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Ethology http://people.tamu.edu/~j-packard/ Texas A&M University WFSC 422/632 (on campus 500 or 600; DE 651, 700 or 720) Wildlife & Fisheries Sciences Slide 1

L e a r n i n g , D i s c o v e r i n g a n d S h a r i n g K n o w l e d g e

EthologyTexas A&M University | Department of Wildlife & Fisheries Sciences

Adaptations: Stressful ConditionsPresentation 3.1

Dr. Jane M. [email protected]

Learning goals •“Stress”- compare FP & SP •Examples of behavioral adaptions to stressful conditions

Slide 2

FP: Folk Psychology Q3.1

“Stress is bad- avoid it”

“Stress is good- it motivates us”

“What is bad for humans is also bad for animals”

“Conditions good for humans are also good for other animals”

Lear

ning

Spe

ed &

Qua

lity

Source: Jenson 1998:Fig 6.4

Why are these statements worded in terms of FP? Is stress always bad? What is the evidence from research on learning, that suggests there is an optimal amount of stress, which is beneficial for training resilient responses? What is resiliency?

Slide 3

SP: Scientific Perspective Q3.1

Each species is physiologically adapted to a tolerance range of external physical conditions (e.g. tropical butterfly, Huey 1994:113)

In response to extreme conditions above or below that “comfort zone” the body responds in a manner that brings the organism back into the comfort zone

1. behavioral response threshold2. acute physiological fight/flight response threshold3. chronic healing response threshold

too low too high

Stressor (temperature and/or humidity)

Comfortzone distressdistress

danger danger

1

2

3

1

2

3

Behavioral reflex (fight or flight) e.g. reflexive jerk away from a wasp sting Acute means short term (seconds to hours) e.g. cortisol response activates swelling around the sting Chronic means long-term (several weeks) e.g. “holing up when a bone is broken” e.g. tolerate the heat at a football game longer with something to drink How does this relate to a “systems approach”, e.g. a thermostat?


SP: Scientific Perspective – body systems Q3.1

Stressorstimulus

Reptile brain

Muscleaction

Adrenal gland

Avoidanceresponse

SOURCE: Dugatkin 2009:83

behavioral responses are viewed by scientists as influenced by 3 physiological systems

• sensory systems • central nervous system • muscle systems

through the reptile brain, the behaviors also have feedback loops affecting these systems through the “reptile brain” and affecting the hormonal messengers in the body

• acute- neurotransmitters (noradrenaline, adrenaline)

• chronic- cortisol, thyroid (TSH, T3, T4) To test hypotheses, we make a distinction between general “stressful conditions” and a specific “stressor stimulus”; the result is the “stress response”

Slide 5

Example: Tolerance range of butterfly species

X-species adapted to xerophilous conditions, e.g. swallowtails Hot and dry Low elevations & latitudes Use quarries at higher latitude

M-species –mesophilous, e.g. monarch medium moisture Higher elevations & latitudes

Problem: protect dispersal corridors connecting habitat fragments- within tolerance range

TEXT: Remember the example of the people picnicking in mountains on a windless day…too hot for butterfly SOURCE: Benes, Kepka & Konvicka 2003 (Conservation Biology) For more sources, find: Parmeson, C et al. 1999; Thomas, C.D. 1995, 2000; Warren, M.S. 1993

Slide 6

Butterfly Response on a hot windless day (stressor)

X-species- conditions outside comfort zone

Behavior- land in shade

Acute- fall to ground, crawl to shade

Chronic- immobilized (death if conditions do not change)

M-species- conditions in comfort zone

Actively feed on nectar,

replenish water reserves in body

Elaborations tying the example in with the concepts (synthesis integrating grad and undergrad textbooks)

• acute- escape the stressor • chronic- potentially lethal


Adaptations to extreme conditions Q3.2

Stressor Response SpeciesHeat Burrow under ground Lizards and rodentsCold Bask and huddle Marine iguanasDryness Excrete protective shield Fairy shrimpRains “big bang” reproduction Mound termitesWinter starvation

