Classification and Taxonomy
Classification of living things was born out of necessity! In the early and mid 1800s a man by the name of Carl Von Linne was growing up a farmer in Southern Sweden. At the age of 16 or so he entered university to become a doctor and soon after switched to the University of Upsalla in order to study botany. He would spend the rest of his life there; first as a student and then as a professor of Botany.
This, however, is not why classification came about. As Carl and his friend Petris were attending Upsalla, they discovered that animals and plants were named through the use of common names that only a select few in a select circle would know. It was frequently the case that a person with a specimen on one side of the campus would be using a different name than a peson with the same specimen on the other side of the campus! There was no organization as to how things were being named.
This, by itself, wasn't a big deal until you factored in any learning derived from those collections; learning such as what was harmful and what was not, what was a new species and what wasn't, what medical disease you had and whether or not there was a cure or medicine for it. . . . .
Currently life on planet Earth is divided into five (5) major kingdoms; six (6) if you split Monera and seven (7) if you add viruses. These kingdomes are the top most category of the current classification scheme and contain organisms that are loosely related. In other words, grass and trees are together and elephants and crickets are together, and mushrooms and mold are together. You'll remember that as we go from Kingdom to species, the number of organisms decreases and the relatedness increases!
Animal Kingdom: These organisms are multicellular, heterotrophic (they have to go and get their food), have a nucleus (eukaryotes), and are relatively complicated.
Plant Kingdom: These organisms are multicellular, autotrophic (they can make their own food through photosynthesis), have a nucleus (eukaryotes), and are relatively complicated with both a cell wall AND chloroplasts.
Fungi Kingdom: These organisms are multicellular, heterotrophic (they have to get their food), have a nucleus (eukaryotes), somewhat complicated with a cell wall but no chloroplasts.
Protists Kingdom: These organims are single celled, can be heterotrophic OR autotrophic, have a nucleus (eukaryotes), are a complicated cell with both animal and plant cells among the various species of protista. . . . .
Monera and The Immune System
According to different sources, a disease is any circumstance in which the cells are being attached causing a breakdown in physical or functional health and equilibrium. Therefore, the cold is a disease but being poisoned by the venom of a snake is not.
Most diseases are caused by viruses or bacteria. You'll recall that these two things belong to the kingdom Monera and are very, very old indeed. Bacteria are prokaryotes (no nucleus) whose major benefits are decomposition of dead things, helping you to digest, and extraction of vitamins that, without them, you couldn't do. They also make you sick. Luckily, only about 5% of so of ALL bacteria in the world cause illness and a smaller percentage may cause death.
Bacteria are very basic cells consisting of a cell membrane, cytoplasm, DNA/RNA, and ribosomes. They are also surrounded by a cell wall- which gives them shape. Cell walls are also found in Plants (duh!) and Fungi- but that's another story.
Bacteria reproduce through something called Binary (two) Fission (to split). We just call it Mitosis! . . . .
Vaccine: Weak or dead pathogens that are injected into a person and will cause the immune system to create antibodies without the person have to experience illness. Should the live pathogen enter the body, the immune systems will immediately attack it.
In the late 18th century a man by the name of Edward Jenner was experiencing the devistating effects of a smallpox epidemic. All around the village/town people were dying of smallpox (like chickenpox but more severe and found both outside and inside the body). He noticed that one particular group of people were not being affected by smallpox- the milk maids; girls about 14 who would go out and milk the cows.
What the milkmaids DID experience was cowpox- a mild form- which they caught from the cows and quickly recoved from in a matter of days. Jenner hypothesized that the disease cowpox was somehow giving the girls the ability to avoid getting smallpox. In that light, he designed a (cowardly) test. Jenner scraped the puss from a cowpox lesion and scratched it into a 5 year old boy- his son- who soon developed cowpox. He recovered, as the milkmaids did, and after a few weeks Jenner then infected the 5 year old with smallpox!
Should his hypothesis be wrong the 5 year old would surely have died. Luckily, Jenner was correct and the boy never contracted smallpox. Soon, everyone was being inoculated with cowpox and recovering. The incidence for smallpox dropped dramatically! . . . .
Antibody "memory"- how they link up
An antibody is a chemical "lock and key" that connects a pathogen with a WBC, Killer T cell, or spikey protein.
Each antibody is manufactured for a specific pathogen (disease) and remains in the blood stream to help protect you if/when the pathogen infects you again. Antibodies have, for all sakes and purposes, two "ends". One end is a specific shape (say, round) for every antibody that is ever manufactured. This round shape receives the "ball" shape that is on every WBC, Killer T cell, and spikey protein in a particular person. No matter how many are made, the one end- in this case- is always round. No matter how many WBC, Killer T cells, and spikey proteins are made, they always have a ball shape that fits into the antibodies round shape.
When a pathogen infects the body, it has a specific shape on it also- say a pointy arrow. When the antibody is manufactured, one end is the round shape (to attach to the WBC, Killer T cells, and spikey proteins) and the other end is made to receive the pathogen's shape- in this case, a triangle shape to receive the arrow shape. . . . .