The study of life

Warm-up:What does it mean to be alive?What is the definition of life?

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

•Biologists explore life from the microscopic to

the global scale

• From the biosphere to organisms

Figure 1.3

1 The biosphere

• 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

• Eleven themes that unify biology

Table 1.1

LET’S TALK ABOUT THIS CLASS

What is your definition of life?

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