Lecture Notes Midterm To Final (6 12) Biol 1902 PDF

Preview

Summary

Lecture 5b - Environmental StressesSub-zero temperatures – cause two types of problems for animals Warmth A few more ways endothermic animals stay warm: -On cold days animals can bask in the sun (ex grouse) -Drop down their body core temperate by 12 degrees c (less heat is lost because there is less...

Description

Lecture Notes Midterm-Final Lecture 5b - Environmental Stresses Sub-zero temperatures – cause two types of problems for animals 1. Warmth A few more ways endothermic animals stay warm: -On cold days animals can bask in the sun (ex.ruffed grouse) -Drop down their body core temperate by 12 degrees c (less heat is lost because there is less of a gradient of change (hot and go outside, it’s a shock). There is a cost! = cannot stay awake very well = TORPOR. (in torpor?=torpid) SHORT TERM DORMANCY -Dangers to Torpor= not as aware of predators, body temp gets to critical level Other animals go inactive! Freeze Avoidance -Go to a place where it stays above zero “frost avoidance” -Frogs go to the bottom of ponds (bullfrogs) -Snakes go in the ground below the frost line -“Hibernaculum”=place of hibernation -Turtles go to the bottom of ponds, preferably ones with moving water to get oxygen -Toads and salamanders dig 2. Mobility Physical adaptations - Long legs (ex. moose) - Large paws – bigger surface area (ex. Hare) - Deer and caribou have large surface area in feet and split toes - Bigger wider hoofs in caribou to make up for small legs - Large hind feet (weasels) - On birds – foot covering act as snowshoes (thick feathers of Ptarmigan) - Large feet of Ruffed grouse, grow snowshoes for winter only in form of scales on toes Behavioural Adaptations - Subnivean space under snow used as travel Choose a place where there is less snow (ex. white tailed deer move to sheltered area “yard”). In this “yard” ___ Browse line identifies deer yard. - Wolves – travel in a trail to break the snow - Otters have short legs and do a lot of traveling on land over winter – slide on their bellies! (called tobogganing) Mink do this too. Another way to solve winter problems: MIGRATION This solves food, mobility, warmth problems! -Birds- often fly to south America (Brazil) Ex. World champion Migratory bird ARTIC TERN 20,000 roundtrip each year - power the flight through fuel (stored fat subcutaneously – because more energy) - Most song birds travel at night so as to not overheat, the wind is not as strong at night (calmer, cooler, safer) - Some fly only in day time (ex. Hawks) because hitch a ride on thermals and soar “Thermal hop” for hours without flapping wings once. Soaring is up, and gliding is down - Roller coaster flying “bounding flight” (by smaller birds) - Humming birds fly during the day time as well. (feed off of flowers all the way south) - Day flyers: Black birds,

Lecture Notes Midterm-Final -

-

How do they find their way?? Daytime: visual cues ex. Coast of north America, mountain ranges, the sun. Nighttime: stars, constellation patterns, earths magnetic field. Some birds fly both at day and night Sandpiper flew 8 days (5100km) straight! (Redknots) Rhodopsin – a photo pigment in the eye is likely involved with electromagnetic interaction Banding reveals migration secrets (tracking device) Migration, partly learned, partly prgrammed (time programmed, direction learned V shaped flock conserves energy

-Monarch butterflies- when they leave they never come back. Lay their eggs and slowly move north and start process again. Go to Mexico! Lake Ontario and Erie you will see a lot of them. -Dragonflies (Green Darner)- down toward eastern seaboard PLANTS – how do they survive? - Ice inside cells kills plants… - solution 1: Go dormant underground and stay in a warmer enviro under the snow. - Solution 2: plants become cold hardy (similar to freeze tolerance in animals) Take water out of branches leaves etc or allow water to evaporate which increases solute concentration. This depresses the freezing points. Add sugars to depress freezing, unsaturated fats(don’t freeze as fast) surround membrane cells because ice cannot penetrate the cell membrane. Make the cell walls more bendable. -

