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How are foraging modes defined? What are the two major foraging modes we talked about in class?

Foraging modes traditionally defined based on behavioral patters of locating and capturing prey. Two foraging modes talked about were 1.) Sit-and-wait foraging (ambush foraging) and 2.) Active foraging (wide foraging).


Compare and contrast Sit-and-Wait foraging with Active foraging.

Sit-and-Wait Foraging  Use little time and energy searching for prey items  Stationary behavior and attack mobile prey when detected within field of vision  Most energy spent on capturing and handling prey items **often more territorial and generally wait for food to come into territory. **generally seen in Iguanians  Movement times, rates, & percentages are lower in sit-and-wait foragers  Lower/limited endurance & higher sprint speeds in sit- and-wait foragers  Daily energy use & intake lower in sit-and-wait foragers Active Foraging  Actively move through environment searching for prey items  Much energy used during searching phase  Little energy used in capture of prey item **generally smaller prey so they don't have to wrestle with it to catch and eat it. **generally seen in non-iguanian squamates  Activity body temperatures higher in active foragers BOTH are foraging modes exhibited in reptiles and amphibians.


What is the Optimal Foraging Theory?

 Traditional explanation for the evolution of foraging modes  In presence of competition, individuals best able to exploit resources should have selective advantage  Fine-tuned by natural selectionultimate pay-off should be greater reproductive success  Overly simplistic theoryforaging is complex  Few studies support associated predictions


What are some factors that influence foraging behavior?

External factors include prey availability, predation risk, social interactions (e.g.. competition), habitat structure, and opportunities for thermoregulation. Internal factors include hunger, learned experiences, age, sex and reproductive state, etc. Historical factors include sensory limitations, morphological characteristics (e.g. mouth shape, head size), physiological constraints (sprint speed), and behavioral set (conservative foraging mode)


What are the different ways that amphibians and reptiles can detect prey? Specifically, how do Caecilians, Batrachians, Crocodylians, Chelonians, and Squamates detect?

 Prey may be detected by visual, chemical, tactile, and/or thermal signals  May have reliance on a single system or used in combination  Caecilians: Tentacles for chemosensory cues  Batrachians: Visual cues  Crocodylians: Visual and tactile cues  Chelonians: Visual, tactile, & chemical cues  Squamates: Use all forms  Subgroups may primarily use one sense


Define and describe Visual Prey Detection.

 Primarily important for the sit-and-wait predators  Common in iguanians and cordylids; also most anurans  Success in prey capture generally requires binocular perception of prey item  Align head (and body) with prey  Exceptions: Chameleons  Large and well-developed eyes  Prey movement often required


Define and describe Chemosensory Prey Detection.

 Three avenues for detecting chemical cues from the environment 1. Olfaction: Nasal chamber 2. Vomerofaction: Vomeronasal (Jacobsonʼs) organ 3. Taste (gustation): Oral cavity  Olfaction and vomerofaction rely on airborne and/or surface chemical cues  Olfaction: Long-distance detection; Presence of food and general location  Vomerofaction: Short-distance detection  Gustation: Primary function is food discrimination  Involves taste buds of oral cavity


In what groups is chemosensory prey detection found in amphibians and reptiles? What is the traditional and new view of how this was derived in squamates?

 Olfaction and vomerofaction:  Important in “scleroglossan” squamates and plethodontids salamanders  Fine-tuned vomerofaction in snakes and other deeply fork- tongued squamates  Recent evidence in crocodylians and aquatic turtles; Historically thought to be primarily visual and tactile focused  The “Squamate Story”  Traditional theory relating squamate diversification; Evolution of vomerofaction-based foraging system in “scleroglossans" from ancestral visual-based system as seen in iguanians  Now: Iguanian condition is derived and vomerofaction is ancestral  Did evolution of sit-and-wait foraging aid in iguanian diversification?  Evolution of vomerofaction may still have allowed for the diversification of squamates


Define and Describe Auditory Prey Detection.

 All amphibians and reptiles can hear and/or sense vibrations  Generally, not thought to be important for foraging; Recent anecdotal evidence suggestions prey may be detected by auditory or vibration related cues in some groups


Define and describe Thermal Prey Detection.