Bilumia (over-eat) then anorexia (under-eat)

Ground squirrels, grizzly bears

SOURCE: Huey (1994:113-121) in Halliday (ed.,1994)

3.2 For non-migrators, example of adaptation to extreme conditions? See chapter: “Survival Skills” See video “Finding the Way”

Slide 8

SUMMARY Q3.1, Q3.2

FP: assumes “stress” is the same for humans and other species

SP: define tolerance range for each species

stress is outside that range

behavior, acute, chronic responses

examples of behavioral adaptations with the function of reducing

stress for sedentary species (non-migrators)

Summary beyond the tolerance threshold, if animals do not escape (acute response) they are likely to die or have reduced reproduction (chronic response)

Slide 9

Action Items- Adaptations to stressors

Prepare answers for 3.1. Compare FP & SP on…stress… 3.2 Non-migratory adaptations to stress…

Search index in textbook Dugatkin (2009:30) “stress” Halliday (1994:135) “squirrel”

Some recommended sources on Web of Science: Benes, Kepka & Konvicka 2003 (Conservation Biology) Parmeson, C et al. 1999; Thomas, C.D. 1995, 2000; Warren, M.S. 1993

Dialogue Volunteer to chat on Q3.1, Q3.2 Post examples/sources to Blog Unit 3

Q3.1 Compare FP and SP on behavioral adaptations to stress (example)? Q3.2 For non-migrators, example of adaptation to extreme conditions?


How does a stressor influence learning (Dugatkin 2009)?

Want to learn more? relevant questions from the audience

Slide 11

Effect of stressor (shock) on learning

SOURCE: Dugatkin (2009: 88)

Slide 12

Timing of shock influenced learning in rats

SOURCE: Dugatkin (2009: 89)


What is another example of adaptation to a stressor (other than migration)?

Slide 14 Example: Tenebrionid beetle “fog drinking” (mealworm)

Namib Desert- little rain but night

fog

Crawls onto crest of sand dune

Faces wind & lifts abdomen

Droplets condense & trickle into

mouth

Drinking increases body water 34%

Source: art.com

Slide 15

CDEF Analysis- “fog drinking”

C: stimulus- fog; response- climb to crest, face into wind, lift abdomen

D: instinctive- this occurs in all individuals of the species; fixed action pattern

F: those genotypes for “fog drinking” increased under dry conditions; non-drinker genotypes died out

E: divergence- other tenebrionids do not do this; another beetle species digs trenches

120 of Halliday; see also video “Finding the Way”




Migration: Cause & FunctionPresentation 3.2


Learning Goals •Cause of migration •Function of migration

Slide 2 Worldwide migrations

SOURCE:Berthold (1994:125)

SOURCE: Berthold (1994:125) In this lecture, we will elaborate on two well documented migrations: eels and monarchs

Slide 3

SOURCE: Berthold (1994:127), Dugatkin (2009:445)

FALL

WINTER

Spectacular show of migratory monarchs is an ecotourism draw in mountainous forests of Mexico, toward which all the monarchs from east of the Rocky Mountains migrate each winter. How? Why?

Ethology http://people.tamu.edu/~j-packard/ Texas A&M University WFSC 422/632 (on campus 500 or 600; DE 651, 700 or 720) Wildlife & Fisheries Sciences Slide 4 Migration: Pattern of adaptation Q3.3

Proximate Cause (Structure)

Sensory systems (navigation)

Motivational systems (reproductive)

Neuromuscular systems (swim, fly, walk)

Ultimate Function

Animal moves into climatic (physical) conditions within its

tolerance range (comfort zone)

Those genotypes that migrated were more likely to

survive/reproduce than those that did not

Sensory systems (e.g. eyes sense relative light:dark daylength; see landmarks or stars; sense magnetic field) Motivational systems (physiology, e.g. turn on & off activity “switch”) Neuromuscular systems (swim, fly, walk)

Slide 5 Example: Monarch butterfly migration

CAUSE: Spring/summer- photoperiod fly north and reproduce on southern

milkweed species offspring fly north & reproduce on northern

milkweed species Clock-shifted studies of timing due to

light:dark cycle (Perez et al. 1997, cited in Dugatkin 2009:445)

CAUSE: Fall- photoperiod Newly emerged butterflies do NOT

reproduce and fly south eastern population: overwinter in mountain

forest in Mexico (volcanic magnetic anomalies?)

