EOC Review 08-09 Goal 4: The learner will develop an understanding of the unity and diversity of life CLASSIFICATION -binomial nomenclature-system of biological classification in which each organism is given a two-part name. The first part of the name is the genus and the second part is the species name. The genus should be capitalized; the species should not. The entire name should be written in italics or underlined Example: Homo sapiens means this organism belongs to the genus Homo and the species identifier is sapiens. -The system of binomial nomenclature was developed by Carolus Linnaeus. Linnaeus improved on the classification system developed by Aristotle. His system classified organisms based primarily on morphological similarities. - Organisms are classified using seven taxa (singular = taxon) - The taxa are shown below arranged from most general or most inclusive to most specific King Phillip Came Over For Good Spaghetti. Plants and Fungi use division instead of phylum. Classification of Living Things- 3 Domains and 6 Kingdoms Domain Bacteria Archaea Kingdom Cell Type Cell Structures Eubacteria Prokaryote Cell walls with peptidoglycan Archaebacteria Prokaryote Cell walls without peptidoglycan Unicellular Unicellular Autotroph or heterotroph Autotroph or heterotroph Number of Cells Mode of Nutrition Eukarya Protista Eukaryote Cell Walls of cellulose in some; some have chloroplasts Most unicellular; some colonial; some multicellular Autotroph or heterotroph Fungi Eukaryote Cell walls of chitin Plantae Eukaryote Cell walls of cellulose; chloroplasts Animalia Eukaryote No cell walls or chloroplasts Most multicellular; some unicellular Multicellular Multicellular Heterotroph Autotroph Heterotroph 26 Examples Common Reproductive Methods Streptococcus, Escherichia coli Methanogens, halophiles Usually Asexual by Binary Fission Usually Asexual by Binary Fission Amoeba, Paramecium, Slime molds Giant kelp Most commonly asexual. May be sexual or asexual Mushrooms, yeasts Mosses, ferns, flowering plants May be asexual by budding, fragmentation or spores. May be sexual by spores May be asexual (rhizoids, budding, or fragmentation) or sexual EOC Review 08-09 Sponges, worms, insects, fishes, mammals May be sexual or asexual - Due to new understanding of evolutionary relationships from new methods including DNA analysis, biochemical analysis and better observation of embryological development, these classification systems are undergoing change. ANIMALS -endoskeleton - an internal framework of bones and/or cartilage. EX; humans -exoskeleton -an external skeleton. EX: lobster INVERTEBRATES Animals without backbones Phylum Porifera Example Organism - Sponges Type of Symmetry - Asymmetrical Regulation Nutrition - filter feeders Reproduction - Hermaphroditic – Capable of both sexual and asexual reproduction. – In sexual reproduction water currents carry sperm to neighboring individuals. Asexual reproduction by fragmentation and regeneration. No movement (sessile) Other characteristics - Lack tissues and organs - Least complex animals - Internal Transport - No nerves or muscles, but individual cells can sense and react to changes in the environment. Phylum Annelida - Annelids segmented worms such as earthworms and leeches - Bilateral symmetry - Exchange gasses through skin. 27 EOC Review 08-09 - Eliminate waste and excess water through excretory tubules called nephridia. - Nutrition – Open digestive system running length of organism. - Internal transport – Closed circulatory system running length of organism. - Reproduction – Sexual – sperm and egg are released into water where fertilization takes place. - Support and movement-Each segment has longitudinal and circular muscles that contract, compressing fluid to form a water based hydrostatic skeleton. - Key Characteristics- Segmentation Phylum Arthropoda -Arthropods such as spiders, crabs, & insects. - Type of symmetry – bilateral - High degree of cephalization, and ventral nerve cord. - Open circulatory system. - Most carry out respiration through spiracles, microscopic holes in the exoskeleton and body wall. Branching networks called tracheae extend from holes to all body parts. - Support and movement chitinous exoskeleton, - Paired, jointed appendages - Key Characteristics- Segmented bodies – often divided into head, thorax, and abdomen - External skeleton - Jointed appendages VERTEBRATES - Animals with backbones Phylum Chordata -Chordates - Bilateral symmetry - Coelom present - have notocord, dorsal nerve cord, pharyngeal gill slits, and a tail at some stage in life. Subphylum Vertebrata -Vertebrates - Most of the notocord is replaced by a spinal column composed of vertebrae that protect the dorsal nerve cord. - Recognizable head containing a brain. Class Amphibia Body covering - - skin often slimy. Lacks scales Nervous system – well developed brain. Endocrine system – the hormone thyroxine triggers metamorphosis. Cardiovascular system – 3 chambered heart, allows some mixing of oxygenated and deoxygenated blood. Respiratory system – Amphibians