Unit 2

Study of Life

Biology

8 Characteristics of Life

• What makes something alive or living?

• Brainstorm your ideas now?

Here are the Answers.

Characteristics of Life

1. Living things are made up of units called cells

Characteristics of Life

2. Living things reproduce.

Characteristics of Life

3. Living things are based on universal genetic code.

Characteristics of Life

4. Living things grow and develop.

Characteristics of Life

5. Living things obtain and use materials for energy.

Characteristics of Life

6. Living things respond to the environment.

Characteristics of Life

7. Living things maintain a stable internal environment. Homeostasis

Characteristics of Life

8. Taken as a group, living things evolve-change over time.

Classification of Life

• Life on Earth constantly changes.

• This process led to Biodiversity.

• Biodiversity is the variety of living organisms in a given area.

• Biologists have identified and catalogued 1.5 million species so far.

• 2 to 100 million additional species yet to be discovered.

Why Classify?

• To study the great diversity of organism, biologists must give each organism a name.

• Taxonomy classifies organisms and assigns each organism a name.

• Latin and Greek are languages that would understood by all, so those are the languages that are used for scientific names.

Binomial Nomenclature

• Carolus Linnaeus, botanist developed two word naming system.

• Always in italics, first word is capitalized, second word lowercase.

• Examples are as follows:

Linnaeus’s system of classification

Example of classification

Traditional Classification vs. Modern Classification

• Linnaeus’ classified organisms according to their physical structures and anatomy.

• Modern classification classifies organisms according to their evolutionary descent, not just physical similarities.

• Let’s think about the dolphin????

Cladogram

• Useful tool used to understand how one lineage branched from another in the course of evolution

• Representing a evolutionary tree, Phylogenetic tree (more on that in evolution unit)

Practice• What are the 2 parts that

make up the Latin name of a species?

• Using the cladogram, which animals have claws/nails?

• Which animals have fur/mammary glands?

• To what is the chimp most closely related to?

Is a hippopotamus more closely related to a pig or to a whale? List 3 reasons to

defend your answer.

HIPPO WHALE

Based on physical comparisons (particularly dental structure and number of toes) it was originally thought that hippos were most closely related to pigs but DNA analysis indicates that hippos are more closely related to whales!

Evolutionary Link• Whales and hippos had a common water-

loving ancestor 50 to 60 million years ago that evolved and split into two groups:

The cetaceans (whales, The cetaceans (whales, dolphins, and porpoises)dolphins, and porpoises)

The pig-like anthracotheres – The pig-like anthracotheres – died out less than 2.5 million died out less than 2.5 million years ago, leaving only the years ago, leaving only the hippo as a descendenthippo as a descendent

Cladogram

How are cladograms constructed?• Organisms are grouped together based on their shared

derived characteristics (trait modified from the ancestral trait).

Dichotomous Key

• A device used to easily and quickly identify an unknown organism.

• The user of the key is presented with a sequence of choices between two statements based on characteristics of the organism. By always making the correct choice, the name of the organism will be revealed.

Here is an example from your book

Kingdoms and Domains

• Original kingdoms were plant and animal.

• Currently 6 Kingdoms- Plantae, Animalia, Fungi, Protista, Eubacteria, Archaebacteria

• More recently, Three Domains were created which are larger than the Kingdoms

• Here is the graphic organizer!

Chemistry of LifeBiochemistry

• Life depends on chemistry.

• Chemical reactions keep you alive.

• Living things are made of chemical compounds

• Let’s learn about the chemistry of life.

THE NATURE OF MATTER

• Begins with the basic unit of matter• The atom

• Sub atomic particles are smaller particles that make up the atom

– Neutrons

– Protons

– Electrons

Elements

• A pure substance that consists entirely of one type of atom.

• 100 or more elements are known.

• Two dozen are commonly found in living organisms

Watersingle most abundant compound

• Compound made of two or more elements

• One molecule of water is made of 2 Hydrogen atoms and 1 Oxygen atom

• Many substances can be dissolved in water.

• Pure water is neutral on the pH scale

pH Scale

• A measurement system to indicate the concentration of H+ ions in a solution.

• pH scale goes from 0 to 14

• Below 7 (1-6) is an acid.

• Above 7 (8-14) is a base.

pH scale

ORGANIC VS. INORGANIC COMPOUNDS

• Inorganic Compounds does not contain Carbon and Hydrogen together

• Non-living• Water is an example –

H2O

ORGANIC VS INORGANIC

• ORGANIC– MUST CONTAIN

HYDROGEN AND CARBON

– ALL LIVING THINGS HAVE ORGANIC COMPOUNDS

– 4 major compounds

•

Four Major Organic Compounds

• Carbohydrates

• Lipids

• Nucleic Acids

• Proteins

Carbohydrates

• Made up of carbon, hydrogen, oxygen

• Main source of energy for living things

• Example of Simple Sugar – Glucose

• Example of Complex sugar - Starch

Lipids

• Made up of carbon and hydrogen

• Energy storage• Part of cell membrane• Examples are fats,

oils, waxes

Nucleic Acids

• Made of hydrogen, oxygen, carbon, nitrogen, phosphorus

• Stores and transmits genetic information

• Examples are RNA and DNA

• Chains of nucleotides make up Nucleic Acids

Protein

• Contain hydrogen, oxygen, carbon, nitrogen

• Used to make bones, muscles, fight off disease

• Chains of amino acids make up proteins

• DNA stores instructions for arranging amino acids into proteins

• Special proteins are called enzymes

Chemical Reactions and Enzymes

• Chemical Reactions changes one set of chemicals into another set of chemicals. Chemical reactions always involve the breaking of bonds and the formation of new products.

Enzyme

• Enzyme is a special protein that acts as a catalyst

• A catalyst is a substance that speeds up chemical reactions that take place in cells.

• Cells use enzymes to speed up chemical reactions that take place in cells

Factors that Effect Function of Enzyme

• Temperature

• pH

Enzyme’s shape is altered or denatured.

Lock and Key Model

• A substrate is the substance that the enzyme reacts with.

• The enzyme binds with substrate.

• When reactions is done, products are released and enzyme is free to start process again.