Download - DIVERSITY OF LIVING THINGS
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