> Biology 1-H Study Guide Chapter 13 Geologic Time Scale Earth was thought to be roughly 4 billion years old o Fossils show the history of evolution o Earth very old and changed over time due to weathering and external forces 1778 James Hutton o proposed that the earth had changed o rocks, mountains and valleys had been changed by rain, heat, cold, volcanoes and natural forces. 1830 Charles Lyell o explained past events because the earth is always moving, ground is shifting, twisting and burying rock layers Fossils: preserved remains of ancient organisms o Some resemble animals alive today but some do not, giving scientists a clue to the organisms of the past Geologic Time Scale: date earth’s past using rocks o Determines the position of rocks in relation to other layers. Determine the order in which they were formed. Relative dating: o Compares layers to determine the age of rocks. Not absolute, age only determined in relation to the rocks around it. o Easy to be wrong – rocks could have shifted putting them in a different order. Radioactive Dating: o Use radioactive elements which decay (break down) into non-radioactive elements at a very steady rate. o Measure the rate of decay in half-lives: time it takes to degrade ˝ of the atoms in the sample o Each radioactive element has a different ˝-life o Uranium 238 4.5 billion years --- Lead 206 o Potassium 40 1.3 billion years ---Argon 40 o Carbon 14 5770 years --- Nitrogen 14 o Provides natural clocks: measure the amount of radioactive material and the element it becomes and work backwards to get the age of the sample. o Uranium and Potassium are very useful for very old materials, but 14C is used for everything else, especially living things o Living things take 14C in from the atmosphere and stop taking in C when they die making it easy to calculate the age o Absolute Dating: allows for dating the actual age of the sample. o Using this data - the Earth has been dated to be 4.5 billion years old The Fossil Record Fossils can be large or small o Parts of animals and plants or whole animals/plants, eggs, footprints and animal droppings How fossils form Ice: preserves specimens well. When thawed, the specimen is mostly intact. Tree sap: hardens into amber and becomes a very good preservative. Often traps whole insects which get caught in the sap. Tar pits, peat bogs and quicksand: can also trap animals and animal remains. Encase the animal and protect it. Sedimentary rock o Formed when exposure to rain, heat and cold breaks down existing rock into small particles of sand, silt and clay. o Particles are carried along by streams and rivers and will eventually settle out of water and cover dead organisms. o As sediment piles up it exerts pressure protecting the organisms stuck inside o Fossils can be petrified (turned into rock) – if the sediment invades the soft part of the organism and becomes compressed and pressurized. Fossils provide clues to past organisms o Do not have fossils for all organisms which existed o Fossil record is incomplete · Many animals die and vanish without leaving a proper fossil · Organisms which live far away from water and where sediment forms · Finding fossils embedded in tons of rock is difficult – can sometimes be exposed by weather – wear away the uppermost layers to reveal fossils beneath Fossil preservation: can sometimes be so good that tiny microstructures can be seen - other times difficult to determine what species the fossil is Paleontologists: scientists which study fossils o Work to create fossil record and find more preserved collective history of Earth’s organism o Fossil record hard to complete but many places have enough fossils to show a distinct evolutionary pattern Examples: Evolution of the horse: OVERHEAD · Evolution took place over 50 million years · "Dawn horse" from the Eocene epoch – very small horse with different foot and leg bones · grew into a larger horse with hooves that increased it’s ability to run Shark teeth – found buried in the sand of the Arizona desert Showed that the desert was once covered by ancient seas Fern fossils in Canada – once had a much warmer, tropical climate Biology 1-H Study Guide Chapter 17 Section 17.1 Viruses 1935 structure and nature of viruses discovered by American biochemist Wendell Stanley Worked on TMV – tobacco mosaic virus which infects crops of tobacco plants causing their leaves to get a blotchy pattern called a mosaic. o Eventually kills the plant o Infects entire crops – was very detrimental to the tobacco farming community Caused by a virus – noncellular particle made of genetic