respire through lungs and skin in adult form, and through gills 28 EOC Review 08-09 and skin in larval stage. Reproductive system - /external fertilization. - eggs usually laid in water and fertilized externally. Digestive system – mouth, esophagus, stomach, small intestine, large intestine, cloaca. Excretory system – kidneys remove wastes from blood. * Parental care of fertilized eggs is common among amphibians. Ex: Frog Class Reptilia Body covering – Dry, scaly, watertight skin Nervous system – Brain controls and regulates behavior. Jacobson’s Organ – specialized sense organ in the roof of the mouth of reptiles. Cardiovascular system - 3 chambered heart. Respiratory system – Large lungs Reproduction – Internal fertilization. All reptiles produce amniotic eggs. Ectothermic – warms body by absorbing heat from its surroundings. Ex: snake, lizzard. Class Aves Body covering - feathers Nervous system – large brain relative to body size. Cardiovascular system - - 4 chambered heart for complete separation of oxygenated and deoxygenated blood. Respiratory system – Lungs connected to air sacs. Air sacs store air but do not participate in gas exchange. Reproduction – Internal fertilization and Shelled eggs Birds are the only animals that have feathers, which are modified scales. Birds also have hollow bones that make it easier for them to fly. Endothermic Lay shelled, amniotic eggs. Class Mammalia Body covering – all mammals have hair on at least part of body. Nervous system – well developed Cardiovascular system – 4 chambered heart Respiratory system – lungs. Reproductive system – Internal fertilization. Variation among mammals monotremes - are mammals that lay eggs. Ex: platypuses and spiny anteaters. Most monotremes are found in Australia. 29 EOC Review 08-09 Marsupials are mammals that give birth to underdeveloped young that usually mature in the pouch of the mother. Placental mammals – Give birth to young after a much longer period of development. During development the mother provides nourishment and oxygen to the offspring through the placenta. Support - endoskeleton Young nourished with milk secreted by mammary glands. Endothermic -Different types of teeth are useful for eating different types of food. - Carnivorous mammals (meat eaters), such as dogs, cats, and wolves have strong, sharp incisors and canines that are used for biting and ripping flesh from their prey. Even their molars are sharp as they are used to slice meat into smaller pieces. -Herbivorous mammals (plant eaters) eat plants that are tough and require thorough chewing. They have flattened incisors that grasp and tear through the vegetation. (Ex: Deer) They chew by moving their jaws from side to side, using flattened molars to grind the plant food. 30 EOC Review 08-09 THE HUMAN BODY CIRCULATORY SYSTEM The circulatory system is responsible for transportation of substances throughout the body. -red blood cells- (a.k.a. erythrocytes) are biconcave, disc shaped cells with no nuclei, that contain hemoglobin, and transport oxygen and some carbon dioxide. Cannot reproduce and have limited life span. -white blood cells-(a.k.a. leukocytes) help fight infection. When a person has an in infection their white blood cell count increases. Path of blood through the human body. Superior and Inferior vena cava---- Right atrium ----through tricuspid valve ---- into right ventricle ---- into pulmonary arteries ---- to lungs (where oxygen is added to the blood) ----- into pulmonary veins --- to left atrium ---- through bicuspid valve ---- into left ventricle ---- aorta ---- to body. ENDOCRINE SYSTEM The endocrine system consists of glands that transmit chemical messengers called hormones throughout the body. These hormones help the body maintain homeostasis. Adrenal glands – fight or flight response. (Adrenaline) Pancreas – produces insulin, which helps regulate glucose levels in the blood. 31 EOC Review 08-09 Thyroid – controls cellular metabolic rate. IMMUNE SYSTEM -cancers- diseases in which cells grow and reproduce uncontrollably. Cancer cells are more like embryonic cells than differentiated cells. They also have abnormal shape, unique antigens on their surfaces, and selfantigens. It is likely that many cells become cancerous during a persons lifetime, but they are destroyed by the immune system. -antigen- foreign substance that induces an immune response and interacts with specific antibodies - anitibody – protein that helps destroy pathogens -white blood cells- play an important role in the immune response. White blood cells are also called leukaocytes -vaccine – a solution containing a harmless version of a virus, bacterium, or toxin that causes an immune response when introduced to the body. (Causes the body to produce antibodies to the bacteria or virus) DEVELOPMENT -cell differentiation- developmental process by which generalized cells become specialized in order to form such structures as the brain and spinal cord. -Cell specialization is critical to the success of multicellular organisms. -only certain genes are active in a given cell