1. The science of naming & classifying organisms.
Taxonomy
The science of naming & classifying organisms.

2. Why Classify?
Think of a supermarket.

3. Classifying helps us: Organize items into meaningful groups
Can show the relationships between organisms
Helps prevent confusion among scientists.

4. Naming
What do you call this animal?

5. Devil Cat

6. Ghost Cat

7. Mountain Lion

8. Screaming Cat

9. Puma

10. Florida Panther

11. Cougar

12. There are at least 50 common names for this cat.
Common names vary according to region.

13. A scientific name eliminates the confusion of common names.
Scientists agree to use a single name for each species.
= Felis concolor

14. Early Naming
When scientists first attempted to name species, they used descriptions, but these words could be very long. (10-20 words) (polynomial)
Based on common names
Different scientists would still describe different characteristics

15. Carolus Linnaeus Swedish, 1707-1778, botanist
Described organisms with two word names, instead of polynomials
Developed binomial nomenclature
First word = genus name
Second word = species name
Named over 20,000 species!

16. Why binomial nomenclature?
Much easier than a 10+ word name under old “polynomial system”
Same name no matter where you go = consistent
Less confusion
Unique name
Binomial = SCIENTIFIC NAME

17. Binomial Nomenclature Rules
2 – part name
Must be from Latin or Greek roots
First letter of genus name must be capitalized
First letter of species name is NOT capitalized
Written in italics (typed) or underlined (handwritten).
Ex. Ursus arctos or U. arctos
Names must be approved by an Int’l Naming Authority

18. Linneaeus’ Taxonomic hierarchy
Names organisms and their relationships from very broad to very specific
Each level is called a taxon (plural = taxa)

19. Classification Hierarchy for organisms
Kingdom
Phylum (pl. phyla)
Class
Order
Family
Genus (pl. genera)
Species (most specific)

20. Note: Domains have recently been added above Kingdoms.
Many levels have sub-levels. For ex. Sub-phylum or sub-species.
Good idea to think of a way to remember the levels.
Ex. “Dr. King Phillip Cried Out For Goodness Sake”

21. Pause
Can you make up your own?

22. How did Linnaeus Classify?
Linnaeus had only 2 kingdoms – Animalia & Plantae
He classified things according to visible similarities and differences.
This isn’t always true - Some organisms look similar but are not closely related. (Ex. Pg 452, barnacles and limpets)

23. Classification
Biologists now use phylogeny ; evolutionary relationships between organisms as a primary means of classification.
For ex. All members within a genus would share a common ancestor.

24. House cat vs. cougar Taxon House Cat Cougar Kingdom Animalia Phylum
Chordata
Class
Mammalia
Order
Carnivora
Family
Felidae
Genus
Felis
Species
catus
concolor

25. Phylogenetic Trees
A phylogenetic tree is a family tree that shows a hypothesis about the evolutionary relationships thought to exist among groups of organisms. It does not show the actual evolutionary history of organisms.
Why a hypothesis?

27. Bird Phylogenetic tree

28. Evidence
Phylogenetic trees are usually based on a combination of these lines of evidence:
Homologous structures
Fossil record
  Embryological relationships
Biochemical relationships (Chromosomes and DNA)

29. Homologous
Structures
-structures that are
similar in different
organisms because
they descended from
a common ancestor.

30. Fossil

31. Chromosomes and DNA
- The more similar DNA sequences of two species, the more closely related they are.

32. Embryological relationships
-organisms that have embryological similarities are more closely related.

33. Cladograms
A cladogram is a diagram that shows the evolutionary relationships among a group of organisms.
Shows when different groups diverged from a common ancestral line
DO NOT give an indication of time to evolve.

34. Cladograms cont’d
Points where they diverge are often noted with a feature that was different between ancestral group and a “new” feature in the group that split off.
These features are called derived characteristics (characteristics arising from evolutionary changes)

35. Cladogram vs Phylo. tree

36. Cladogram Activity Organism Derived Character Backbone Legs Hair Trout
Human
Lizard
Earthworm
Identify the organism in the table that is least closely related
Construct Cladogram

37. 1. What trait separates the least closely related organism from the other animals?
2. List the organisms in order from the least closely related to the most related.
Lack of backbone
Trout, lizard, human

38. 4. Where would you insert a frog in the cladogram?
3. Do lizards and humans share a common ancestor more recent than the earthworm? Explain.
4. Where would you insert a frog in the cladogram?
3. Yes, humans and lizards shared ancestor with legs and backbone. Evolved after earthworm’s lineage.
4. Between Trout and lizard – It has legs

39. Drawing a Cladogram

40. What is a species anyway?
Biological species concept
A group of actually or potentially breeding natural groups that are reproductively isolated from other groups.
BSC’s problems
Hybrids
Sterile offspring of two different species
Asexual organisms

