Chapter 1Biology in the 21st Century

1.1 The Study of Life

Life is found everywhere…. › Yellowstone Pools› Bottom of the Ocean› Ice in Antarctica

All living things and the places they are found on Earth is the biosphere

Where do we find life?

What is the biosphere?

1.1 The Study of Life Biodiversity = variety of

life in an area› Increases from poles to the

equator› Why would it be greater

closer to the equator? 2 million species

› 10,000 more discovered › 50,000 go extinct

What is biodiversity?

*What Characteristics do Organisms share?

Made up of cells Need a source of energy React to their environment

› Why is this important? Reproduce

› Why is this important?

1.2 Unifying Themes of Biology

All levels of biology have systems (organized group of related parts that interact to form a whole)› Ear, tree, cardiovascular

system, digestive system Structure and function are

related› Red blood cells vs. brain

cells› Molars vs. incisors

What are some examples of systems?

How are structure and function related?

1.2 Unifying Themes of Biology

Organisms must maintain homeostasis› Maintained in 2 ways

Negative feedback Behavior

Reptiles sitting in the sun Eating to get your blood sugar back

up Evolution – the change in

living things over time› Helps explain diversity

How do organisms maintain homeostasis?

Independent/Dependent Variables

What does independent mean?› The independent variable is the variable

that WE choose to change; what is being manipulated

Independent/Dependent Variables

What does dependent mean?› The dependent variable DEPENDS on the

independent variable› The dependent variable is what we are

looking at, what we study to see if it changes

Control Group

The control group is a group that does not have anything changing

Why would you use a control group?

Example 1 Dr. Imanut wants to examine whether a new drug

increases the maze running performance of older rats. Just like aging humans, older rats show signs of poorer memory for new things. Dr. Imanut teaches two groups of older rats to find a piece of tasty rat chow in the maze. One group of rats is given the new drug while they are learning the maze. The second group is not given the drug. One week after having learned the maze, he retests the rats and records how long it takes them to find the rat chow.

What is the independent variable?◦ Age of the rats, type of maze, length of time it took the rats

to run the maze, presence or absence of the drug What is the dependent variable?

◦ Age of rats, type of maze, length of time it took the rats to run the maze, presence or absence of drug

Example 2 A researcher wanted to study the effects of

sleep deprivation on physical coordination. The researcher selected 25 year-old male college students and deprived some of the subjects of either 24, 36, or 45 hours of sleep then had them complete an obstacle course for time.

In the study, what was the independent variable?

In the study, what was the dependent variable?

Place in Order

a) Theoryb) Observationc) Hypothesisd) Experimentatione) Supporting Evidence

1.3 Scientific Thinking and Processes

All scientific inquiry starts with observation› Qualitative vs.

Quantitative data› From the picture on

the next slide, come up with 3 quantitative and 3 qualitative pieces of information

What is the difference between qualitative and quantitative data?

Like all science, biology is a process of inquiry.

Scientists record observations as data. Scientists form a hypothesis Scientists test their hypotheses and

analyze their data.

A theory explains a wide range of observations.

Supported Change based on new evidence.

What is a theory?

Imaging technologies provide new views of life.

stoma

stoma

stoma

Imaging technology is used in medicine.› X-ray images› Magnetic

resonance imaging

› Functional MRI

What kind of imaging technology is used in medicine?

® Knowledge of biology helps you understand:® Your health®Environmental systems

brain

lungs

heart

liver

kidneys

Why might knowledge of biology be useful?

Biology presents many unanswered questions.

Over the past 50 years, biological knowledge has greatly increased.

There are still many questions to answer in biology.

– How are memories stored in the brain?

There are still many questions to answer in biology.

– How are memories stored in the brain?

surface proteins

lipid

envelope

nucleic acid capsid

– Does life exist on planets other than Earth?

– How do viruses mutate?