What is a Living Being?All living beings have the following 7 characteristics:1. Living Beings are Composed of Cells: • Single-cell or Unicellular organisms have everything they need to be self-sufficient. • Multicellular organisms, specialization increases until some cells do only certain things.2. Living beings have a chemical composition and are highly organized. All living beings are composed of chemical elements, the most popular being: C, H, N, O, P, S – which are called the primary bioelements.
• The primary bioelements are organized to form biomolecules, which can be classified as organic (containing C) or inorganic (no C). Biomolecules are organized to form organelles within a cell.
Living beings must be able to organize simple substances into complex ones. Living beings organize cells at several levels:– Cells – the smallest form of life– Tissue - a group of cells that perform a common function.– Organ - a group of tissues that perform a common function.– Organ system - a group of organs that perform a common function.– Organism - any complete living thing.
•3. Living Things Use Energy Living things take in energy and use it for maintenance and growth. Autotrophs or Heterotrophs. Autotroph is an organism which uses simple inorganic molecules and energy from the sun to produce organic molecules Heterotroph is an organism which uses organic molecules for growth
4. Living Things Respond To Their Environment - Living things will make changes in response to a stimulus in their environment. Mimosa pudica http://www.youtube.com/watch?v=g0LFBM3hOLs5. Living Things Grow • Cell division - the orderly formation of new cells. • Cell enlargement - the increase of mass. Cells grow to a certain size and then divide. • An organism gets larger as the number of its cells increases.
6. Living Things Reproduce • Reproduction is not essential for the survival of individual organisms, but must occur for a species to survive. • All living things reproduce in one of the following ways: • Asexual reproduction - Producing offspring without the use of gametes. • Sexual reproduction - Producing offspring by the joining of sex cells.7. Living Things Adapt To Their Environment • Adaptations are traits giving an organism an advantage in a certain environment. • Variation of individuals is important for a healthy species.
Questions:1. Do all living things have all of the characteristics of life? If your answer is no, give an example.2. Name some non-living thing that uses energy.3. Name some non-living thing that grows.
What is a cell?It took a long time for people to discover cells and to figure out what they were. Most cells are microscopic, meaning that we need to use a microscope to see them. Everything we know about cells is called “cell theory”.
History of Cell TheoryThe word cell (from theLatin word for chamber,cello) wasn’t used as abiological term until 1665.That’s when RobertHooke, an Englishscientist, looked at a thinslice of a cork plant undera compoundmicroscope he had builthimself. Hooke noticedsmall holes surrounded bywalls and named thesetiny pores cells.
History of Cell TheoryAntonie Philips van Leeuwenhoek (the father of microbiology) was a Dutch scientist who is credited to have been the first person to observe microscopic observations of live cells. In 1674, Van Leeuwenhoek observed muscle and blood cells, and many microogranisms through microscopes he had built himself.
History of Cell TheoryIn 1839, German scientists Theodor Schwann stated that all animals are made up of different kinds of cells and Mattias Jakob Schleiden stated that all plants are made up of different kinds of cells. Schwann and Schleiden stated that cells are the basic units of life and that all living beings are made of cells.But where did cells come from?
History of Cell TheoryIn 1855 the German scientist Rudolph Virchow stated that every cell originates from another existing cell. Virchow demonstrated the first evidence of cell division.
History of Cell TheoryEventhough cell theory was becoming popular among the scientific community in the 19th century people still believed of spontaneous creation of cells through non-living
Cell Theory says that….2. All living things or organisms are made of cells.4. New cells are created by old cells dividing into two.6. Cells are the basic building units of life.
Discussion Question• Make a timeline of the scientific discoveries leading to cell theory• State the three postulates of cell theory
There are two types of cells: Prokaryotic Cells and Eukaryotic Cells
These are two distinct types of cells with STRUCTURAL differences. Prokaryotes Eukaryotes Archaea Animal PlantBacteria
The Six Kingdoms: Plants, Animals, Protists, Fungi, Archaebacteria, Eubacteria.In the previous slide we saw 3 kingdoms. In theclassification of living things we have 6 kingdoms.
The identification and classificationof living beings is called taxonomy.Discussion of taxonomy began withAristotle but it was popularized bythe Swedish scientist, CarolusLinnaeus in the 18th century.Linneus classified all living thingsinto two kingdoms: Plantea andAnimalia. Linnaeus also beganbinomial nominclature; a twonamed naming system. ex.: Humans = Homo sapiensWe now classify things first withtheir domains; Archea, Bacteria,Eukarya. Domains are later dividedinto kingdoms, then phylums, andso on
Prokaryote Cell A single celledorganism that doesnot have a nucleus. Add this to your vocabulary book
Traits of Prokaryotes:(pro-care-ee-ohts) 2. They do not have a nucleus, and their genetic material is not stored in the nucleus. 4. They have some organelles, but not many. 3. They are less complicated that eukaryotes. 8. Prokaryotes are found in the domains of Eubacteria and Archaea.
Bacteria may be small but they are powerful!During the 14th century, 25% of Europe was killed by a bacteria (Yersinia pestis) called the Bubonic Plague, also called Black Death. This bacteria was spread to humans through fleas and rodents.
But at the same time we need bacteria to live!1. Bacteria are decomposers and without them all other organisms would not be able to survive.2. We use bacteria in our digestive system to help digest our food. There are approximately ten times as many bacterial cells as human cells in the human body!3. We could not make cheese or yogurt without bacteria.
Eukaryote CellA more complex cell with a nucleus and many organelles. Add this to your vocabulary book
Traits of Eukaryotes:(you-care-ee-othts)1. They all have a nucleus where the genetic material of the cell is stored.2. They have many organelles that work together to help the cell function.
More traits of Eukaryotes:(you-care-ee-othts)1. Eukaryotic cells are much more complex than prokaryotic cells.3. They can be just one cell or can make up more complex multi-cellular organisms.6. All plants, animals, fungi, and protists are eukaryotic cells.
Think – Pair - ShareWhat do you think is the main differencebetween a prokaryotic cell and a eukaryotic cell?
The nucleus!Prokaryotic cells do not have a nucleus and eukaryotic cells do have a nucleus. This allows eukaryotic cells to make multicellular organisms and perform more complex functions.