BIOL 3999: Issues in Biological Science - PowerPoint Presentation

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BIOL 3999: Issues in Biological Science

GLOBAL CHANGE BIOLOGY

Dr. Tyler Evans

Email:

tyler.evans@csueastbay.edu

Phone: 510-885-3475

Office Hours: M,W 10:30-12:00 or by appointment

Website: http

://evanslabcsueb.weebly.com

/Slide2

PREVIOUS LECTURE

linear relationship between temperature and CO2

Ocean and atmospheric temperature is increasing and will continue to increase over the next centurySlide3

e

stablish basic principles regarding the effects of elevated temperature on function across levels of biological organizationprovide background information that will assist in understanding mechanistic basis for vulnerability to heat stress and global

warmingTODAY’S LECTURESlide4

EFFECTS OF TEMPERATURE ON BIOLOGICAL SYSTEMS

m

ulti-cellular life (metazoans) is confined to a narrow temperature range

100°C

50°C

0°C

-80°C

h

ot springs bacteria

h

ot springs algae

d

esert insects

3

0°C

c

amels, some birds, some turtles

m

ost birds, mammals

s

hore animals

m

ajority of life

Antarctic minimum (few mammals, birds)

desert maximum

8

0°CSlide5

EFFECTS OF TEMPERATURE ON BIOLOGICAL SYSTEMS

r

eflected in global patterns of species richness

m

ajority of species concentrated to a narrow band of latitudes where temperature is most conducive to life

e.g. MARINE ENVIRONMENT

p

lants and animals are drastically affected at all levels of biological organization by any change in their thermal environmentSlide6

TEMPERATURE HAS A DOMINANT EFFECT ON BIOLOGICAL PROCESSES

BIOCHEMICAL: (a) ENZYMES

temperature is measure of the molecular motion of within a material. At higher temperatures there is more molecular vibrationif molecules are moving sufficiently fast, they can react when collide with each otherenzyme reaction rate rises sharply with temperature as substrates react with enzyme catalysts (within certain functional limits)

t

emperature increases enzyme rate until the enzyme itself becomes denatured (unfolded) and no longer functionalSlide7

enzyme

stability

temperature

Antarctic (-2 to 2°C)

North Sea (2 to 18°C)

Mediterranean

(5 to 25°C)

Indian Ocean

(20 to 28°C)

East African Lake

(

25

to 28°C)

THERMAL STABILITY OF ENZYMES IN MARINE ANIMALS FROM DIFFERENT HABITATS

r

ange of temperature that enzymes are functional under is related to temperature regimes experienced in their native habitats Slide8

BIOCHEMICAL: (b) MEMBRANES AND CELL STRUCTURES

m

embranes are essential to cellular function lipids in membranes exist as a “liquid crystal”: not quite solid, not quite liquidthis delicate balance can be easily disrupted by temperatureas temperature increases, membranes become more fluid. As temperature decreases membranes become more rigid Slide9

altering the lipid composition of membranes

can help organisms maintain function over a specific range of temperatures

BIOCHEMICAL: (b) MEMBRANES AND CELL STRUCTURESSpecies

Body Temp (°C)

Choline

Ethanolamine

Serine inositol

Arctic

Sculpin

0

0.59

0.95

0.81

Goldfish

5

0.66

0.34

0.46

Goldfish

25

0.82

0.51

0.63

Desert Pupfish

34

0.99

0.57

0.62Rat

371.22

0.650.66

longer and saturated

fatty acids (without carbon double bonds) are more rigid and maintain membrane function at relatively higher temperatures

choline lacks carbon double bonds and its proportion increases in species that inhabit warmer environments

RATIO OF SATURATED: UNSATURATED FORMS OF SOME FATTY ACIDS

changes are catalyzed by DESATURASES, controls formation of double bondsSlide10

BIOCHEMICAL: (c) STRESS PROTEINS

t

emperature change can induce the production of a class of proteins called heat shock proteins (Hsp’s)induction of these proteins is again related to typical thermal regimes experienced in natureorganisms in warm environments produce Hsp’s at higher temperatures than those inhabiting colder environmentsassist in folding denatured proteins and thus maintaining their function

i

s

a metabolically costly response: re-folding requires ATP

t

hree

Hsp’s

interacting with an unfolded client protein (red)Slide11

TEMPERATURE HAS A DOMINANT EFFECT ON BIOLOGICAL PROCESSES

PHYSIOLOGICAL: BI-PHASIC RESPONSE

b

iological processes generally exhibit a two phase response to increases in temperature:

