Intro

6 characteristics of living organismsHighly organized and complicated structureMetabolism – all chemical rxns that happen in an organismGrowthAbility to maintain fairly stable internal environment (homeostasis)Ability to respond to stimuliReproduction

Cell theory1. The cell is the fundamental unit of structure and function in living organisms. 2. All cells arise from pre-existing cells by division.3. Energy flow (metabolism and biochemistry) occurs within cells.4. Cells contain hereditary information (DNA) which is passed from cell to cell during cell division.5. All cells are basically the same in chemical composition in organisms of similar species.6. All known living things are made up of one or more cells.7. Some organisms are made up of only one cell and are known as unicellular organisms.8. Others are multicellular, composed of a number of cells.9. The activity of an organism depends on the total activity of independent cells.

Cytoplasm: All the living part of cell inside cell mem & excluding nucleus

Organelle: Specialized structure in cytoplasm of cell which carries out specific function

Eukaryotic: Internal mem systems; contains mem-bound organelles & nucleusOrganelles:

Nucleus: Enclosed by nuclear envelope [double mem]; often containing visible nucleoli > produce ribosomes; contains genetic materialEndoplasmic reticulum: forms an interconnected network of tubules, vesicles, and cisternae within cells. Rough endoplasmic reticulums synthesize proteins, while smooth endoplasmic reticulums synthesize lipids and steroids, metabolize carbohydrates and steroids, and regulate calcium concentration, drug detoxification, and attachment of receptors on cell membrane proteinsGolgi apparatus: Process and package macromolecules, such as proteins and lipids, after their synthesis and before they make their way to their destinationLysosomes: Digestive enzymesMitochondria: ATP, cellular respirationRibosomes: protein synthesisCytoskeleton: internal system of protein fibres & tubules that extends throughout cytoplasm of eukaryotic cell; composed of actin microfilaments, intermediate filaments & microtubules; gives shape to cell & provides support for cell extensions such as villi & axons of nerve cells

Both p & a have mem, cytoplasm, vacuole/vesicles, nucleus, ER, golgi ap, mitochondria, nucleolus, ribosome

Intro to Natural Selection

Evolution: Change, over time, in heritable characteristics of organisms, resulting in alteration of structure & fn, & leading to diversity of living forms

Adaptations: Features of structure & function which suit an organism to environment

Natural Selection-Preference of traits which aid species in survival – individuals with these traits more likely to survive & produce offspring (less preferable traits which do not aid in survival are not carried on as the individuals die off & produce less offspring).-Doesn’t create adaptations, but screens heritable variations in each generation, increasing occurrence of beneficial traits & eliminating less successful ones.1. Individuals in a pop aren’t identical; they vary (sometimes only slightly) in structure, fn, & behaviour2. Some variation heritable, determined by organism’s genetics (parent → offspring)3. All living things have tendency to overproduce (more produced than environment can support).4. Despite overproduction pop’s remain relatively stable ( many individuals fail to survive & reproduce)∴

5. Diff individuals leave different #s of descendants – depends on chance of survival to reproductive age, # offspring produced, & survival & reproduction of offspring. Individuals with characteristics that successfully adapt them to envi more likely to pass these traits on to next generation.∴

Descent with Modification-Changes arising via natural selection could lead to alteration of a population & eventually emergence of new species-Common ancient ancestor – as descendents dispersed into new habitats, they accumulated diverse adaptations fitting them to varying ways of life

Taxonomy & Systematics

Influence of Darwin’s work on biological classificationDescent from common ancestor (descent w/ mod) altered structure of classification system; evolutionary links between tiers; & natural selection

Phylogeny: evolutionary history of species or group of related species & line of descent of a species or higher taxonomic group

Systematics: Taxonomy which takes evolution into account

Artificial system of classification-classification that groups organisms together on basis of a few convenient characteristics rather than on the basis of evolutionary relationships-1 general fn: to serve as a practical aid in organizing & communicating info about organisms

Natural system of classification-a taxonomic classification that groups organisms or objects together on the basis of the sum total of all their characteristics, & tries to indicate evolutionary relationships-has same fn as a but in addition expresses a theory of relationships among organisms

