To make it easier to study this organism's biologist has sorted them into groups. This sorting is called Classification. Living organisms have evolved over 100 of millions of years. Living organisms are all related to one another biologist classify them by putting closely related organisms in to the same group.
The vertebrates
One group of the organisms is the vertebrates. The vertebrates all belong to a large group or phylum, called chordates. The chordates all have a stiffening rod that runs along inside the upper surface of their body. In the vertebrates this rod has been replaced by a row of bones have vertebral column or backbone.
There is a smaller and easier way to remember vertebrates classes: FARM-B
Fish: Nearly all fish live in water. Their skin is moist and covered in scales. Gaseous exchange occurs through gills and fins and tails assist in movement and the balance in the water. Fish have a sense organ called the lateral line running along the side of the body, it can detect vibrations in the water.
Amphibian: The class amphibians contains frogs, toads, salamanders and newts. Theses animals have smooth moist skins with no scales. The adults have four limbs and they live on land but they always have to go back to the water to breed. They lay their eggs in the water, where they hatch in to tadpoles, the tadpoles breathe through gills like fish , but under go a dramatic change called Metamorphosis , to become adult and breathe through lungs and their skin.
Reptiles: The reptiles have tough scales all over their body they may live in water like turtles and crocodiles or on land like many lizards and snakes most reptiles apart from snakes have four legs. Reptiles have rubbery shelled eggs which are always laid on lands.
Mammals: Any vertebrate with hair is a mammal. Mammals have a prominent flap on the out side of the ear called Pena. They do not lay eggs, the young mammal develop in side the body of the mother attached to her by the umbilical cord and placenta after birth the young are cared for by their parents and feed on milk from their mothers mammary glands. Mammals have four kinds CANINES, MOLERS, INSICORS and PREMOLARS. Unlike other organisms they only have one kind of teeth.
Birds: Birds are closely related to reptiles, their body is covered with feathers which help to keep them warm, some parts of the body usually the lower part of their legs, are covered with scales instead of feathers they lay eggs with hard shells all birds have either beaks or bills, and all have 2 wings for flight.
Arthropods: If you judge success by sheer numbers the phylum arthropoda wins by a huge margin. The arthropods do not have a back bone they are called invertebrates they have a skeleton out side the body, called an exoskeleton and jointed legs. The exoskeleton covered by a water proof layer called a cuticle protects water proof and supports and allow movement to occur.
With in the arthropods there are 3 main classes:
1) Arachnids ( arachnida)-Spiders, ticks and scorpions.
2) Crustaceans (crustacean)-Lobsters, crabs and wood lice.
3) Insects (insecta)-Ants, butterflies and lady birds.
4) Myra pods-Millipedes and centipedes
remember: Insects are segmented in to 3 parts 1) head 2) thorax 3) abdomen and the legs in most insects are usually attached to the thorax and wings to the thorax also insects have six legs and 2 pair of wings in most cases except a certain fly and have one pair of antennas and have compound eyes.
Remember: Arachnids are segmented in to two parts cephalothoraxes and the abdomen cephalothoraxes just simply mean that their head is attached to their thorax and they have 8 legs also they have no antennas and they have eyes a good example is a spider.
Remember: Crustaceans are also cephalothoraxes and have jointed legs they have a hard shell covering them called a ( carapace) covering their segmented body and they have a calcified skeleton made out of calcium salts and they have above 8 and less then 20 as a range for the number of legs they own. They have 2 pairs of antennas
Remember: MYRA PODS are highly segmented they have one pair of antennas and they are leg jointed their exoskeleton is made of chitin and they have a head and they also have eyes the range of legs they have is above ten less than twenty good examples of Myra pods are centipedes and millipedes.
Fungi :In some ways fungi are a little like plants, They grow rooted to the spot and do not move around. However, fungi do not photosynthesis, and do not have chlorophyll. Instead, they feed on other living or dead organisms. They do this by producing enzymes which seep out from the fungus in to what ever it is growing on. The enzymes digest this food, which is then soaked up into the fungus's body. This is called Apostrophic feeding.
The main body of a fungi is called a Mycelium. It is made up of many threads called Hyphae. The hyphae grow through what ever the fungus is feeding on-perhaps a piece of bread, or through the soil. Each hyphae is surrounded by a cell wall, but this is not made of cellulose like that of plant cells. Different fungi have different substances in their cell walls, but many of them have cell walls made of chitin-the exoskeleton of insects is also made of chitin. At a certain time of year, some fungi grow a (mushroom) above the ground. This is for reproduction, which is done by producing thousands of tiny spores.
