Ecology
2 main types of phagocytic cells (engulf and destroy pathogens) in mammalian body-> neutrophilis=circulate in blood macrophages= migrate thru body or reside permanently in organs/ tissues
2 additional types -> dendritic cells= stimulate development of adaptive immunity eosinophils= discharge destructive enzymes against parasites
intermediate disturbance hypothesis: disturbance= discrete event that results in the removal of individuals from the community (wildfire, hurricane) high levels of disturbance-> diversity low bc disturbance itself is suppressing diversity low levels of disturbance-> diversity low bc get high levels of competitive exclusion how do disturbances improve diversity? keeps dominant competitor in check
3 levels of biodiversity-> genetic, species, community (ecosystem) 1.2 million species described, estimated 9 million not discovered annual conservation costs 4 billion why conservation? 1) untapped resources -> lots of opportunity for more agri, medicine (sponge used to develop anticancer med), engineering (geckos-surf area bc of threads on feet help them stick)
coriolis effect= deflects air to the right in N hemisphere (clockwise) and to the left in the S hemisphere (ccw) air and water particles are moving W to E at a faster velocity at 0 degrees latitude
4 major abiotic components of climate= temp, precipitation, sunlight, wind macroclimate= consists of patterns on the global, regional and landscape level microclimate= consists of very fine patterns, such as those encountered by the community of organisms underneath a fallen log warm, wet biomes most likely located at 0 degrees latitude
vertebrate kidney: 1 million subunits in kidney= nephron Glomerulus and Bowman's Capsule Proximal Convoluted Tubule Loop of Henle Distal Convoluted Tubule Collecting Tubule/ Duct
85% cortical nephrons. Juxtamedullary are critical glomerulus-> filtration bowman's capsule 180 L of initial filtrate/ day filtrate= H2O, salt, HCO3-, H+, urea, glucose, AA, some drugs
Distal Convoluted Tubule: contribute to regulation of K+ and NaCl secretion of K+ and H+ to filtrate reabsorption (to interstitial fluid) of NaCl, water, and HCO3- contributes to pH regulation
Collecting duct: filtrate into urine water loss concentrating urine permeable to water in medulla but under control via aquaporin channels and hormones some reabsorption of NaCl and urea to interstitial fluid, increasing osmolarity of interstitial fluid. some urea reabsorbed to medulla, but urine is still hyperosmotic
biodiversity= balance of extinction and speciation. generally trending towards increasing biodiversity current extinction rates 1000x higher than background rates estimated 11k-58k species lost annually threats to biodiversity: 1) habitat loss= long leaf pine savanna- 3% of 92 million acres remain 2) invasive species= characteristics of invasive species=pioneer species, high dispersal rates, usually found in disturbed habitats why are they successful? have no diseases, no herbivores, no parasites, no predators. better competitors than native species. Adapted to similar enviro.
Ex: burmese python-people keep as pets and release when they get too big-> eat lots of birds and mammals 3) pollution= heavy metals, fertilizers, plastics 4) overexploitation= overfished, overhunted Ex: bison, gray wolf, cod Extinction vortex= small pop-> inbreeding, genetic drift-> loss of genetic variablity-> lower individual fitness and pop adaptability-> lower reproduction, higher mortality-> smaller pop
adaptive immunity key parts: 1) lots of receptors means that new pathogens are readily encountered 2) self-tolerance 3) activation increases specific b and t cells 4) immunological memory means a stronger response for previously encountered pathogens
SARS-Cov-2 (pathogen)-> has spikes= antigen <- b cells binds -> b cell makes lots of antibodies -> antibodies bind to antigen preventing spikes from piercing cells for pathogen
immune system= how your body fight pathogens (bacteria, fungi, viruses) innate immunity (all animals) = recognition of traits shared by broad ranges of pathogens using a small set of nonspecific receptors. rapid response pathogens-> barrier defenses= skin, mucous membranes, secretions internal defenses= phagocytic cells, natural killer cells, antimicrobial proteins, inflammatory response
adaptive immunity (vertebrate only) -> recognition of traits specific to particular pathogens, using a vast array of receptors. slower response pathogens-> humoral response= antibodies defend against infection in body fluids cell-mediated response= cytotoxic cells defend against infection in body cells
humoral immune system= antibodies neutralize or remove pathogens from fluid cell mediated immune system= t cells destroy infected host cells
after vaccine, you feel bad b/c of body's primary immune response
tropical rainforest= highly diverse (150-450 cm rain, 22-27 ° C) temperate broadleaf forest= deciduous trees (50-225 cm rain, 13-22 °C) temperate grassland (midwest)=great for farming (25-80 cm rain, 4-29°) desert= (0-35 cm rain, 8-24°C) northern coniferous forest= wet enough to support trees, common at 60° latitude (40-250 cm rain, 2-16°C) tundra= relatively dry (0-110 cm rain, -8-4°C)