Colonial: org consists of group of cells, tightly bound to each other, commonly forming sheets, balls, or threads; the cells aren’t specialized ( similar to each other in form & fn; each cell potentially free living if colony disturbed)

Organic cmpds: large, complex; contain C backbone; produced by living cells; requires E to make them; E released when broken down into io cmpds (store E); living cells made up of them (proteins, starch, fat, etc)

Autotrophic: capable of producing complex organic materials, such as sugar, from simple chemicals such as water & CO2, most commonly via photosynthesis

Heterotrophic: unable to synth complex organic materials from simple inorganic chemicals; these organic materials must be obtained in the diet

Absorption: digestive enzymes released outside body & digested nutrients taken in via absorptionIngestion: other orgs consumed whole or in pieces then digested inside gut

Mode of NutritionAble to Synth o cmpds from io

materialsE source C source

Photoautotroph yes light CO2 (io)Chemoautotroph yes io cmpds CO2 (io)Photoheterotroph no light ocmds

Chemoheterotroph no io cmpds ocpmds

Groups Cell Type (p or e) # Cells (uni…) Mode of NutritionArchaea

prokaryotic unicellular or colonialsome autotrophic, some

heterotrophicBacteria

Protistseukaryotic unicellular, or colonial,

some multicellularheterotrophic or

autotrophicAnimals multicellular heterotrophic by ingestion

Fungi heterotrophic by absorption

Plants autotrophic

Archaea & Bacteria

Origin of prokaryotic cells – 3.5 billion years ago↓ developed ability to photosynthesize; initially unicellular, some colonies

Origin of eukaryotic cells – 2 billion years agoOrigin of multicellular organisms – 1.2 billion years ago

Specialized cells working co-ordinately w/1 single organism

CharacteristicDomain

Bacteria Archaea EukaryaNuclear Mem absent absent presentMem-bound Organelles

absent absent present

Peptidoglycan in Cell Wall

present absent absent

Mem Lipids unbranched branched unbranchedRibosomes 70s 70s 80s

RNA Polymerases one several severalInitiator AA in

Psynthformylmethionine methionine methionine

Bacteriasuccess in #s & habitat range

1. Variety of nutrition, diff ways2. Asexual reproduction (quick)3. Respond quickly to external changes; rapid exchange of genetic material allows advantageous adaptations to spread quickly (eg resistance)4. endospores: special cells enclosed in hard wall; can survive harsh conditions (lack of nutrients/water, excessive heat/cold, poisons); open in favourable conditions5. existed long time → lot of time to adapt to diverse habitats

Structural characteristics used to distinguish among bacteriaCell shapeCell wall compositionMotilityMode of nutrition

4 roles of bacteria in biosphere1. pathogens

Diseases in plants/animals; grow in host; release poison or endotoxin when bacteria dies or exotoxins as bacteria grow

2. decompositionBreak down waste/dead plants/animals → return elements such as C, O, N to envi in forms that can be used by other orgs

3. fixation of io elementsEg. N in atmosphere converted to ammonia nitrate needed by plants

4. industrial usesInactivate contaminantsProduce chemicals (methane)Food products (cheese)Synth drugs/hormonesBreak down sewage

Protists

Symbiosis: close association of 2 diff sp’s living in direct contact w/ each other

Mutualism: mutually beneficial relationship b/w 2 sp’s whether or not sp’s are in direct contact w/ each other

Eukaryotes acquiring internal mem systems1. Infolding of plasma mem. By this process nuclear envelope, ER, golgi ap, & certain other structures may have formed

2. Endosymbiosis. According to endosymbiotic theory, chloroplasts & mitochondria are remnants of ancient prokaryotic cells that took up residence in other, larger prokaryotic cells. Possibly were parasites or were captured.

a. some present-day orgs have endosymbiotic relationships in which participants haven’t lost their separate identities. These relationships may resemble earlier stages in the evolution of eukaryotic cellsb. chloroplasts & mitochondria are very similar to certain kinds of bacteria. They’re the same size, have mems w/ molecular components resembling those of prokaryotic plasma mems, they have own DNA in form of circular molecule just as in prokaryotes, & they reproduce in the same way bacteria do (by a splitting process)

