extreme environments

Question 1

birds are… (feautures)

Answer 1

warm blooded
endothermic
capable of controlled body temp - homothermic
capable of high metabolic rates
air breathing
dependent on freshwater - low salinity
low in body mass and high in power output

Question 2

what are extreme environments for birds

Answer 2

primary
-max and min temp = showlanders theory of endothermerm, upper critical temp need adpatations to cool you down so dont die of heat stress, lowerr critical temp ie. shivering
- water- need access to fresh
- low oxygen in high altitudes and at a depth in water ie. geese flying in Himalayas ie. special muscle fibres with tissue with mitochondria, poor decision making due to disorientation also starvation of glucose to brain as needed to make choices
- food - quality and quantity
- light = sufficient for forgaing
secondary = predictability of environemntal conditions and resources in time and space

Question 3

SDM

Answer 3

species distribution models
- take environmental variables and use in model form to predict how much of each species in specific habitat based on protectories
can look at surface temp,sea temp and snow cover etc

Question 4

global land surface temps

Answer 4

hotter ares ie. africa, low species diveristy

Question 5

sea surface temp

Answer 5

major driver of productivity of marine food webs
-hot spots of maintence of sea surface temp

Question 6

global snow cover

Answer 6

• not a complete loss of species, low number due to special adaptations
• loss of ice decreases populations

Question 7

global rainfall

Answer 7

rely upon this to drink sometimes
drives plant growth and habitat
- most biodiverse areas have most rainfall

Question 8

global chlorophyll

Answer 8

look at chlorophyll a as key element of productivity of marine food webs
ashmols halo - sea birds nesting, central place foragers, large enough numbers gathering youd expect to see greater depletion of prey in waters

Question 9

global artificial light

Answer 9

ALAN = artificial light at night
europe and USA has lots

Question 10

challenges for birds in deserts

Answer 10

• water avaivilty low because evaporation exceeds precipitation

Question 11

challenges if high altitude

Answer 11

• low density air with less oxygen and reduced heat retention
  high latitude associated with marked chnages in habitat structure/availiabilty
  shoe=rt day lengths winter
  reduced growing seasons and hence truncated breeding seasons of prey and consumers

Question 12

farmland bird population trends

Answer 12

Farmland bird populations in the UK have experienced a significant decline, with a 61% drop since 1970. This decline is primarily attributed to changes in agricultural practices, such as intensified farming methods, increased pesticide and fertilizer use, and the loss of hedgerows
- generalists much better adapted
agrochemicals impact

Question 13

wetland bird pop trends

Answer 13

declined by 7% in england
due to habitat loss and degration
climate change

Question 14

woodland birds

Answer 14

ovrpopulated with deer and destroy a lot of trees which can affect woodland diveristy birds

Question 15

scholanders model of endothermy

Answer 15

metabolic rate against ambient temperature
- want to sit in thermal neutral zone and we are constant metabolic rate- RMR - resting
- outside too low - LCT - lower critical temp and raising metabolic rate to move towards neutral zone
ie. thermogenic shivering
UCT = upper critical temp means overheating, hyperventilate, die of heat stress

Question 16

counter current heat exchangers

Answer 16

• heat exchangers are large arteries in leg carrying oxygen loaded blood to the foot and thin walled veins carrying cold venous blood to core
  heat from the artery warms venous blood by moving down temp gradient recycling heat to body temp

Question 17

regional heterothermy

Answer 17

produced by heat exchanger birds legs and tibial nerve in European herring gull leg exposed to temps between 38 and 0 along length
single neuron evolved a condition mechanism that operates over wide temp range

Question 18

gular fluttering

Answer 18

rapid pumping of air across internal moist surfaces that enhance evaporative cooling
some birds cool brain through heat exchange in the ophthalmic rete - cools arterial blood destined for brain using venous blood returning from nasal or oral cavities after evaporative cooling

Question 19

ostrich

Answer 19

large thermal inertia
= feathers long and sparsely distributed over back
- feathers erect after high temp and intense radiation to thicken thermal shield between incident radiation and skin
- poor coverage of feathers allows air to circulate between them prompting cooling of skin
- great adaptations for water conservation in desert conditions =

Question 20

salt glands

Answer 20

truly pelagic seabirds spend most of their lives at sea with limited access to freshwater
- tubenoses = have specialised salt glands that extract salt from capillaries