-

-

-

-

This process is called ACCLIMATION. Two stage process. Step 1: triggered in a change in the photo period (the changes in the sun) how do plants sense this?? Being researched currently. Phytochromes = light sensitive photo pigments and cells go dormant and plant becomes sensitive to temp. Chemical process Step 2: triggered by cold temperatures (colder rains, cooler nights etc) Some trees can stand cold to -80 degrees Celsius!!!!! Ever greens: Keeping needles creates problems (more exposure to cold temp; solar radiation. Xanthophyll pigments help to protect this) SKUNK CABBAGE: generates heat to melt snow around it (a living thermostat) Problem 1:Desiccation “aka drying out” (coniferous trees) the worst temp= sunny and calm Conifers size and shape is very important to retain water(short and small needles) Close stomata to retain stomata HEATH PLANTS – retain leaves but have hairy undersides to trap moisture FERNS curl up for the winter to retain moisture Short branches solves problem 2 Some shapes shed snow with their short branches. BALSAM FIR have a spire shape BLACK SPRUCE are spindly ----- these shapes help shed snow! (problem 2) -----butttt Christmas trees!  Deciduous trees Drop their leaves! Colours already inside the leaves, green chlorophyll covers the colour, so in fall when chlorophyll breaks down and true colours show. Red is manufactured – generates heat (an adaptive colouration- is manufactured at the end of summer. Eg. RED MAPLE (some are yellow, some turn red) different sexes! Female: leaves are yellow; males turn red!! Second problem: Weight on limbs- loss of leaves helps for deciduous

Lecture Notes Midterm-Final Heat can cause a problem too! Plants Problem 1: Dessication - To solve: Curl leaves up, close stomata, go into dormancy - Abscisic (ABA) Acid – induces dormancy in plants in times of drought Animals -

-

Seek shade, become inactive, move to where it is cool Surface area reduced in contact with the sun DRAGONFLIES: change their posture (back end up in the air for shade – called obelisk) TIGER BEETLES: move bodies away from heat by “stilting” (extend legs like stilts) or borough Liquids in body hold more heat, loose heat? Shove blood to extremities  DRAGONFLIES push blood into abdomen  DUCKS – countercurrent in legs – put more blood into it (reverse of winter)  BEAVERS: shove blood into big tail HONEYBEES: different, work together to keep nest cool. Two groups, one near the outside, and one near the babies, cool babies by creating a fan with their wings! “Aircool” FOXES/ MAMALS: panting is a form of evaporative cooling. BIRDS: pant too! BOOBIES (birds): Gular Fluttering – vibrating their throats to cool the blood BEES: Uses evaporative cooling using nectar TURKEY VULTURES: unusual way of evaporative cooling: Pee on their legs MOURNING DOVE: uses hyperthermia – raise their body temperatures (mid 40’s) one more degree would be fatal to them.

Lecture 6a – A Resourceful Menu (Herbivores) Challenge number 2: Nutrition Plants produce: Autotrophs - Need chlorophyll – raw ingredients Animals consume 1. Eat plants “Herbivory” - Seeds, nectar, sap, leaves, bark, roots, every part of the plant is eaten - MAPLE SPINDLE GALL MITES: eat leaves from the inside - Some eat dead plant material – these animals are called “DETRITIVOREs” - MILLIPEDE: eats pollen near water in the spring - WORMS are detritivores - BLACKFLY LARVAE: cling to rocks or beaver dams with their back end and steadily use labral brushes to sweep food into their mouths “FILTER FEEDING” - Larger animals filter feed – MALLARD, DABBLER, and PUDDLE DUCKS. Filtering part of the bill called Lamellae. The tongues help in this process too! - Need adaptations to eat nectar : proboscis (tongue to suck up nectar), HUMMINGBIRDS and WOODPECKERS have “Hyoid process”: Muscles that shove the tongue out and pull it back in again - an adaptation for getting nectar. - Another filter feeder, FILTER SPONGE - Bugs have probing mouthparts called “stylets” APHIDS, -

Plant tissues are another source of food! Hard to eat because of the structural components (cellulose)