1.) activity increases as a consequence of the of the rate-enhancing effects of temperature on enzymes

2.) at higher temperatures the destructive effects of temperature take over and rates of activity decline

Temperature

Rate of

process

r

ate enhancing effects

d

estructive effectsSlide12

PHYSIOLOGICAL: BI-PHASIC RESPONSE

a

number of physiological processes show this two phase responsese.g. HEART RATEheart rate a various temperatures for intertidal porcelain crabs

t

emperature (°C)Slide13

i

n the crayfish, first sign of heat stress is breakdown of normal permeability of gill membranes, so that

ion gradients critical to survival are

disrupted

CELLS AND ORGANISMS: “WEAKEST LINKS”

e

ffects of temperature on cells and organisms is the result of “weak links”, essential processes that are more vulnerable to heat stress than others

w

eak links establish functional limit for cells and organisms beyond which death occursSlide14

UPPER CRITICAL TEMPERATURE

weakest links in responses to temperature will determine the UPPER CRITICAL TEMPERATURE, the maximum tolerable temperature for

the whole organism

100°C

50°C

0°C

-80°C

h

ot springs bacteria

h

ot springs algae

d

esert insects

3

0°C

c

amels, some birds, some turtles

m

ost birds, mammals

s

hore animals

m

ajority of life

Antarctic minimum (few mammals, birds)

desert maximum

8

0°CSlide15

TERMINOLOGY IN THERMAL BIOLOGY

ENDOTHERM: body temperature principally dependent on internally generated metabolic heat

birds and mammalsECTOTHERM: body temperature principally dependent on external heat sources (almost exclusively the sun)everything else: insects, reptiles, amphibians, fish, marine invertebrates

EURYTHERMAL (‘

eury

’ =

greek

for wide)tolerates and is active within a wide range of temperaturestemperate insects and reptiles function between 8-38°CSTENO

THERMAL

(‘steno’

=

greek

for

narrow)

tolerates and is active within a

very narrow

range of

temperatures

most

mammals and birds and some organisms from very stable environmentsSlide16

STRATEGIES IN THERMAL REGULATION

1.) MIGRATION (AVOIDANCE)

2.) ACCLIMATIZATION/ACCLIMATION (TOLERANCE)3.) ADAPTATION (EVOLUTION)Slide17

STRATEGIES IN THERMAL REGULATION

1.) MIGRATION (AVOIDANCE)

location and use of appropriate climatic conditions in time and space

Monarch butterflies cannot survive the Northern winter so migrate great distances to warmer habitats in Mexico

e.g. LONG DISTANCE MIGRATIONSlide18

STRATEGIES IN THERMAL REGULATION

1.) MIGRATION (AVOIDANCE)

location and use of appropriate climatic conditions in time and spacee.g. SMALL-SCALE USE OF MICROCLIMATESfor

very small organisms like ants environment is very “fine-grained”, with conditions varying widely in time and space. These creatures may have access to a range of microclimatesSlide19

STRATEGIES IN THERMAL REGULATION

1.) MIGRATION (AVOIDANCE)

only works if you can move!

p

lants and trees

b

arnacles in the intertidalSlide20

STRATEGIES IN THERMAL REGULATION

2.) ACCLIMATIZATION/ACCLIMATION (TOLERANCE)

plants and animals vary considerably in their tolerance of temperaturebiochemical, cellular and/or physiological processes are adjusted to compensate for variations in their thermal environmentreferred to as ACCLIMATIZATION when occurring in nature and ACCLIMATION when it occurs in the lab.

a

ct to keep biological processes operating at roughly the same rate across a range of temperatures

e.g. LATITUDAL GRADIENTS

e.g. SEASONAL GRADIENTS

e.g. ALTITUDINAL GRADIENTSSlide21

some

species of marine invertebrates occupy have biogeographic ranges that extend across a wide temperature gradient. acclimatization

is used to ensure proper function at a range of temperatures STRATEGIES IN THERMAL REGULATION2.) ACCLIMATIZATION/ACCLIMATION (TOLERANCE)e.g. LATITUDINAL GRADIENTS

t

he purple sea urchin (

Strongylocentrotus purpuratus

) inhabits

nearshore

marine environments from Alaska to MexicoSlide22

small birds that are resident in cold climates generally show marked winter increases in

