1/30/11

1

Life and Diversity

Dr. Waggoner BIOL 1400

Common Features of Living Things

•  Chemistry—living things, or organisms, are made up primarily of the elements carbon, hydrogen, oxygen, and nitrogen (CHON) arranged in a great many highly complex molecules – The elements phosphorus and sulfur are also structurally

important—the mnemonic CHNOPS is useful here – Many other elements are used, but not structurally

•  Metabolism—organisms take in energy and matter from the outside, and use these to build up (anabolism) and break down (catabolism) their own substance

Common Features of Living Things •  Cells—organisms are made

up of one or more cells: subunits, containing genetic material and bounded by a cell membrane

Common Features of Living Things •  DNA—organisms contain DNA, which is the

genetic material—it carries information about what the living thing is and does

•  Heredity—organisms pass on their features to future generations; they "breed true"

•  Descent with Modification—organisms' features can shift over multiple generations in response to their environment

•  Ecology—every organism interacts with its environment, and with other organisms, in complex ways, positive, negative, and neutral

1/30/11

2

One more property of life is that there’s a huge number of varieties of living thing. . .

•  Mammals: 4000 species known •  Birds: 9000 species known •  Fish: 25,000 species known •  Flatworms: 13,000 species known •  Molluscs: 50,000 species known •  Arachnids: 98,000 species known •  Insects: 900,000 species known •  All living things: >1,500,000 species known

–  Actual number: No one knows, but 10,000,000 is a conservative estimate; others estimate it at 50,000,000 or more

How can we keep track of all of these?

Even in American English, one type of animal may have several names. . .

Perch? Sunfish?

Bream? Bluegill?

And sometimes very different animals are called by the same

name. Both of these fish are commonly

known as "sunfish", for example. . .

In America, the bird on the left is a "robin"; in Britain, "robin" means the bird on the right.

1/30/11

3

And it gets worse when you have to communicate with speakers of other languages!

Sinezhaberny solnechnik

Crapet arlequin

Mojarra oreja azul

Blauer Sonnen- barsch

Sólborri

Perca-sol Slouwang-sonvis

To make matters worse, about 10,000 new species of organism are discovered each year—such as the “Yoda

bat”, discovered in New Guinea in 2009. . .

. . . this frog, discovered in 2007 in a remote part of the South American country of Surinam. . .

. . . the pink handfish, described in 2010 from Tasmanian waters. . .

1/30/11

4

. . . or this deep-sea beast, first seen in 2007 off the Philippine Islands and affectionately known as the

squidworm.

God has allowed him to see more of His created work than any mortal before him. God has

endowed him with the greatest insight into natural knowledge,

greater than any has ever gained. . . .

Carl Linnaeus (1707-1778) was a Swedish physician with a healthy ego! He saw himself as having a divine mission to

study and classify the natural world.

Linnaeus went back to the ancient Greek philosopher Aristotle, who had classified things in terms of what made a group of things alike (their genus) and what made each

one different from the rest (its species).

Genus: Man (has two eyes, a nose, two ears, etc.)

Species: Aristotle (has a bald spot, big nose and beard, goes around philosophizing, etc.)

Consider these roses. They’re all recognizably roses, with similarly shaped leaves, flowers, etc.

And yet, each is a different kind of rose—each one is a separate species. (We’ll define what a species is

more precisely later on.)

1/30/11

5

Binomial nomenclature: Biological species should be given standardized two-part Latin names: one word for

the genus, followed by one word for the species

Names like this were much easier to deal with, and replaced the long Latin names that had previously

been in use among scholars.

Rosa canina Rosa sylvestris alba cum rubore, folio glabro

To this day, we use Linnean-style names in Latin because they are standardized (according to some very boring

rules) and used internationally.

Panfish? Sunfish?

Bream? Bluegill?

This solves the "robin problem", since the two birds have different scientific names.