material and protein that can invade living cells Structure: o Core of nucleic acid (RNA or DNA) protected in a protein coat called a capsid o Can be simple or complex in a variety of shapes – page 357 Fig 17-3 all of the shapes of viruses o Complex viruses: bacteriophage Virus which infects bacteria o Capsid, nucleic acid core and tail which is used to attach to bacteria Example: T4 which contain DNA and about 30 proteins o Specificity: specific viruses target specific cells in specific organisms · Usually specific to cells which exist in certain types of individuals Life cycle · Viruses must invade cells to reproduce · Must use host cells machinery to replicate DNA and make more virus Lytic Virus: uses the cells machinery and then causes the cell to burst freeing all of the newly produced viruses. Example: T4 Virus 1. Infection: contact with host activates virus then the virus injects its DNA into the cell. 2. Growth: DNA begins to work inside the host cell · Host cell cannot tell the difference between its own DNA and the virus’ DNA · RNA polymerases of the host cell create mRNA for the virus · Viral mRNA begins to destroy the cell by turning off the synthesis of important biochemicals · Also produces a viral gene which destroys the host DNA 3. Replication: the mRNA of the virus is used to replicate thousands of DNA and protein to make more viruses · DNA and proteins are assembled into new viruses which are released when the cell breaks · Newly synthesized virus is now free to infect other cells Lytic infection: repeated cycles of infection, growth and replication taking over many cells until the body is riddled with infection. Lysogenic Infection: o Infects the cell but does not immediately reproduce and lyse o Viral DNA is injected into the host cell and DNA is incorporated into host DNA o Known as a prophage – can stay inserted for a short time or for may generations · Prophage activity: prophage insertion blocks the entry of other viruses into the cell and can add useful things to bacterial DNA · Whole inserted prophage is relatively inactive – virus is not reproducing and not causing harm · Once prophage comes out of genome it begins to replicate and direct the synthesis of new viral particles · Usually sudden changes to the cell cause the viral DNA to go from prophage to active state · Then goes thru lytic cycle as already discussed Retroviruses · Contains RNA · Produces a DNA copy of RNA genes which is then inserted into the host genome as a prophage · Called retro because it must work backward from RNA to DNA · Uses the same cycle after RNA is turned into DNA when it can then use the host’s machinery Viruses and Living Cells · Viruses depend upon the host cell for nutrition, respiration and machinery. · Technically they are parasites depending entirely upon another living organism for its existence · Debate over whether viruses are alive – cannot replicate or even feed on their own. Section 17.2 Prokaryote: single celled organism without a nucleus or membrane bound organelles Facts: · Bacteria and single celled organisms · 10 billion in a spoonful of soil · More than 10 billion in your mouthNumber of bacteria and prokaryotes outnumber all eukaryotes · Phyla: Eubacteria, Archeabacteria, Cyanobacteria, and Prochlorobacteria 1. Eubacteria o True bacteria o Largest phylum o Cell wall protects contents from injury o Have flagella for movement 2. Cyanobacteria o Photosynthetic (blue-green bacteria) o Contains blue pigment phycocyanin and chlorophyll a o Fresh and salt H2O, very hot spring, arctic region, very diverse group 3. Archeabacteria o ancient bacteria o earliest bacteria o simple metabolism with adaptations to the harshest conditions 1. Thermacidophiles: are adapted to live in hot, acidic environments 2. Extreme Halophiles: adapted to require a high concentration of salt 3. Methanogens: killed by oxygen – live in anaerobic conditions o Produce methane gas (CH4) o Live in stagnant H20, sewage treatment plants etc. o Remove organic compounds to make CH4 into the atmosphere which can then be turned into CO2 o CH4 can be used directly as an energy source if there is a great enough quantity. 