Test 3

1. Compare and contrast the concepts of parallel and convergent evolution.

Themes of Amniote Evolution:

• Increased independence from aquatic environments

• Stronger and more diversified environments

  • Jaw musculature

  • Dentition

• Increased activity

  • Improved locomotion

  • More efficient respiration

  • Increased metabolism

Parallel Evolution of Body Posture and Locomotion:

• Trend for limbs under body

• Both lineages include bi-pedal taxa (use their 2 back limbs, legs, to walk)

• Both lineages include some volant (flying) taxa

• Undulating side to side when walking counters pressure they would use to breathe, better to have limbs move in the same direction as they are moving in, limbs underbody

Parallel Evolution of Endothermy:

• Evolved in birds (archosaurs)  and mammals (synapsids)  in parallel, but independently, from different reptilian ancestors (shift in posture)

Benefits?

• Helps control body temperature, enzyme kinetics, can have physiology running optimally when needed

• Less reliant on water

• Supports large embryos (mechanical support, efficient gas exchange, waste storage without diffusion to external environment)

• Waterproof skin, helps keep water in 

Costs?

• Must be laid on land

2. Identify and explain parallel adaptations/evolutionary trends in the synapsid and sauropsid lineages with respect to the following

   1. Sustained activity

      1. Resolve conflict between respiration and locomotion

      2. Respiratory efficiency

Sauropsids:

1. Inspiration: intercostals pull rib anterior, diaphramatic pulls liver posterior, ischiopubic rotates pubis

2. Expiration: rectus and transversus abdominus rotates pubic bones dorsally

3. Curiassal breathing in therapod dinosaurs

4. Gastralia: ventral set of ribs used for ventilation 

Birds:

1. Inspiration: longissimus dorsi pulls ilium and lifts pelvis, while sternum rotates ventrally

2. Expiration: other muscles in image pull tail and pubis downward, while sternum returns to resting position 

3. Jaw mucles and temportal fenestrae

   1. Buccal pumping no longer necessary

   2. Jaw muscles diversify

   3. Bite and squeeze now possinle

2. Endothermy

   1. Insulation: fur, hair, feathers, pockets of air between skin and outside environment traps heat and keep warm air

Keratin: Hair, feathers, scales, hooves, claws, etc. primarily made of keratin, Alpha keratin in all vertebrates, Sauropsids also have beta keratin in scales and feathers, Chickens, legs covered in what looks like reptile skin, feathers on body

3. Excretion while conserving water

   1. Excreting nitrogenous waste: need to retain moisture while eliminating NH3+

Synapsids: 

• excrete highly soluble, less toxic urea (primitive condition)

• Highly concentrated liquid

Sauropsids: excrete urea (urine) + concentrated uric acid (solid)

Synapsyd/ Mammalian Kidneys:

• Loop of henle unique to mammals (synapomorphy)

  • Extension of the long tube that concentrates urine- mammals produce the most concentrated urine of any amniote

  • Anti-diuretic hormone (ADH) changes the permeability of the collecting duct to water- when water is scarce, tubile is highly permeable so water can flow back to tissues

  • Tubules in nephron always passing regions of increasing osmolality, so water always being pulled back into tissues (counter exchange)

Increased Gas Exchange:

• Synapsid lungs evolved when oxygen content of atmosphere were high

Sauropsid Kidneys: 

• Uric acid precipitates of solution in cloaca, and cloaca reabsorbs water and some salts

3. Use the examples provided in this lecture to support the argument that evolution is not a teleological process

Teleology: any philosophy that seeks to explain phenomena by the purpose they serve rather by their postulated causes

• Proposes that observed phenomena are designed with a purpose 

• Hypothesis: Evolution doesn't have a goal or a purpose

Lepidosaurs:

1. List and describe synapomorphies of lepidosaurs and squamates

Lepidosairs (snakes and lizards)- squamates

Synapomorphies:

• Keratinous, overlapping scales

• Epidermis periodically shed

Squamate Synapomorphies:

• Determinate growth 

• Cranial kinesis

2. Place lepidosuars, squamates, and sphenodon in a phylogenetic context

3. Briefly describe life history characteristics of squamates

• 4800 spp. of “lizards” (paraphyletic)

• 2900 spp. of snakes (monophyletic, nested within lizards)

Life History and Reproduction:

• Oviparity, eggs laid and developed outside of the mother

• Viviparity, live births

1. Viviparity evolved numerous times in both lizards and snakes 

2. Chorioallontic placenta (homoplasy with placental mammals)

3. Clutch size Highly Variable

   1. 1-> ~25

   2. Relates to body size and foraging mode

4. Provide several examples to illustrate how phylogeny can inform our understanding of character evolution in reptiles

Lizards:

• Body form reflects foraging style

• Small insectivores, Long bodies to be able to quickly chase insects

• Thick bodies, food doesnt run away dont need to be fast

• Ant specialists, thick scales, eat food that bites them back

• Nocturnal insectivores, large eyes, sit in once place and wait for food to come by, long sticky tongue at times

• Legless lizards, actively moving through complex substrates 

• Large carnivores, very strong, chasing mammalian prey

Hunting modes:

• Sit and wait predators

• Widely foraging predators

5. Identify and explain several examples of homoplasy in lepidosaurs

Parthenogenesis: reproduction from an unfertilized egg, no males necessary (asexual reproduction)

• Evolved multiple times, example of homoplasy

• Offspring will not have equal amount of homologous chromosomes, cant do meiosis properly

Costs and benefits:

• Not worrying about stds

Squamate thermoregulation:

6. Highly efficient behavioral thermoregulation

   1. Habitat selection

   2. Orientation to sun

   3. Body contour changes

7. Color changes

8. Vasodilation 

9. Evaluate the different hypotheses for the ancestral origin of snakes

10. Define, compare and contrast two different kind of mimicry

Mimicry: the act of imitating someone or something 

Mullerian Mimicry: models mimic one another

Costs: predator learns to avoid a particular color pattern, 

Benefits: Predators always has the same situation

Batesian Mimicry: harmless mimic

Costs: parasitizing the models, predator sees the mimic is tasty

Benefits: look like something toxic

11. Form and Function

• Describe how the body form of various lepidosaurs relates to foraging behavior

Lizards:

• Body form reflects foraging style

• Small insectivores, Long bodies to be able to quickly chase insects

• When presented with a body form, predict behavior

• Thick bodies, food doesnt run away dont need to be fast

• Ant specialists, thick scales, eat food that bites them back

• Identify and explain how different phenotypes relate to sit-and-wait vs actively foraging predators

• Nocturnal insectivores, large eyes, sit in once place and wait for food to come by, long sticky tongue at times

• Legless lizards, actively moving through complex substrates 

• Large carnivores, very strong, chasing mammalian prey

Hunting modes

Sit and wait:

• Venom important

• Thermoreception

Active foragers:

• Constrictors

  • Slow movement, chemosensation important, can eat large pray

• Nonconstrictors

  • Fast movement, visually oriented, capture small pray

Constrictors: long bodied

12. Describe the benefits of cranial kinesis

• Muscles are more efficient when they exert force perpendicular to point of action 

• Being able to rotate the quadrate, strong palatal muscles can exert larger force when gape is wide

• Become frontal and parietal when this is achieved through loss of lower temporal bar 

S&W: thick and agile

Highly active foragers: thin and fast

Arboreal: thin, maneuver 

Sea Snakes: 

How do they do this?

13. Small heads, eat prey bigger than their heads

14. Through extreme cranial kinesis, upper temporal bar lost, dentary bones unfused

15. Describe the different forms of snake locomotion

Snake locomotion

1. Lateral undulation

2. Concertina

3. Rectilinear

   1. Thick bodied snakes like boas and pythons

4. Sidewinding

16. Explain how different snakes envenomate prey (or potential predators), and briefly describe the components of snake venom

Snake venom:

• Rear-fanged

• Opisthoglyphous

  • Venomous colubrids

  • Larger rear fangs with smaller anterior

• Front- fanged

  • Proteroglyphous

    • Elapidae

    • Hollow lungs

Turtles:

