Bio - Topics 1 and 2 (Science as a Process and Characteristics of Life)

scientific method definition

a way of knowing based on observation, experimentation, and data analysis. Helps us collect evidence that supports or contradicts our hypothesis.

scientific method steps

1. observation/question

2. Hypothesis

3. experiment

4. analyze data

5. communicate findings

step 1 - observation/question

what do you want to know about how the natural world works?

step 2 - hypothesis

based on previous experiments, what do you predict the outcome to be?

step 3 - experiment

test your hypothesis in a controlled experiment

step 4 - analyze data

is there a trend in your data? did the independent variable affect the dependent variable?

step 5 - communicate findings

good experiments must be replicable. Other scientists can verify your findings (or not), making them more reliable

good experimental design elements

1. a testable question and hypothesis

2. clearly identified variables

3. larger and appropriately selected sample

4. control group and experimental groups

5. data collection

6. ability to be replicated

1. testable question and hypothesis

“if…then…because…”

If →IV

then →DV

because →why does the relationship exist? some sort of scientific reasoning

2. clearly identified variables

a) and IV - the variable you manipulate

b) a DV - the variable you measure, changes as a result of the manipulation

c) CVs - everything else to ensure that the data is produced solely from our manipulation of the IV

3. large and appropriately selected sample

a) larger sample sizes reduce the impact of outliers

b) appropriate, randomly selected, “blind” sample groups help prevent confirmation bias

blind vs double blind

blind - hides treatment group from the participants

double-blind - hides it from participants and researchers

4. control group and experimental groups

d) EG - where the independent variable is manipulated

e) CG - IV is not manipulated, and we can compare EG to CG to see if the IV had any effects

5. data collection

collect data objectively, quantitative data

ability to be replicated

should yield similar results over multiple trials, and by other experimenters

pseudoscience

a belief or process that masquerades as science in order to achieve legitimacy

-often lack of properly controlled, replicable experiments which provide the foundation for science

red flags to watch for when looking for pseudocience

-lack of controlled experiments

-small sample size (anecdotal evidence)

-no randomization/blinding

-confusing correlation and causation

1. Organization based on Cells

1. all organisms have one or more cells

2. cells are the basic units of structure and function in organisms

3. all cells come from other cells

2 main categories of cells

prokaryotic and eukaryotic

prokaryotic

small and simple, lack nucleus and other membrane-bound organelles

-eubacteria and archaebacteria

eukaryotic

larger and more complex, have a nucleus and membrane bound organelles

-animals, plants, fungi, protists

2. response to stimuli

stimuli are changing factors outside of the body

ex: seed germination is a response to stimuli like moisture and soil temperature

3. homeostasis

maintaining a stable INTERNAL environment

ex: sweating, shivering, regulating blood sugar

4. metabolism

obtaining and using energy

ex: eating food or photosynthesis

5. growth and development

applies to changes in an individuals’s lifetime

growth → getting taller

development → puberty

6. evolution

changes in a population over MANY GENERATIONS

-this does not apply to individuals, rather populations

ex: tall necked giraffes

7. reproduction

can be sexual (receive DNA from TWO parents) or asexual (receive DNA from ONE parent)

-offspring

-bees transporting pollen (plant sperm) for plants, ameoba dividing

viruses are

genetic info in a protein shell

-they trick the host into reproducing (inject DNA into cell so the cell reads it reproduces it)

viruses

viruses lack cells, so they rely on host cell to carry out the characteristics of life:

-reproduction

-metabolism

-homeostasis