4. Prochlorobacteria o Contains chlorophyll a and b as the principle pigments o Closer to green plants than cyanobacteria o Only 2 species ever discovered Identifying Monerans · Single celled although they form colonies which seem like multicellular organisms · Diameter (1 – 5 um) · 3 shapes o rod (bacillius) o spheres (coccus) o spirals (sprillus) · cell surface: wall containing peptidogylcan o polymers of modified sugars linked with short polypeptides Gram staining: separate bacteria into 2 groups based on the differences in the cell wall. Stain with two biological stains: crystal violet (purple) and safranin (red) o Gram positive (purple): simple walls, with a large layer of peptidogylcan o Gram negative (red): more complex structure with less peptidogylcan. Outer membrane have lipopolysaccharides attached. Obtaining Energy Autotroph: only needs CO2 – make their own food Heterotroph: need at least 1 organic nutrient as a source of carbon to make food o Phototroph: use light energy o Chemotroph: energy from chemicals taken from the environment Bacterial Respiration · Gives energy for all the life activities of bacterium thru respiration and fertilization · Respiration: process which involves oxygen and breaks down food molecules to release energy · Fermentation: enables cells to carry out energy production w/o oxygen o Obligate aerobes: need a constant supply of oxygen o Obligate anaerobes: do not require oxygen and are poisoned in the presence of it Example: Clostritium botulinum · Found in soil - if exposed to air they are unable to grow · Find space w/o air can grow very quickly and produce large amounts of a toxin and cause botulism · Interferes with nerve activity causes paralysis and even death · Found in canned found – especially food canned at home · Facultative anaerobes: do not require oxygen but are not poisoned by its presence Bacterial Growth and Reproduction · Reproduce every 20 minutes in optimal conditions · Usually takes 1-3 hours to complete the reproductive cycle · Conditions not usually optimal so growth of bacteria doesn’t get out of hand. Binary Fission o Bacterial cell grows to double its size and then replicates its DNA o Splits in half producing 2 identical daughter cells o No genetic recombination Can do a form of sexual reproduction known as conjugation o Exchanging genetic material between bacteria o Long protein bridge forms and connects cells o DNA passes along bridge from donor to recipient o New DNA becomes incorporated into bacterial genome allowing for recombination o Adds to the diversity of Kingdom Monera Surviving harsh conditions: · endospores: thick walled structures which can withstand the harshest conditions allow bacteria to hibernate until conditions become more favorable. Importance of Bacteria · Used in food: bacteria found in yogurt, buttermilk, sourcream, pickles, sauerkraut, etc. · Used to digest petroleum oil in spills · Produce antibiotics · Develop a close relationship with other organisms o Symbiosis: inhabit the digestive tracts to help digestion, they also make vitamins which we cannot make ourselves o Cows use bacteria to digest cellulose · Recycle and decompose dead organic material. All other organisms are dependent on these nutrients o Saprophytes: bacteria which digest organic material and use it as a source of energy · Bacteria added to human waste to breakdown organic material – releases nitrogen gas and carbon dioxide Section 17.3 Pathogen: disease causing agent o Affects an organisms ability to perform a vital function Virulence: ability to cause disease o Many levels dependent on characteristics of pathogens and host Resistance: ability of host to cope with the pathogen o Genetics can a role, but most resistance is conferred during the lifetime of the organism Immunity: resistance acquired or inherited to a specific pathogen o Host produces antibodies which are specific to the pathogen which destroy the pathogen o Resistance is cumulative: response is greater the second time infected – why most people don’t get chicken pox more than once Viruses: small pox, AIDS, polio, measles, mumps and influenza o Only sure way of preventing infection is with an immune response Vaccines: contains killed or weakened pathogenic agents which cause the body to produce an antibody response so when the body is re-exposed to the disease a stronger defense will be mounted Interferons: small proteins produced by body cells infected with a virus which make it difficult for the virus to infect other cells. Pathogenic Bacteria and Disease · All eubacteria · Spread thru water, food, and air · Causes human diseases such as cholera, leprosy, tetanus, and diphtheria · Many eubacteria enter the body via food and water, replicate in the digestive tract and exit the body via feces without harming the host. o If the feces enter the drinking water supply, the organisms which drink the water become sick o Happens where sanitation isn’t good o Typhoid and dysentery come from water-born bacteria Often not the actual bacteria, but