THERMOGENIC CAPACITY (overall capacity for heat production) that are accompanied by winter increases in cold hardiness

winter triggers an increases in pectoralis muscle mass, generally ranging from 10-30% in small birdsincreased reliance on fats to fuel sustained shivering in winter relative to summer

STRATEGIES IN THERMAL REGULATION

2

.) ACCLIMATIZATION/ACCLIMATION (TOLERANCE)

e.g. SEASONAL GRADIENTS

Black capped chickadee

Poecile

atricapillusSlide23

STRATEGIES IN THERMAL REGULATION

2.) ACCLIMATIZATION/ACCLIMATION (TOLERANCE)

e.g. ALTITUDINAL GRADIENTS

d

ecreased oxygen

concentration

at high altitudes stimulate the production of red blood cells in humans

t

his increases the capacity for oxygen transport to cells and tissues

r

eason why many athletes train at altitudeSlide24

STRATEGIES IN THERMAL REGULATION

t

he capacity to acclimatize or acclimate is often referred to as an organisms PHENOTYPIC PLASTICITY, essentially how much an organisms can modify processes to function in a new environmentphenotypic plasticity can be captured in TOLERANCE POLYGONS2

.) ACCLIMATIZATION/ACCLIMATION (TOLERANCE)

s

urvival may be possible over a range of temperatures (i.e. resistance), but certain physiological functions like growth and reproduction are limited to specific temperatures windowsSlide25

STRATEGIES IN THERMAL REGULATION

2.) ACCLIMATIZATION/ACCLIMATION (TOLERANCE)

Area of the tolerance polygon describes phenotypic plasticity

SPECIES

AREA

OF TOLERANCE POLYGON

HABITAT

Goldfish1220Freshwater, widespreadBullhead trout

1162

Freshwater, widespread

Lobster

830

Marine, widespread

Greenfish

800

Marine, widespread

Silverside

715

Marine, widespread

Flounder

685

Marine,

temperate

Trout

625

Freshwater/marine,

temperate

Puffer fish

550Marine,

temperateChum salmon

468Freshwater/marine,

temperateRock Perch47

AntarcticSlide26

STRATEGIES IN THERMAL REGULATION

3.) ADAPTATION (EVOLUTION)

permanent changes in an organisms DNA that alters the function of particular proteins that happens to prove beneficial in new environmentSlide27

STRATEGIES IN THERMAL REGULATION

3.) ADAPTATION (EVOLUTION)

e.g. CHANGES IN PROTEIN STABILITY

Mytilus galloprovincialis

Mytilus trossulus

Warm-adapted

Cold-adapted

l

actate

dehyrodgenase

(LDH),

an important enzyme in anaerobic metabolism contains an amino acid substitution in

M. galloprovincialis

that confers additional stability to the enzyme at high temperature. This contributes to the increased heat tolerance of this species.

temperature

LDH enzyme

activity

M. galloprovincialis

M.

trossulus

Slide28

EXTINCTION

lethally hot temperatures exerted a direct

effect on the end-Permian mass extinction (250 million years ago)also inhibited the ability of remaining animals to proliferate following the extinction eventa role for temperature stress in Earth’s most severe extinctioninverse relationship between the temperature and biodiversity during this period

temporary loss of both marine and terrestrial vertebrates

reduced size of the remaining invertebrates.

96% of marine life

70-80% of terrestrial lifeSlide29

LECTURE SUMMARY

Temperature has a dominant effect on biological systems

biochemical levelenzyme activitymembrane fluiditystress proteins (Hsp’s)

p

hysiological

b

i-phasic response: rate-enhancing followed by destruction

heart rate

c

ells and organisms

“weakest links”

Strategies in thermal regulation

m

igration (avoidance)

a

cclimatization/acclimation (tolerance)

a

daptation (evolution)

Temperature and Permian Mass ExtinctionSlide30

MORE INFORMATION

BIOLOGICAL EFFECTS OF TEMPERAURE

Wlimer, Stone & Johnson. (2005) Environmental Physiology of Animals (2nd edition). Blackwell Publishing Company, Oxford, UK. CHAPTER 8: Temperature and its effects (pp 175-222)

TEMPERATURE AND TRIASSIC EXTINCTION

Yadong

Sun et al. (2012) Lethally hot temperatures during the early Triassic greenhouse. Science. 338: 366.Slide31

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INTERTIDAL-PORCELAIN CRABS