1. Classification of Organisms
Chapter 18

2. Why Classify?
Biologists use classification to organize living things into groups so that the organisms are easier to study. 2

3. For Example These organisms have been classified by their color. Red
Green 3

4. 4

5. One Possible Solution
Animals
Plants
???? 5

6. Our modern classification system originated with
two main classifications, plants and animals. Over
the years, scientist came up with certain “plants”
that really did not act like plants, they couldn’t
make their own food. So the kingdom Fungi was
formed. 6

7. This lead to the creation of the Kingdom Protista.
When microscopes were invented, scientists discovered new single celled organisms. Some were animal-like, some were plant like and some were both.
This lead to the creation of the Kingdom Protista. 7

8. As the microscope improved, scientists
discovered that many of the single celled
organisms were quite different. Some of them
had a nucleus and others did not. This lead
to the Kingdom Monera, the kingdom of the
most simplistic organisms, Bacteria. 8

9. Taxonomy- The study of how living things are classified
Asistotle – he had the first classification system that group animal according to how the moved or where they lived.
Swim Fly Walk /crawl
He also had subgroups for organisms that shared other characteristics
Carolus Linnaeus (1730s)- Swedish – He placed organisms in groups according to observable features and physical characteristics. 9

10. Linnaeus’s Naming System
Linnaeus had a two name system called
Binomial Nomenclature
Felis concolor is the scientific name for a puma.
Felis
Is the genus name- it is written first and is always capitalized
concolor
Is the species name – it is written second and is always lower case 10

11. Linnaeus used the Latin language because that was the language that
was dominant around the world at
that time. This is why even today
organism’s scientific names are always
in Latin. 11

12. Along with the two major Kingdoms, Plant and Animal, Linnaeus came up
with several sub-classifications for those
kingdoms. They are: Kingdom, Phylum,
Class, Order Family, Genus, and Species.
What Kingdom are you in?
What phylum are you in? Why? 12

13. Levels of classification
Kingdom
Phylum
Class
Order
Family
Genus
Species
Kindly Pay Cash Or Furnish Good Security 13

14. The Human Species Kingdom: Animalia (Animal in Latin) Phylum: Class:
Order:
Family:
Genus:
Species:
Animalia (Animal in Latin)
Chordata (Spinal Cord)
Mammalia (have mammary glands)
Primates (two mammary glands)
Hominoidea (bipedal)
Homo
Sapiens 14

15. Homo sapiens When you refer to an organism
scientifically, you always use the
genus and the specie names.
Therefore, the human species would
be referred to as:
Homo sapiens 15

16. Recognizing Species
Biologists usually define species based on appearance and structure
Biological species- group of actually or potentially interbreeding natural populations, reproductively isolated from other such groups
Hybrids can be made between two species

17. Evolutionary History
Convergent evolution- organisms evolve similar features independently
Example: anteaters- long, sticky tongue; few teeth; large salivary glands

18. Evolutionary History
Analogous characters- similar features of organisms that evolve independently
Phylogeny- evolutionary history of a species

19. Cladogram
Cladogram- diagram based on patterns of shared, derived traits that shows the evolutionary relationships among groups of organisms

20. Cladogram
Differences in morphological, physiological, molecular, and behavioral level between organisms
New derived characters will show up on the cladogram as groups evolve

21. Conclusion The classification system for organisms
have been around for a long time. It has
endured several changes and is quite
complex. Without it modern biology could
not exist, much in the same way that
a grocery store would go out of business
if it did not have a classification system. 21