 Infrared (long wavelength light) receptors evolved multiple times in boids and pythonids, and once in Crotalinae  Multiple labial pits in boid and pythonids  Single pit (=loreal pit) between eye & nostril in pit vipers  Organ consists of thin, highly enervated membrane stretched across open cavity  Structure allows precise detection of distance & direction  In rattlesnakes, head cooled when snake is excited  Allows even more precise thermal differentiation (0.003o C)  Pit organs are enervated by trigeminal nerve"  Wired to visual cortex  Thermal images are integrated with visual images  Snakes see the thermal profile of infrared source superimposed on visual image


Define and Describe Tactile Prey Detection.

 Known method of detection, but still poorly understood  Mechanoreceptors in skin  Lateral line system in aquatic amphibians  Crocodylians?  Enervated epidermal appendages  Barbels around lower jaws in many aquatic turtles  Lure-like tongue of Alligator Snapping Turtle (Macrochelys temminckii)  Head tentacles in the Tentacled Snake (Erpeton tentaculatum)


Where in amphibians and reptiles did the projectile tongue feeding evolve?

 Projectile tongue independently evolved in different groups of amphibians and reptiles  Amphibians: anurans and some salamanders  Reptiles; within Chamaeleonidae


Describe projectile tongue feeding in Caudata.

 Most terrestrial salamanders feed by capturing prey with a large, moist/sticky tongue  Tongue barely protrudes from the mouth (only a few millimeters) (Non-chamaeleonid iguanians & Sphenodon are similar)  More substantial tongue projection evolved in several lineages:  Salamandridae; Chioglossa & Salamandrina  Plethodontidae; several groups  All forms are lungless; Buccal floor freed from respiratory function (=buccal pump) & removes constraint on hyobranchium


Describe the typical feeding sequence of projectile tongue feeding in Caudates.

 Typical feeding sequence in Caudata: 1. Tip of mandible often placed in contact with substrate 2. Muscle contraction raises skull 3. Contraction of the paired muscles draw hyobranchium (=hyobranchial skeleton or hyoid apparatus) forward; Tongue supported by hyobranchium; Pushes tongue out of mouth. 4. Tongue generally changes shape; Well defined ridge anteriorly, with central depression; Prey adheres to sticky secretions of tongue 5. Tongue retracted by contraction of separate muscle Net result: tongue protruded only a few millimeters from mouth


How does the typical feeding sequence of Caudates differ in Plethodontid Salamanders?

Plethodontid Salamanders 

 Most pronounced in bolitoglossines

 Some project tongue up to half their body length

 Same muscles are involved as in other caudate “minimal” projectile tongue feeding

 Muscles and hyobranchium more greatly modified

 Prey adheres to sticky surface of tongue and is drawn back into mouth

 Feeding sequence takes only 4-6 milliseconds

 Main components of projectile tongue: Y-shaped hyobranchial skeleton; Long, tapering epibranchial cartilages; Paired ceratobranchial cartilages; Basibranchial cartliage (Supporting base of tongue; tongue not attached to floor of mouth); & Specialized muscles: Subarcualis rectus I (Tightly coiled around epibranchials) & Retractor muscle


Describe Projectile Tongue Feeding in Anurans.


  Most species feed via a projectile tongue
  May be combined with lunging body toward prey
  Tongue essentially flipped out of the mouth
  Anterior end of tongue attached to floor of mouth;
posterior portion is free
  Tongue supported by genioglossus muscles

   Tongue projection not as rapid as salamanders   Takes ~ 35-40 milliseconds

  Not all anurans rely on projectile tongue; Rhinophrynus: Feeds on ants and termites (Relies on tongue protrusion) & Pipidae: Tongueless (suction feeding)


What is the feeding sequence of projectile tongue feeding in Anurans?

 Feeding sequence:
1. Genioglossus contracts & stiffens forming a stiff rod
2. Submentalis muscle also contracts; Short, transverse muscle at front of mandible; Contraction causes muscle to bulge upward
3.  Submentalis pushes on stiffened tongue; Propels tongue upward and forward

4. Free posterior end of tongue flipped forward and downward onto prey; Prey adheres to sticky tongue surface
5.  Contraction of hyoglossus muscle retracts tongue


Describe projectile tongue feeding in Chameleons.

