Chapter 1: The Nature Of Science Nd The Characteristics Of Life Flashcards
What is meant by “science”?
Body of knowledge about the natural world
Has to be independently verified by people
Does this actually work?»_space;> subject it to scientific investigation
Built largely on peer review and repeatability helps us get closer to the truth
A way to explain the truth
As a whole it can tell us the implication of things
Are anecdotes and beliefs reliable evidence for conclusions?
NO - but can be a good starting point for study
The Scientific Method
Observations (comes from previous knowledge) (causation - what would cause this phenomenon?)
Hypothesis (to establish causation)
Predictions
Test
Hypothesis is either supported or rejected
Scientific Hypotheses
Attempts to identify a cause for some effect
Needs to be independently testable and repeatable - potentially falsifiable
Based an accumulation of observations
Provisional
Caveat that some information could come up alone the way to prove it false
Scientific theory
A principle or law after it has been repeatedly confirmed through diverse methods of testing
When it is accepted by the majority experts as the best explanation f the truth about the phenomenon
EX: Gravity, evolution…
Hypothesis is prior to developing a theory
Independent variable
The cause
In an experiment, generally only one independent variable is manipulates at a time - there can be several levels of this one variable
Observational studies
Careful and repeated recording of and summarizing events
Looking and creating logs of events - not manipulating anything
Analytical studies
Compared two or more variables - establishes correlations
Use observations and data points, compare them to one another
Limitation = spurious correlations: appears that one variable affects another but it doesn’t - no truth behind it
Experimental science
Attempt to establish cause and effect relationship
Goal is to establish causation
Ideally provides a prediction for future similar events
Dependent variable
The effect
Many dependent variables can be measured
Controlled variables
Held constant across all groups
Both control groups and treatment groups are given the same conditions
Only want to be testing changes in the independent variable
Control group
Proposed cause
Independent variable is not present or is held at a default level
Experimental group
Proposed cause
Independent variable is present
Multiple treatment levels may be used
AKA treatment groups
Increasing confidence in experimental conclusions
Effective use of control groups
Randomization
Replication of experimental and control groups (higher sample size)
Statistical analysis (summarizing events)
Summary statistics
Taking a bunch of data points, adding them and dividing them all out (mean or error - variation(+or- some number is how you describe that variation))
Analytical statistics
T-test: statistical test that compares means and variation between two samples
T-test: determines in variation is enough to call the different in mean “statistically significant”
Biology’s 2 basic themes
- Flow/use of energy
2. Flow of information: within cell/organisms (communication, growth, development) and between organisms
All life shares 6 common traits
- Are composed of one or more cells
- Reproduce and use DNA
- Obtain energy from their environment to support metabolism
- Sense and respond to their environment
- Actively maintain their internal conditions
- Are capable of evolving as a group
- Living organisms are composed of cells
Cells are the basic unit of life and are the foundation for all living things
- Living organisms reproduce and use DNA
DNA is genetic material that contains all of the instructions for building new organisms
Every cell in a single organism contains a full set of the same DNA instructions
A gene is a segment of DNA that codes for a special protein, which in turn, results in a physical trait
Asexual reproduction vs sexual production
Organic molecule
Any molecule that has a carbon or nitrogen connected to a hydrogen
EX gas is organic
- Living organisms obtain energy from their environment
Any organism that can capture energy in or from inorganic molecules is an autotroph (plants - they create organic molecules through photosynthesis) (water is inorganic)
Metabolism
Capture, storage, and use of energy by an organism
- Living organisms sense and respond to their environment
Detect, interpret, and act upon stimuli
Behavior
Response to stimuli
Environment
Anything outside of the cell
Stimulus
Anything received by the cell
- Living organisms actively maintain their internal conditions
HOMEOSTASIS- any process used by an organism to maintain a particular range of internal conditions
EX temp, salt, thirst from sweating, acidity, hunger
- Groups of living organisms evolve
A species is a group of organisms that interbreed under natural conditions to produce fertile offspring
A group or organisms within a species that shares a common geographical locale is called a population (interact together)
Evolution
Flow of genetic information
Change in types of genes in a population over generation
Individuals of not evolve - ONLY GROUPS because you can’t develop new traits or genes
Adaptive traits allow an individual to survive and reproduce and at be passed on
Maladaptive traits are traits that hinder reproductive success/survival
Adaptation
Evolution of a population or species usually causes them to increase survival and reproduction
Natural selection
**
Artificial selection
Human influence on the evolution of species
DOMESTICATION - selectively breeding organisms for traits that we find useful
Biological Hierarchy
- Atoms
- Molecules
- Cells
- Tissues
- Organs
- Organ systems
- Organisms
- Population
- Community
- Ecosystem
Biosphere
The entire earth
Living and non-living components
