the study of life warm-up: what does it mean to be alive? what is the definition of life?
TRANSCRIPT
Which of these are considered living?
orderadaptation
Response to the environment
regulation
Energy processing
reproduction
Growth and development
Life is the property or quality that distinguishes living organisms from dead organisms and inanimate matter, manifested in functions such as metabolism, growth, reproduction, and response to stimuli or adaptation to the environment originating from within the organism. American Heritage Dictionary
Life is a characteristic that distinguishes objects that have Signaling and self-sustaining processes from those that do not, either because such functions have ceased (death), or else because they lack such functions and are classified as inanimate. Wikipedia
Life is a distinctive characteristic of a living organism from a dead organism or a nonliving thing as specifically distinguished by the capacity to grow, metabolize, respond (to stimuli), adapt, and reproduce. Biology Online
• From cells to moleculesCell
8 Cells
6 Organs and organ systems
7 Tissues
10 Molecules
9 Organelles
50 µm
10 µm
1 µm
Atoms
Figure 1.3
SCIENTIFIC INQUIRY
At the heart of science is inquiry
Biology blends two main processes of scientific inquiry:
Discovery scienceHypothesis-based science
Biology blends two main processes of scientific inquiry:
• Discovery science– Describes natural
structures and processes as accurately as possible through careful observation and analysis of data
• Hypothesis-based science, inquiry that asks specific questions– Usually involves the
proposing and testing of hypothetical explanations, or hypotheses
WHAT IS A HYPOTHESIS?
A possible explanation that can be tested and falsified. It is an explanation on trial.
We all use hypotheses in solving everyday problems
Observations
Questions
Hypothesis # 1:Dead batteries
Hypothesis # 2:Burnt-out bulb
Prediction:Replacing batterieswill fix problem
Prediction:Replacing bulbwill fix problem
Test prediction
Test does not falsify hypothesis
Test prediction
Test falsifies hypothesisFigure 1.25
• In this case study– Mimicry in king snakes is examined– The hypothesis predicts that predators in non–coral snake
areas will attack king snakes more frequently than will predators that live where coral snakes are present
Scarlet king snake
Scarlet king snakeKeyRange of scarlet king snakeRange of eastern color snake
Eastern coral snake
NorthCarolina
SouthCarolina
Figure 1.27
A Case Study in Scientific Inquiry: Investigating Mimicry in Snake
Populations
To test this mimicry hypothesisResearchers made hundreds of artificial snakes, an experimental group resembling king snakes and a control group of plain brown snakes
(a) Artificial king snake
(b) Brown artificial snake that has been attacked
• After a given period of time– The researchers collected data that fit a key
prediction
Figure 1.29
In areas where coral snakes were present, most attacks were onartificial brown snakes
Key
% of attacks on artificial king snakes
% of attacks on brown artificial snakes
Field site with artificial snakes
17%
83%
NorthCarolina
SouthCarolina
XXXX X
XX
XX XXX
XX
In areas where coral snakeswere absent, most attackswere on artificial king snakes
84%
16%
Key