41. How many are out there? Scientists currently estimate that
There are ~10 million species worldwide
(8.7 non-bacteria)
Only ~1.5 million identified and classified
Will take ~ 480 years to id and classify the remainder
Most unnamed species are small or microscopic

42. “Nature is messy; Science is tentative; as long as these truths remain relevant to biological research, scientific names will continue to be revised.” - Aidan Martin, shark biologist

43. Activity Time! - Brainstorm different kinds of fruit
Then categorize them

44. Identifying organisms with a dichotomous key
A dichotomous key is a device that can be used to easily identify an unknown organism.
The word dichotomous comes from two Greek words that together mean, "divided in two parts".

45. Identifying organisms with a dichotomous key
A dichotomous key consists of a series of two part statements that describe characteristic of organisms.
At each step of a dichotomous key the user is presented with two choices.
As the user makes a choice about a particular characteristic of an organism they are led to a new branch of the key.
Eventually the user will be led to the name of the organism that they are trying to identify.

46. What makes a good key? Choices are clear and unambiguous (clear)
Must have only 2 choices per step
Use the fewest number of choices possible to determine identity (no extraneous choices)
Uses characteristics that are observable – not based on information of what is possible or what the organism can do or hidden characteristics. (For organisms, where it is found can be a valid identifying point)

47. Pause
Activity time!!!
Create a Dichotomous Key to identify students in this class (or other larger classes)

48. Now let’s use a dichotomous key to identify aliens!

49. The 6 Kingdoms Prokaryotes (Used to be 1 kingdom, Monera) Eukaryotes
1. Eubacteria
2. Archaebacteria
Eukaryotes
3. Fungi
4. Protista
5. Plantae
6. Animalia

50. CELLS (Prokaryote and Eukaryote)
The domains Bacteria and Archaea are prokaryotic.
The domain Eukarya is eukaryotic.
Let’s compare and contrast Prokaryotic cells vs. Eukaryotic cells.

51. This is a Prokaryotic cell!!

52. These are Eukaryotic cells!!

54. Similarities They both have DNA as their genetic material.
They both have cell membranes.
They both have ribosomes.
They have similar basic metabolism.
They are both amazingly diverse in forms.

55. Differences Eukaryotes have a nucleus, while prokaryotes do not.
Eukaryotes have membrane-bound organelles, while prokaryotes do not.
Cell division in Eukaryotes is a much more complicated (and therefore amazing) process, than is possible in prokaryotic cells.
Eukaryotic cells are, on average, ten times the size of prokaryotic cells.
Eukaryotes undergo mitosis; prokaryotes divide by binary fission (simple cell division).

56. Pause
Worksheet time!!!!

57. Overview of the 6 kingdoms
Eubacteria
Unicellular
Prokaryotic
“Common bacteria”
Cell walls composed of peptidoglycan
Archaebacteria
Live in extreme environments
Cell walls not made of peptidoglycan and cell membranes contain unusual lipids

58. Bacteria
Characteristics: prokaryotic, unicellular; can be autotrophic (produce energy by chemosynthesis) or heterotrophic; have cell walls; reproduce asexually
Interesting facts: their ancestors were probably the first living things on Earth; the Kingdom Bacteria comprises the greatest number of living things on Earth
Example: bacteria and cyanobacteria

59. Protista Characteristics: eukaryotic,
mostly unicellular but some multi-cellular (giant kelp); no cell walls;
reproduce sexually and asexually; hetero- and autotrophic; lots of variety (plant-like, animal-like, and fungus-like)
Interesting fact: the Euglena can feed on other organisms like an animal, but it can also perform photosynthesis like a plant if light is available
Examples: Euglena, amoeba, and kelp

60. Fungi Characteristics: heterotrophic;
unicellular or multi-cellular eukaryotes;
decomposers (absorb nutrients from decomposing, dead organisms or waste);
plant-like, but lack chlorophyll, so they can’t carry on photosynthesis;
have cell walls (chitin)
Examples: molds, yeasts, mildew, mushrooms

61. Plantae Characteristics: stationary, multicellular eukaryotes;
autotrophic (use photosynthesis as a source of energy);
Cell walls made of cellulose.
tissues organized into organs and organ systems;
use meiosis in reproduction
Over 350,000 species identified so far
Include mosses, ferns, conifers, and flowering plants

62. Animalia Characteristics: heterotrophic multi-cellular eukaryotes;
have advanced tissues and complex organ systems;
no cell walls;
movement by muscle contraction;
quick response to stimuli with specialized nervous tissue to coordinate responses;
utilize meiosis in reproduction

63. Pause well end
Graphic Organizer time!!!!