  Represents a clade within the Chamaeleonidae
  Capable of projecting tongue ~1.5-2X their snout-vent length

  Main components of projectile tongue:
  Tip: external sticky pad and powerful circular muscle (=accelerator muscle)
  Accelerator muscle wrapped around anterior extension (=processus entoglossus) of hyobrancial skeleton; Accelerator muscle constricts on processus entoglossus
  Hyoglossus muscle attached to posterior end of tongue tip;  At rest, loosely pleated behind tongue; Retracts tongue to mouth


What were the two different feeding environments mentioned in class?

 What are the advantages and disadvantages of each?

Two feeding environments are Terrestrial and Aquatic.

  Methods of feeding in aquatic and terrestrial environments differ

  Advantages of aquatic feeding & disadvantages of terrestrial feeding: 

1.) Food manipulation accomplished without much effort in aquatic environment & effort required in terrestrial  

2.) Saliva not required for food lubrication in aquatic but required in terrestrial

  Disadvantages of aquatic feeding and advantage for terrestrial:

1.) Predator movement generates pressure waves & moves prey away in aquatic but not in terrestrial



Define and describe suction feeding in aquatic environments.

  Aquatic salamanders (adults&larvae), aquatic frogs, tadpoles, some turtles use suction feeding
  Essentially Sucking/drawing food into mouth
  Two main factors must be overcome: 1.) Initial inertia 2.) Water viscosity **Requires great deal of force

  Involves negative pressure in the buccal cavity via expansion of buccal cavity
  Generate enough pressure to draw prey into mouth
  Must be rapid to prevent prey escape

Suction Feeding
  Mouth opening usually small which allows directional suction;

EITHER 1.) Unidirectional flow of water through buccopharyngeal cavity; Only possible when gill slits present

2.) If no gill slits, depends on bidirectional flow


Define and describe unidirectional flow suction feeding in aquatic environments.


  Aquatic Salamanders; Larval and highly paedomorphic salamanders possess gill slits

  Two phases involved with suction feeding
1.) Expansive phase: Jaws open, hyoid apparatus drops, and buccopharyngeal cavity expands; Rapid flow of water into and through the buccopharyngeal cavity (negative pressure)
2.) Compressive phase: Rapid elevation of mandibles (=closing mouth), hyoid apparatus elevated; Water ejected through gill slits (positive pressure

  Tadpoles: Employ different mode of suction feeding;  Unidirectional flow of water & continuous suction feeding by continuous pumping of buccal cavity (not in bursts)


Define and describe bidirectional flow of suction feeding in aquatic environments.

What are the different ways this is made more efficient in Anurans, Turtles, and Tadpoles?

  Bidirectional flow is when food is pumped into the mouth, but then the water must go back out of the mouth;  less efficient because loss of prey item more likely

  Anurans; Adult Pipid frogs; Xenopus and Pipa also use forelimbs to place food in mouth.

  Turtles; Some aquatic turtles employ suction feeding; No gill or pharyngeal slits = bidirectional flow; Before opening mouth (=dropping lower jaw), hyoid is elevated in order to maximize the amount of negative pressure generated 

 Tadpoles;  Water continuously passed across a filter; Most tadpoles feed on suspended phytoplankton or scrape algae from substrate; Alternating dropping and elevating the buccal floor (=floor of mouth) of buccal cavity moves water through system = buccal pump; Suspended food particles trapped by filter; Particle filtration takes place in pharyngeal cavity; Sieving through branchial filters or entrapment by mucus filaments (mucus entrapment);  Mouth parts generally have several rows of small keratinized structures on oral disk surrounding mouth or labial teeth (labial tooth rows)


Explain in detail the suspention feeding by bidirectional flow in tadpoles.

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What are the different mechanisms that have evoloved for terrestrial feeding?


  Different mechanisms have evolved for terrestrial feeding
  Major specialized mechanisms involved:
  Tongue protrusion (including projectile tongue)
  Cranial kinesis; squamates (particularly snakes!)
  Constriction
  Venom delivery

  Akinetic skulls and nonprojectile tongue feeding
  General characteristics are rigid skull and hinged mandible


Describe Akinetic Skull and Nonprojectile Tongue Feeding in Caecilians. 

