• SA:V ratio
• blue whales are too big to live on land
• we dont have animals like dragons because the wings are too small to hold such a giant body mass
• insects can't be too big because the exoskeleton would eventually not be able to hold it

• Smaller animals have a higher SA:V ratio than larger.
• Body surface area increases with square of body length
• mass increases with cube of body length. as you get longer, you get much heavier
• SA:V ratio effects circulation, respiration and temperature regulation

Circulation: for very thin or very small organisms. It is cheap with very little/ no ATP expenditure. Single celled protists. Since diffusion takes a long time, it has to be a high SA:V ratio

Respiration: same thing

Endotherm: metabolism can internally regulate body temperature. Able to do more things and more versatile in varying environments.

Ectotherms: body temperature determined by the environment. Most insects, most fish, amphibians, most reptiles. Ectothermy is very cheap in energy expenditure. (see frogsicle)

• steady state of the physiological condition of the body
• Thermoregulation: steady body heat- Insulation, Circulation, Adaptations, Behavior, Avoidancde
• Osmoregulation: balance between water and salt in body

related to homeostasis

-arteries and veins are proximal in animal appendages, heat goes from the artery blood to the vein blood to make appendages warm.

1) Insulation: skin, fur, feathers, fat, blubber, goosebumps (trap air under our hairs)

2) Circulation: vasodilation and constriction, counter current heat exchange

3) Adaptations: panting, sweating (cools down), mucous?

4) Behavior- migrating, huddling, basking (ectotherms can be homeotherms because of behavioral changes)

5) Avoidance: Torpor- physiological state where metabolism slows way down, low activity. Hibernation (winter) and Estivation (summer)

• To obtain energy (ATP!)- monomers of proteins, carbs and fats
• Biosynthesis- growth and reproduction, carbon and nitrogen, storage (definition- building complex compounds from monomers)
• Essential Nutrients: 1- Amino Acids 2-Fatty acids 3- Vitamins 4- Minerals
• Our body needs 20 proteins, 8 of which are essential,   meaning from the diet
• There are 13 essential vitamins serving as coenzymes

• Body needs 20 proteins, 8 essential
• Fatty acids- membranes and hormones (unsaturated are double bonded carbonds, saturated are fatty acids saturated with hydrogen)
• Vitamins- needed in lower amounts, serving as coenzymes. there are 13
• Minerals- inorganic compounds- calcium, phosphorus, iron, magnesium. enzyme cofactors. *Osteophagy is when animals eat animal bones to get essential minerals
• Scurvy: Vitamin C deficiency- spongy gums, bleeding membranes

• Carnivors: Incisors (front), Canines (next), premolars and molars. clearly for ripping apart flesh
• Herbivores: incisors and a big gap to their premolars, small or no canines
• Omnivores: all in a row, canines that aren't as sharp

• Carnivores: short intestine, small cecum, shorter colon- don't have to digest plants, which are harder to break down
• Herbivores: big ol cecum, really long colon and intestine for breaking down plants
• Cecum: home for symbionts to break down cellulose

Scurvy: Vitamin C deficiency

• takes place in mouth and esophagus
•  eating

• break down of food into molecules usable by the cells
• begins with saliva in the mouth- salivary amylase breaks down starch and glycogen (small carbohydrates)
• then to the stomach, where enzymes, such as pepsin and highly acidic gastric juice which are important in protein digestion. Stomach also stores food.
• Positive feedback- pepsin can make more pepsin from pepsinogen
• Negative feedback- H+ breaks down gastrin to stop the process
• PNS->Gastrin> H+, Pepsinogen, Mucus> Pepsin
• Small intestine breaks down food into molecules usable by cells (6 mtrs long in small intestine)
• Pancreas produces digestive enzymes

Occurs in the small intestine 

• digested molecules must enter the body
• small intestine is very folded has has a large SA to accomplish this
• Villi and microvilli- folds on folds. these aid in the absorption

occurs in the large intestine

• concludes food processing
• very important in water processing
• borrows 90% water from circulatory system. If it doesn't give enough back, diarrhea. If it gives too much back, constipation

Pancreas: produces digestive enzymes, such as trypsin, chymotrypsin, carboxypeptidose (polypeptides -> amino acids). Nuclease: nucleic acid->nucleotides; Amylase: polysaccharides-> disaccharides; Lipase: fat drops->glycerol-> fatty acids Pancreas aids in the break down of main nutrients.

