Classifying Living ThingsClassifying Living Things Similarities and Differences Similarities and Differences

Among OrganismsAmong Organisms

ClassificationClassification

• Classification is the process of grouping things based on their shared traits.

• Biologists use classification to organize living things into groups, so that the organisms are easier to study

• The scientific study of how living things are classified is called taxonomy.

Living vs. Nonliving ThingsLiving vs. Nonliving Things

Object Cells Grow And

Develop

UseEnerg

y

Reproduce

RespondTo

Stimuli

AdaptTo

Change

Nonliving

No No Maybe No No No

Living Yes Yes Yes Yes Yes Yes

Living ThingsLiving Things

Scientists have identified and described about 1.5 million species of organisms and are not sure how many more species remain to be discovered.

Living things vary in shape, size, and other characteristics…however all living things share certain similarities.

StructureStructure All living things are composed of cells. A cell is the basic unit of structure and

function in an organism. Unicellular (single celled) Multicellular (many cells)…specialized cells

(blood cell, skin cell, brain cell, etc…)

Growth and Growth and DevelopmentDevelopment

All living things grow and develop.

Some organisms show very limited growth, like bacteria, and others change completely through metamorphosis.

Some organisms hatch from eggs and other organisms are born alive.

ReproductionReproduction

All living things reproduce.

Reproduction involves passing on hereditary information to their offspring.

Response to StimuliResponse to Stimuli All living things respond to stimuli. A stimulus is anything that causes a response. Living things respond to various stimuli, including: light,

sound, touch, smell, and taste. Some living things have specialized structures to detect

stimuli and to respond to it. Some organisms respond slowly( plants w/sunlight) and

others respond quickly (hot stove).

Energy UseEnergy Use All living things use energy

to carry out functions such as growth, development, reproduction, and responding to stimuli.

In addition…living things use energy to perform functions such as digestion, respiration, excretion, and circulation.

Not all organisms depend on the same energy source. Plants = light energy Animals = take in nutrients

from plants, other animals, or both

Adapt to ChangeAdapt to Change All species change themselves and adapt to change

around them over time. Organisms develop adaptations, or traits/behaviors, that

increase an organisms chance of survival. Not all adaptations follow the same pattern. Bacteria

that are resistant to antibiotics have changed over the last 50 years, whereas the alligator has not changed in the last 200 million years.

ClassificationClassification SystemSystem

• Carolus Linnaeus is the Swedish scientist who developed a classification system based on the organisms’ observable features; it’s morphology.

• Linnaeus’s naming system is called

binomial nomenclature because each organism is given a two part name.

Binomial NomenclatureBinomial Nomenclature• The first part of the organism’s name is its genus.

This is a classification grouping that contains similar, closely related organisms.

• The second part of the organism’s name is its species. A species is a group of similar organisms that can mate and produce fertile offspring.

• These terms are unique and no other species can have this same name. Scientific names are designed to tell you something about an animal's relationships with other animals.

Humans = Homo sapiens

7 Levels of Classification7 Levels of Classification• Today’s classification

system uses several levels to classify organisms. The more characteristics that organisms have in common, the more levels they share.

• Kingdom • Phylum • Class • Order • Family • Genus • Species

5/6 Kingdoms of Organisms5/6 Kingdoms of Organisms Bacteria (Monera)

Archaebacteria Eubacteria

Protists Fungi Plants Animals

Recent EventsRecent Events

Recently scientists have proposed that living things be classified into even larger groups called domains.

The three domains would be: Bacteria, Archaea, and Eukarya.