Lecture Notes Midterm-Final Challenge one: ingestion -SLUGS and SNAILS break off plant tissues with “radula” inside their mouths – its like a chainsaw! -CATERPILLARS have external “mandibles” -Leaf blotch miner (moth larvae) eats leaves inside out -MAMMALS use modifies teeth to ingest- 2 sets of teeth: 1. Incisors to bite off, 2. Molars to grind. Need to keep sharp: keep growing, and self sharpen. Yellow is enamel, therefore durable. To power, need strong muscles: front teeth powered by “temporalis” back teeth driven by masseter” -GROUSE eat a lot of buds (plant tissues) -SPRUCE GROUSE eat conifer needles but birds do not have teeth… gizzards do this function! (a part of the stomach) MANDIBLES, RADULA, CHEEK TEETH, GIZZARDS = all do the same thing! But are not physically the same “ANALOUGOUS STRUTURES” Challenge two: digestion -need digestive enzimes -SLUGS and SNAILS can produce the digestive enzymes - Caterpillars waste a lot! - MOOSE, DEER, have a 4 parted stomach and get help from bacteria living in their “rumen”(main chamber in the stomach). Then regurgitate and chew food again (cud) -HARES, BEAVERS, have intestinal pouches called “caeca” where bacteria lives and processes food further. Poop and then eat again and then this poop is hard and no more nutrients “coprophagus”= animals that eat their poop. -Birds have caeca as well -PORCINES – do not eat droppings- have a large intestinal track – makes up ¼ of mass Fruit is another main source of nutrients for birds and animals - Full of sugar and carbs - Most animals only want the pulp or flesh and pass out seeds Eating fruit and eating seeds are two different kinds 1. Seed predators - FINCHES eat seeds “seed predators” - EVENING GROSBEAK have massive conical bill for crushing seeds – built in can opener to slice off coating to get to seeds - GOLDFINCH have small fine bills to get into thistles and pull seeds out - CROSSBILLS (white / red beak) to get into cones (are nomadic) - Different kinds of bills to get at certain types of seeds “Niche Partioning” - BLUE JAYS pound seeds open: ex acorns 2. Seed dispersers - Passing out seeds – dispersing seeds ex. BEARS - Those who eat fruit eat when its available only ex ROBINS - WAXWINGS eat fruit year round – eat berries whole because need to eat a lot of them – have adapted large gapes and short intestines – 20 minute digestion Plants also have chemical defences-- Animals overcome this in many ways: - MONARCH caterpillars sequester the toxins - OTHER CATEPILLARS Have a saliva to neutralize toxins

Lecture Notes Midterm-Final -

-

MILKWEED BEETLE cuts off the supply of chemicals to an area of the plants they are eating (vein draining)*** GROUNDHOGS have enzymes to neutralize the toxins they consume (specialized and general). “Mixed function Oxidases MFO’s” Some herbivores are specialists (ex. PINE SAWFILES eat only pine needles) Others are generalists (ex. BEAVERS eat a large variety of plants) Others switch their foods seasonally to gain a varied diet Ex. MOOSE: spring= fresh growth; winter= balsam fir; but these are very low in sodium…. Therefore in summer they eat aquatic plants! Which are full of sodium and store it in the rumen fluids (**Rumen= bacteria breaks down food that animal cannot digest soooo bacteria in exchange gets free room and board**)… also in early spring go to road side edges to obtain salt

Lecture 6b – A Resourceful Menu (Predatory) Recap: 1. Animals eat plants… 2. Eat other animals Advantages Disadvantages *Proteins are already packaged (much more return *Can be hard to find for effort) *Can be hard to catch – a lot of energy to catch *Animal tissues are easier to digest *Animals can physically fight back

