Notes: Classification of Living ThingsScientists have discovered and named over _______________________________ different organisms, and the list continues to grow every day.

__________________________________ is a way of grouping things into categories based upon their characteristics.

The science of classifying all living things is called __________________________________. The way we classify organisms is based upon a system developed over 200 years ago by Carolus Linnaeus.

According to his system, organisms are placed into groups called _________________. Linnaeus created 7 taxa:

Kingdom (__________________________________) Phylum

Class Order

Family Genus

Species (__________________________________)

A large number of organisms belong to the same kingdom. Fewer belong to the same phylum, and so on.

Species is the smallest , most ______________________ category. Organisms of the same species are a group of genetically distinct organisms.

Two organisms in the same genus are quite similar because they diverged (came from) a recent common ancestor. However, some form of selection in the past caused them to separate into different groups or species.

The diagram below shows Linnaeus’s classification of a grizzly bear starting with its Kingdom.

Notice the diversity of the organisms that are in the same kingdom as the grizzly bear.

o How many taxa do the fox & grizzly bear have in common? ___________

o If two organisms are in the same phylum, does that mean that they must be in the same class? ___________

o Which animal in the diagram is most closely related to the grizzly bear? _______________________________

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How we define a species?

As we learn more about the organisms around us, the definition for a species has changed over time.

If we have two organisms that look alike, how do we know if organisms are the same species? Scientists use several characteristics to determine this.

A species is defined as organisms that:

1. Have a similar shape/structure (morphology). Organisms of the same species don’t have to be

identical. Many species have great variation in their appearances. Some examples include:

Ex: ____________________________________________________________________________

Ex: ____________________________________________________________________________

2. Are able to mate AND produce fertile offspring. Two giraffes reproduce and give birth to a baby giraffe. Once that giraffe matures, it will reproduce and have babies of its own. A ___________________________ & a donkey have a similar appearance. When mated, their

offspring is a mule. As it turns out, mules are sterile and can’t reproduce. While both the horse & donkey are in the genus Equus, they are classified as two ______________________ species.

3. The organisms must be a natural population. That means if the only time these animals might be found together is in captivity, they would not be the same species. ________________________ & ________________________ belong to the genus Panthera. In

nature they are found on different continents. Sometimes in captivity, these animals have been known to mate and produce offspring called a Liger or a Tigon (which are often sterile).

o Liger = Lion (male) x Tiger (female) o Tigon = Tiger (male) x lion (female)

Linneaus realized that referring to organisms by their common name could be quite confusing.

While some common names refer only to one specific species (i.e. Lion and Walrus); Other common names refer to many different species (there are 34 different species of _________________)

Linnaeus realized that each species needed a universal scientific name. These names were made up of the last two taxa (______________________________ + ________________________________).

Each scientific name is unique for that species. These names are in _____________________ so they often sound unusual to us:

The scientific name for humans is ___________________________________.

All humans are in the genus _____________________ and species name ________________________. Kingdom Animalia

Phylum Chordata Class Mammalia

order Primate family Hominidae

genus Homo species sapiens.

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Full Classification

Today, the system has been modified in several ways:

1 – Based upon ______________________________ evidence, the classification of some organism had to be changed. We are more accurately able to tell how closely related organisms are by comparing their ______________ or _______________________________.

2 – A larger taxa (classification group) was added to the system called ______________________________. Organisms are placed into one of three domains based upon the complexity of their cells

prokaryotes = no nucleus eukaryotes = nucleus

Within each domain, organisms are placed into a _________________________. Organisms in the same kingdom share several important characteristics such as cell structure or how they obtain and use energy (heterotrophs = eat autotrophs = make own food).

Classification Groups from biggest to smallest (broadest to most specific)

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Study Guide: Introduction to Classification

1. What is the scientific name of the grizzly bear? ______________________ ___________________ (refer to the chart on page 1 of your notes).