  Compact and rigid skulls; Adaptation for burrowing; Some lineages have limited cranial kinesis
  Well developed (relatively large), recurved teeth; Assists with prey capture and restraint/retention
  Tentacle: Chemosensory function


Describe Akinetic Skull and Nonprojectile Feeding in Turtles.


  Generally, heavily built skulls (Retained, primitive condition)

  Absence of cranial kinesisis likely a secondary loss (=derived condition); Occurred early in turtle evolution

  Extant taxa lack teeth; Upper and lower jaws covered with sheaths = rhamphothecae (Composed of keratin)

  Jaws often modified for different diets

  Broad crushing jaws for feeding on hard-bodied prey (=durophagous) like mollusks and crustaceans                                         U.S. taxa: Graptemys, Malaclemys

  Narrow jaws with sharp rhamphothecae for Slicing/dismembering soft-bodied prey; “chopping”                                                     U.S. taxa: Apalone, Chelydra

  Sharp rhamphothecae & rearward motion of lower jaw; Primarily seen in testudinids; Herbivorous diet so rhamphotheca modified for slicing plant material


What are the different jaw modifications found in terrestrial feeding turtles and what is each modification for?

  Jaws often modified for different diets

  Broad crushing jaws for feeding on hard-bodied prey (=durophagous) like mollusks and crustaceans                                         U.S. taxa: Graptemys, Malaclemys

  Narrow jaws with sharp rhamphothecae for Slicing/dismembering soft-bodied prey; “chopping”                                                     U.S. taxa: Apalone, Chelydra

  Sharp rhamphothecae & rearward motion of lower jaw; Primarily seen in testudinids; Herbivorous diet so rhamphotheca modified for slicing plant material


Describe Akinetic Skull and Nonprojectile Tongue Feeding in Crocodilians.

  Heavily built and rigid skulls
  Open mouth by lifting the skull (unlike caecilians
& turtles); Extensive muscles allow a very forceful, downward bite

  Primarily carnivores

  Broadest skulls are generalists; Assists feeding on large, hard-bodied prey
  e.g., Alligator mississippiensis

  Slender jaws feed primarily on fish 
  Some species of Crocodylus
  Gavialis & Tomistoma exhibit the greatest specialization

  All lack “slicing” teeth and exhibit “rotational feeding” that allows them to pull off larger chuncks of food for feeding instead of swallowing the whole prey item; More important for larger prey items

  Possess a pyloric gizzard; A muscular posterior region of stomach; Aids in digestion of large and bony prey via grinding


Describe Akinetic Skull and Nonprojectile Tongue Feeding in Sphenodon.

  Generalist;  feeds on small vertebrates and invertebrates
  Acrodont dentition, with complex pattern; (Pair of enlarged incisor-like teeth at front of upper jaw; Pair of canine-like teeth at front of lower jaw; Smaller marginal teeth along maxilla and dentary; Palatine teeth are parallel to maxillary teeth)

  Prey capture and manipulation
  Small inverts captured with sticky tongue (slightly
  Larger prey are impaled on enlarged anterior teeth; Crushing and shearing of prey within mouth


Describe Akinetic Skull and Nonprojectile Tongue Feeding in Amphisbaenians (long, legless lizards).

  Compact and rigid skulls; Secondarily derived condition
associated with burrowing

  Diet of invertebrates & small vertebrates; Some have sharp, recurved teeth; Pleurodont or acrodont dentition

  Some species actually tear or shear off pieces of prey items which requires twisting of body and/or head.


What is the primary purpose of the evolution of venom delivery systems in squamate reptiles?


  Venom delivery systems present only in some squamate reptiles

  Multiple (=independent) origins

  Primary purpose is prey capture & digestion
  Ancestral function was more likely related to digestion
  Defense is a current secondary role


What are the traditional views on venomous squamates and derived morphology?

What was evidence for this idea?


 Traditionally, all extant “venomous” squamates belong to the Anguimorpha & Serpentes

  Only one extant “lizard”: Heloderma

  Slightly grooved mandibular teeth in extinct Estesia mongoliensis

  All others are snakes (i.e., viperids, elapids, and some “colubrids”)


Discuss envenomation in Heloderma.