Liver: detoxifies alcohol and other toxins, releases bile salts to break up fat globules

• Wood frog. A picture of a frog completely frozen but not dead- the only amphibian in the arctic circle (Alaskan tundra)
• Freezes. No breathing, heart stops and organs dehydrate. Use glucose and urea as a cryoprotectant - they don't freeze! 
• It's extremely cheap! When its outside environment warms up, it thaws out and goes on with its life!

• Coprophagy: consumption of poo
• Why do some animals do this? inefficient digestion, herbivores trying to get nutrients, 10% on first round?, bacteria, vitamins and nutrients (fermentation and symbionts) or habitat! Dung balls, bettle larva
• Ecosystem service!

Purpose: transport- good stuff to all cells in the body (Oxygen, essential nutrients)

Oxygen: interface of circulatory with respiratory. blood goes to the lungs to get oxygen. AKA gas exchange

Essential nutrients: interface of circulatory with respiratory. Blood takes the nutrients from digested food in the small intestine 

• occurs in cnidarians, flatworms, single celled protists
• benefit: very cheap, requires no ATP- sufficient in very thin animals with high SA:V ratio
• takes a long time: diffusion ~ distance^2

• happens in arthropods and most molluscs
• bathes organs directly without blood vessels
• hemolymph: pool of blood that bathes the organs
• more pricey than diffusion, still really cheap
• no high blood pressure system

• blood inside a very extensive vessel network of arteries, veins and capillaries 
• Disadvantage: allows for greater metabolic demands: very expensive in ATP
• Advantage: Animals with closed are larger and more active, can do more things
• Most endotherms, most mammals, some molluscs (cephalopods), earthworms, vertebrates

• Two atria, two ventricles (powerful, muscles)

Right ventricle: deoxygenated

Right atrium: deoxygenated

Left ventricle: oxygenated

Left atrium: oxygenated

Bernoulli's Principle: rate of flow of a liquid is inversely proportional to total flow area. 

*Capillaries seem to go against this, because the flow slows way down going from arteries to capillaries. however, total area of capillaries is much bigger than that of arteries, so it does slow down. (like going from one hose to five hoses)

Arteries: heart-> capillaries: thicker in their wall with a greater elasticity than veins. This is because they have to handle much higher pressure

Veins: capillaries-> heart

Capillaries: venules, arterioles facilitate material exchange.  Do the interchange with digestive and respiratory. They are thin walled with close proximity and very slow flow. This allows oxygen, nutrients and waste to flow to and from the tissue

Blood: Red Blood Cells

• erythrocytes
• biconcave disks (SA:V, material exchange) 
• produced in bone marrow
• no nucleus or mitochondria to make room for hemoglobin- releases and grabs onto oxygen at the right time. (4 heme groups with iron, which has an affinity to oxygen)
• EPO:  hormone that promotes creation of erythrocytes. related to illegal blood doping because the more RBCs you have, the more O2 you get. 

• have a nucleus: how they get DNA from blood. 
• plays a huge role in immune system

• aid in blood clotting, no nucleus
• Open wound: 1-platelets bind to collagen to form a plug 2- release clotting factor: proteins activate
• Protein: Fibrinogen is the unactivated form of fibrin. Fibrin makes threads that compose the clot. 

• Cardiovascular disease: causes of 50% of US deaths
• Artherosclerosis: deposition of plaque in arteries. The kicker is that the plaque stimulates clotting in places you don't want to clot. Limits oxygen to heart and brain- causes heart attack
• Care for teeth, care for heart: recent findings that link gingivitis to cardiovascular disease
• Can it be infectious? bacteria getting into arteries and veins from open wounds

Stroke: death of nervous tissue in the brain, blockage of arteries in head

Heart attack: death of cardiac muscle, prolonged blockage of coronary arteries

For gas exchange. 

