DIVERSITY OF LIVING THINGSOrganization of Organisms

Diversity The vast diversity of living things is

astounding! Biologists study differences between

organisms in order to classify them Diversity within species is important to

the species survival Humans depend on the Earth’s

biodiversity for food and products

Biodiversity Biodiversity is the variability of

all living organisms -- including animal and plant species -- of the genes of all these organisms

Biodiversity makes up the structure of the ecosystems and habitats that support essential living resources, including wildlife, fisheries and forests.

Helps provide for basic human needs such as food, shelter, and medicine.

Why do Scientists Classify Organisms?

Is 30-100 million kinds of organisms on Earth!

Need to keep them organized

Classification: the process of grouping things based on their similarities

Classification of Living Organisms

Biologists use taxonomy and phylogeny to organize organisms

Sexual reproduction maintains genetic variability which provides a greater diversity of genotypes that can survive environmental changes; in turn ensuring a species survival!

Diversity of Species

Taxonomy About 2300 years ago Aristotle first

started to group animals according to their habitat

Aristotle observed animals’ appearance, behaviour, types of movement and observed similarities and differences

He used the differences to divide them into smaller subgroups

In 1665 when the microscope was discovered, many varieties of microscopic organisms were discovered

Taxonomy Now, there were lots of organisms and

the need for an effective classification system became evident

John Ray in the 17th century was first to use the word species (organisms of similar shape and size)

Linnean System of Classification Carolus Linnaeus simplified classification by

the 18th century He used binomial nomenclature that is still

used today When classifying, each organism receives a

two-part scientific name First part of any scientific name is called the

genus, the second part of called the species The language used is Latin which was used

by scholars at that time

Linnean System of ClassificationExample: genus species Canis familiaris

(dog!)

Often instead of repeating the genus we used the initial

Example: Escherichia coli becomes E coliPlease note the genus is always

capitalized and the species is NOT.

System of Classification There are 7 levels or taxa of

classification. Taxa are used to group organisms by

their similarities according to structure and/or evolutionary history.

Remember the first letter of this sentence:

King Philip Came Over For Good Spaghetti

There are 7 Levels of Classification

Kingdom Broadest levelPhylumClassOrderFamilyGenusSpecies Most Specific level

Levels of ClassificationThink of the classification system as an upside down pyramid. The Kingdom is the largest part and can hold the greatest number of organisms such as all the animals or all the plants.

As you move down the pyramid each level or ‘room’ gets smaller; it can hold fewer and fewer organisms. However, the members have more traits in common and begin to look alike.

The species is the smallest ‘room’ in the classification system and is only large enough for one kind of organism – only humans, only houseflies, etc.

Levels of Classifica

tion

Housefly Human

Kingdom Animalia AnimaliaPhylum Arthropoda ChordataClass Insecta MammaliaOrder Diptera PrimatesFamily Muscidae HominidaeGenus Musca Homo

Species domestica sapiens

Dichotomous Keys A tool allowing a scientist to determine the identity

of species – a means of classifying any living species on Earth

Keys consist of a series of choices that lead the user to the correct name of a species

Dichotomous means ‘divided into 2 parts’

So, dichotomous keys always give 2 choices in each step

Classify: shoe, burger, belt, celery, fries

1.a. Clothing: Go to 2 1. b. Not Clothing: Go to 3

2. a. Fits on your feet: Shoes 2. b. Fits around your waist: Belt

3.a. Vegetable: go to 4 3. b. Meat: Burger

4.a. Green vegetable : Celery 4. b. Not green: Fries

This can also be drawn in a Classification Tree:

Objects

Clothing Not Clothing

Fits on Feet Fits around waist Vegetable Meat Shoes Belt Burger

Green Not Green Celery Fries

…kingdoms next!

Kingdoms Before we learn exactly how biologists

classify different organisms, we’re going to learn about the first taxa level: the Kingdom

There are 6 Kingdoms for all organisms Anyone know them? Animalia, Plantae, Fungi, Protista,

Eubacteria, Archaebacteria

Before We Examine the Kingdoms...

Remember the CELL?????

Let’s Review:http://www.cellsalive.com/cells/3dcell.htm

Two Types of Cells:Prokaryotes Eukaryotes

A type of cell A type of cell

Simple cell; were here first and for billions of years

Complex cell; evolved from a prokaryote-like ancestor

Are extremely successful as organisms

Many are successful; some organisms made of eukaryotic cells become extinct

Cytoplasm contains enzymes, ions and ribosomes, floating freely inside the cell membrane

Cytoplasm has suspended membrane – surrounded organelles such as a nucleus, chloroplasts, vacuoles and ribosomes

DNA has no membrane separating this area from the rest of the cell

Is a ‘true’ nucleus surrounded by a membrane that contains DNA. A nucleolus contains RNA.

Compare the Pictures

Prokaryotic Cell Eukaryotic Cell

Kingdom Eubacteria Have classified 4000 of 4 000 000

Are prokaryotes

Found everywhere; often called ‘true bacteria’

Kingdom Archaebacteria Live in harsh, salty, acidic conditions and

volcanoes

The first forms of life

Are prokaryotes

Only realized to be different from Eubacteria in 1996 due to advances in genetics

Kingdom Protista Single celled eukaryotes

115 000 species, all very diverse in cell structures, patterns of nutrition, reproduction and habitats

A ‘grab bag’ of organisms that do not fit into other kingdoms! Some are animal-like, fungus-like or plant-like

Examples of Protista Zooflagellates are animal-like protists Sleeping sickenss is caused by a parasitic

zooflagellate called Trypanosoma gambiensis Humans contract the disease if bitten by a

tsetse fly infected with it Once inside, zooflagellate multiplies in the

bloodstream, destryoing red blood cells and attacking other tissue

Symptoms: fever, chills, skin rash Disease can be fatal

Smear of Trypanosoma gambiensis

Examples of Protista Algae is a plant-like protista Resemble plants because they have

chloroplasts Some species are single celled, others

are multicellular Algae perform 50 to 75% of all

photosynthesis on Earth = free oxygen

Plant-Protista Debate Some algae can be classified as both

Depends on how ‘plants’ are defined

But most plants have adaptations for living on land (cell walls, roots, stems) and all multicellular algae are marine; they don’t have these adaptations

Algae are therefore considered Protists

Kingdom Fungi Eukaryotes that build cell walls but not

with cellulose like plants: FUNGI ARE NOT PLANTS!!!

No photosynthesis; they depend on other organisms for nutrients

Examples: mold, yeast, mushrooms

Examples of Fungi

Kingdom Plantae Unicellular, mostly multicellular organisms;

eukaryotes

Cell walls contain cellulose (a complex carbohydrate that forms the main part of plant cell walls)

Have chloroplasts (an organelle present in algae and plant cells that contains chlorophyll and is involved in photosynthesis) & carry out photosynthesis

Examples of Plantae

Kingdom Animalia Multicellular organisms

Have cell membranes not cell walls

Cells are organized into tissues, organs and systems (e.g. – respiratory or digestive system)

Divided into vertebrates (backbone) and invertebrates (no backbone)

Examples of Animals