2. What language is used to give scientific names to all living things? _____________________

3. What is the genus of the red maple if its scientific name is Acer rubrum? _________________

4. The largest group in the current system of classification is the __________________________ ; The

_________________ is the smallest classification group.

5. Fill in the name of each missing taxonomic category on the right in the chart below:

Taxon Green Frog Mountain Lion Domestic Dog Human

Kingdom Animalia Animalia Animalia Animalia

Chordata Chordata Chordata Chordata

Class Amphibia Mammalia Mammalia Mammalia

Anura Carnivora Carnivora Primates

Family Ranidae Felidae Canidae Hominidae

Rana Felis Canis Homo

Species clamitans concolor familiaris Sapiens ↑6. Which taxon (category) includes the most specific characteristics? __________________________

7. Which taxon above includes a larger number of species, an order or a phylum? ______________

8. What is the scientific name of the green frog? ___________________________________________

9. Which taxa do all four organisms have in common? ______________________________________

10. Which two organisms in the chart are the most closely related? ____________________________ &

__________________________________; How many taxa do they have in common? ____________

11. Which animal is least closely related to the human? ______________________________________

12. For two organisms to successfully mate (produce fertile offspring), they must be the same ______

13. Which taxa is larger than a family, but smaller than a class? ________________________________

14. Since all of these organisms are in the animal kingdom they must be in the same domain. What is the

name of the domain that they are classified in? ____________________________________

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Hair

Jaws

Placenta

Segmented BodyMulticellular

Notes: Ways to Show Evolutionary Relationships

Cladogram (Phylogenetic trees) are used to show how organisms & their ancestors evolved from one another. Organisms shown share a common ancestor (located at the bottom of the tree/branches). The simplest (most primitive) animals will be at the base of the chart. The most complex (or most highly evolved) will be at the top of the chart (farthest from the base).

Use the cladogram to the right to answer the following questions:

1. Which animal is the most primitive? ________________2. Does the perch possess a lungs? __________________3. What features are shared by the salamander & mouse?

_____________________________________________4. Why is the derived characteristic ‘feathers’ not written on the main axis

like all of the other characteristics? _________________________________________________________________________________________

A Cladogram can be constructed for any group of organisms. Use the cladogram on the right to answer questions 5-8.

5. Which animals on the cladogram have limbs? ______________________________________________

6. Which animal on the cladogram is the most complex?______________________________________________

7. What characteristic(s) is/are listed for the sponges?______________________________________________

8. What characteristics are shared by the lizard & the earthworm?______________________________________________

Molecules reflect evolutionary relationships. Comparing the _________ and _______________ (which are made of amino acids) of different species provides strong evidence for evolution.

Finding the number of differences in the genetic information between different species helps determine how closely related two organisms are. In the cladogram on the left, the greater the evolutionary distance from humans, the greater the number of amino acid differences in the hemoglobin protein (polypeptide).

Notes: Classification Keys (see pages 462-463 for additional information)

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Limbs

A classification key, also knows as a ___________________________________ key, is useful in identifying unknown organisms (but is not limited to being used with living things).

Use the dichotomous key to identify the organisms by their scientific names.

Organism A Organism B Organism C Organism D

____________________________

__________________________

_________________________

__________________________

Begin on line 1 (reading choices a and b). Choose the statement that matches your organism. Follow the Go To directions until you come to a line that identifies the organism by name.

1a. organism with two or four functional legs . . . go to 21b. organism without two or four legs . . . . . . . . . go to 3

2a. organism without wings . . . . . . . . . . . . . . . . . Canis familiaris2b. organism with wings . . . . . . . . . . . . . . . . . . . Passer domesticus

3a. organism is unicellular . . . . . . . . . . . . . . . . . . go to 43b. organism is multicellular . . . . . . . . . . . . . . . . go to 5

4a. organism swims freely in water . . . . . . . . . . . Balantidium sp4b. organism is anchored to substrate . . . . . . . . . Stentor sp.