Why do we need gas exchange? To get oxygen, needed for aerobic respiration of monomers -> ATP

To dispose of CO2, Vocalization

• Gas exchange using body surface
• very cheap
• needs HIGH SA:V ratio, need LOW metabolic demand
• have to stay wet (why?)
• eg: protists, flatworms, cnidarians

• only aquatic 
• easy for them to keep wet, only the oxygen content of water is much lower than that of air (about 1%)
• Ventilation: water is moved past gills by muscular activity
• Counter current exchange: water and blood moving in opposite directions. O2 goes out of water into blood. If they were parallel it would be much less efficient. 
• Needs a high SA:V ratio, gill SA can exceed that of body. 

• occurs in arthropods and insects who have an open circulatory system(hemolymph is not involved in gas exchange).
• Air is lighter and O2 rich, travels through a huge network of tubes to deliver air to every single cell
• Must keep wet with high SA:V
• This means that oxygen transport is one of the major limitations on insect size. They can't be bigger, because that would decrease the SA:V ratio

• Meganeura
• size of a small hawk
• consumes amphibians and other insects
• hada tracheal system- how?
• Current O2 content- 20%, Carboniferous- 35% O2
• Perfectly preserved Illinois rainforest- found predatory scorpions that were the size of a small car

• mammals, birds, reptiles, many amphibians
• very high SA and very low diffusion distance. Lungs are highly vascularized
• Bronchial system: network of tubes getting smaller and smaller- bronchioles -> alveolus
• capillaries are right on top of alveoli- gas from the alveoli moves into the blood in the capillaries
• this minimizes diffusion distance, maximizing S.A. for gas exchange.
• Gas dissolves into the solution

• Medulla oblongata monitors CO2 levels by using cues from changes in pH.
• lower pH= higher CO2 (this is why hyperventilating can be dangerous. expelling CO2 but not getting oxygen tricks your brain into thinking you're getting enough oxygen)
• CO2 reacts with water to form carbonic acid

• in lungs, the gas dissolves into the blood
• in trachea, the gas does not dissolve into solution, it just goes to the cells
• lungs want to maximize surface area and minimize diffusion distance 

• increases our oxygen transport 70X- important to our survival
• Hemoglobin is a protein with 4 subunits (hemes) containing iron- iron binds with oxygen to make oxyhemoglobin
• It binds oxygen reversibly- high CO2 lowers the blood pH. Hemoglobin releases oxygen. Low CO2 levels raise the blood pH, hemoglobin grabs on to oxygen

much less pressure at high elevation-> hypoxia (low oxygen)

underwater the pressure increases a lot

MHC proteins! Very important and extremely diverse (each individual has a different MHC protein) - they are expressed on the surface of a cell, serving as an ID badge- if it lacks the badge, the immune system wants to kill it. 

The immune system would be useless without a way to differentiate between good and bad.

Skin, Phagocytes, Antimicrobial peptides, Inflammation, Natural killers

They are nonspecific because they provide general "lines of defense" against all foreign cells

• protective barrier
• mucous membranes
• chemical defenses such as sweat- sweat is highly acidic, trying to get in the way?
• Injury creates and opening- way in for the unwanted stuff

• Phagocytosis -"eat em!"; actually engulfs and ingests invaders
• White Blood Cells- 3 different types: 1) Macrophage (big eaters) 2) Neutrophils (first responders), make up most of phagocytes 3) Esinophils (deals with macroparasites) 
• Recognize via MHC proteins, but not perfect. (eg schistosoma- blood fluke mimicing our mhc proteins)

• "kill em!"- proteins that chemically attack pathogens
• Complement System: more than 30 proteins- complex cascade of proteins attacking invaders
• Interferons: used in treatment of viral infections and cancer

Chemical and cellular response to injury/  or localized infections

Promotes wound healing

1-Injury allows pathogen in- histomine is release, letting the immune system know

2- Blood flow increases (swelling), clotting factor is activated (phagocytes come onto the scene)

3- Wound closes, pathogen killed

• "dissolve em!" 
• These cells destroy viral infections and cancerous cells 
• They "lyse" or break open the infected cells
• They are actual cells instead of proteins or something else

-B cells and antibodies, mature in the bone marrow, 

• antigens: forgein proteins/ complex sugars. -isolated molecules, toxins, fragments of bacteria
• Produce antibodies in response to antigens

Two types: 1)Effector Cells: plasma cells, short lived cells to comobat antigen, they are the initial defense

2) Memory cells: long lived, secondary response. can respond rapidly and strongly to a second exposure to the antigen. The whole idea behind vaccination.