1. List and describe synapomorphies of turtles

Synapomorphies:

• Shell, carapace and okastrib

1. Made of dermal bone

• Several unique aspects of cranial skeletal morphology

2. Ribs outside of pectoral girdle

3. Configuration of otic capsule and jaw adductor

4. No teeth, horny beak

2. Explain and distinguish two types of biological constraints

3. Universal, physical constraints

Functional Constraits:

Universal, physical constraints

1. The laws of physics constrain what adaptations are possible for any organism

4. Evolutionary history of a lineage can lead to physical constraints (phylogenetic constraints)

Phylogenetic constraints

1. Evolutionary history of a lineage leads it down a path, which limits the possibility for certain kinds of adaptations

5. Briefly describe life history characteristics of turtles

Life history:

• Oviparious

• 5-100 eggs

• No parental care

• Embryonic development 40-60 days

• Offspring are often much smaller than adults

• Long lived, slow to reproductive maturity

• Explain temperature-dependent sex determination

6. Describe migration and navigation in general, and discuss specifically in reference to turtles

• Costs and benefits

• Mechanisms of navigation

  • Sea turtles migrate, must nest on land, evolutionary -> phylogenetic constrant

  • Use olfaction, light, ocean currents, earth’s magnetic field

• Approaches to investigating migration and navigation

7. Discuss the state of and threats to turtle conservation

• Habitat loss

Archosaurs:

1. Define Mass Extinction, and describe the typical pace of recovery, as well as how mass extinctions influence future biodiversity

Mass extinction: rapid event in which a significant number of all species on the planet become extinct across a wide range of habitats. 

• Result in at least 75% of species in a short period of time

• Can be triggered by various catastrophic events, volcanic eruptions, asteroid, climate changes, change in sea level

Pace of recovery:

• Depends on ecosystem, adaptability of surviving species, and availability of ecological niches.

• Can take millions of years

Influence of biodiversity:

• availability of ecological niches

• Shifts in dominant groups 

• Reduced biodiversity and evolutionary bottlenecks

• Adaptive radiation

• Long term evolutionary patterns 

2. List the synapomorphies of Archosaurs, and place them in a phylogenetic context.

• Triangular orbit 

• Laterally compressed teeth

3. Add Archosaurs and Crocodilia to your growing phylogeny. 

4. Identify and describe some of the consequences of plate tectonics and mass extinction for biodiversity

• Plate tectonics: movement of Earth’s lithospheric plates, float on the more fluid asthenosphere beneath

  • Continental drift, when the plates move continents drift apart or collide

  • Mountain Building and Erosion, the collision of plates can create mountain ranges which can alter climate patterns, form new habitats, create barriers of species migration

  • Ocean Formation and Closure: influences the opening and closing of ocean

5. Identify and explain various examples of homology and homoplasy illustrated by the traits discussed in this topic. 

• Long bones hollow, convergent with birds

• Some of lost teeth in favor of beak

6. Describe ways that we might use different kinds of evidence to make inferences about the behavior of extinct organisms

• Fossils, parents and eggs

• Local structure

7. Identify the two major lineages of dinosaurs

Ornithischia and Saurischia

• Chia: hip

• Ornia: reptile

• Saur: dinosaur

• Identify examples of dinosaurs in each lineage

Ornithopods:

• Large, herbivorous, bipedal/ quadrupedal

• Parental care

Thyreophora:

• Plating, spikes or club on tail

• Herbivorous

• Plates, function, no one really knows, defense, thermoregulatory surface area

Marginocephalia: 

• Herbivorous

• Ceratopsians diverse and especially common in cretaceous, evolved from bipedal ancestor, frills sexually dimorphic

Sauropods:

• Enormous herbivores, largest terrestrial vertebrates

• Skeletal adaptations for large size

• Recognize the morphological differences in pelvic morphology, and relate them to improved locomotion

• Sarischia: bone points toward the front of the animal, flares into keel at the forward end

• Ornithischians: reversed pubis, points towards the tail and lies alongside and parallel to ischium