at any given time. The active cells produce enzymes that guide the chemistry and thus the development of the cell. -Chemicals called inducers can signal genes to become active or inactive. Inducers are released by adjacent tissues and passed on to the cell that they are to act on. -Cell division during development of an embryo can produce cells with different chemical compositions of their cytoplasm. These differences can also influence cell specialization NERVOUS SYSTEM **-neurotransmitters must be released to transmit an impulse from one neuron to the next. 32 EOC Review 08-09 Digestive System 33 EOC Review 08-09 SKELETAL SYSTEM Primary functions are support and protection of internal organs. Also provides a framework for attachment of muscles. Ligaments- connect bone to bone. Tendons- connect muscle to bone. EXCRETORY SYSTEM -Kidneys are main organs. - Kidneys filter wastes from the blood. INTEGUMENTARY SYSTEM Skin is the main organ. Serves as a protective layer to underlying tissues Kingdom Plantae - Plants regulate body processes using hormones - Auxin- plant hormone with growth regulating effects including: Growth of stems toward light Growth of roots downward and stems upward The dropping of fruit or leaves from a plant. 34 EOC Review 08-09 PLANTS NONVASCULAR PLANTS Ex: mosses, liverworts, hornworts VASCULAR PLANTS SEEDLESS PLANTS Ex: Ferns GYMNOSPERMS Ex: Conifers such as pine trees - SEED PLANTS ANGIOSPERMS (FLOWERING PLANTS) Ex: Apple Tree all plants have a life cycle that involves alternation of generations- this means that the plants produce two alternating generations of plants- a haploid gametophyte stage and a diploid sporophyte stage. The gametophyte stage produces gametes while the sporophyte stage produces spores. 35 EOC Review 08-09 The life cycle of a nonvascular plant (a) such as a moss, is characterized by a gametophyte that is larger than the sporophyte. The life cycle of a vascular plant (b) such as a fern is characterized by a large sporophyte and a very small gametophyte. -vascular tissues- tissues that transport materials from one part of a plant to another. Function much like arteries or veins in humans. Bryophytes- nonvascular plants- do not have vascular tissues. Do not have true roots, true stems, or true leaves. They have root like structures called rhizoids. and leaf like structures. -nonvascular plants must live in very moist environments. EX: mosses and liverworts Tracheophytes -vascular plants- have vascular tissues. They are far more developed and far more numerous than nonvascular plants. EX: fern, bean, corn, pine tree, maple tree, geranium. -xylem- vascular tissue that transports water and dissolved minerals in plants. -phloem-vascular tissue that transports sugars (food) in vascular plants. -xylem and phloem form the transport system in plants much like the blood vessels form the transport system in your body. Ferns - Are seedless vascular plants -Reproduce using spores produced through meiosis. - Spores are stored in cases on the underside of the fern leaf in cases called sori. Some plants are not capable of photosynthesis, but are also capable of digesting insects. These insectivorous plants are often found in soils that are low in nitrogen and other important nutrients that can be supplied by eating the insects. - Examples of insectivorous plants include the venus flytrap, pitcher plant, and the sundew. Study the diagram of flower parts -ovary-site of egg (female gamete) production in flowers -stamen- site of pollen (male gamete) production -cross pollination- transfer of pollen from the flower of one plant to the flower of another plant. This may be accomplished through wind pollination or through pollen transport by insects. 36 EOC Review 08-09 - insects and angiosperms evolved simultaneously and because of this they suit each other’s needs very well. -plants that are wind pollinated must produce more pollen than plants that are insect pollinated. -This figure shows the parts of a bean seed, a corn seed, and a pine seed. -Seeds are composed of three main parts: 1. Seed coat for protection 2. Food supply- Endosperm and cotyledons- the food supply is needed to nourish the developing plant until it is able to carry out photosynthesis. 3. The embryo, which is divided into three parts: the radicle, hypocotyl, and epicotyl. -Angiosperm- flowering plants whose seeds are contained in a fruit. (oats, strawberries, broccoli) - Angiosperms are divided into two main groups: monocots and dicots -Some plants are not only capable of photosynthesis, but are also capable of digesting insects. These insectivorous plants are often found in soils that are low in nitrogen and other important nutrients that can be supplied by eating the insects. -Examples of insectivorous plants include the venus flytrap, pitcher plant, and the sundew. 