air from ocean going up in altitude bc of mtn-> dumps lots of precipitation on side of mtn w/ ocean on other side of mtn-> rain shadow=little precipitation
lypmphocytes: b cells= arise from stem cells in bone marrow and develop in bone marrow t cell= arise from stem cells in bone marrow and develop in thymus gland
antigen receptor= surface proteins on ( b and t cells) that bind antigens ( b and t cell receptors) one cell may have 100K antigen receptors antibody= a protein produced by b cells that combines w/ a specific antigen and facilitates the destruction of antigen. y= shaped. can bind to free floating antigens as well antigen recognition-> b and t cells have antigen receptors on their plasma membranes. b cells make antibodies. t cells don't
in descending portion of loop, filtrate more conc b/c loses water osmotically in ascending portion of loop (inner medulla) - salts move out passively in ascending portion of loop (outer medulla) - salts move out of filtrate w/ active transport
ascending portion transport epithelium lacks water channels. water doesn't leave. If goal is to conc urine why does it become more dilute in ascending portion? mvt of salt out of ascending creates gradient for descending to passively pass water
Basic Processes of Excretory Organs: filtration, reabsorption, secretion, excretion
basic struct of excretory organs= consists of a tubule composed of transport epithelium
osmalarity= # of solute particles in 1 L of solvent
cell w/ 275mOsmol/L is in plasma w/ osmalarity= 300 mOsmol/L -> water leaves cell
innate immunity: Ex-> TLR 3= binds dsRNA, common to some viruses TLR 4= binds lipopolysaccharides, common to bacteria TLR 5= binds flagellin, protein found in bacterial flagella
cellular innate defenses -> innate immune cells in mammals detect, devour, and destroy invading pathogens these cells recognize groups of pathogens using TLRs= toll-like receptors TLRs recognize fragments of molecules characteristic of a set of pathogens
species diversity-> species richness= # of diff species in community relative abundance= the proportion of each species in the community Shannon Wiener Index= H'=-sum of pi ln(pi) species 1 = abundance 15 species 2=abundance 30 15/45 ln(15/45) + 30/45ln(30/45) = -.636 (-1)= .636
communities w/ higher diversity are more productive and more stable in their productivity better able to withstand and recover from environmental stresses more resistant to invasive species=organisms that become established outside their native range
each variable=1 dimension quantify niche by categorizing activity range for all abiotic dimensions if x- axis is a limiting resource then competition occurs intraspecific and interspecific competition can limit growth intensity of intraspecific competition increases w/ density greater overlap= greater competition
competitive exclusion principle=2 species can't occupy the same niche superior competitor will drive the other to extinction how do so many species exist? niche partitioning=split up niche-> disruptive selection
filtrate most conc at bottom of loop how important is the ability to conc urine? 180 L initial filtrate -> 1.5L urine excreted = less than 1% where is interstitial fluid most conc? inner medulla
control of urine conc-> involves the hormone antiduretic hormone (ADH) and the permeability of the collecting tube. increases in ADH increases the permeability of collecting tube to water normal blood osmolarity= 285-295 mOsm/L blood osmolarity increases (sweating a lot) -> osmoreceptors in hypothalamus release ADH-> water reabsorption and specific neurons in hypothalamus generate thirst -> drink water -> normal blood osmolarity
logistic growth- dN/dt = rN[(k-N)/k] respond faster to limiting resources=get smoother logistic curve environmental resistance= the sum of the environmentally limiting factors acting on a population- both abiotic and biotic
density-independent= have same impact on all pop regardless of density. birth/death rate the same at all pop densities ex: floods, droughts, storms density-dependent= has impacts which are proportional to the pop density. birth/death rate vary w/ pop density ex: competition (low pop density-no competition, high pop density- high competition) predation (more predators come w/ high pop density) disease (spreads more easily w/ high density pop)
organisms which use energy to convert inorganic molecules into organic mcs=primary producers gross primary productivity= amount of energy assimilated net primary productivity= energy assimilated- E used for respiration by primary producer
direction of arrow in food web=indicates mvt of E primary producer-> primary consumer-> secondary consumer-> detrivore apex predator=top of food web no one eats them bc they're huge and not many of them most food webs only have 4-6 trophic levels bc only 10% E gets transferred each trophic level.