  2 extant species of Heloderma:
1. Gila Monster (H. suspectum)
2. Beaded Lizard (H. horridum)

  Large venom gland associated with mandible; Located on lateral side; Gland homologous to mandibular gland (=gland of Gabe) of varanid (and other toxicoferan) lizards;  Venom travels to labial side of mandibular tooth row via 1-5 ducts

  Posterior mandibular teeth possess anterior and posterior grooves

  Must maintain bite on prey for envenomation

  Prey: Small mammals, ground nesting birds & eggs, small reptiles


Discuss venom delivery in snakes.

  Most snakes lack complex venom delivery systems; No modification of teeth (=aglyphous condition)

  Venom delivery shows various degrees of specialization and has multiple origins 

  Venom glands have a maxillary location; “Well developed”, secretory gland found in 30-40% of

  Usually placed into 2 traditional morphological groups:
1. Rear-fanged: Opisthoglyphous condition
2. Front-fanged: Proteroglyphous and solenoglyphous conditions


Discuss venom delivery in Opisthoglyphous.

REAR FANGED CONDITION:  Seen within the “Colubridae”

  Enlarged, grooved posterior maxillary teeth

  Two traditional competing hypotheses
1. Many independent origins, or 2. evolved early in colubrid history with many secondary losses

  Venoms of most rear-fanged snakes are weak and delivery system is inefficient; Venoms likely play a bigger role in prey digestion

  Local examples: Trimorphodon, Hypsiglena

  Some are quite dangerous (Africa & Asia); ie. Boomslang (Dispholidus typus) and Rhabdophis


Discuss venom delivery in Proteroglyphous.

 ONE OF THE FRONT-FANGED CONDITIONS:  Exhibited by elapid snakes

  Hollow fangs anteriorly located

  Relatively short (compared to vipers) and fixed in an erect position

  Other maxillary teeth located posteriorly


Discuss venom delivery in Solenoglyphous.

 ANOTHER FRONT-FANGED CONDITION:  Exhibited by viperids

  Hollow fangs anteriorly located

  Relatively long (compared to elapids)

  Fangs are hinged; Fold back when mouth is shut & erected when mouth is opened = rotation of short maxilla; Other maxillary teeth generally absent


Discuss venom delivery in Atractoaspis. 

Atractaspis (Lamprophiidae)

  The stiletto snakes or burrowing vipers

  Odd group of venomous snakes with unique dentition condition (similar to solenoglyphous with front-fanged condition)

  Relatively long, hollow fangs on short maxilla

  Fangs swing outward


Discuss venom delivery in snakes in terms of efficiency.

  Anteriorly located and hollow fangs generally more efficient at venom delivery

  50-60% in rear-fanged vs 80-95% in front-fanged snakes



Discuss the evolution of venom and compositino of venom. 

  Traditionally, elapid venom is largely neurotoxic, while viperids possess largely hemotoxic venom

  Finding many exceptions to this rule
  Venoms a mix of a large number of polypeptides/ proteins (toxins) with varying biological activities

  Toxins in snake venoms recruited from body proteins and then incorporated into venom system
  Many toxins first originated in common ancestor of Iguania, Serpentes and Anguimorpha (Toxicofera; =Venom Clade)
  Toxins produced by maxillary and mandibular glands
  Subsequent evolution of more potent toxins in Serpentes and helodermatids
  Also loss of maxillary (helodermatids) and mandibular (snakes) glands; elaboration of venom producing glands


Discuss the evolution of fangs.

  Where did the enlarged, anteriorly placed fangs come from?
  Derived from the enlarged posterior fangs from “colubrids”

  Future studies need to continue developmental studies from a wider range of colubroid taxa exhibiting varying dentition conditions


What is the theory of sexual selection?

Who originally formulated the idea?

What does it lead to?

  Originally formulated by Charles Darwin
  Explains evolution of secondary sex characteristics

It is a special type of selection that favors traits/phenotypes that increase the probability of mating

(vs. Natural selection that affects overall survival & acts upon traits that adapt an individual to itʼs environment

Sexual selection leads to differences between the sexes; Secondary sexual characteristics (E.g., larger body size, crests, bright/showy coloration)
Specie that exhibit secondary sexual characteristics have sexual dimorphism


What are the general outcomes of sexual selection?