Ecologically they fall into 3 categories:1. Heterotrophs that feed by intracellular digestion2. Heterotrophs that feed by absorption3. Photoautotrophs

Green, brown, & red algae include some multicellular sp’s, mostly saltwater

Fungi3 ecological categories

1. Decomposers absorb nutrients from wastes or dead remains2. Mutualists absorb nutrients from living plant or animal organisms but benefit these organisms in some way3. Parasites or Pathogens absorb nutrients from living host, damaging or weakening it

Composed of tiny threads called hyphae (sing hypha) which pack tightly together to form a mycelium.

Have cell walls reinforced by chitin

Share more recent common ancestor (heterotrophic protest which lived in colonies) w/ an’s than w/ plants

Human uses1. Antibiotics2. Baker’s yeast3. Alcoholic beverages4. Flavouring5. Food

Vascular Plant Structure

Tissue: an aggregate of cells similar in structure & fn

1o cell wall-All plant cells-Materials secreted by plasma mem-Thin-Stretches easily as cell grows-Protects-Helps to maintain shape-Cellulose: long chainlike carbohydrate; major component in cell walls

2o cell wall-Some plant cells-At maturity-Located b/w primary cell wall & plasma mem-Usually more cellulose than primary-Contains lignin for strength & rigidity (next to cellulose most abundant large organic molecules in plants)

Middle lamella

Thin layer of sticky substances that glue the cells togetherIn some plant tissues it is also lignified

ParenchymaLiving cells, unspecialized in structure & fn, w/ thin, stretchy primary wallsMost plant cells start out asSome mature into other cell typesSome remain parenchyma entire life & carry out fns like psynth & food storageSome parenchyma cells are Meristematic

Able to divide to produce new cellsElongation of shoots & roots under control of apical meristem (apic = tip)Concentrations of meristematic parenchyma at root ends & buds of shoots

Usually large central vacuole at maturity

CollenchymaAlive at maturityLack 2ndary wallsPrimary walls irregularly thickened – additional strength while still stretchy for growthOften arranged in supportive columns in young growing stems

SclerenchymaThick, lignified 2ndary wallsUsually dead at maturityMost common forms are fibers (ex. hemp, jute, flax)Support in plant parts no longer growing

Tracheids & vessel elements (Water-conducting cells of xylem)Dead & hollow at maturity2ndary wallsTracheids

Long, tapered cells similar to the fibers of sclerenchymaWater passes from one tracheid to next via pits that penetrate cell wallsLignified walls provide support to plant

Vessel elementsMore efficient than tracheidsLarger diameterLarger holes in walls b/w adjacent cellsThinner walls thus less support than tracheids

Sieve-tube membersConducting cells of the phloemTransport sugars & other organic materialsAlive at maturityOnly primary wallsSimilar to parenchyma but lack a nucleus &

contain other certain organelles

Some plant tissues, ex. columns of collenchymas, only one cell type (collenchymas thus cell type and tissue type). Other plant tissues have several cell types; ex. angiosperms – xylem tissue has both tracheids & vessel elements & interspersed among the water-conducting cells other cell types like sclerenchyma fibres and parenchyma.

Nonwoody (herbaceous) eudicotIn middle of stem large region of parenchyma. In ring around parenchyma are vascular bundles, w/ xylem on inside & phloem on outside. B/w x & p & extending b/w adjacent bundles is narrow band of meristematic parenchyma: vascular cambium. In some eudicots cells of VC divide to produce additional x & p. V bundles may be capped by aggregation of

sclerenchyma. Cells on outside surface of stem, covered by waxy cuticle, form epidermis. Beneath epidermis are patches of collenchyma

In monocot stem vasc bundles scattered; no vasc cambium. Thus monocots unable to enlarge their stems by 2ndary growth. Only few species (ex. bamboo & palms) become woody, & way in which they produce wood has little in common w/ eudicot way.

