Is It Dead Or Alive?

By: Diantha Smith

Living things have characteristics that distinguish them from nonliving things. Living things

• use energy• respond to their environment • grow and develop• produce waste • reproduce

What do you think?Source: http://talibiddeenjr.files.wordpress.com/2008/04/science_living-non-living.pdf

“Living Test”Characteristics of Life

• Does it use energy?

• Does it produce waste?

• Can it grow and develop?

• Can it respond to the environment?

• Does it reproduce?

Non-living Test

• Does someone/something else have to make it?

• Does someone/something else have to move it?

• Was it once living, but not anymore?

Is a fish alive?• Does it use energy?

• Does it produce waste?

• Can it grow and develop?

• Can it respond to the environment?

• Does it reproduce? YES

Is a car alive?

• Does it use energy?

• Does it produce waste?

• Can it grow and develop?

• Does it respond to its environment?

• Does it reproduce? NO

Is a tree alive?• Does it use energy?

• Does it produce waste?

• Can it grow and develop?

• Can it respond to its environment?

• Does it reproduce? YES

Is a sandwich alive?• Does it use energy?

• Does it produce waste?

• Can it grow and develop?

• Does it respond to its environment?

• Does it reproduce? NO

Is a cloud alive?

NO

• Does it use energy?

• Does it produce waste?

• Can it grow and develop?

• Does it respond to its environment?

• Does it reproduce?

Is a cartoon alive?

NO

• Does it use energy?

• Does it produce waste?

• Can it grow and develop?

• Does it respond to its environment?

• Does it reproduce?

Is the sun alive?

NO

• Does it use energy?

• Does it produce waste?

• Can it grow and develop?

• Does it respond to its environment?

• Does it reproduce?

Is a starfish alive?

YES

• Does it use energy?

• Does it produce waste?

• Can it grow and develop?

• Does it respond to its environment?

• Does it reproduce?

Is a bacteria alive?

YES

• Does it use energy?

• Does it produce waste?

• Can it grow and develop?

• Does it respond to its environment?

• Does it reproduce?

Survival Needs• Energy to carry on life processes• Materials for growth and reproduction • Space to live and grow

Identify three living things in this picture.

How do they meet their needs?

All living things are made of cells

The cell is the smallest unit of living things.

Unicellular

• Unicellular organisms are those that contain just one single cell.

• The main groups of unicellular organisms are bacteria, protozoa, unicellular algae, and unicellular fungi (yeasts).

• Single-celled organisms have been on Earth for 3.8 billion years.

• Although they are only one cell, they are complex.

bacteria

protozoa

unicellular algae

unicellular fungi

Multicellular OrganismMulticellular organisms are those that are made up of more than one cell. In multicellular organisms all the cells coordinate with each other in order to regulate the various functions of the body

The microscope led to the discovery of the cell

Schleiden and Schwann"all living things are composed of living cells"

"All living cells arise from pre-existing cells". 

Louis Pastuerthere was no spontaneous creation of cells from non-living matter

people believed that mice can arise in the pot with grain, shut by dirty shirt.

• AdvantagesA Transmission Electron Microscope is an impressive instrument with a number of advantages such as:TEMs offer the most powerful magnification, potentially over one million times or moreTEMs have a wide-range of applications and can be utilized in a variety of different scientific, educational and industrial fieldsTEMs provide information on element and compound structureImages are high-quality and detailedTEMs are able to yield information of surface features, shape, size and structureThey are easy to operate with proper trainingDisadvantagesSome cons of electron microscopes include:TEMs are large and very expensiveLaborious sample preparationPotential artifacts from sample preparationOperation and analysis requires special trainingSamples are limited to those that are electron transparent, able to tolerate the vacuum chamber and small enough to fit in the chamberTEMs require special housing and maintenanceImages are black and white

• The following gives you a description of two types of EMs,the Transmission (TEM) and Scanning Electron Microscope(SEM).

• Transmission Electron Microscopes• The transmission electron microscope (TEM), the first type of EM, has many commonalities with the optical

microscope and is a powerful microscope, capable of producing images 1 nanometer in size.• They require high voltages to increase the acceleration speed of electrons, which, once they pass through the

sample (transmission), increase the image resolution.• The 2-d, black and white images produced by TEMs can be seen on a screen or printed onto a photographic plate.• Although recent innovations in software help to minimize, TEM resolution is hampered by spherical and chromatic

aberrations.• The TEM is a popular choice for nanotechnology as well as semiconductor analysis and production.• Scanning Electron Microscopes• Reflecting light microscopes are the optical counterpart to scanning electron microscopes (SEM) and produce

similar data.• SEMs are primarily used to obtain topographical information.• In this type of EM, a series of solenoids pulls the beam back and forth across the sample, systematically scanning

the surface; it detects secondary electrons emitted from the surface and produces an image.• Although SEMs are approximately 10 times less powerful than TEMs, they produce high-resolution, sharp, black

and white 3D images.

On September 17, 1683, Leeuwenhoek wrote to the Royal Society about his observations on the plaque between his own teeth, "a little white matter, which is as thick as if 'twere batter." He repeated these observations on two ladies (probably his own wife and daughter), and on two old men who had never cleaned their teeth in their lives. Looking at these samples with his microscope, Leeuwenhoek reported how in his own mouth: "I then most always saw, with great wonder, that in the said matter there were many very little living animalcules, very prettily a-moving. The biggest sort. . . had a very strong and swift motion, and shot through the water (or spittle) like a pike does through the water. The second sort. . . oft-times spun round like a top. . . and these were far more in number." In the mouth of one of the old men, Leeuwenhoek found "an unbelievably great company of living animalcules, a-swimming more nimbly than any I had ever seen up to this time. The biggest sort. . . bent their body into curves in going forwards. . . Moreover, the other animalcules were in such enormous numbers, that all the water. . . seemed to be alive." These were among the first observations on living bacteria ever recorded.