The Scientific Study of Life

Chapter 1 – Part 1

Why do we study Biology?

• Biology is all around us - all living things are part of this subject.

• The living things we see as well as the things we can’t see make up the realm of biology. — All containing genetic material (or DNA).

• Bacteria• Plants• Animals

What is Life?

• Defined by its components• Cell - basic unit of life - you are made of

millions of unique cells• Organism - the living individual consisting of

one or more cells - bacteria are unicellular, humans are multicellular

• What is a cell? • Membrane enclosed• Contains genetic material (DNA)• Able to produce proteins and carry out

specialized functions

Organization of Life - The Individual Organism

• Atoms: smallest particles that make up living structures

• Molecules: atoms bonded together• Organelles: formed by multiple molecules -

carry out specialized functions within the cells (but aren’t found in all cells)

• Tissues: only in multicellular organisms - a collected of similar cells

• Organs: a collection of similar tissues• Organ Systems: collections of organs that are

responsible for carrying out tasks

Applying Individual Organism Organization Try to fill in after reading through “Life is Organized”.Click to show the characteristic - try to

fill in the example on your note guide before clicking to show the answer.

Characteristic Give an Example

Atoms

Molecules

Organelles

Tissues

Organs

Organ Systems

Characteristic Give an Example

Atoms Na, Cl, H, C - any of the elements found on the periodic table

Molecules NaCl, KCl, H2O - Combinations of atoms

Organelles Nucleus, Endoplasmic Reticulum, Chloroplast

Tissues Skin, Muscle, Nervous, Leaf Epidermis

Organs Heart, Liver, Leaf

Organ Systems

Cardiovascular, Nervous, Visible portion of plant

Organization of Life - Beyond a Single Organism

• Population: members of the same species living together in the same place at the same time

• Community: populations of different species in a region - squirrels and plants living in the same forest

• Ecosystem: living and nonliving components of a given area - squirrels, plants and soil that are found in one place

Figure 1.2Biological Organization

Organization - Emergent Properties

• Structures that are formed by the interaction of smaller parts

• Caused by physical and/or chemical interactions

• If the structure - here the vessel - is disrupted, the functions - carrying blood - is lost.

Figure 1.3

Life and Energy

• The process of life are driven by energy. Metabolism is the acquiring and using of energy to live.

• Producers: “Autotrophs” - produce own food by obtaining energy and nutrients from nonliving sources.

• Example: Plants that use light energy• Consumers: “Heterotrophs” - obtain energy by

eating other organisms (either living or dead).• Example: Humans that consume plant and

animal products• Decomposers: heterotrophs that obtain energy

from waste or dead organisms.• Example: fungi or bacteria

Figure 1.4How each energy classification is

related.

Life Maintains Internal Constancy

• In order for a cell to function correctly, the internal environment must be kept within strict parameters.

• Temperature• Nutrient Levels• Waste Levels

Homeostasis

• The process of a cell or organism maintaining a constant internal environment - equilibrium.

• Can you think of 3 examples of this?1. Temperature of the human body must by

near 98.6 degrees Fahrenheit.2. Reptiles sun themselves in order to maintain

temperature.3. Plants take in carbon dioxide and release

oxygen from cells as a waste product.

Life Reproduces, Grows and Develops

• Reproduction allows for the generation of offspring similar (or identical) to the parent cell.

• Asexual: Genetic material from one parent so the offspring are all identical.

• Single Celled Organisms such as bacteria.

• Molds• Sponges

• Sexual: Genetic material from two parents leading to new combinations in offspring. More variation in population.

• Plants• Animals

Fungus that produces spores for asexual

reproduction

Figure 1.5

Tree and deer both undergo sexual reproduction - higher genetic variability in offspring.

Life Evolves

• How do organisms become well suited to their environments? - Through the process of adaptation.

• Adaptation: inherited characteristics/behaviors that allow an organism to survive & reproduce in a certain environment.

• Can you think of 3 examples of adaptation?

3 Ways:

• Reptiles that utilize camouflage.• Fish can “breath” under water by using gills.• Human skin color that varies by regions of the

world due to the amount of sunlight available.