the toxins which the bacteria release get to high and effect the host. Biology 1-H Study Guide Chapter 18 18.1 Kingdom Protista: 1st eukaryotic kingdom (with nuclei and organelles) · Unicellular · Oldest fossils are 1.5 billion years old – evolution from Monerans took about 2 billion years Classification · Diverse group of 115,000 species · Difficult to classify due to the similarities to animals, plants and fungus · Kingdom created because these organisms resembled animals, plants and fungi but were unicellular · Kingdom of exclusion – if it doesn’t fit in other 4 kingdom, it must be a protist Evolution of Protists 1st protist believed to have evolved by symbiosis between prokaryotes · recall: symbiosis – living together in close association · come form the fact that many organelles resemble prokaryotic organisms ex: chloroplasts are like blue/green bacteria · Margulis’ Endosymbiont Hypothesis: prokaryotes lived inside one another as endosymbionts, forming a team where each member served a purpose. Eventually they could not live without each other and evolved into 1 organism. Ex: protist Cyanophora paradoxa · Contains chloroplasts which are actually blue – green bacteria which can be grown outside of the protist (demonstrating the endosymbiont theory) 18.2 Animal – like Protists 4 phyla of protists with animal-like qualities 1. Ciliophora: cilia bearing protists o Live singularly or in colonies (like bacteria) o Have cilia (short, fine hairs) on outer surface whose beating provide locomotion o Live in both fresh and salt water o More than 7000 species – Paramecium is the most common Paramecium o 350 um in diameter (large for a unicellular organism) o have a pellicle – outerlayer cell membrane and underlying structures o trichocysts: defense mechanisms which produces tiny bristles o 2 nuclei – macro and micronucleus o gullet: indentation which obtains food. Once trapped food is transferred to a food vacuole o waste is excreted from the anal pore o contractile vacuoles – removes excess water o reproduces by binary fission but can also perform conjugation when conditions are tough 2. Zoomastigina: animal-like protists with flagella o Move using a flagellum (long whip like tail) o # of flagellum can vary o absorb food through the cell wall o asexual or sexual reproduction – undergo meiosis to produce gametes which fuse together to form new organisms 3. Sporozoa: spore producing parasitic protists o Nonmotile – they do not move o Parasitic: live on host and cause harm on worms, humans, insects, fish and bords o Reproduce by means of spores (groups of cells in a protective membrane which invade host) 4. Plasmodium: protist which causes malaria o Infects the Anopheles mosquito which is transferred to humans during bites o Inside humans, Plasmodium affects RBCs and liver cells causing them to burst 5. Sarcodina: protists with false feet o Use a projection of cytoplasm as a false foot called a pseudopod o Major organism: ameba § Moves using pseudopod § Eats by engulfing other cells How Animal-like Protists Hurt and Help the World Harmful Relationships: § A lot of protists are parasites which affect animals, plants and other protists § Ex: plasmodium – causes malaria § Ex: Tryanosoma – causes African Sleeping Sickness § Ex: Entamoeba – causes amebic dysentery Helpful Relationships: § Serve as food for other organisms in seas, rivers and lakes § Trichonympha – lives in digestive system of termites which allows them to digest the chemical bonds in woods so they can get nutrition from it. Get into protist by digesting feces of other termites 18.3 Plant-like Protists o 3 phyla o plant-like, carry out photosynthesis with the pigment chlorophyll o have flagella 6. Euglenophyta: flagellates with chloroplasts § Uses flagella for locomotion § Most common organism – euglena Euglena § Long cell with 2 flagella at the front end § Red eyespot to find light for photosynthesis § Can live as a heterotroph when there is no sunlight § Pellicle is unique because of its ridges which are attached to microtubules to hold cells shape § Reproduces by binary fission 2. Pyrrophyta: fire protists o Part of dinoflagellates o Chloroplasts and 2 flagella (1 wraps around like a belt, other used as a tail) o Covered by thick plates which look like armor o Many are luminescent (give off light) o Only eukaryotic cells whose DNA do not have histone proteins 3. Chrysophyta: golden protists o Made of yellow-green algae, golden-brown algae, diatoms o Cell walls have pectin instead of cellulose o Store food in the form of oil instead of starch 4. Diatoms o Produce