Studying Life

Chapter 1.3

What is “Biology”

• Biology is the science that seeks to understand the living world

• “The study of life and how they interact”

With each other

Interactions

With other animals

With people

Characteristics of Life

• What is life? What is needed to “be alive”??

• How can you classify all living things?– What must they do or have the ability to do?

Living things share the following eight characteristics:

1. Living things are made up of units called cells2. Living things reproduce 3. Living things are based on a universal genetic code4. Living things grow and develop5. Living things obtain and use materials and energy6. Living things respond to their environment7. Living things maintain a stable internal environment8. Taken as a group, living things change over time

1. Made up of Cells

• Small units that make up life

• A Cell is a collection of living matter enclosed by a barrier that separates the cell from its surroundings

• Can be unicellular (made up of only one cell) or multicellular (made up of many cells)

2. Reproduction

• Must be able to produce new organisms

• Can be done using:– Sexual Reproduction where two parent cells unite

to form offspringor – Asexual Reproduction where the new organism

has a single parent

3. Based on a Genetic Code

• Offspring usually resemble their parents

• Inherit these traits in the reproduction process

• Passed on through DNA using their genetic code to produce the offspring

4. Growth and Development

• All living things grow during at least part of their lives

• For many organisms, development includes periods of rapid and dramatic change

5. Need Materials and Energy

• Organisms need materials to stay alive

• The combination of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes is called metabolism

6. Response to the environment

• Organisms detect and respond to stimuli from their environment

• A Stimulus is a signal to which an organism responds – Can be external (from the environment like light

or temperature) or it can be internal (from inside the organism like sugar levels in the blood)

7. Maintaining Internal Balance

• Things are always changing around us but we need to maintain a constant set of conditions

• Homeostasis is maintaining a fairly constant set of internal conditions, such as temperature, water content, salinity, and pH

• Think about sweating and shivering… think about the “Homeostasis of the Eye Lab” that we did

8. As a group, we change over time

• Organisms will always grow and change over time to make the best of their surroundings and conditions

• Species will evolve to be better suited for their climates, food selection, and availability of other necessary resources (water, mating patterns, habitat, etc.)

Midway “checkpoint” questions

• Lets discuss and answer the following questions:

1. Describe 5 characteristics of life2. Compare sexual and asexual reproduction3. What biological process includes chemical

reactions that break down materials?4. What is homeostasis? 5. Give two examples of homeostasis and explain

how the organism maintains this “happy balance”

Branches of Biology

• Living things come in many different shapes, sizes, and habits

• Living systems also range in size from groups of molecules that make up structures inside cells to the collections of organisms that make up the biosphere.

• No single biologist could study this diverse

What CAN we study??

• Molecules• Cells• Organisms• Populations of a single

kind of organism• Communities of

different organisms in an area

• The biosphere (the part of the earth that contains all ecosystems

**REALLY, we can study the smallest

thing all the way up to the largest groups

Copy the Following Table in Your Notes

Levels of OrganizationBiosphere

Ecosystem

Community

Population

Organism

Groups of Cells

Cells

Molecules Groups of atoms; smallest unit of most chemical compounds

INC

RE

AS

ING

IN

S

IZE

Copy the Following Table in Your Notes

Levels of OrganizationBiosphere

Ecosystem

Community

Population

Organism

Groups of Cells

Cells Smallest functional Units of life

Molecules Groups of atoms; smallest unit of most chemical compounds

INC

RE

AS

ING

IN

S

IZE

Copy the Following Table in Your Notes

Levels of OrganizationBiosphere

Ecosystem

Community

Population

Organism

Groups of Cells Tissues, organs, and organ systems

Cells Smallest functional Units of life

Molecules Groups of atoms; smallest unit of most chemical compounds

INC

RE

AS

ING

IN

S

IZE

Copy the Following Table in Your Notes

Levels of OrganizationBiosphere

Ecosystem

Community

Population

Organism Individual living things

Groups of Cells Tissues, organs, and organ systems

Cells Smallest functional Units of life

Molecules Groups of atoms; smallest unit of most chemical compounds

INC

RE

AS

ING

IN

S

IZE

Copy the Following Table in Your Notes

Levels of OrganizationBiosphere

Ecosystem

Community

Population Group of organisms of one type that live in the same area

Organism Individual living things

Groups of Cells Tissues, organs, and organ systems

Cells Smallest functional Units of life

Molecules Groups of atoms; smallest unit of most chemical compounds

INC

RE

AS

ING

IN

S

IZE

Copy the Following Table in Your Notes

Levels of OrganizationBiosphere

Ecosystem

Community Populations that live together in a defined area

Population Group of organisms of one type that live in the same area

Organism Individual living things

Groups of Cells Tissues, organs, and organ systems

Cells Smallest functional Units of life

Molecules Groups of atoms; smallest unit of most chemical compounds

INC

RE

AS

ING

IN

S

IZE

Copy the Following Table in Your Notes

Levels of OrganizationBiosphere

Ecosystem Community and its nonliving surroundings

Community Populations that live together in a defined area

Population Group of organisms of one type that live in the same area

Organism Individual living things

Groups of Cells Tissues, organs, and organ systems

Cells Smallest functional Units of life

Molecules Groups of atoms; smallest unit of most chemical compounds

INC

RE

AS

ING

IN

S

IZE

Copy the Following Table in Your Notes

Levels of OrganizationBiosphere The part of earth that contains all

ecosystems

Ecosystem Community and its nonliving surroundings

Community Populations that live together in a defined area

Population Group of organisms of one type that live in the same area

Organism Individual living things

Groups of Cells Tissues, organs, and organ systems

Cells Smallest functional Units of life

Molecules Groups of atoms; smallest unit of most chemical compounds

INC

RE

AS

ING

IN

S

IZE

Biology in Everyday Life

• In this class, you will see that more than any other area of study, biology touches your life every day

• In fact, its hard to think of anything you do that is not affected by it

• Biology can help people understand that humans are capable of predicting and trying to control their future and the future of the planet

What do we NOW know??

1. Describe the AT LEAST 5 of the 8 characteristics of life

What do we NOW know??

2. What topics might biologists study at the “community” level of organization?

3. How about at the “groups of cells” level?

What do we NOW know??

4. What is the difference between “asexual reproduction” and “sexual reproduction”?

5. What is homeostasis? Give two examples of how homeostasis is maintained.

What do we NOW know??

6. What biological process includes the chemical reactions that break down materials??

Test Thursday!!Keep Studying!