Lecture 7a – A Resourceful Menu Continued (Predatory) Animals eating animals: Predation Some eat from the inside while the animal is still alive! AHHH (Parasitiods) Others eat without killing the animal! (ex. ticks) Others eat animals that are already dead – Scavenging Three challenges to eating animals: Locate, Capture, Immobilize 1. Locate Adaptations for locating prey: Visual - Must have keen eyesight (ex HAWKS: have a large number of cones for sharp vision. Also have a dense pack of cones in the back parts of their eyes (“fovea”) - Eyes are more towards the front of the head for depth perception! To judge how far away prey are. - Hunting at night (Ex GREAT GREY OWL= Eyes are large and have lots of “glycogen rich” rods for sensitive vision . Owls have the most frontly placed eyes which creates a disadvantage therefore have developed 270 degree neck rotation “Crepuscular” active in low light conditions. - Eyes are adaptations too! OWLS Magnified 2-3 times. TIGER BEETLES have compound eyes - GROUND BEETLES are nocturnal - DRAGONFLIES are visual hunters- can have as many as 28,000 individual eyes (ommatidia)! One big picture, but highly refined - WHIRLIGIG BEETLES can see above AND below the water at the same time! (eyes are half above and half below the water) - SPIDERS have 8 individual eyes (simple NOT COMPOUND). Front eyes (in the middle of the front of the face – Anterior median eye) Middle eyes; back eyes == the field of view is whole! NO blind spots! Can move their retinas position to change their field of view - JUMPING SPIDERS, CRAB SPIDERS are visual hunters

Lecture Notes Midterm-Final Adaptations for locating prey: Hearing - FOXES have large ears to magnify sound - OWLS hear very well, but have no external pinnae! They hear with their faces (dish shape gathers sound) The rings help direct the sound (facial disks) the ear openings are on the side of the head. One is higher than the other. To create crosshairs to allow pinpointing of sound (sound comes to one ear before the other) 300 thousands of a second. The more nocturnal the animal is, the greater asymmetry of the ears A call to attract: Squeaking/Squealing: Magnet for hawks, owls, wolves… -

-

BATS: use sound to find their prey: echolocation. 1st search phase 2nd approach phase 3rd feeding buzz (the highest frequency) Need these different phases because the higher the sound, the shorter it travels. If youre searching, need to go far enough ahead of you. Shrews also use echolocation (ultrasound)

Adaptations for locating prey: Smell (olfactory) - Foxes have long snout to analyze scents - Vomeronosal organ (aka Jacobson’s organ) for better scent analysis (in nose) and finer discrimination of odours (snakes forked tongue) - Certain times are better for hunting (sunset) Why? Less wind. Cooler. When an animal walks around, leaves scent molecules and rise into the air, butttt at dusk, cooler air does not rise and scent trail is easier to follow! Adaptations for locating prey: Tactile - RACOONS have touch sensitive paws - OTTERS have tactile sensors around the mouth (whiskers called “vibrissae”) to find food FOXES, and many mammals also have these - EASTERN WHIP-POOR-WILL have “bristles” much like vibrissae around the mouth “Rictal bristles” SAME STRUCTURES THAT LOOK ALIKE BUT ARE DIFFERENT STRUCTURES = ANALOGOUS - STAR NOSED MOLE have weird noses - Imeres organs – in nose - SANPIPERS have tactile senses in their bills! => “herbst corpuscles” in the tip of their bills - DUCKS (at the end of there bill) the “nail” of the bill has sensory cells - WOODPECKERS have “herbst corpuscles” in their tounges Adaptations for locating prey: Heat sensors - SNAKES have heat sensors “heat pit” to locate prey and can notice a fraction of a degree change. Can also aide in finding shade 1.1 Active Searching - Hunting - Ex WOLVES, TIGER BEETLES, SOME SPIDERS 1.2 Ambush Hunting - Using crypsis to wait for food - Ex MANTIDS, OWLS, CRAB SPIDERS, 1.3 Trapping - Creating traps to obtain food (flight intercept traps) - Ex WEB BUILDING SPIDERS