Xylem & phloem form continuous conducting systems throughout body of vasc plant. Arrangement diff b/w roots & stems. No vasc bundles in eudicot root, instead xylem & phloem located in central cylinder called stele. Xylem typically forms an X shaped (or + shaped) figure in very middle, & phloem lies b/w legs of the X or +. Separating xylem & phloem is vasc cambium. Change in arrangement of tissues occurs in short transition zone b/w roots & stems.

Support in Plants

Gen adaptations plants have evolved as result of competition for light

Shade-tolerance: ability to grow & reproduce in dm light

Ability to colonize disturbed habitats (*shade-intolerant)Structures & mechanisms for support of plant body (xylem)

Parenchyma & other cell types w/ flexible cell wall provides mechanical support through turgor pressure (force exerted by the fluid contents of a cell against its wall) by pushing adjacent cells tightly together.

Adaptations of plants for climbingTendrils: slender coiling structures- modified leaves or stems (ex grapes, garden peas)Twining stems: ex kiwis, scarlet runner beansAerial roots: above ground roots (ex English ivy)Barbs: spines/thorns (ex roses, blackberries)

Plant Kingdom

Resources req by plants1. Light psynth2. CO2 psynth3. Oxygen cell resp4. Minerals contain various elements needed by plants5. Water basic medium in which chem. Processes occur & reactant in some processes

4 major events in evolution of plants1. evolved from aquatic green algae ~500 million years ago; were terrestrial

2. evolution of vascular plants (plants that have tissues specialized for transport: xylem transports water & minerals & phloem transports sugars & other o materials)3. evolution of seed plants (gymnosperms & angiosperms)4. evolution of angiosperms (evolution of flowers & fruits; some attract animals as pollinating agents)

Nonvascular plantsMosses: Upright posture w/ stem-like & leaf-like structures; anchored to ground by rhizoidsLiverworts: Simpler body, lacking stem-like & leaf-like structures, that’s flattened to ground

Ferns→Spores (single-celled reproductive structures carried away by wind) produced on underside of leaves

Characteristic Gymnosperms AngiospermsDiversity ~800 sp’s more than 250k sp’s

Gen Morphology woody sp’s both woody & non-woody sp’s

Leavesusually needle-like or scale-

likeusually flattened (“broad-

leaved” plants)Seeds naked enclosed in fruit

Pollen Transport windwind in some sp’s, animals in

many others

Water Habitat Land HabitatWater

availabilityclose to ea cell

below land surface; evaporates quickly above

Minerals close to ea cell on or below land surfaceGases dissolved at low conc plentiful in air

Support provides buoyancy & support much less support of plants

Lightcuts out some wavelengths & lowers

intensitymore light available

Temp little fluctuation, slow change changes more rapid, wider extremesReproductio

nmotile gametes swim

water seldom available for swimming gametes

Dispersal water carries offspring to new locationwater seldom avail to carry offspring to

new locations

Problem Adaptation of land plantsobtaining water & mineral nutrients when they no longer surround

entire plantroots

transport of water w/i plantxylem

supporting body in medium lacking buoyancetransport of food from sites of manufacture to sites of use phloem

preventing evaporation from surfaces exposed to air cuticleobtaining gases for psynth & respiration stomata

obtaining sunlight for psynth leavescoordinating plant growth & response to changes in envi hormones

getting gametes together w/o reliable supply of water for sperm pollendispersing new individuals to suitable locations airborne spores & seeds

Population: interacting group of individuals of same sp’s

Community: populations of all sp’s in an area

E.syst: interacting biotic & abiotic components of an area; dynamic

Eco.succession: predictable series of communities that replace each other in an area

Climax community: relatively stable community that arises after gen climatic conditions of area remain the same (making succession slow)

Biome: major type of e.syst; classified on dominant vegetation

iocmpds: small, simple; abiotic

ocmpds: structural materials found w/I living cells; provide E used by cells

Biogeochemical cycle: pattern of movement of an element from abiotic envi through living producers, consumers, & decomposers back to envi

BiomeSeasonal

CharacteristicsDominant Vegeation

Soil Characteristics

Common Plant +

Adaptation

Common Animal +

AdaptationTundraTaiga

(Coniferous)Temp

RainforestTemp

GrasslandTemp Decid/

Broadleaf ForestDesert

Tropical Rainfoirest

Gen process of E flow in e.syst

Sunlight –(converted by photoautotrops)→ chem. E (in bonds of molecules) –(cell resp)→ heat (which dissipates from e.syst)