global macroclimate: insolation= solar energy/ area decreases towards poles b/c of greater depth of atmosphere, greater angle of incidence ave temperature decreases, variation increases towards poles
earth not heated evenly-> differential heating of earth's surf affects air mvt and precipitation more solar E-> more evaporation-> more precipitation (equator) deserts at 30 degrees N and S of equator bc of hadley cells - dry air cells return to earth and create a high pressure system
impact community diversity-> latitude/climate, area (size), level of disturbance diversity peaks in tropics-> there is higher evapotranspiration, greater area, more stable temp, less disrupted by glacial periods islands closer to mainland will have greater immigration larger islands will have more niches, fewer extinctions/ greater richness
extinction rate increases w/ increasing # of species bc niches being filled up where lines intersect= # of species you would expect to find (graph of rate immigration/extinction vs # of species) smaller, more isolated habitats will have less species bigger, more connected habitats will have more species
Responses to salinity -> osmoregulators= maintain a constant internal enviro for water or ions hyperosmoregulators (freshwater fish)= maintain higher osmalatity than surrounding sea water
hypoosmoregulators= maintain lower osmalarity than surrounding sea water osmoconformers= vary as the external conditions vary both strategies occur among animals in same enviro
hyperosmotic side = higher solute conc, lower free water conc
hypoosmotic = lower solute conc, higher free water conc
how does immune system recognize specific invaders? have antibodies and antigen receptors that bind to specific epitopes antibodies and antigen receptors produced by b cells billions of diff ones possible
if antibodies are proteins how can you make so many if you only have 20k genes? (1 million b cell antigen receptors and 10 million t cell antigen receptors) antibody gene reaarangement-> DNA of undifferentiated b cell -> lots of diff combinations possible
warm water near LA is why we arent desert-> lots of evaporation-> lots of precipitation benthic zone= organic and inorganic sediment at bottom of aquatic zones benthos= communities of organisms in benthic zone pelagic= in water detritus= dead organic matter, falls from the productive surf water and is an important source of food
in oceans and lakes, a temperate boundary= thermocline separates the warm upper layer from cold deeper water= stratified (warm and cold water have diff densities- don't mix) many lakes undergo a semiannual mixing of their waters= turnover this mixes oxygenated water from surf w/ nutrient-rich water from bottom upwelling= in oceans, on-shore currents bring nutrients from bottom to surf summer/winter = stratified spring/autumn= mixing
Proximal Convoluted Tubule-> secretion (into filtrate) (to tubule) of ammonia and H+ ions Reabsorption (leaving filtrate) (to cortex) of NaCl, nutrients (glucose), and water No net change in osmalarity of filtrate filtrate volume decreases
loop of henle -> descending= reabsorption of water ascending= impermeable to water. reabsorption of NaCl (thin, passive) and (thick, active transport)
Undiscovered species helpful to humans? Have unknown future problems loss of species-> loss of opportunities more diverse communities are more stable species provide ecosystem services like water filtration or wave breaks
loss of species may have detrimental effects on other species species have intrinsic value
community= a group of pop of diff species which inhabit a common enviro and interact w/ one another types of interactions: competition (-/-), predation (+/-), herbivory=prey is plant (+/-), symbiosis -> parasitism (+/-), mutualism (+/+), commensalism (+/0), amensalism (-/0) cow and cattle egret= commensalism acacia tree and ant= mutualism cow in field trampling grass= amensalism penicillium fungus producing an antibiotic= amensalism
niche=role of an organism w/i the community or relationship of a species to all aspects of the enviro (biotic + abiotic) based on activity (tolerance) range for an environmental variable
Most significant of wastes are nitrogenous breakdown products of proteins and nucleic acids. Some animals convert toxic ammonia to less toxic cmpds
nucleic acid -> nitrogenous bases -> NH2 proteins -> AA -> NH2 NH2-> uric acid (birds, reptiles, insects) NH2 -> NH3 (most aquatic animals) NH2 -> urea (mammals, amphibians, sharks)