Lecture Notes Midterm-Final “Flight intercept traps”  orb weavers – normal webs  funnel weavers- spiders wait in the end of the funnel for something to hit it  Sheet web spiders- web contains knockdown strands which when they hit it, fall into capture sheet  Why are webs highly visible at dawn? Webs attract due – webs absorb moisture “hygroscopic” to remain flexible and becomes invisible after sucking up moisture  Some webs can be stronger than steel! Can stop a bird in flight  Webs contain 6 + types of silk  Spiders recycle their silk from broken webs  To build a complex orb web takes … 20 minutes on average! WOW!  ARGIOPE (garden spider- orb weaving spiders) – structure was thought to stabilize web “stabilimentum” … but actually reflects ultraviolent rays and attracts insects -

-

“Pit fall traps”  MOLE traps  ANT- LION Larvae- prey falls into sand pit and ant lion larvae inject poison in them “Aggressive Mimicry”  Fireflies – females attracting the poisonous males  Fish in finding nemo

2. Capture - OWLS and HAWKS use their talons - OSPREY have special feet for catching fishies – rough feet for a better grip; and a reversible toe for a better grip - OWLS have an opposable toe - SPIDERS use their legs - PRAYING MANTIS have raptorial legs - FOXES use their mouth - TIGER BEETLES capture with their mandibles (mouth) - DUCKS – bills modified with tooth like projections for grabbing fishes - FROGS use their tongues – extensible and sticky saliva– “ tongue flick” and so do WOODPECKERS 3. Immobilize Once captured a prey must be killed - FOXES, COYOTES use a “shake and break” technique - WOLVES use a “slash and shock” because search for larger prey - Carnivores must have large “canines” and strong “temporalis” (muscles that power mouth) - WEASLES bite into the cranium - CATS bite into the neck vertebrae - SNAKES  some swallow their prey whole  BLACK RAT SNAKES, MILK SNAKES are constrictors  MASSADSAUGA RATTLESNAKE uses poison that immobilizes and injects digestive enzymes  CRAB SPIDERS and ASSASSIN BUGS do the same thing - ROBBER FLIES inject their prey with poison that immobilizes and injects digestive enzymes - SHORT TAIL SHREW only local mammal also has a poison bite -

Indigestible parts are left behind -- selective feeding

Lecture Notes Midterm-Final    

(HAWK plucks off feathers, eats meat and leaves bones) this is called “selective feeding” Other mammals employ this as well (FISHERS eating porcupines “skinning”) Other animals (WEASLES, WOLVES)pass indigestible bits through their body “scats” OWLS swallow prey whole – gizzard sorts meat and digests it and regurgitates bone and hair

Predators don’t live an easy life! - Can be injured by prey -- Can fight back (DEER kick) - Can be hurt during the chase (HAWK impaled by shrub) - Environmental hazards (small animals ingest toxins and stay in- bigger animal ingests 2 small animals and toxins stay- bigger animal eats 5 animals and builds up -- “bioaccumulation” - COMMON LOON killed by BOTULISM – a bacteria in water – fish – loon – dead - Humans persecution (ex. COYOTES, EASTERN WOLF) The number one problem facing predators= STARVATION Have to chase (success rate is one in 10), what if you’re sick? What if you’re old? Predators play important roles: Push natural selection and evolution

Lecture 7b – Until Death Do us Part (Parasitodism) The “host” can be killed or left alive in the process of eating prey from the inside  Left alive – parasites  Kill host – Parasitiods ex. BARCONID WASP larvae living in caterpillars. TACHNID FLIES are also parasitiods as larvae How does this happen?? FOUR ways 1. Eggs are lain right on the host 2. Eggs are lain on leaves so caterpillar accidentally eats them 3. Eggs can also be injected 4. Paralyze pray and burrow them in the ground with eggs (ex. THREAD WAISTED WASP, SPIDER WASPS, DIGGER WASPs, CERECERS DIGGER WASP chews hole How do parasitiods find their prey? 1. Visual searching - FLESH FLIES investigating caterpillar- must be perfect – p must shut down any defences prey (such as caterpillars) may have. Do this through polyDNA viruses (inject them) this may also change the prey to adapt prey for their young. - Eye laying tool called “ovipositor”. Can be long to inject into wood or short to inject onto caterpillars - _____ burns into wood with their ovipositor to insert eggs into grubs in trees - PELECINID...