Download
1 / 65
650 likes | 761 Views
Agenda 4/6/10. Parking Lot Question Contest Correlation Graph Learning Matrix LAB TODAY . I can statements for TODAY! . I can describe the cell theory! I can explain the specialization of cells! . Living things vs. Nonliving things. Living things are different from nonliving things.
E N D
Agenda4/6/10 • Parking Lot • Question Contest • Correlation Graph • Learning Matrix • LAB TODAY
I can statements for TODAY! • I can describe the cell theory! • I can explain the specialization of cells!
Living things vs. Nonliving things • Living things are different from nonliving things. • How would you define LIFE? • Is fire alive?
Characteristics of Life • Living things have these characteristics: • Organization • The ability to develop and grow • The ability to respond to the environment • The ability to reproduce
All living things are made of cells. • Unicellular organisms are made of a single cell. • Organisms made up of many cells are called multicellular organisms.
The microscope and the discovery of cells • A microscopeis an instrument which makes an object appear bigger than it is. • It took the invention of this relatively simple tool to lead to the discovery of cells. In the 1660s, Robert Hooke began using microscopes to look at all sorts of materials. Anton van Leeuwenhoek took up similar work in the 1670s. They were among the first people to describe cells.
Hooke vs. Leewenhoek • Robert Hooke gave the cell its name. While looking at a sample of cork, a layer of bark taken from an oak tree, he saw a group of similarly shaped compartments that looked to him like tiny empty rooms, or cells. • Anton van Leeuwenhoek was one of the first people to describe living cells. He looked at a drop of pond water under a microscope. Imagine his surprise when he saw that a drop of water was full of living things!
Cells come from other cells. • The studies of Hooke and Leeuwenhoek made people ask if all living things have cells. • There was another important question scientists were trying to answer: Where do cells come from? • In the 1850s people studying all types of living cells observed the same thing—that cells divide. One living cell divides into two living cells. Here, under the microscope, was evidence of where cells come from. Life comes from life—that is, one cell comes from another cell.
CELL THEORY! • The observations and evidence gathered over a long time by many scientists are summarized in the three concepts of the cell theory: • Every living thing is made of one or more cells. • Cells carry out the functions needed to support life. • Cells come only from other living cells.
Different cells perform various functions. • Organisms can be classified by their cell type. • Look around you at this moment. The living organisms you see may number 10, 20, 100, or 1000, depending on where you are. What you are not seeing, but what is also there, is a huge number of unicellular organisms. • For example, there are at least 2–3 million bacteria living on each square centimeter of your skin.
Cells in multicellular organisms specialize. • Most multicellular organisms consist of many different types of cells that do different jobs. • For example, most animals have blood cells, nerve cells, and muscle cells. The cells are specialized. • Specializationof cells means that specific cells perform specific functions.
Specialization of Cells • Cells in many-celled organisms are often quite different from each other. • Specialized cells are only found in many-celled or multi-cellular organisms.
I Can Statements for TODAY!! • I can explain the specialization of cells. • I can explain how cells, tissues and organs are organized into systems. • I can describe how organisms are classified by cell types.
Louis Pasteur • The work of the French scientist Louis Pasteur shows how an understanding of cell theory can have practical uses. Pasteur lived in the 1800s, when there was no mechanical refrigeration in homes. People were used to having foods spoil, like milk going sour. During this time, many people died from diseases such as typhoid fever, tuberculosis, and diphtheria. Pasteur's work showed that microscopic organisms were involved both in the spoilage of food and in disease.
Louis Pasteur • Pasteur observed that milk that turned sour contained large numbers of tiny single-celled organisms called bacteria (bak-TEER-ee-uh). He developed a process, now known as pasteurization, in which heat is used to kill the bacteria. Killing the bacteria keeps milk fresh longer. The fact that bacteria cause milk to sour or “sicken” made Pasteur wonder whether microscopic organisms could also be the cause of sickness in humans and animals.
Bacteria and Spontaneous Generation • Using a microscope to study air, water, and soil, Pasteur found microorganisms everywhere. He found bacteria in the blood of animals, including people who were sick. Pasteur referred to the microorganisms he observed as “germs.” He realized that an understanding of germs might help prevent disease. Pasteur's work led to the first animal vaccinations for cholera and anthrax and to a treatment for rabies in humans.
Bacteria and Spontaneous Generation • At the time that Pasteur was doing his research, there were scientists who thought that bacteria grew from nonliving materials, an idea called spontaneous generation. Pasteur conducted a now famous series of experiments that disproved spontaneous generation and confirmed the cell theory. He showed that cells come only from other cells. Two of those experiments are shown above. Both began with a sealed flask containing boiled broth. In the first experiment, the flask remained sealed, while in the second experiment, the top of the flask was broken to expose the contents to air. Bacteria grew only in the second flask.
Spontaneous Generation vs. The Cell Theory • Spontaneous Generation is the idea that bacteria can grow from nonliving materials. • Cell Theory supports the idea that cells come only from other living cells.
Specialization of Cells • Cells in a multicellular organism are specialized. The ways in which the cells work together and interact depend on the organism. • In more complex organisms, such as plants and animals, cells are not only specialized but grouped together in tissues. A tissueis a group of similar cells that are organized to do a specific job. So tissue is a group of cells working together.
Organization of Specialized Cells • Different tissues working together to perform a particular function represent another level of organization, the organ. • The eye is an organ that functions with the tarsier's brain to allow sight. A leaf is an organ that provides a plant with energy and materials.
Organs and tissue working together • Different organs and tissues working together form an organ system. An organism may have only a few organ systems. The organ systems of plants include roots, stems, and leaves.
Organs and tissue working together • Other organisms have many organ systems. Humans have 11 major organ systems, made up of about 40 organs and over 200 types of tissue. The human nervous system, for example, includes the brain, the spinal cord, nerves, and sensory organs, such as the ears and eyes.
Tissue, Organs and Organ Systems working together • An organism itself represents the highest level of organization. It is at this level that we see all the characteristics we associate with life. If an organism is a complex organism—a human, for example—it will consist of trillions of cells grouped into tissues, organs, and organ systems. However, a simple organism, like a sponge, meets its needs with a body made up of only a few types of specialized cells.
Organ, Single Cell Tissue or Organ System? • Heart_______________ • Heart, blood, and vessels________________ • Inside of your mouth_____________________ • Liver_______________ • Kidney_____________
Organ, Single Cell Tissue or Organ System? • Bacteria______________ • Eye________________ • Bicep muscle____________________
Microscope Lab • Please read all directions for microscope use. Directions are located next to each microscope in the classroom. • Complete the lab as you observe pond water under the microscope. ASK QUESTIONS IF YOU NEED HELP!!!!!!!
What technological tool helped with the discovery of the cell theory?
The cell theory applies to all organisms, including you. State the three parts of the cell theory and describe briefly how they relate to you.
What does it mean for an organism to interact with the environment?
What are two other characteristics of living things that have not been mentioned?
What are the four main characteristics common to all living things?
Who was the first person to observe living cells through a microscope?