Food chain/web: desc. Path E takes as it moves from 1 org to the nextFood chain: 1 sequence of orgs through which E can moveFood web: several paths (interconnecting food chains)

Detritovore (ingestion) & decomposer (absorption): feed on dead tissue of level below; operate at all T.lev’s

Gross 1o production: Amount of light E converted to chem. E by pa’s during given period

Net 1o production: (g1op – E lost as heat through cell resp); Amount of E avail to 1o consumers

Psynth: CO2 + H2O + sun E → C6H12O6 (sugars) + O2

Cell resp: C6H12O6 + O2 → CO2 + H2O + E (ATP & heat)

W5

Nutritional reqs of ht’s: o substances & io minerals

Digestion: enzyme catalyzed process of breaking down food into molecules small enough for the body to absorb

Ingestion: food taken into a gut or gastrovascular cavity where enzymes carry out extracellular digestion

Endocytosis: plasma mem folds inward, closing particles of food in a pocket which then pinches off to form food vacuole which then fuses w/ lysosome & digestion is carried out by lysosome’s enzymes

Evolutionary trend in animals from intra- to extra- cellular digestion: ancient protists fed by endocytosis, as did 1st animals (intracellular digestion w/ aid of lysosomes) ( majority of modern animals feed by ingestion, only sponges now rely entirely on intracellular digestion)

Ecological significance of trend: animals have diversified into wide range of consumer rolls (many ways of feeding on large pieces of food) from protest-like ancestors that could only feed on microscopic particles of food

structure fnoral cavity physical break down by teeth; saliva chemically digests starch

stomachstores food; physical breakdown by churning; chem d by cell lining secreting gastric

juice (HCL, pepsin→chem d of protein)liver produces bile (emulsifies fat, which increases SA→easier to d

gall bladder stores bile

pancreassecretes bicarbonate ions to neutralize acidity in duodenum; enzymes secreted break

down starch & other large carbohydrates & fat

small intestinedigestion completed in SI; digested nutrients absorbed into blood; secrete some

enzymes

4 adaptations of human SI for absorption of digested nutrients: long, folded, villi, microvilli

Fns of human LI: absorption of water; excretes certain salts when they’re too conc’d in blood; synth of vitamins (by bacteria); rectum holds feces until elimination

mutualism both sp’s benefit + +commensalism one sp benefits, other sp unaffected + 0consumer-resource

one sp benefits, one sp harmed

+ -

parasite/hostpredator/prey (kills host/prey)parasitoid/host (kills host/prey)herbivore/plant

competition both harmed- -exploitative

interference

Interference competition: interaction b/w 2 sp’s in which the use or defense of a resource by each sp reduces the amount of that resource that’s avail to the other sp; physical interactions

Exploitative competition: both sp’s suffer b/c they share limited resource; use of the resource by 1 sp leaces less to be used by other sp; no physical interactions

True predatorscarnivores that kill their prey before consuming it; usually animals

Insect parasitoidsMainly wasps & flies; lay eggs in/on/near other insectsTheir larvae consume the living tissues of the hosts, eventually killing them

Herbavores & parasitesdamage their hosts but don’t necessarily kill themh-animals that eat green plants or seeds/fruitsp-can be from any of the kingdoms; often complex life cycles w/ several hosts

detritivoresno direct effects on the pop’s that provide them w/ foodfeed on dead o material

plant & animal defenseschemicals that deter consumers or are poisonouscamouflage/cryptic colouring to blend inwarning colourationmimicry

Animals

Evolved from an-like protists“colonial” hypothesis: colonial protozoan evolved into an when its unspecialized cells began to take on diff structs & fns; protozoan ancestors of an’s: choanoflagellates

For animals that have controlled locomotion it’s advantageous to have 1 end of body specialized for going in front → typically equipped w/ sense organs for detecting food, predators, & other impt features of envi, w/ a conc of nerve cells (brain) to receive & interpret messages from sensory devices, & w/ mouth & other feeding structs. In an an w/ head & moves undirectionally, bilateral symm is efficient, balanced design for entire body. Echinoderms revert to radial symm →suggested earliest echin’s were non-motile ans & radial symm gave advantage of facing evnvi equally in all directions