intricate cell walls rich in silicon (main ingredient in glass) o Flat and small with beautiful etching o Pictures on page 398 Fungus-like Protists · Slime molds: found near rich sources of food (rotting wood, compost, wet lawns) · Stages of life make them appear as amebas, mold and fungus · 2 phyla 1. Acrasiomycota: cellular slime mold § Begin as individual cells which look like amebas § Group together to form a large mass which acts as one organism § Reproduce using a reproductive structure called a fruiting body 2. Myxomycota: acellular slime molds § Start as a cellular ameba § Produce structures known as plasmodia which contain thousands of nuclei enclosed in a single cell membrane How Plant and Fungus-like Protists Hurt and Help the World Harmful: o Euglena most common – especially in areas with lots of waste and sewage help to recycle o when too much waste create blooms – masses of cells can be harmful to humans o ex: red tide – blooms of dinoflagellate Gonyaulax polyhedron – can cause paralysis and death Helpful: o make-up a considerable part of phytoplankton – photosynthetic organisms at surface of the ocean o provides food for other organisms Biology 1-H Study Guide Chapter 33 33.1 Characteristics of Mammals · very diverse group · range in size from a field mouse to an elephant · can swim, fly and run Definition: mammals are endothermic animals which means they can generate heat internally. · They maintain a constant body temperature o Conserve heat with a combination of fur, hair and fat o Cool body using sweat glands · They are also viviparous: young develops in the mother and born alive o Females have mammary gland which produce milk for their young · Several kinds of teeth based on the type of food they eat · Well developed breathing muscles including a diaphragm · 4 chambered heart with 2 atria and 2 ventricles is the center of a 2 circuit circulatory system to carry oxygen to different parts of the body Evolution of Mammals 1st mammals · very small (looked like a tree shrew) · nocturnal – did not need energy from the sun · 1st evolved at the end of Cretaceous period · split into 3 groups monotremes: most primitive § only 3 species left § include duckbill platypus and anteater marsupials: pouched animals § use pouches to carry around young § include opossums, kangaroos, wombats and koalas placental mammals: mammals with placenta o have a placenta to filter blood o includes mice, cats, dogs, whales, humans Fossils records incomplete for placental mammals o Underwent adaptive radiation (convergent evolution) in North America while marsupials did similarly in Australia and South America Form and Function in Mammals Limbs and organs have evolved to fit each species and its environment Go over the major similarities and differences 1. Feeding Carnivorous mammals (cats and dogs) · have sharp teeth called incisors and canines to help rip the flesh of prey · Carnivores use up and down chopping movement of their jaws · Evolved sharp claws and the ability to run to chase and catch prey Herbivorous mammals (cows and giraffes) · o Eat tough plants o Evolved strong lips and flat edged incisors that grasp and tear vegetation o Move jaws side to side to grind food Most mammals cannot digest cellulose (do not have the enzyme) so they store plant material in a section of the digestive tract called a rumen Rumen – has symbiotic bacteria to break down cellulose. Animals regurgitate the partially digested food and they eat it normally (cows chewing their cud) Smaller animals have a cecum, similar to a rumen. Humans used to have, has evolved into an appendix Other kinds of eaters: o Blood drinkers: vampire bats use razor sharp incisors and saliva with an anti-clotting agent o Filter feeders: giant blue whales use large plate like teeth (baleens) as filters to get small animals and plants as food Respiration · All mammals use lungs and 2 sets of muscles · Chest muscles pull and push air by moving ribs · Diaphragm contracts to help change the size of the chest cavity · Use air and vocal cords to produce sound Internal transport · Arrangement of pumps and vessels · 4 chambered heart · transports blood with gases to and from the lungs and body tissues Excretion · Highly developed kidney to control the composition of all body fluids · Extract waste in the form of urea and add water and other waste to make urine · Kidneys filter blood, control hormones, regulate pressure, and retain important compounds kike sugars and salts Response · Most highly developed brain with 3 main parts o Cerebrum: thinking and learning o Cerebellum: coordinates