• Helper T cells: first response to antigen presenting cells, stimulates proliferation of B cells and Cytotoxic T cells
• Cytotoxic T Cells: identify and destroy cells- expose pathogen to the rest of the immune system to kill it.

• T cells respond to antigen fragment presented on surface of body's cells 
• Deals with intracellular virus 
• T cells mature in the thymus

• activating memory cells (secondary immune response) to weakened version of pathogen - related to less pathogenic, killed or weakened toxins
• how smallpox was erradicated 
• flushot and HIV only within year protection
• HPV most common STI: cervical cancer, throat cancer, genital warts

• new research showing that not all individuals are equally infectious. 80/20 rule- 80% of infected people are infected by 20% of people already infected (based on a lot of things- lifestyle, profession, etc)
• Typhoid Mary: unsanitary cook in early 1900s- linked to 47 cases of typhoid. She was a healthy carrier- didn't feel sick but was infected with typhoid. They put her on an island.
• Esther Mok: SARS (severe acute respiration syndrome) 100+ infections linked to this 26 year old flight attendant.

balance between salt and water in the body

movement of water or solutes

keeps the good, loses the bad

Good: water, nutrients, vitamins

Bad: salt, nitrogenous bases

• Hypertonic: net water loss, cell dessicates and crashes in on itself. dries out.
• Hypotonic: net water gain, cell swells and often ruptures
• Isotonic: no net loss/gain

• marine environments are hypertonic (more solutes in the water) the animals drink lots of water to get the water and pee concentrated urine. 
• freshwater is hypotonic- plenty of water, less solutes, pee a lot of dilute urine
• terrestrial- dessication. terrestrial animals need to conserve water at all costs: they use many different things for this: skin, exoskeleton, waxy cuticle, shell

• Ammonia: extremely toxic, but is soluble in water. Animals with access to water are more likely to excrete ammonia as waste, so they can get rid of it quickly. (Fishes and aquatic insects)
• Urea: much less toxic than ammonia. mammals, turtles and adult amphibians excrete urea. Land animals have it because they need to be able to store it. They can't just leak all the time. (energetically expensive)
• Uric acid: "salt snot" excreted by birds (out the nose), insects, reptiles. Not soluble, but a semi solid paste, very expensive to make. Made by animals needing to conserve water. 

• extremely important: allow for life on dry land
• 1500 L of blood per day are filtered by kidneys- eliminates toxic waste, 99% of water, vitamins and sugar
• highly expensive metabolically
• Uses nephrons to filter (about 80 km of tubules). They filter blood, reabsorb thing we want to hold on to, excrete
• Filtration: removing waste through the nephron on to urine

Nephrons: important parts and their functions

• Glomerulus: ball of capillaries where blood is filtered
• Bowman's capsule: entrance to nephron- water and solutes are transferred from blood to here
• Loop of Henle: important- descending and ascending limb where water and solutes are reabsorbed. (descending pulls water, ascending pulls salt)

• Descending limb of loop of henle loses water
• Ascending limb loses salts

ADH: hormone. brain makes ADH, which go to nephrons and tell them to produce more concentrated urine, tells them to take more water out of the blood. 

ADH basically tells kidneys to pull more water.

What does alcohol do to this process? Suppresses ADH, causing you to dehydrate. Diuretic.

Gout: accumulation of uric acid, often stored in joints

Kidney stone

Offspring identical to single parent

No meiosis

No fusion of sperm or egg

Rapid and cheap

Loss of possible genetic diversity (no crossing over or recombination)

Budding: plants, fungi, cnidarians, worms

Fission: unicellular- protists, prokaryotes, eukaryotic organelles (chloroplasts), sea anemones- basically rips in half

Fragmentation: unintentional- animal needs to be able to regenerate- fungi, plants, sponges, cnidarians, sea stars, annelids

Parthenogenesis: females producing offspring from an unfertilized egg- parthenogenesis and sexual reproduction can take same in some species or even one individual!

• Parthenogenesis: Komodo dragon named Sungai was isolated for two years, but laid eggs that actually hatched!
• Offspring can only be male
• Females are ZW genes

Yes- sex creates more variable genetics- ability to adapt

Protection from mutations

Sex is extremely expensive- energy, time and resources. Dangerous to seek mates