Western population : overwinter in Calif.

Q3.3 CAUSE of migration for a species of your choice?

Slide 6 Example: Monarchs (continued)

FUNCTION: Those that flew north with spring “green up”…

found more green luscious milkweeds to lay eggs

food for caterpillars in north when plants dried up in the south

more caterpillars survived

FUNCTION: Those that flew south without reproducing in fall…

more butterflies survived the cold dry winter in protected forests

reproduced early the next spring on slopes of the mountains

Image source: Peggy Greb & Stephen Ausmus

3.4 FUNCTION of migration for a species of your choice?

Ethology http://people.tamu.edu/~j-packard/ Texas A&M University WFSC 422/632 (on campus 500 or 600; DE 651, 700 or 720) Wildlife & Fisheries Sciences Slide 7 SUMMARY- Pattern of migration Q3.3, Q3.4

PC: Cause (Structure)- think in terms of genotypes that code for

sensory, motivational & action systems

UF: Function- those genotypes that avoided extremes were more

likely to survive & reproduce than those that did not

Example: monarch butterflies

Key authors: Lincoln Brower, F. A. Urquhart

Slide 8 Action Items- Patterns of migration

Prepare answers for 3.3. Cause of migration…. 3.4. Function of migration…

Some recommended Key authors on Web of Science: Lincoln Brower F.A. Urquhart



Slide 9

What is a marine example of cause and function of migration?

Want to learn more?

relevant questions from the audience


Example: Eels (European & American)

Cause- juvenile “Alewives”

Carried by saltwater currents from Sargasso Sea to coast

Follow freshwater gradient upstream at rivers

Cause- mature adult eels

Carried by river currents & heavy rains to the ocean (freshwater is

outside salinity comfort zone)

Follow unknown stimuli to the Sargasso Sea

Q3.3 CAUSE of migration for a species of your choice?

Slide 11

Example: American Eels (continued)

Function- juveniles

Those that moved to coastal rivers found more food and grew to

reproductive size

Those that did not migrate never grew large enough to reproduce

Function- mature adults

Those that left rivers and spawned in Sargasso Sea had more

offspring survive (few predators)

Those that spawned in the rivers passed on few genotypes

because all the predators ate the eggs

4 FUNCTION of migration for a species of your choice?





Migration: Development & EvolutionPresentation 3.3

Learning Goals •Development of migration-heritability •Evolutionary history of migration

Slide 2

Development: seasonal time-scale

http://www.rosegardening101.com/archives/climate-zones-and-rose-gardening/

Variation with Latitude & Altitude

This map shows how the time for development during warm summer months varies with latitude and altitude (tolerance zone).

Otherwise, conditions are stressful

Slide 3 Evolution: geological time-scale

Glacial expansion and retreat North/south migration of caribou, waterfowl northern radiation of milkweeds (monarch egg plants)

Uplift of mountains- e.g. Rockies, Andes, Tibetan plateau Separation of eastern and western populations of monarchs migration of ungulates up and down mountains

Continental drift- e.g. break up of Gonwandaland http://www.scotese.com/sfsanim.htm Texas Through Time http://www.ig.utexas.edu Migration of eels from Sargasso Sea in northern Atlantic

• American population travels west• European population travels east

These are a few of the hypotheses about why the geological history of the globe shaped the migrational patterns of different species. Go to the web links and drag your mouse to activate the “time machine”.


Process of Adaptation by migration Q3.5, Q3.6

Q3.5 Development in individuals

Is a sense of direction inherited?

Is the ability to learn landmarks inherited (stars, landscape,

magnetic patterns)?