movements o Medulla: regulates body functions · Highly developed senses to gain information about environment o Eyes: vary greatly in mammals. Only monkeys, apes and humans can see color well b/c other organisms descended from nocturnal creatures with only black/white vision o Ears: humans do not have very sensitive hearing. Certain mammals can hear very low or high frequencies o Smell and Taste: more highly developed in mammals other than humans Movement · 4 limbs (or similar features) · evolved for the type of movement. Remember homologous structures (wings, flippers, etc.) Reproduction Monotremes: egg-laying mammals o Oviparous – lay eggs but the young still nurse on the mother Marsupials: o Viviparous but the womb lacks enough nourishment for the whole gestation. o Fetus goes into the marsupium (pouch) and nurses until it is big enough to be independent Placental Mammals: o Develop similarly with an embryo that has nourishment o Also forms a placenta which exchanges nutrients and wastes with the mother o Allows the fetus to stay inside the mother longer Gestation period: amount of time spent developing ranges form a few weeks to 2 years in elephants After birth, the mother provides a period of time for protecting and caring for the young Section 33.2 Important Orders of Living Mammals Classifying mammals uses several important characteristics · Structure of teeth · Kinds of bones in the head · Method of reproduction Monotremes: egg-laying mammals · Only 3 species exist in Australia and New Guinea · Includes the duckbilled platypus and spiny anteater Marsupials: pouched animals · Australia: home to kangaroos and wallabies · N. America: opossums (nocturnal creatures) Placental Mammals: 16 orders Order Insectivora: insect eaters · Includes: tree shrews, hedgehogs, shrews, moles · Similar to 1st mammals, have a very high metabolic rate and must eat constantly to stay alive Order Chiroptera · Includes: different species of bats · Closely related to insectivore, but eat different foods such as fruit, frogs or blood · Usually nocturnal and use echolocation for sense · Live in colonies, sleep hanging upside down with wings wrapped around the body Order Rodentia · Includes: mice, rats, squirrels, beavers, porcupines, gophers · 2 long front teeth used for chewing wood · teeth grow throughout life because they are constantly being worn down · short gestation period · small animals Order Lagomorpha · Includes: rabbits and hares · Resemble rodents with long sharp teeth and the type of diet · Gestation short and they produce lots of offspring Order Carnivora · Includes: cats, dogs, wolves, bears, weasels, hyenas, seals · Most are terrestrial, stalking and chasing prey · Sharp teeth and claws · Seals and walruses – live in water, but ancestors were land dwelling Order Cetacea: aquatic mammals · Includes: whales, dolphins, porpoises · Breath sir and have lungs but circulatory system allows deep, long dives · Blubber is subcutaneous fat to keep mammal warm · Mate and bear young in the water · Carnivores (but a few are filter feeders) Order Sirenia: aquatic mammals · Includes: manatees (sea cow) related to elephants, slow, large sea creatures · Live in the tropics or warm oceans · Eats water plants Order Artiodactyla: large grazing mammals · Includes: sheep, goats, hippopotami, giraffes and pigs · 2 toes but evolved from 5 toes · even-toed ungulates (hoofed mammals) Order Perissodatyla · Includes: horses, zebras, tapirs, rhinoceroses · Odd-toed ungulates Order Proboscidea: trunked mammals · Includes: elephants · Used to have mammoths and mastedons but they are now extinct · 2 species still exist: Indian and African Elephant but both are in danger of being extinct Order Primates · Includes: monkeys, gorillas and humans · Highly developed cerebrum · Different branches such as New World Monkeys like the squirrel and spider monkey which live solely in trees and have a prehensile tail (can use it grasp and climb) · Old World Monkeys like chimps and apes do not have a prehensile tail How Mammals fit into the World · Evolved from reptiles 200 mil years ago and underwent massive adaptive radiation (divergent evolution) · Humans can inhabit many different habitats · Herbivorous mammals eat plants and are in turn food for larger carnivores · Domesticated mammals used for food and for pets Biology 1-H Study GuideChapter 36Comparing Vertebrates 1. The Evolution of the Vertebrates · 1st appeared more than 500 mil years ago · Vertebrate family tree (see tree on pg 786) – represents one hypothesis on how vertebrates evolved Scientists agree on the basic