Phylum Symm #gut open’s body cav level cmplx

other

Porifera asym 1* spongocoel cellsCnidaria rad 1 gv cav tissuesPlateyhelminthes bi 1 gv cav osystNematoda bi 2 pseudoc osystMollusca bi 2 body cav osystAnnelida bi 2 body cav osystEchinodermata rad 2 body cav osyst

Chordata bi 2 body cav osystNervous System

neurons: individual nerve cellscell body: where organelles of a neuron, including nucleus, are located; long extensions of plasma mem branch off both sides of cell body…dendrites: receive signals from receptors or other neurons & carry them towards cell body; in gen highly branched & relatively shortaxons: transmit messages from cell body to other nerve cells or effectors (muscles & glands); in gen longer & branch only close to terminal end (at end of branches are swellings: axon terminals)

Sensory neurons: carry info from P receptors on surface of body or embedded in organs to brain and spinal cord of CNS

Interneurons: in CNS, connect nerve cells, form complex pathways that enable animals to perceive incoming stimuli & initiate responses; in brain responsible for coordination of

responses & higher fns (thoughts & emotions)

Motor neurons: transmit info out from CNS to P effectors (glands & muscles of body)

When impulses reach axon terminals they trigger release of neurotransmitters (common NTs: acetylcholine Ach & norepinephrine/noradrenaline). NT released into synaptic cleft (small gap b/w terminal & dendrites of another axon); NT picked up by dendrites, initiating electrical response in 2nd neuron. If nerve terminates at muscle or gland NT triggers response in that tissue. Transmitter can have either excitatory or

inhibitory effect depending on type of receptor it acts upon.

Reflex arcStimuli from receptor initiate electrical impulses that are carried by sensory neuron to spinal cord. NTs released from axon terminal of sensory neuron excite motor neuron which carries impulses to muscle. Release of NT from this P neuron causes muscle to contract, correcting the original thing. Protect body from injury & assist in balance. May also stimulate interneurons which carry signal to brain.

Cerebral spinal fluid circulates through centre of nerve cord, carries nutrients & hormones throughout brain & spinal cord; removes wastes & provides cushioning.

MeningesL: 3 mems around brain & spinal cordF: Protection from injury

-Outermost mem is tough

Peripheral NS Central NS (made up of brain; & single hollow dorsal nerve cord which integrates simple responses such as reflexes & carries info to & from brain)

Somatic NS Autonomic NS

Sympathetic NS Parasympathetic NS Entericl NS

Vertebrate NS

-Cerebral spinal fluid(CF) b/w mems acts as shock absorber

VentriclesL: 4 fluid-filled cavities in brain, continuous w/ central canal of spinal cordF: CF acts as shock absorber Nutrition- circulating CF comes from blood capillary networks over ventricles

Cerebrum (cerebral hemispheres)L: 2 very large hemispheres in anterior forebrainF: Perception & interpretation of sensory impulses Association of impulses concerned w/ emotion & intelligence Motor fn controlling muscular movement

ThalamusL: 2 swellings, 1 in each side of posterior forebrainF: Relay station for all sensory impulses to cerebrum Some sensory impulses like pain, temp, & touch interpreted here

HypothalamusL: Below thalamus, above pituitaryF: Control of autonomic NS & so regulates heart rate, norm body temp, water balance,

movement of food through digestive tract, thirst, sleep, etc Carries messages b/w NS & endocrine syst (2 major control systs of body); lies

above pituitary & releases chems which stimulate or inhibit the pituitary

CerebellumL: Large butterfly shaped structure just below posterior portion of cerebrumF: Coordination of muscular movemens (make movements smooth not jerky) Maintenance of posture Maintenance of equilibrium (balance) by using info from inner ear

Brain StemL: Consists of midbrain, pons, & medulla oblongataF: Conduction pathway for motor & sensory impulses b/w cerebrum & spinal cord