  Two general outcomes of sexual selection:
1. Selection upon traits that allow males to better compete with other males (male-male competition); Examples: Larger body sizes, loud mating calls
2.  Selection upon traits that lead females to prefer one male over another (female mate choice); Examples: Ornamental structures, bright colorations, mating calls

  Favored explanation: Signal of health & quality
  Often responsible for evolution of “extravagant” traits
  “Fisherʼs runaway selection”


Which sex is generally under more intense sexual selection? Why?

What is a common mating system because of this?

Males generally under more intense sexual selection

  Reproductive success of females limited by energy intake for clutch/brood; Limited number of eggs and/or clutches; Most reproductively active females successfully mate

  Reproductive success of males limited by number of mates; Sperm is cheap

  Polygyny (multiple females) is common when males contribute little or nothing towards parental care


Discuss how there may be conflict between sexual selction and natural selection acting on an organism.

  At times they may be opposed;  Trait that may increase probability of mating may decrease probability of survival
  Example: Loud/ conspicuous advertisement call may increase probability of predation
  There are always trade-offs   Need to survive and reproduce


What type of mating system do the majority of herps have?

What are two things that dictate male mating strategies?

 Majority of herps display polygynous mating systems (many females with one male)
  Various behavioral tactics utilized by males 

Male strategies dictated by:

1. Spatial distribution of females (aggregated vs dispersed)

2. Temporal receptivity (short vs long period)


Explain Explosive Mating Aggregations seen by many anurans.

Explosive Mating Aggregations

  Often in temporary ponds and during early spring
  Short breeding period (one to several nights) with large number of individuals with males competing for mates
  Strong selection pressure for short breeding period; Ephemeral nature of breeding pond; Cannibalism & predation

  Males arrive first & are more abundant
  While calling, males move around searching for potential mates

EXAMPLE OF THIS: Wood Frog, Lithobates sylvatica


Explain Explosive Mating Aggregations seen by salamanders.

  Characteristic of Ambystomatid salamanders
  Winter and/or early spring breeding
  Males court females; deposition of multiple spermatophores

  Hynobiid salamanders
  Males form mating balls around deposited egg sacs (a bunch of salamanders joined on top of the eggs to fertilize them)


Explain Explosive Mating Aggregations in Reptiles.


  Rare among reptiles
  Occurs in some Thamnophis and European natricine snakes
  Form large communal hibernacula during winter & in spring, males emerge first, then intercept and mob females
  Successful males deposit waxy sperm plug


What are some generalities about Explosive Mating Aggregations?

1. Males outnumber females (Possibly because greater mortality in females, delayed sexual maturity of females, or annual mating by males, but not by females)

2. Successful males generally mate only once or few times & many males do not mate

3.  Male-male competition driving sexual selection (rather than female mate choice)


What are some tactics for mate searching?

Mate searching done because individuals largely solitary and potential mates are widely dispersed
 Mate searching is common in many aquatic turtles, lizards, snakes, and
some salamanders
1.  Individuals have large overlapping home territories; During breeding season males are more active & females often produce pheromones; Even with this most males never find mates in given breeding season, and there is little male-male competition (nor female mate choice)

2. Multiple males aggregate around female; Males remain with female for extended periods of time and multiple matings are common; there is male-male competition, but no combat (mate guarding); Overall, multiple males per female; females involved with multiple aggregates

3. Males fight over females; Prolonged searches generally absent; no large aggregations & males spend short time with females

4.  Males search for females in aquatic medium (Some salamandrids); Females may release water borne pheromones; amplexus prevents other males from mating (mate guarding)


Discuss mate guarding as seen in salamanders and anurans.

Is it common in any other groups?

If so, which ones?

 Males remains with female to defend and prevent other males from mating

  Amplexus behavior assists in guarding females; This consists of attendance, prolonged copulation, chasing off other males (active combat).

  Mate guarding before and/or after copulation; Male-male competition generally occurring
 This causes polygyny to be less prevalent
  Weaker sexual selection

Frequent among emydid turtles and some tortoises; they have aggressive contests

Common in many non-territorial lizardsLacerta (guard females for hours to days) & Scincid lizards

Less common in snakes; but they have prolonged copulation that may last hours to days or male-male combat in some pythons, viperids, elapids, and colubrids


What is a lek? 

What group has this as their general mating system?

What other groups do this?


