Strategies of Life

Strategies of Life

Biology– branch of science dealing with living

systems– How do we define life?

• What do all living things have in common?

• How do we describe life’s diversity?• What is the basic unit of life?

Strategies of Life

All living organisms have the following characteristics

Strategies of Life

8 Characteristics of Life– ordered and complex– part of larger system of matter and energy– depends on chemical reactions– requires water– organisms grow and develop– regulate their use of energy and respond to

environment– share genetic code– descend from common ancestor

Strategies of Life

Linnaeus 1700’s Swedish naturalist developed the first classification

system The System included

Broadest categories are “kingdoms” Only two kingdoms were recognized

plants and animals Now most biologists recognize five

kingdoms

Strategies of Life

Five Kingdoms– Monera

• Bacteria

– Protista • Protozoans

– Fungi• Mold and mushrooms

– Plants • All plants

– Animals• All animals

Strategies of Life

Cells – The Basic Unit of Life

– Single Cell Organisms• Monera (NO nucleus)• Protista

– Multi Cell Organisms• Fungi• Plants• Animals

Strategies of Life

Classification of organisms narrows

KingdomPhylum

ClassOrderFamilyGenusSpecies

Strategies of Life

Scientific Name = Genus + species– Species is the narrowest category– For example: Human = Homo sapiens– Only the same species can produce

offspring which are both viable and fertile

Strategies of Life

Human Classification Kingdom – Animal Phylum – Chordates

Subphylum – Vertebrates Class – Mammals Order – Primates Family – Hominids Genus – Homo Species – sapiens (note: species begins with

lower case)

Strategies of Life

Category Katydid Anaconda Gorilla Human

Kingdom Animal Animal Animal Animal

Phylum Arthropod Chordate Chordate Chordate

Class Insect Reptile Mammal Mammal

Order Orthopiera Squamata Primate Primate

Family Tettigonlidae Boidae Pongidae Hominidae

Genus Scudderia Eunectes Gorilla Homo

Species turcata murinus gorilla sapiens

Strategies of Life

Modern Classification of Organisms– Began in the 1950’s– Based on DNA– Comparison of genetic maps

• More closely related, more sequences in common

• Entire human genome now sequenced

Strategies of Life

How many different species are there?

1.4 million identified 3 – 30 million estimated

Which phylum is most successful in the number of species and total mass?

Arthropods

Which arthropods are most numerous?

Insects

Strategies of Life

Species Distibution

Insects 53%

Other animals

20%

Higher plants 18%

Protozoa 2%

Fungi 5%

Algae 2%

Monera 0%

Species Distibution

Insects 53%

Other animals

20%

Higher plants 18%

Protozoa 2%

Fungi 5%

Algae 2%

Monera 0%