Q3.6 Evolution of species

H1: continental drift

H2: uplift of mountains

H3: glacial expansion & retreat

Think of a video : PD: Change over lifetimes of individuals UE: change over phylogenetic history of a species

Slide 5

Logic of Natural Selection- monarch migration

V (C): if there was variation in the ancestral population such that

some genotypes only moved up and down the mountains, and other

genotypes followed the “seasonal greenbelt” in latitude

H (D): if the variation was heritable

D (F): if the genotypes that moved with the seasonal greenbelt were

more successful at reproducing as the glaciers receded

P (E): then the genotypes for staying in the mountains would have

decreased and the genotypes for migrating with the seasonal

greenbelt would have increased, resulting in the migratory adaptation

seen in the modern species

Slide 6

DEVELOPMENT: Monarch migration Q3.5

Heritable ability to switch directions depending on

environmental conditions (photo-period)

Maturation controlled by temperature at emergence

Warm summer- butterfly matures and flies north to lay eggs

Cold fall- butterfly does not lay eggs and flies south

Mature monarchs that overwinter fly down the mountain reproduce on the closest milkweeds in the lowland green zone offspring follow the spring green zone north

Image source: Peggy Greb & Stephen Ausmus

Q3.5 How does migration DEVELOP in a species of your choice?

Ethology http://people.tamu.edu/~j-packard/ Texas A&M University WFSC 422/632 (on campus 500 or 600; DE 651, 700 or 720) Wildlife & Fisheries Sciences Slide 7 EVOLUTION: Monarch migration Q3.6

Ancestral species was a tropical butterfly that moved uphill during the dry season and downhill during the wet season

When the glaciers receded, the distribution of milkweed moved further north; new species evolved that were adapted to northern climates

Monarchs diverged from the tropical ancestors, still not tolerating cold latitudes or dry summers, but migrating with the “seasonal greenbelt”

Q3.6 Why did migration EVOLVE in a species of your choice?

Slide 8

SUMMARY

DEVELOPMENT: think in terms of what is instinctive/learned

and how this changes with age or conditions

EVOLUTION: think about how continents diverged, glaciers

moved, or mountains arose

Examples: monarch migration (see extra slides for eels)

Summary •understand how development and evolution are both like “videos” of change through time; only development is at the scale of the lifetimes of individuals and evolution is on the time scale of geological epochs

Slide 9 Action Items- Process of migration

Prepare answers for 3.6. Development of migration…. 3.4. Evolution of migration…

Some recommended Key authors on Web of Science: Lincoln Brower F.A. Urquhart




What is a marine example of development and evolution of migration?

Want to learn more?

relevant questions from the audience

Slide 11

Worldwide migrations- focus on eel

SOURCE:Berthold (1994:125)

SOURCE: Berthold (1994:125) In this lecture, we elaborated on monarchs; another well-known migration is eels

Slide 12

Example: Migratory Eels

Development- juveniles

Instinct in juveniles- American genotype navigates to a different

current than European genotype

When saltwater tolerance shifts to intolerance, they move to rivers

Development- adults

Stages of maturity- physiological changes related to reproduction

are dependent on size not age (effect of environment)

When freshwater tolerance shifts to intolerance, they move to sea

Q3.5 How does migration DEVELOP in a species of your choice?


Example: Eels (continued)

Evolution- juveniles & adults

Ancestors reproduced and grew in Sargasso sea before the

continents drifted apart

Derived- travel long distance to rivers

Divergence of American & European stocks (genotypes)

Q3.6 Why has migration EVOLVED in a species of your choice?

Slide 14 Logic of Natural Selection- eel migration

V (C): if there was variation in the ancestral population of eels, such that some drifted with ocean currents and some did not before the continents separated

H (D): if the tendency to move into the ocean currents was heritable

D (F): if those genotypes that moved into and drifted with the ocean currents were more likely to grow to reproductive age (because they found better food in the rivers) compared to those genotypes that stayed in the Sargasso Sea

P (E): then the genotypes for juvenile migration would have persisted in the population even as the continents drifted apart and the river coastline moved further and further away from the Sargasso Sea

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