37 EOC Review 08-09 Leaf cross-section -stomata- pores in the leaf. Are opened and closed by guard cells on either side of the stoma; this helps control moisture loss. During the day Carbon dioxide enters through the stomata to be used in photosynthesis. The products of photosynthesis, water vapor and oxygen, exit through the stomata. -guard cells control the opening and closing of the stomata. -palisade mesophyll- column shaped cells with many chloroplasts. Most photosynthesis takes place in the palisade mesophyll. - Kingdom Fungi - Common examples: yeast and mushrooms - Play an important role in the environment as decomposers. - Many reproduce both sexually and asexually. Asexual reproduction is often by formation of spores. - Fungi can be parasites of plants or humans (athletes foot). - Fungi form a symbiotic relationship with either an algae or cyanobacteria. The result is called a lichen. - Fungi also form a symbiotic relationship with the roots of plants. The result is called myccorrhizae. The fungi help the plants to absorb more water, and also release enzymes that free nutrients in the soil for the plants to use. In return, the plants provide the fungi with the products of photosynthesis. -Kingdom Protista-very diverse group. - The definition of Protists has shifted as knowledge has increased. -all are eukaryotic -made up of 3 groups of organisms 1. plantlike protists- called algae. Uni or multicellular. autotrophic 2. animal like protists- called protozoans. Unicellular. heterotrophic 3. fungus like protists- called slime molds. uni or multicellular depending on life stage. All heterotrophic 38 EOC Review 08-09 -examples: Ameba Paramecium Kingdom Monera - Bacteria -only kingdom that has prokaryotic organisms. Prokaryotes are organisms that lack a membrane bound nucleus and other membrane bound organelles. VIRUSES, -Viruses are composed of genetic material enclosed in a protein coat or capsid. They cannot reproduce outside a living host and are thus not considered living. Antibiotics DO NOT work against viruses. Since viruses have such high mutation and reproductive rates, they can adapt to changing environments quite well. Indeed, since the only way they can reproduce is by infecting a cell they must be able o evolve faster than their host cells. If not, then the host cells would adapt, evolve to where a virus would no longer be able to infect. Cells change their surface receptors so viruses cannot attach. The viruses change their surface proteins so they can attach to the changed cell surface receptors. The viruses must always stay ahead of the evolution game. They are very very good at this. 39 EOC Review 08-09 HIV/AIDS - Caused by a virus - Affects the immune system - Transmitted by exchange of body fluids Influenza/The flu - Caused by a virus - Affects the respiratory system - Transmitted through direct contact with infected individuals Smallpox - Caused by a virus - Affects the skin - Transmitted by droplets - The disease is now treated after a successful worldwide vaccination program Bacteria and bacterial Illnesses - Prokaryotic cells - Treated with antibiotics Strep Throat - Caused by streptococcus bacteria - Affects the respiratory system - Transmitted by droplets Parasites - Malaria is caused by a parasitic protist called Plasmodium - The life cycle is completed in multiple organisms, primarily mosquitoes and humans Coevolution Coevolution is the mutual evolutionary influence between two species (the evolution of two species totally dependent on one another). Each of the species involved exerts selective pressure on the other, so they evolve together. The most common example of coevolution exists between flowering plants (angiosperms) and their pollinators. 40 EOC Review 08-09 Interactive role of Genetics and Environment Sickle cell anemia and malaria Sickle cell is a disorder caused by a recessive gene. Individuals who inherit two copies of the recessive allele will have sickle cell anemia; individuals who inherit only one of the alleles are said to have sickle cell trait. People with sickle cell trait are resistant to the malaria parasite, therefore, in areas where malaria kill large numbers, it is an advantage to have sickle cell trait. Lung/mouth cancer and tobacco use Tobacco use (smoking or smokeless) increases the risk of lung and mouth cancer. Skin cancer, vitamin D, folic acid and sun exposure The body needs some exposure to the Sun to produce adequate amounts of vitamin D. Excessive exposure to the sun’s rays increases an individual’s risk of developing skin cancer. Getting sufficient amounts of the B vitamin folic acid may provide some protection against skin cancer, Diabetes (diet/exercise and genetic interaction) You may have heard diabetes is genetic but genes are not the only risk factor for diabetes. Lifestyle factors including obesity and physical inactivity leads to Type 2 diabetes. These risks coupled with a genetic predisposition are the unpleasant recipe for Type 2 diabetes. PKU and diet Phenylketonuria (PKU) is a genetic disorder which results in an inability to break down the amino acid phenylalanine. The build-up of phenylalanine in affected individuals results in mental retardation. If children are tested at birth and placed on a special diet low in phenylalanine, they will