  Lek: Aggregation of males on a traditional site to attract females

  General mating system of anurans

  Males gather in common area (may or may not be aquatic)
  Variety of calling sites
  Chorus may not be located at site of oviposition

  Often strong sexual selection to increase rate, intensity, and/or complexity of call; Male-male competition via vocal interaction (Out-signal neighboring competition)

  Greater amount of female mate choice; Females selecting based on call types/characteristics

  Other lekking taxa: Some salamandrids in ponds, some iguanids (Iguana iguana in dead trees & Amblyrhynchus at basking sites near shore), & some crocodilians 


What fields study multispecies patterns and the processes and mechanisms that generate such patterns?

Biodiversity biology &/or Macroecology


What is studied in biodiversity biology and macroecology?

Be sure to define what is meant by each segment of the answer.

Study of multispecies patterns and the processes and mechanisms that generate such patterns

Multispecies patterns: Number of species, population densities of the species, patterns of resource use, species distribution sizes

Processes and/or mechanisms: Competition, predation, environmental/physiological tolerances, historical factors


What is a community composed of overall?

What do biologist often focus on?


Overall, community is composed of all plant and animal species at a given locality or area

biologists often focus on a selected subset (=assemblage)

because communities are very diverse


Discuss the differences in changes over time in a community short term vs long term.

Communities and their various assemblages are usually dynamic

  Short term: Changes not usually as dynamic

  Long term: Species assemblages change and move; Speciation, extinction, and immigration/emigration


What is one of the first and most basic tasks when studying a community?

Determine species diversity

  How many species are present = Species richness

  Requires long-term and/or extensive
sampling for accurate estimates

  Rare species found less frequently and may go un-noticed with small sample sizes

  “Ecologically specialized” species may also be sampled infrequently


Species diversity and richness vary from place to place, but what are some general patterns that do exist?

Just list them, not discuss them.

  Latitudinal variation; North/south gradient

  Elevational variation

  Climatic patterns


Discuss the latitudinal patterns that are seen in species diversity gradients.

Which groups fit this pattern and which do not?

  Latitudes further north and south of equator generally have lower species diversity (Pattern long known and evident in many plants and animals)

Increases in latitudes = decreases in mean temperature and increase in seasonality

  Overall, anurans, crocs, and snakes fit pattern. Lizards also, but extremely diverse in Australia.

  Turtles and salamanders do not fit this pattern as well (=more restricted areas of high diversity)

  Turtles: Eastern North America and SE Asia
  Salamanders: Eastern North America, southern Mexico and Guatemala


Discuss elevation patterns seen in species diversity gradients.

What groups display this type of pattern?


Species diversity decreases with increase in elevation

  Increases in elevation = decrease in temperature, increase in moisture, increase/decrease in habitat complexity

  Most amphibians and reptiles display this pattern, but there is an Exception: Plethodontid salamanders of Nuclear Central America (Few lowland tropical species, but many montane species)



What is the main determinant of climate?

Why does climate matter?

In general, main determinant of climate is latitude

As latitude increases the mean temperature decreases & magnitude of change between seasons (=seasonality) increases  (Moisture generally decreases).

Climate has a big affect on species diversity
  Big variables are temperature and rainfall


What is the one of the most cited studies for amphibians and reptiles species diversity?

What did it study?

What were the results?

For amphibians and reptiles, one of the most cited studies is Schall and Pianka (1978)

 It was a comparative study of U.S. and Australian herpetofauna


Anuran and turtle diversity; Highly and positively correlated with mean annual rainfall & Negatively correlated with mean annual sunshine

Lizard diversity; Highly and positively correlated with mean annual sunshine; Negatively correlated with mean annual rainfall

Snakes diversity; Positively correlated mean annual sunshine (U.S.) Opposite in Australia; Positively correlated with mean annual rainfall


What does historical biogeography use to explain geographic distribution of species and clades?


Historical biogeography uses phylogenetic information to help explain geographic distribution of species and clades.

Aswer questions like:
  Why have certain clades dispersed to some areas, but not others?

  Primary focus has been on the geological connections between areas


What paper advocated for the consideration of interplay between niche conservatism and niche evoltion and clade ages?

  Wiens and Donoghue (2004): Advocated the consideration of the interplay between niche conservatism and niche evolution, & clade ages

"Time-for-Speciation Effect" (TSE)

30-50 mya major speciation events in certain geographical areas