The Diversity of Life

Biology

The study of life.

What characteristics do you look for to determine if something is living or non-living?

There are six basic characteristics of life. All living things posses the following traits.

1. Show an orderly structure,or organization, of tiny units called cells.

2. Reproduce to make more living things. 3. Change during their lives through growth and

development.4. Adjust to their surroundings.5. Obtain and use energy to run the processes of

life.6. Pass on traits to their offspring.

2 types of Reproduction

1. ASEXUAL (binary fission) a single parent passes exact copies of it’s DNA to it’s offspring. Occurs in bacteria and single celled organisms such as the amoeba.

The single-celled amoeba demonstratesa simple method of asexual reproduction; it divides in half by a process called fission, producing two smaller daughter cells. Aftera period of feeding and growth, these two daughter cells will themselves divide in half.

2 types of Reproduction

2. SEXUAL - organisms having genetic characteristics derived from two parents are produced.

Male and female reproductive cells (gametes) unite to form a single cell, known as a zygote, which later undergoes successive divisions to form a new organism.

Adjust = HOMEOSTASIS

• Organisms respond to their external environment and then process the internal demands accordingly.

• The maintenance of stable internal conditions in spite of changes in the external environment.

Example: temperature of a human is always around 98.6 regardless of the temperature outside.

Why Do We Classify Living Things?

There are an estimated 10 million to 30 million species on earth.

Classification determines methods for

organizing the diversity of life on earth by

providing a framework of logic and order so

that relationships among living things and

once living things can be seen easily.

Carolus Linnaeus

• Used physical characteristics to classify living things.

Example: bats fly like birds, but have fur and produce milk so they are placed into the mammal group.

• Linnaeus’ classification system is known as binomial nomenclature.

• Every organism is given a two-part scientific name.

1. Genus name is always placed first, is capitalized and underlined. Homo

2. The second word describes the organism in scientific terms. It is always lowercase and underlined. Sapiens

Human binomial name = homo sapiens

TAXONOMY

• Science of classifying organisms.

• Scientists identify new organisms and determine how to place them into an existing classification scheme.

• Scientists who study the grouping and naming of organisms are known as taxonomists.

CLASSIFICATION LEVELS

• 7 major levels• The system goes from most general to the most

specific.• Kingdom King Phillip came

Phylum over for good spaghetti.

Class If two organisms are in the

Order same order are they also in the same

Family same class? Phylum? Kingdom?

Genus Species

SPECIES

• A GROUP OF SIMILAR LOOKING ORGANISMS THAT SHARE SIMILAR CHARACTERISTICS AND CAN INTERBREED WITH ONE ANOTHER TO PRODUCE FERTILE OFFSPRING.

horse + donkey = mule (non-fertile offspring)

species + species = non-species

The Six Kingdoms

1. Archaebacteria Collectively 1 and 2

2. Eubacteria are known as Monera.

3. Protista

4. Fungi

5. Plantae

6. Animalia

I. Archaebacteria

• Ancient bacteria

• Prokaryotes (do not have a true nucleus), single celled organisms.

• Live in extreme environments such as salt lakes, swamps and VERY deep within the ocean.

II. Eubacteria

• True bacteria

• Found in practically every environment on Earth.

III. Protista

• First eukaryotic kingdom (true nucleus)

• Contains multicellular and unicellular species.

• Heterotrophic – feed off of others.

• Motile – able to move.Examples include Ameobas, Parameciums and

kelp.

Peter Parks/Oxford Scientific Films

Amoeba Engulfing a Paramecium

An amoeba, a single-celled organism lacking internal organs, is shown approaching a much smaller paramecium, which it begins to engulf with large outflowings of its cytoplasm, called pseudopodia. Once the paramecium is completely engulfed, a primitive digestive cavity, called a vacuole, forms around it. In the vacuole, acids break the paramecium down into chemicals that the amoeba can diffuse back into its cytoplasm for nourishment.

IV. Fungi

• Eukaryotes• Unicellular or multicellular• Nonmotile -cannot move• Mostly decomposers – obtain energy by

breaking down organic material that they absorb from the environment.

• Cell walls contain chitin – tough outer covering found on insects.

Examples of Fungi

V. Plantae• Eukaryotes• Multicellular• Nonmotile• Photosynthetic autotrophs – make their own

food.• Cells have cell walls.

VI. Animalia

• Eukaryotic

• Heterotrophic

• Multicellular

• Most are motile

Animalia

• 99% of the organisms in Kingdom Animalia are invertebrates – meaning they lack a backbone.

• Organisms that have a backbone are called verterbrates.

Animalia

• The Kingdom Animalia is divided into 6 phyla:

1. Sponges and Cnidarians

2. Mollusks

3. Worms

4. Arthropods

5. Echinoderms

6. Verterbrates

1. Sponges and Cnidarians

- The only animals that

do not have tissues.

- Mostly marine.

- Ex. Jellyfish, corals

2. Mollusks

• Have something called a coulomb (sac-like structure) that encloses their internal organs.

• Most have a hard external skeleton (shell).

• Ex. Snails, oysters, clams, octopuses

2. Mollusks

3. Worms

• Cylinder shaped bodies.

• Live on both land and water.

4. Arthropods

• Most diverse of all animals.

• Have an external skeleton.

• Have jointed appendages, such as antennae and jaws.

• High rate of reproduction.

• 2/3 of all animals.

4. Arthropods

5. Echinoderms

• Ability to regenerate a lost limb.

• Ex. Sea stars, sea urchins

6. Verterbrates

• Internal skeleton made of bone.

• Includes mammals, fish, birds, reptiles and amphibians.

Dichotomous Keys

• Identification key that contains pairs of contrasting descriptions.

• After each description the key either directs you to another comparison or identifies the object.

1a Butterfly exhibits only one color. Boring butterfly

1b Butterfly has two or more colors. Go to 2.

2a. Butterfly has a red body.

2b Butterfly has a black body. Go to 3.

3a. Butterfly contains the color red. Inachis io

3b. Butterfly contains the color orange. Danaus plexippus