what do antibodies do? attack the antigen 1) antibodies bind to the antigen and neutralize it 2) antibodies bind the antigen and clump the pathogens. the clump is then engulfed by macrophages
opsonization= make pathogens easier for macrophages and neutrophils to identify antibodies bind to antigen and then activate the complement system= proteins and antibodies trigger a membrane attack complex and pathogen lyses
adaptive immunity: immune cells selectively destroy specific invading microbe, virus, etc remember the invader-> allows for rapid response to invader if it reappears in future need antigen receptors
pathogen=organism, virus, viroid, prion that causes disease antigen= any substance that elicits a response from B or T cells. typically part of a pathogen epitope= accessible region of an antigen to which an antigen receptor or antibody binds
population= group of individual of same species living at same time in same general area change in pop size= birth-deaths+immigration-emigration pop growth rate- N/t=B-D N/t=rmaxN rmax=innate capacity for growth, biotic potential N=# of individuals death rate> birth rate -> r<0 our pop growth is exponential not linear (thanos solution doesn't work)
predict pop size - N=N. e^rt N.= initial pop size what impacts rmax? age of 1st reproduction, seasonality or frequency of reproduction, litter/clutch size problem w/ exponential model= assumes unlimited resources pop growth slows near carrying capacity= max # of individuals an enviro can support= k
predator and prey cycles follow each other human pop shows exponential growth agri, industrial revolution, vaccination -> led to pop booms (raise carrying capacity) how rapidly is human pop growing? 1% annually (80 million) annual percent increase is declining
pyramid= rapid growth rectangle= no growth inverted pyramid= declining pop global carrying capacity- predicted global pop of 9-11 billion in 2050. carrying capacity for humans is uncertain women given more freedom/rights -> choose to have less children -> pop growth slows
in a temperate lake, dissolved oxygen in the benthos will be lowest in the summer microbes use more oxygen in summer bc metabolic processes are faster earth is round= differential heating
saltwater more dense-> freshwater floats on top upwelling zone= wind pushes surf water away from coast-> deep water replaces it oligotrophic lake= nutrient-poor and generally oxygen rich eutrophic lake= nutrient rich and oxygen poor
how does immune system make more of 1 specific antibody? b cells w/ antigen receptor bound w/ the antigen are stimulated to reproduce (mitosis)-> makes more b cells w/ that antigen receptor/antibody and they release free antibodes. clonal selection
self tolerance= cells w/ antigen receptors that bind to the body's own cells are destroyed via apoptosis clonal selection= antigen ends up selecting which lymphocytes will make clones (have to be activated)
Major Histocompatibility Complex (MHC) molecules -> protein on surf of host cell that presents antigen fragment
t cell antigen receptor bind to pieces of antigens on surf of host cell as part of MHC
lymphocyte activated by match b/n receptor and antigen (epitope) cloning begins some cells become effector cells= short-lived and deal w/ antigen b effector cells= plasma cells t effector cells= helper t cells and cytotoxic t cells others become memory cells
the specificity of immunological memory-> primary immune response= response following initial infection secondary immune response= if infected a 2nd time
ecology= scientific study of biotic and abiotic factors that determine the distribution and abundance of organisms why learn about it? improve economy, agri, forestry, fisheries + wildlife biomes= major communities classified by the predominant vegetation
to understand the abundance and distribution of organisms understand climate= weather of location of long period of time (often 30 yrs)
freshwater fish -> water less conc -> fish tends to gain water, lose salt -> urine less conc, lots of vol marine bony fish -> water more cond -> fish lose water, gain salt -> urine slightly less conc terrestial vertebrate -> lose body water to air, urine more conc
type and quantity of animal's waste may greatly affect its water balance
freshwater and marine: gyres (current) go clockwise in N. hemi gyres go ccw in S hemi water temp varies a lot bc of currents. (latitude not as good indicator)
warm ocean currents run past east side of continents N hemi-> water coming up from equator= warm on east water coming down from artic= cold on west S hemi-> water coming up from artic= cold on west water coming down from equator= warm on east