MidbrainL: Short region posterior of thalamusF: Reflex centre for movements of eyes & head in response to sight & sound impulses

PonsL: Forms floor of anterior hindbrain; b/w medulla & midbrainF: Bridge b/w cerebellum & cerebrum & bridge b/w medulla & midbrain; all sensory fibres to cerebrum & motor fibres to spinal cord pass through it Has pneumotaxic centre which regulates respiratory centre in medulla

Medulla OblongataL: Last part of brain, just above spinal cordF: 3 vital centres located in medulla

Cardiac centre which regulates heartbeatRespiratory centre which regulates rate & depth of breathingVasomotor centre which regulates BP by controlling diameter of blood vessels

Location of entres for some reflex actions such as swallowing, sneezing, & vomiting

PNS lies outside brain & spinal cord; 2 divisions: somatic & autonomic NS; each div subdivided into sensory/afferent div carrying impulses from receptors to CNS, & motor/efferent div carrying impulses away from CNS.

Somatic: sensory neurons carry impulses to CNS from somatic receptors in head, limbs, & body wall & from specialized organs for hearing, vision, taste, & smell. Motor neurons carry impulses from CNS to skeletal muscles where they release NT acetylcholine which causes muscles to contract. Conscious control/voluntary.

Autonomic: 3 divs: parasympathetic, sympathetic, enteric. Autonomic sensory neurons carry impulses to CNS from autonomic sensory receptors in visceral organs. Autonomic motor neurons conduct impulses from CNS to glands, smooth muscle in visceral organs, & cardiac muscle in heart. Involuntary/not under conscious control

Symp & parasymp systems include 2 neurons & 1 ganglion. Ganglia: collections of cell bodies w/i peripheral NS.

Enteric: SNs carry impulses from gastrointestinal tract to CNS. MNs carry impulses from CNS to smooth muscle & glands of gastrointestinal tract, stimulating contractions of muscles in lining of gut as well as release of hormones & digestive secretions

Sympathetic: usually predominates during periods of stress or emergency, initiating ‘fight or flight’ response. Sympathetic nerves release

norepinephrine/noradrenaline causing increased heart rate & constriction of blood vessels (↑BP), widening respiratory pathways allow greater air flow into lungs, & stimulating release of sugars into blood for E production. At same time signals from symp syst inhibit activity of digestive & sexual organs

Parasympathetic: neurons release acetylcholine. Slows heart rate, constricts respiratory pathways, stimulates activity of digestive & sexual organs. Gen involved in relaxing body & homeostasis.

Constriction of blood vessels & activity of sweat glands controlled solely by sympNS as is mobilization of sugars & fats for E production

Medulla oblongata responsible for autonomic output regulating respiratory, cardiovascular, & digestive fn. Hypothalamus crucial for many emotional & behavioural responses. Changes in BP, heart rate, & breathing associated w/ changes in emotional state are due to action of hypothalamus on the medulla oblongata which in turn acts via autoNSb

Diff. b/w Phylums

Ph. Cnidaria-Diffuse system of nerve cells that covers body-Nerve impulses can travel in either direction along each fibre of nerve net-Stimulation of any part of body sends messages across entire surface initiating response from entire animal

Ph. Platyhelminthes-Nervous impulses conducted in 1 direction along nerve fibres → allows info to be transferred to specific set of nerves or muscles-Nerve fibres groups together into pairs of longitudinal nerve cords that run down ventral (lower) surface-Clusters of nerve cells in anterior region act as primitive brain → receive input from sense organs & cont. movements of body; increase ability to monitor changes in envi & respond

Ph.’s Annelida & Arthropoda-Brain larger, more complicated; small clusters of nerve cells called ganglia located in each segment along longitudinal nerve cords; results in greater degree of coordination

Locomotion

Specialized muscle cells containing contractile fibresMuscle cells can actively contract, causing them to shorten in length

Relaxed fibres can be lengthened but only if pulled by some external forceTherefore active contraction of muscle fibres, not lengthening, which work of movement & locomotion