develop normally and not suffer any ill effects. Immune Response Nonspecific or Innate Immunity - Intact skin- first line of defense - Body secretions Mucus- keeps tissues from drying, traps microorganisms so they are swallowed and passed to the stomach where they are destroyed. Sweat, tears, and saliva all contain the enzyme lysozyme which breaks down the cell walls of some bacteria. Inflammation ▪ Occurs in response to tissue injury ▪ Characterized by 4 symptoms: redness, swelling, pain, and heat. 41 EOC Review 08-09 Phagocytosis of Pathogens ▪Phagocytes are white blood cells that destroy pathogens by surrounding and engulfing them. ▪Macrophages – (big eater) type of phagocyte that engulfs damaged cells or pathogens that have entered the body’s tissues. Acquired Immunity - Acquired immunity- defending against a specific pathogen by gradually building up resistance to it. - An acquired immune response occurs when the immune system recognizes an antigen and responds to it. - Antigen-a foreign substance that stimulates an immune response. Often, antigens are proteins found on the surface of bacteria or other foreign substances such as pollen. - Antibodies- are proteins in the blood plasma produced in reaction to antigens that react with and disable antigens. - The development of acquired immunity is the responsibility of the lymphatic system. - Acquired Immunity involves two main types of cells, T cells and B cells. There two main types of T cells, and two main types of B cells. Each cell type has a unique function. Helper T cells Activiate B cells “Help” B cells T cells Killer T cells Release enzymes that produce holes in the pathogens, thus killing them B cells Produce antibodies B cells Memory B cells Remain in the bloodstream to respond rapidly if the same pathogen invades the body again. Acquired Immunity can be active or passive Passive Immunity- is developed when an individual receives antibodies that were generated in another host. Examples: - Mother passes antibodies to unborn child through the placenta or to the infant through the mother’s milk. - Injecting antibodies from another animal or human into a person. A person bitten by a snake may be injected with antibodies from an animal that is immune to the snake bite. Active Immunity- is obtained when a person is exposed to antigens and produces antibodies. Examples: - Once a person recovers from an infection, they will usually be immune if exposed to the pathogen again. - Active immunity can be induced artificially by vaccines. If a person is given a vaccine containing a weakened, dead, or partial portion of the pathogen, the body will produce antibodies to the pathogen. 42 EOC Review 08-09 Nutrition Aspects of nutrition that contribute to optimal health Six basic kinds of nutrients are essential to proper body function; carbohydrates, fats, proteins, minerals, vitamins, and water. Poor nutrition can lead to obesity, malnutrition and vitamin deficiencies. Parasites Vector, symptoms, and treatment for malaria Malaria is an infectious disease caused by a parasite, Plasmodium, which infects red blood cells. The symptoms characteristic of malaria include flu-like illness with fever, chills, muscle aches, and headache. Some patients develop nausea, vomiting, cough, and diarrhea. Cycles of chills, fever, and sweating that repeat every one, two, or three days are typical. There can sometimes be vomiting, diarrhea, coughing, and yellowing (jaundice) of the skin and whites of the eyes due to destruction of red blood cells and liver cells. Key interventions to control malaria include: prompt and effective treatment with artemisinin-based combination therapies; use of insecticidal nets by people at risk; and indoor residual spraying with insecticide to control the vector mosquitoes. Toxins Lead: Lead pipes and deteriorated lead-based paint in older homes and high levels of lead contaminated house dust are the most common sources of lead poisoning in U.S. children. Lead is much more harmful to children than adults because it can affect children’s developing nerves and brains. The younger the child, the more harmful lead can be. Unborn children are the most vulnerable. Children get lead in their bodies when they put lead objects in their mouths, especially if they swallow the lead object. They can even get lead poison on their fingers from touching a dusty or peeling lead object, an then putting their fingers in their mouths or eating food afterward. Tiny amount of lead can also be inhaled. Mercury: Mercury has traditionally been used to make products like thermometers, switches, and some light bulbs. Mercury in the air eventually settles into water or onto land where it can be washed into water. Once deposited, certain microorganisms can change it into methylmercury, a highly toxic form that builds up in fish, shellfish, and animals that eat fish. Fish and shellfish are the main sources of methylmercury exposure to humans. Mercury exposure at high levels can harm the brain, heart, kidneys, lungs, and immune system of people of all ages. 43