbes, demonstrated through his swan-neck flask experiments which disproved spontaneous generation.