CH 1: An intro to Biology

Biology

The scientific study of life on Earth

What is the purpose of scales (e.g., levels of organization) in biology?

To help us organize our study of life on Earth

How do we define “life?”

Life is defined by a set of characteristics

What are the characteristics of living things?

Order, growth, reproduction, response to stimuli, energy transformations, and evolution

What are the characteristics of living things products of?

All of the characteristics are products of chemical reactions that manifest themselves as physical, physiological, or behavioral (animals only) phenotypes

• Are manifestations of the chemical and physical properties, and interactions of matter

Levels of Biological Organizations

1. Atoms

2. Molecules and Macromolecules

3. Cells

4. Tissues

5. Organs

6. Organ systems

7. Organism

8. Population

9. Community

10. Ecosystem

11. Biosphere

Atom

Is the smallest unit of an element that has chemical properties of the element

• All matter is composed of atoms

Molecules and Macromolecules

• Atoms bond with each other to form molecules

• A polymer (polypeptide) consists of many molecules bonded together and is called a macromolecule

• Carbohydrates, proteins, and nucleic acids (DNA and RNA) are important macromolecules found in living organisms

Cells

• The simplest unit of life is the cell

• A cell is surrounded by a membrane and contains a variety of molecules and macromolecules

• Unicellular organisms are composed of one cell, whereas multicellular organisms, such as plants and animals, contain many cells

Tissues

• In multicellular organisms, many cells of the same type associate with each other to form tissues

• Ex: muscle tissue

Organs

• In complex multicellular organisms, an organ is composed of two or more types of tissue and carries out a particular function

• Ex: heart is composed of several types of tissues including muscle, nervous, and connective tissue

Organ Systems

• In multicellular species, organs are typically a part of a larger, interacting system

• In animals, such as birds and mammals, the heart is apart of the circulatory system

Organism

• All living things can be called organisms

• Biologists clarify organisms as belonging to a particular species (related group of organisms that share a distinctive form and set of attributes in nature)

• The members of the same species are closely related genetically

Population

• A group of organisms of the same species that occupy the same environment

Community

• A biological community is an assemblage of populations of different species

• The types of species found in a community are determined by the environment and by the interactions of the species with each other

Ecosystem

• Are formed by the interactions of a community of organisms with their physical environment

Biosphere

• The biosphere includes all of the places on Earth where living organisms exist

• Life is found in the air, in bodies of water, on the land, and in the soil

Five Fundamental Themes of Biology

1. Evolution

2. Structure and function

3. Information

4. Energy and matter

5. Systems

Evolution

• The diversity of life evolved over time by processes of mutation, natural selection, and genetic exchange

• As a result populations become better adapted to the environment in which they live

Structure and function

• Basic units of structure define the function of all living things

Information (flow, exchange, and storage)

• The growth and behavior of organisms are activated through expressions of genetic information

• Genetic material composed of DNA provides a blueprint for the organization, development, and function of livings things

• During reproduction a copy of this blueprint is transmitted from parents to offspring (is heritable)

Pathways and transformations of energy and matter

• Biological systems grow and change via processes that are based on chemical transformation pathways and are governed by the laws of thermodynamics

• All living organisms acquire energy and matter from the environment and use them to synthesize essential molecules and maintain the organization of their cells and bodies

Systems

• Living systems are interconnected and interacting

• The interactions of living systems result in emergent properties, which are properties that manifest themselves as the result of various system components working together, not as a property of any individual component

• When the parts of an organism interact with each other or with the external environment to create novel structures and functions, the resulting characteristics are called emergent properties

What are the subdisciplines of biology?

1. Ecology

2. Anatomy and Physiology

3. Cell biology

4. Molecular Biology

5. Systems Biology

Ecology

• Population, community, and ecosystem levels

• Ecologists study the impact of the environment on living organisms

Anatomy and Physiology

• Levels tissue, organ, and organism levels

• Anatomists and physiologists study how the structures of organisms are related to their functions

Cell Biology

• Cellular levels

• Cell biologists often use microscopes to learn how cells function

Molecular Biology

• Atomic and molecular

• Molecular biologists and biochemists study the molecules and macromolecules that make up cells

Systems Biology

• All levels, shown here at the molecular level

• Systems biologists may study groups of macromolecules. The microarray shown in the inset determines the expression of many genes simultaneously

What are the steps of the scientific method?

1. Observations

2. Hypothesis

3. Experiment

4. Analyze results/data

5. Draw Conclusion

Observations

• What you see and your five senses

Hypothesis

• Is a proposed explanation for a natural phenomenon

• Based on observations

• Must be stated as a prediction (expected outcome that can be shown correct or incorrect)

• that is testable (can be shown consistent or inconsistent with data obtained from experiment)

• And is falsifiable (can be shown to be incorrect by additional observations or experimentation)

• Explain the phenomenon

Experiment

• Is conducted to determine if the predictions in hypothesis is correct

• Two ways data is collected in experiments:

• Control group- the sample in the experiment that is treated just like an experimental group except that it is not subjected to one particular variable, dependent variable

• Experimental group- the sample in an experiment that is subjected to some type of variation that does not occur for the control group, independent variable

Data/Analyze Results

• Result of experimentation

• Statistics and graphing

Conclusion

• Draw a conclusion

• Accept or reject hypothesis

• Hypothesis consistent with data or not

Who follows the scientific method?

• Biologists

• Other scientists

Scientific Method

The analysis of scientific evidence, ie, data, requires the use of mathematical modeling and statistics