5a. organism is heterotrophic . . . . . . . . . . . . . . . . go to 65b. organism is autotrophic . . . . . . . . . . . . . . . . . go to 7

6a. organism lives in ocean . . . . . . . . . . . . . . . . . Monodon monoceros6b. organism lives on land . . . . . . . . . . . . . . . . . . Ophiophagus hannah

7a. organism is a tree . . . . . . . . . . . . . . . . . . . . . . Pinus ponderosa7b. organism is an herb . . . . . . . . . . . . . . . . . . . . Taraxicum officinale

Practice Using a Dichotomous Key

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Examine the drawings of the four leaves below. Use the key that follows to identify the leaves. Write the name of each leaf in the numbered box below its picture.

Leaf A Leaf B Leaf C Leaf D

14 cm long

12 cm long

1. 2. 3. 4.

Now use the dichotomous key – what can you tell me about the sugar maple?5. Is the sugar maple star shaped? _____________________6. Are its lobes pointed or rounded? ____________________7. How many lobes does it have on each leaf? ____________

1a. oval leaf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . go to 21b. leaf deeply notched or lobed . . . . . . . . . . . . . . . . . . . . go to 5

2a. leaves with smooth edge . . . . . . . . . . . . . . . . . . . . . . . . go to 32b. leaves with serrate or “sawtooth” edge . . . . . . . . . . . . go to 4

3a. leaves 10 – 15 cm long . . . . . . . . . . . . . . . . . . . . . . . . . magnolia3b. leaves 4 – 7 cm long . . . . . . . . . . . . . . . . . . . . . . . . . . . common pear

4a. leaves 10 – 15 cm long . . . . . . . . . . . . . . . . . . . . . . . . . Spanish chestnut4b. leaves 4 – 7 cm long . . . . . . . . . . . . . . . . . . . . . . . . . . . white elm

5a. four or five lobes total . . . . . . . . . . . . . . . . . . . . . . . . . . go to 65b. many lobes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . go to 7

6a. four pointy lobes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . tulip tree6b. five pointy lobes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . go to 8

7a. lobes pointy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . red oak7b. lobes rounded . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . English oak

8a. star-shaped leaf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . sweet gum tree8b. leaf not star-shaped . . . . . . . . . . . . . . . . . . . . . . . . . . . . go to 9

9a. long, narrow lobes . . . . . . . . . . . . . . . . . . . . . . . . . . . . Japanese maple9b. each lobe having several points . . . . . . . . . . . . . . . . . . go to 10

10a. leaf longer than it is wide . . . . . . . . . . . . . . . . . . . . . . pin oak10b. leaf wider than it is long . . . . . . . . . . . . . . . . . . . . . . . sugar maple

Classification Review

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6 cm long 16 cm long

Use the diagram to the right to answer the next two questions.1. Which organism(s) on the right show segmentation?

_______________________________________________

2. What characteristic do all three organisms have in common?

________________________________________________

3. Most scientific names are written in _________________ (language).

4. The first word of each name is called the ________________. The second word is called the

_________________________.

5. Write the scientific name for humans - _______________________ ________________________.

6. The study of the classification of organisms according to their characteristics is ____________________.

7. List 3 characteristics that animals must have in order to be classified as being in the same species:

_____________________________________________________________________________

_____________________________________________________________________________

_____________________________________________________________________________

8. List the three domains and tell which kingdoms are classified under each domain.

_____________________________---____________________________________________

_____________________________---____________________________________________

_____________________________---____________________________________________

9. According to the classification system used today, list the eight TAXA from largest to smallest.

__________________ __________________ __________________ _________________

____________________ ________________________________________________________

10. A ___________________ ________________ key is also known as a two branching chart which can be used to identify the name of objects or specimen.

Use the diagram shown on the left to answer the questions 11-12:

11. What characteristic(s) are shared by the lungfish and

flounder? ______________________________________

12. Which animal(s) has/have amniotic egg? __________

______________________________________________

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