Cell Theory & Characteristics of living things

Is it living? Beetle

Is it living? Cells

Is it living? Tree

Is it living? Water

Is it living? Paramecium

Is it living? Virus

Is it living? Rock

Is it living? Robot

Random Cell Facts The average human being is composed of around 100 Trillion individual cells!!! It would take as many as 50 cells to cover the area of a dot on the letter “i”

The Discovery of Cells 1665 - English Scientist, Robert Hooke, discovered cells while looking at a thin slice of cork. He described the cells as tiny boxes or a honeycomb He thought that cells only existed in plants and fungi.

Anton van Leuwenhoek 1673 - Used a handmade microscope to observe pond scum & discovered single-celled organisms He called them “animalcules” He also observed blood cells from fish, birds, frogs, dogs, and humans Because of this, it was known that cells are found in animals as well as plants

150-200 Year Gap… Between the Hooke/Leuwenhoek discoveries and the mid 19th century, very little cell advancements were made. This was probably due to the widely accepted, traditional belief in Spontaneous Generation. Examples: -Mice from dirty clothes/corn husks -Maggots from rotting meat

Start of the Cell Theory In 1820, Robert Brown saw a tiny sphere in the middle of plant cells. He referred to it as the nucleus, and soon after these nuclei were also found in animal cells.

Start of the Cell Theory In 1835, Felix Dujardin discovered “protoplasm”. (commonly called cytoplasm) Also claimed that many microorganisms consisted of a single cell.

Start of the Cell Theory 1838 - German Botanist, Matthias Schleiden, concluded that all plant parts are made of cells. 1839 - German physiologist, Theodor Schwann, who was a close friend of Schleiden, stated that all animal tissues are composed of cells.

Start of the Cell Theory 1858 - Rudolf Virchow, German physician, after extensive study of cellular pathology, concluded that cells must arise from preexisting cells.

The original Cell Theory: All organisms are composed of one or more cells. (Schleiden & Schwann)(1838-39) The cell is the basic unit of life in all living things. (Schleiden & Schwann)(1838-39) All cells are produced by the division of preexisting cells. (Virchow)(1858)

Modern Cell Theory Modern Cell Theory has 4 statements, in addition to the original Cell Theory: 4. The cell contains hereditary information(DNA) which is passed on from cell to cell during cell division. 5. All cells are basically the same in chemical composition and metabolic activities. 6. All basic chemical & physiological functions are carried out inside the cells.(movement, digestion, etc.) 7. Cell activity depends on the activities of sub-cellular structures within the cell (organelles, nucleus, plasma membrane)

Characteristics of Life

On your desk Draw your favorite animal in its natural environment List all of the characteristics that make this animal alive. What is Biology? The Characteristics of Life https://www.youtube.com/watch?v=7nKKoxnmTEA

Characteristics of Life All living things have certain characteristics and activities in common. Living things are called organisms . We will examine nine characteristics that all organisms possess.

Characteristics of Life 1. All Organisms are composed of cells Cells are the common unit of life May be one cell like a paramecium (unicellular) or 60 000 000 000 000 cells like the human body (multicellular) The cell is a complex structure made of many smaller parts The parts of a cell must work together in an organized way if the entire cell is to function smoothly Cells use much of the energy they get from food to maintain the organization of all their parts Cells are produced only by organisms and are never organized by non-living material

Characteristics of Life 1.1 Organisms Have Organization All living things are highly organized at both molecular and cellular levels. Organisms take in substances from the environment and organize them in complex ways. Specific cell structures carry out particular functions. Cells and groups of cells are organized by function.

Characteristics of Life 2. Organisms Use Energy Life is a state of constant chemical activity and therefore organisms need a constant supply of energy (growth and maintenance) The sun is a source of energy for almost all organisms because it supplies the energy from which plants make food When living things take energy from food, they release waste energy (heat) If a cell runs out of energy it dies

Characteristics of Life 2. Organisms Use Energy Autotrophs » Produce there own food within their bodies with sunlight, carbon dioxide, and water. Plants produce food in a process called Photosynthesis. Heterotrophs » Cannot manufacture their own food. Must eat other organisms to stay alive.

Characteristics of Life 2. Organisms Use Energy Metabolism » The chemical processes of getting energy from food and using it to maintain the structure and function of the cell

Characteristics of Life 3. Organisms Require Water and Organic chemicals Every living thing ever studied requires water to stay alive. All organisms contain certain kinds of chemicals that are not naturally produced anywhere else – organic chemicals. Organic chemicals are complex and highly organized. Organic chemicals can be made in test tubes, but only living things produce them under natural conditions.

Characteristics of Life 4. Organisms Show Adaptation An adaptation is a structure or behavior that allows survival in a particular environment. This enables species to survive in changing environments. Adaptations are passed from parent to offspring. Examples include: Spines on a cactus are leaves adapted to a dry environment The shape of a dolphins body is streamlined to move through the water smoothly and easily

Characteristics of Life 4.1. Organisms Respond to Stimuli » Irritability Organisms can respond to stimuli in the environment like heat, touch, light. The response of animals is called behavior, and in humans involves emotions. Simple animals and plants respond by tropisms » Turning motion or growth in a particular direction.

Characteristics of Life 5. Organisms Grow and Develop Living things grow and develop when they increase in size. Organisms develop when they change shape or form. All living things grow at some time in their lives. This depends on genetics, nutrition, and metabolism. Living things don’t simply gather more of their own material, they organize it. As the organism matures, visible growth (getting larger) stops, but the organism is always replacing material. Organisms grow by adding living cells inside their bodies or by increasing the size of individual cells.

Characteristics of Life 5. Organisms Grow and Develop » Life Span All organisms have a fairly definite period of life called the life span. There are five stages of the life span; beginning, growth, maturity, decline, death. The length of the stages varies with species and individuals. Life cycles are not found in non-living things.

Characteristics of Life 6. Organisms Reproduce Reproduction is the process by which organisms produce offspring that are similar to themselves. “like produces like” Can be an exact duplicate of parent or some variation. Although it is not necessary for each organism to reproduce, reproduction is necessary for the survival of the species.

Characteristics of Life While a non-living thing may have one or a few of the characteristics of life, only living things have all of them.

Is this true in all cultures / belief systems? NO, not necessarily… First Nations Cultures believe that all things were designed by Creator and therefore have a spirit. Example 1 – A river has a living spirit. Example 2 – A drum is like the heart beat of Mother Earth.