order of evolution· Lobe-finned fish to amphibian to reptiles to birds to mammals · The exact details are sketchy because of holes in the fossil record Trends in Evolution· If closely related evolutionary lines are subjected to different forces of natural selection, they tend to become more dissimilar as they evolve (divergent evolution) · If different evolutionary lines encounter extremely similar forces of natural selection, they tend to become similar to one another as they evolve (convergent evolution) Body Temperature Control· Major evolutionary advance – why? · All of the body’s chemical reactions only occur in optimal temperatures and being able to regulate your our temperature gives you a better chance of survival Recall:· Ectotherms: use heat from the environment to heat the body · Endotherms: generate their own heat and use body structures and physiological functions to regulate their internal temperatures 2. Form and Function in Vertebrates · Different vertebrates have modified their basic structures as they evolved · As vertebrates evolved, organ systems grew more complex Movement among Vertebrates· All vertebrates (except jawless fish) have a backbone or vertebral column made of individual bones called vertebrae o Connected by ligaments which allows movement · In certain fishes and snakes, the muscles are arranged on both sides of the spine to help the organism move. The spine cannot be compressed so it moves back and forth · In most amphibians, reptiles, birds and mammals the muscles and bones of limbs are most important for movement - 2 trends in evolution o the position of limbs move toward the center of the body o movement of the spine changes from side to side to up and down · Position of limbs vary o Salamanders and other amphibians – limbs directly out to the side so they cannot support a lot of weight o Reptiles have limbs more directly under their bodies to support more weight o Mammals have 2 legs directly under them and can support all their weight Feeding Among Vertebrates· Heads show many adaptations – pg 791 picture of skulls o Example: long-billed birds good at getting nectar from flowers o Example: whales and flamingos are filter feeders who use strainers to collect food · Organs of digestive system also differ o Carnivores have shorter tracts with more enzymes for rapid digestion o Herbivores have longer tracts with bacteria Respiration Among Vertebrates· Fish and amphibian larvae use gills to diffuse oxygen into blood · Terrestrial vertebrates (and a few sea creatures) use lungs to take in and release carbon dioxide · Structure of lung differs dependent on amount and level of respiration Examples:o amphibians – lungs are sacs and don’t use much air and can absorb thru the skin o Reptiles – more developed, must rely on only lungs so they have more surface area o Mammals – highly complex and branched lunged with lots of surface area o Birds: most efficient using long sacs to take in air Internal Transport among Vertebrates· If have gills for respiration: use a single loop circulatory system o Heart – gills – body – heart o Heart is simple with only 2 chambers o Atrium receives blood and ventricle pumps blood · If have lungs for respiration: use a double loop circulatory system o 1st loop: blood between heart and lungs to get oxygen o 2nd loop: blood from the heart to the body oxygenated o heart evolved to have partitions to separate oxygenated and deoxygenated blood · Frogs (amphibians) – have a 3 chambered heart o 2 atria and 1 ventricle o blood unmixed in atria but is mixed in ventricle · Reptiles – have a 3 chambered heart o 2 atria and 1 ventricle o ventricle has a partial partition to minimize the mixing of blood in the ventricle · Mammals, birds and crocodilian reptiles – have a 4 chambered heart o 2 atria and 2 ventricles o blood is completely separated the entire time o most efficient at getting and distributing oxygen Excretion among Vertebrates· Eliminates nitrogenous waste and water o Fish use gills and other vertebrates use kidneys · Nitrogenous waste is first made into ammonia which is then turned into a less poisonous compound o Amphibians, cartilaginous fishes and mammals turn ammonia into urea o Birds and reptiles turn ammonia into uric acid o Waste flushed out with water Response among Vertebrates· Cephalization: well developed brain in their head · Size of cerebrum (thinking/learning) increases with mammal complexity Reproduction among Vertebrates· Almost all vertebrates reproduce sexually · Fertilization can be external (fish and frogs) or internal (other vertebrates, mammals)