Question 21

digestive and breeding readiness

Answer 21

zebra finches
opportunistic breeders, time breeding with first rains that provide new plant growth, need fresh plant growth and seeds to gain nutrition for breeding, reproductive tissues are permanently on stand by, plot timing on breeding then see they don’t breed at same time

Question 22

high altitude migration

Answer 22

ie. bar headed geese
- migrate over himalyayas, challenges birds with reduced air pressure and low partial pressure of oxygen
high volume lungs
haemoglobin highly effective at oxygen loading
ability to hypervbentalate when hypoxic
skeltal and cardiac muscle packed with mitochondria

Question 23

flying in water

Answer 23

low light, low oxygen and high pressure
- cut off oxygenated blood supply to locomotor muscles instead delivering oxygen to key organs like brain and heart
- only transient oxygen delivery ti locmotor muscles to prevent lactic acid build up and fatigue

Question 24

seeking shleter and dietary shifts

Answer 24

ie. willow ptarmigan cannot migrate to escape adverse weather
- shelter afforded by burrows in snow drifts in the most adverse of conditions and at roost
- change digestive morphology by extending gut length to maximise what they drive from winter food
eat more grit to aid digestion, extract as much food as possible

Question 25

communal nesting and roosting

Answer 25

- mousebirds, long tailed tits huddle and roost overnight for thermal reasons and to reduce metabolic rates, metabolic costs per bird are negatively related to group size - sociable weavers community nest to reduce cost of thermoregulation and nest maintance

Question 26

seeking water and shade

Answer 26

sandgrouse - arid areas exploit free standing water by saturating their breasts feathers and flying to chicks that drink from them bird in shade opens thermal window by drooping wings

Question 27

extreme behavioural adaptation to migration

Answer 27

- birds migrate to avoid extremes experience long days year round allowing them to feed (ie. shearwaters) at sea and breed successfully, breeding finished they fly,

Question 28

adaption to low light

Answer 28

brown kiwi - forage under low light conditions at night - turned to olfaction/smelling instead - nostrils at tip and touch sensors to feel wriggles of prey olibirds - live in pitch black and use echolocation instead retina of banks of rod receptors highest recorded rod densitu of vertebrate few cones and small eyes witth high pupil diamter allowing max light gathering

Question 29

what are invasive species

Answer 29

one that has been introduced into geographical areas outside of its native range

Question 30

examples of invasive species

Answer 30

rats - seabird hotspots cats take huge numbers of birds mexican thorn = plant with vigor

Question 31

predator free 2050

Answer 31

taken chunk of domestic budget in nz, said to citizen scientists, want to eradictae

Question 32

impact invasive species have on native species

Answer 32

range population dynamics comp for food comp for breeding sites exposure to disease exposure local extinctions

Question 33

adaptive radiation

Answer 33

rapid diversification of a single ancestral lineage into a variety of species each adapted to different ecological niches

Question 34

bad responses of native species to invasive species

Answer 34

b - behavioural = competitive to secure food and breeding opportunities exploratory to overcome neophobia and to allow exploitation of new foraging and breeding opportunities adaptive to expand behavioural repertoires to allow exploitation of ecological niches A- anatomical = external structural to facilitate out competing for food and breeding opportunities - response from invasive plants - ie. body size - internal structural to allow for greater efficiency of digestion or exploitation of new food sources i.e. ruminant stomachs -thermoregulatory = accommodate expansion of climate envelope - energetic to allow survival within energy budget

Question 35

key geographical differences between Antarctic and arctic

Answer 35

Antarctica = 14 million km2 (continent covered by ice) arctic = 5.4 million km3 (mostly covered by sea ice, some land areas such as Russia, Canada)

Question 36

Antarctic geography

Answer 36

- old continent surrounded by ocean no human history high diversity in water, constant temperatures and upwelling of water makes nutrients go to surface

Question 37

arctic circle

Answer 37

young ocean surrounded by land, covered by ice shrinks in summers and expands in winter low arctic has milder and shorter winter, summer temp = 5-10 winter -10--30, high arctic range from -40 to 0 low arctic has more biodiversity and seasonal variation economically important

Question 38

why are conditions in arctic milder compared to Antarctica

Answer 38

- arctic region is surrounded by landmasses and arctic ocean linked to other warmer oceans so gets currents, antarctica isolated ACC - Antarctic circumpolar current - arctic warming at least twice as fast as global avg and experience sea loss due to albedo (sun reflected) - Antarctic ice sheet is 2160m thick