Cnidaria – like hydra, sea anemone-Hydrostatic skeleton → fluid-filled gastrovascular cavity for support-Polyp-have contractile fibres in cells of both outer & inner tissue layers but they develop differently from the true muscle cells in other phyla → longitudinal & circular-nerve net (entire organism responds to a stimulus)-when pissed off, tentacles retracted or brought inside gastrovascular cavity, and body column retracted-Hydras and some sea anemones can move slowly over rocks and sea or stream beds by various means: creeping like snails, crawling like inchworms, or by somersaulting. A few can swim clumsily by waggling their bases

Annelida - earthworms-Hydrostatic skeleton → fluid-filled body cavity (coelom) b/w body wall & gut for support-Earthworms travel underground by the means of waves of muscular contractions which alternately shorten and lengthen the body. The shortened part is anchored to the surrounding soil by tiny claw-like bristles (setae) set along its segmented length. Aided by the secretion of lubricating mucus.-NS: segmented; brain directs responses to stimuli; double ganglia along nerve cord → coordinate alternate contraction of longitudinal & circular muscles-segmented: repetition of series of ~similar sections (segments) along length of body-true muscle cells: longitudinal & circular muscles

Arthropoda-Exoskeleton composed of layers of protein & chitin (material similar to cellulose) enclosing body-Vary in thickness: some regions thick & rigid, others (like joints) thin & flexible-Impermeable to water-insertion end of muscle often joined to a long tendon which is attached to exoskeleton

Flexor: muscles which contract to bend limbExtensors: muscles which contract to straighten limbOrigin: end of muscle attached to stationary part of exoskeletonInsertion: end of muscle attached to part of skeleton that moves

Vertebrates have rigid endoskeleton composed of bone & cartilage which is surrounded by muscles

Cartilage-Contains living cells embedded in fibrous extracellular matrix of collagen fibres (a flexible protein)-Not as rigid as bone-Used to provide cushioning (ex. in disks b/w vertebrae of backbone) & flexibility (ex. costal cartilage b/w ribs allow movement of rib cage-on ends of bone to prevent wear-b/w bones to increase stability

BoneContains living cells embedded in extracellular matrixBone matrix consists of

1. Collagen fibres2. Inorganic materials, mainly calcium phosphate, which gives rigidity & strength to bone

Axial skeleton-Forms central axis of body (skull, rib cage, vertebral column)-fn: protection & support (brain, spinal cord, organs…)

Appendicular skeleton-Consisting of appendages (limbs) & bones that attach them to spine (pectoral girdle for forelimbs, pelvic girdle for hind limbs)-fn: locomotion & interaction w/ environment

Homologous structure – structure of organisms that is derived from a common ancestor

Analogous structure: similarities in structure b/w organisms that were not in the last common ancestor of the taxa being considered but rather evolved separately

Movement in vertebrates result of skeletal muscles acting on bones. Not all skeletal muscles move bones, some stabilize joints, others move skin of the face.Skeletal muscles share 2 common characteristics:

-contractile -using E supplied by metabolism, muscle fibres can shorten)-extensible-if pulled on by outside force they can be stretched

skeletal muscle smooth muscle cardiac mucle

location attached to skeleton most internal organs heartnervous control somatic NS autonomic NS autonomi

c NScell shape long, cylindrical spindle-shaped, tapered

at both endsbranched & woven together

striations (bands)

yes no yes

# of nuclei/cell several one one

Ligaments: long bands of fibrous connective tissue binding bones together

Tendons: bands of fibrous connective tissue connecting muscles to bones; when muscles contract they shorten, causing tendon to pull attached bone towards muscle

Bursae: fluid-filled sacs that ease friction b/w moving parts of joint; 13 bursae in knee joint

Arrangement of muscles

arthropod both vertebrateare inside of skeleton

antagonistic muscles attached to skeleton

are outside of skeleton

hydrostatic exoskeleton endoskeletonstructure fluid-filled compartment of an

animal, muscles change its shape

hard encasement deposited on animal’s surface

hard supporting elements (such as bones) w/i soft tissues of an animal

advantages flexibleregeneration

impermeable to waterprotection

mobilitysupport larger organisms

disadvantages no protection from water losslittle protectionheavy

limit size of organismheavymolting

no protection from water lossless protective