Taxonomy:
Kingdome: there are 5 kingdoms Plants, Animals, Fungus, Bacteria and Protoctista.
Phylum
Class
Order
Family
Genus
Species
_Binomial system by Linnaeas in 1738
_Homo sapiens
Genus species.
Tissues: A tissue is a group of similar cells which work together to perform a similar particular function e.g. Ciliated epithelial cells, RBC, Xylem vessels, Muscle tissues and root hair cells.
Organ: A group of tissues working together to form a particular function.
Organ System: A group of organs that combine and work in the same organism to form a whole large system that may consists of one or more organs e.g. nervous system, digestion system, respiratory system and gaseous exchange system.
Root hair cells: Root hair cells are found near the tips of roots that are growing through the soil. Their functions are to help and to anchor the plant in the soil and to absorb water and in organic ions such as (nitrates) then from the soil you can see that each roots hair cells a long thin part reaching out in to the soil this gives the cell a much larger surface area than usual the large surface area means that a lot of water and inorganic ions will be absorbed and can get in to the cell quickly.
Xylem Vessels: They are found in the roots and stems of plants and there leaves. The veins in a leaf contain xylem vessels. Xylem vessels are made up of many long thin cells called Elements. The elements are arranged end to end. They are very unusual cells because they are dead! Their walls contain a very hard, strong substance called Lignin. Wood is made of xylem vessels, which is why it is so hard and strong. There is nothing alive inside these walls – no cell surface membrane no cytoplasm and no nucleus. All that the xylem vessels contains is water. This is one of there functions- 1) They carry water from the roots of the plant, up through the roots and stem and in to the leaves and flowers. Their other functions is to help and support the plants.
Muscle cells: They are found in many different animals including humans. The muscle cells could be found in the bicep muscles in your arm. Like all animal cells muscle cells have a cell surface membrane, cytoplasm and nucleus-but each cell has many nuclei rather than just one. They look stripy because they are made up of many strands of proteins arranged in a pattern the strands of proteins can slide between each other, making the cell much shorter. This is how muscle cells get shorter or contract.
Red Blood Cells: They are smaller than most of the other cells in the human body they have a cell a surface membrane and cytoplasm but no nucleus. The cytoplasm is full of a red protein called hemoglobin, which carries oxygen from your lungs to other parts of the body. Red blood cells are small so that they squeeze through very tiny blood vessels called capillaries taking the oxygen very close to almost every cell in your body. They are circular with a dent in the middle which gives them a large surface area for their size this speeds of the movement of oxygen in and out of the cell.
Diffusion: The Net movement of the particles of a substance from a region in which they are in a relatively high concentration, to a region they are relatively low concentration (may or may not be across a membrane).
Osmosis: This is a special type of DIFFUSION where there is a net MOVEMENT of WATER across a semi-permeable membrane from a relatively dilute solution to a relatively concentrated one.
More about Diffusion: Diffusion is very important to all living organisms, including humans. You will meet several examples as you continue reading my revision sheet for IGCSE Biology. You have already seen that red blood cells have the function of transporting oxygen around your body. But how does the oxygen get in to and out of the red blood cells?
Your lungs are made up of hundreds of thousands of tiny air-filled sacs, called alveoli. Wrapped round each alveolus are tiny blood vessels called capillaries , through which red blood cells are carried in the blood. Oxygen molecules in the air in the alveoli move randomly around. Some of them go right through the cells making up the well of the alveolus and the wall of the blood capillary, right through the blood plasma, and through the cells surface membrane of a red blood cell. There are usually a lot of oxygen molecules in the air in the alveoli, and not many in side the red blood cells, so the net movement of oxygen molecules is from the alveoli into the blood (although some will, of course, go the other way as well!). The oxygen moves down a concentration gradient, by diffusion.
Diffusion of gas molecules takes place in plants too. In day light, the palisade and spongy mesophyll cells in a plant leaf photosynthesis. They use carbon dioxide and water to make sugars. These sugars may be turned into starch in the leaf. Where does the carbon dioxide come from, and how does it get to these cells?
Air contains carbon dioxide-though not very much. About 0.04% of the air is carbon dioxide. These carbon dioxide molecules bump randomly around. Some of them will go through the stomata on the underside of a leaf, into air spaces in between the leaf cells, into a mesophyll cell and into a chloroplast can be made in to sugar. This keeps the concentration of carbon dioxide molecules inside the chloroplast much lower than the concentration in the air out side the leaf, so there is a concentration gradient from the air to the chloroplast. The net movement of the carbon dioxide molecules is down this concentration gradient.
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