Question 39

Antarctica terrestrial flora

Answer 39

- coastal absence of trees and shrubs, only two flowering plant species- antarctica hair grass and Antarctica pearlwort - around 100 moss species, 25-30 liverwort species and 200-400 lichen species

Question 40

Antarctic terrestrial fauna

Answer 40

- terrestrial insect community extremely limited - antarctic mites feed on moss, algae, decomposing lichens springtails and nematodes are part of antartcic soil ecosystem low biodiversity, high abundance simple food webs few predators

Question 41

ice nucleation

Answer 41

pure water requires low temp to freeze -40 because must achieve critical nucleation point, higher temp due to dust pollen bacteria etc

Question 42

supercooling

Answer 42

- supercooling = process where a liquid or substance is cooled below freezing without turning to liquid - decrease freezing point of their body fluids by - accumulation of cryoprotectants e.g. glycerol to lower freezing point - removal of ice nucleators = food particles, microbes tec, can trigger freezing so some insects empty gut to reduce risk -production of antifreeze proteins AFP = these proteins bind to ice crystals to prevent growth and keep fluids in liquid

Question 43

freeze tolerant

Answer 43

-frozen haemolymph create thermal and osmotic gradient that slows down cooling of cells and isolates them, limits water availability for freezing inside the cells - dehydration protection necessary by osmoprotectants - trehalose, glycerol and proline

Question 44

supercooling point

Answer 44

- ice nucleation begins and body fluids freeze which releases latent heat causing increase in temp in thermocouple reading

Question 45

bark beetle and antarctic midge

Answer 45

larvae die when temp below -20 midge will be alive at -25 FA insects= die when frozen - freeze avoidant FT insect = don't die - freeze tolernat

Question 46

ecological relevant classifications of cold tolerance

Answer 46

FT = Antarctic midge FA = arctic moth chill tolerant = overlap with FT chill susceptible = grasshoppers die near to freezing opportunistic survival = houseflys etc, find shelters

Question 47

weavil Rhynchaenus fagi

Answer 47

chill tolerant, survive cold temp below 0 for limited time, prolonged exposure leads to 100% mortality

Question 48

factors contributing to cold survival

Answer 48

1- behavioural avoidance = migration, microhabitat selection 2- physiological change= phenotypic plasticity = evacuation of digestive system =, reduce bod water, developmental arrest or quiescence (low metabolic activity) 3- biochemical changes - synthesis of ice nucleating agents and anti freeze proteins, membrane adaptation, gene chnages

Question 49

membrane adaptations

Answer 49

unsaturated fatty acids have kinks in chains which prevents tight packing and maintain membrane fluidity, fatty acid chain have double bonds at 30 degree angle

Question 50

RCH

Answer 50

rapid cold hardening - brief exposure to less severe stress to increase tolerance RCH = cellular chnages occur rapidly = adjustments in membrane fluidity, accumulation of cryroprotectants like glycerol activation of heat shock proteins to protect cellular structures reduction in ice nucleation within tissues Doesnt require gene expression changes making it fast and reversible -

Question 51

cryoprotective dehydration

Answer 51

soil invertebrates, highly permeable cuticle, freeze tolerant springtails = use protective dehydration, they lose body water to avoid ice formation inside cells, when temp increases they rehydrate and recover, allows them to survive -20 to -30, involves the loss of virtually all osmotically active water from the body, allowing the organism to avoid freezing by reducing its internal water content and increasing the concentration of solutes.

Question 52

dessication tolerant vs resisitnace

Answer 52

tolerant = survive sig water loss but dont actively prevent resistance = waxy or thickened exoskeltons, modified cuticles, to retain moisture

Question 53

chill coma and CTmin

Answer 53

a temporary state of paralysis induced by exposure to low temperatures, characterized by a complete arrest of movement, which is reversible upon warming - The critical thermal minimum (CTmin), the temperature at which insects lose the ability to coordinate movement and enter a reversible state of complete neuromuscular paralysis,

Question 54

chill tolerant vs sensitive

Answer 54

Chill tolerant insect CTmin is typically around -4°C to 0°C Chill sensitive insects CTmin is usually around +5°C to +10°C