Science High School Reviewer | Grade 4 Science | Life Science | Kingdoms of Life | Lesson 2: Classifying Living Things

Lesson 2 Classifying Living Things . . . . . . . . . . . . . . . . . . 36

Kingdom – is the largest group into which organisms can be classified. All the members of a kingdom share the same basic traits.

How are organism placed into their kingdoms?

· Cell type, complex or simple

· Their ability to make food

· The number of cells in their body

2.1 Six kingdoms of living things

Ancient Bacteria or Archaebacteria – Ancient bacteria have only one cell and no separate nucleus. These organisms may live on land or in water, and many of them live in extremely hot or salty habitats. They make their own food.

Archaebacteria are found in extreme environments such as hot boiling water and thermal vents under conditions with no oxygen or highly acid environments.

True Bacteria or Eubacteria –

Like archaebacteria, eubacteria are single celled. Most bacteria are in the eubacteria kingdom. They are the kinds found everywhere and are the ones people are most familiar with.

Most eubacteria are helpful. Some produce vitamins and foods like yogurt. However, these eubacteria, Streptococci pictured above, can give you strep throat!

Protists –

Slime molds and algae are protists.

Sometimes they are called the odds and ends kingdom because its members are so different from one another. Protists include all microscopic organisms that are not bacteria, not animals, not plants and not fungi.

Most protists are unicellular. You may be wondering why those protists are not classified in the Archaebacteria or Eubacteria kingdoms.

It is because, unlike bacteria, protists are complex cells.

Fungi –

Fungi are organisms that biologists once confused with plants, however, unlike plants, fungi cannot make their own food. Most obtain their food from parts of plants that are decaying in the soil.

Mushrooms, mold and mildew are all examples of organisms in the kingdom fungi.

Most fungi are multicellular and consists of many complex cells.

Plants –

Plants are all multicellular and consist of complex cells.

In addition plants are autotrophs, organisms that make their own food.

With over 250,000 species, the plant kingdom is the second largest kingdom. Plant species range from the tiny green mosses to giant trees.

Animals –

The animal kingdom is the largest kingdom with over 1 million known species.

All animals consist of many complex cells. They are also heterotrophs.

Members of the animal kingdom are found in the most diverse environments in the world.

2.2 Classification of kingdoms into smaller groups

Scientists divide kingdoms into smaller groups. They divide each of these groups into even smaller groups. They continue sorting into smaller and smaller groups.

For the animal kingdom, animals are classified into the following smaller and smaller groups:

Phylum – In this group, animals are classified based on a common ancestor and the animal’s size, shape, and structure. There are seven different phyla.

Porifera, Cnidaria, Platyhelminthes, Annelida, Arthropoda, Chordata, and Mollusca.

Class – The next smaller group is called a class. There are seven different animal classes: jaw-less fish, cartilaginous fish, bony fish, amphibians, reptiles, birds, and mammals.

Order – Each class is divided into small groups again, known as orders. For mammals, scientists have identified as many as 26 different orders. Some of the most popular orders include:

Artiodactyla (even-toed hoofed animals), Carnivora, Rodentia (gnawing mammals), Chiropptera (bats), Cetacea (porpoises and whales), and Primates

Family – A family consists of animals that are even more alike than those in an order.

One example of animal families would be the 12 families that fall under the Carnivora order (Carnivores). The twelve families include:

Felidae (Cats)
Canidae (Dogs, Wolves, Coyotes, African Wild Dogs, etc.)
Ursidae (Bears)
Mustelidae (Weasels, Badgers, Otters, etc.)
Procyonidae (Raccoons, Coatis, Olingos, etc.)
Mephitidae (Skunks, Stink Badgers)
Herpestidae (Mongooses)
Hyaenidae (Hyenas)
Viverridae (Civets, Genets, and Linsangs)
Otariidae (Sea Lions, Fur Seals)
Phocidae (True Seals)
Odobenidae (Walrus)

An additional example would be Lagomorphs, falling under the order Lagomorpha and containing two families:

Leporidae (Rabbits and Hares)
Ochotonidae (Pikas)

Genus –

A genus consists of animals with very similar groups, but members of different groups usually cannot breed with one another. Both the coyote and the timber wolf belong to the genus Canis. But coyotes and timber wolves generally do not breed with one another.

Every animal family is further divided into smaller groups known as genera, or genuses. Each genus contains animals that have very similar features and are closely related.

For example, the Felidae (Cat) family contains genuses including:

Felis (small Cats and domestic Cats)
Panthera (Tigers, Leopards, Jaguars and Lions)
Pumas (Panthers and Cougars)
Leopardus (American Spotted Cats)
Lynxes
Neofelis (Clouded Leopard, Suna Clouded Leopard)
Prionailurus (Asian Spotted Wildcats)
Acinonyx (Cheetah)

Species –

A species is the basic units of scientific classification. Animals of a species have many similar features and characteristics alike, but they are different from all forms of life in one or more ways. Members within a species can breed with one another, and their young grow to look very much like the parents. Each member in a species is assigned a scientific name. The coyote’s scientific name is Canis latrans, and the gray wolf is Canis lupus. Scientist sometimes group animals within a species into even smaller groups because they have another distinctive feature. These groups are called subspecies or varlebes.

2.3 Naming of organisms

Each species within the genus is named after its features and characteristics. The names of animals are based in Latin and consist of two words. The first word in the name of an animal will be the genus, and the second name indicates the specific species. This method of organizing scientific names of animal species was developed by Carl Linnaeus in the 1700’s.

Scientists use the smallest two groups to name organisms. The first part of an organism’s scientific name is its genus. A genus is a group of closely related living things. For example, peach trees and plum trees are in the same genus. They share characteristics such as leaf shape. Both kinds of trees have flowers with parts that develop into tasty fruit. Black-footed cats and house cats are in the genus Felis. They share characteristics such as sharp claws and hunting behaviors.
The second part of an organism’s scientific name is its species. A species is a group of similar organisms that can mate and produce offspring. The species name often describes a characteristic, such as where the organism lives or its color.

The scientific name for the black-footed cat is Felis nigripes. In Latin, nigripes means “black feet.” So this name tells something about what the animal looks like. The scientific name for a house cat tells where it lives. The Latin word domesticus means “of the house.” The scientific name for a house cat is Felis domesticus.

As an example, a dolphin species name is Delphinus Delphis. A red fox is Vulpes vulpes. This animal classification chart of a red fox is an example of Linnaean Taxonomy:

Animal Classification Example 1 – Red Fox
(Vertebrate)
Class: Mammalia (Mammal)
Order: Carnivora (Carnivore)
Family: Canidae (Dog)
Genus: Vulpes
Species: Vulpes vulpes (red fox)

Animal Classification Example 2 – Orang-utan
Kingdom: Animalia (Animal)
Phylum: Chordata (Vertebrate)
Class: Mammalia (Mammal)
Order: Primates
Family: Hominidae (Great Apes)
Genus: Pongo
Species: Pongo pygmaeus (Orang-Utan)

Mnemonics

K-ing

P-hillip

C-ame

O-ver

F-rom

G-reat

S-pain