• Describe evolutionary trends in posture leading to more active styles of locomotion

  • Limbs under body

  • Bipedalism

Birds:

1. Add Aves to your growing phylogeny

2. List and briefly describe bird synapomorphies

• Feather anatomy

  • Archaeopteryx:

    • Important transitional fossil

    • Differentiated feathers, asymmetrical feathers

    • Robust sternum and flexible wrists as in non avian tetrapods

    • Fusion of phalanges similar to modern birds

• Identify the parts of a feather

3. Identify and describe different types of feathers, including their functions

Feather types:

Contour

• Body and flight

• Flight, water resistance, insulation

Semiplumes

• Lie beneath contour feathers

• Insulation

Down

• Rachis shorter than longest barb, entirely plumulaceous

• Insulation

Bristles

• Stiff rachis, barbs only at proximal end

• Around eyes, bill, toes

• Function like eylashes, aid in catching insects in some species

Filoplumes

• Long rachis, short barbs at distal end

• Sensory function, helps bind know when contour feathers need adjustment

4. Co-adapted trait complexes: Explain how different aspects of bird morphology evolved in mosaic fashion, ultimately contributing to more efficient flight

Mosaic evolution: variety of distinct rates within a lineage, increasingly form a complex trait complex, exhibits functional integration

• Describe changes in feather form and function

Tapered wings, slotted wing tips

• Describe changes in other aspects of morphology and physiology: relate form to function, with a particular emphasis on the physics of flight

• Diagram an airfoil and discuss the physics of generating lift

• Describe functional constraints on flight (wing loading, induced drag, generating lift, etc.) and adaptations to overcome them

• Induced drag: vortexes of air at wingtip that counteracts lift

• Aspect ratio: wing/ length ratio

• Tapered wings

• Slotted wing tips

• Wing loading: body mass/ wing area

  • Lower wing loading = less power needed to fly 

Wing loading too high = no fly

• 2.6g/cm2 probably the max for flying

• When presented with various wing shapes, discuss the related flight patterns, and how those wing shapes relate to induced drag

Wing shaped linked and flight style:

• High aspect ration, fast fliers and or high wing loading, low chamber

• Elliptical, slow and maneuverable, low aspect ratio, highly cambered, emarginated tips, rapid flapping

• Dynamic soaring, very high aspect ratio for sustained, fast soaring, need high persistent wings with a vertical gradient (ocean)

• Slotted, high lift, both long and broad, high chamber, good for static soaring, use thermals to lift

• Describe and distinguish the two alternative hypotheses to explain the origin of flight

5. Constraints:

• Explain how various adaptations for flight led to phylogenetic constraints, and explain the nature of those functional constraints

6. Describe the visual and auditory system of birds

Vision

• 4 types of photoreceptor cone cells in retina

• Oil droplets of differing color within cones

  • Characteristic of all sauropsids

Hearing

• Smaller lagena (homologous with cochlea in mammals) than mammals, but 10x as many hair cells/unit of length

• Hair cells tuned to specific frequency ranges

• Relatively large tympanic membranes

7. Define sexual selection and identify the two forms, and give examples of some traits involved

• Use various examples of sexually dimorphic traits in birds to illustrate the concept of sexual selection

Sexual Selection in Birds:

Why choose based upon song characteristics, display, and or plumage?

1. Cardinal on snow, stands out

2. Honest indicators, genetic quality, parasite load/ resistance

3. Quality of territory/ resources

Arbitrary “Aesthetic” Preferences

4. Female preferences may be arbitrary with respect to male quality

   1. Might result from pre-existing sensory biases

   2. Producing desirable males results in more grand offspring

   3. Might initiate “runaway sexual selection

8. Briefly describe different kinds of mating systems and systems of parental care in birds

Mating Syetm Mating Syetm Diversity:

• Polygamy: more than 1 mate per season

  • Promiscuity: males and females both have multiple mates

• Monogamy: 1 mate per season

  • Serial monogamy

  • Genetic monogamy

  • Social monogamy

    • Extra pair copulation (parental care together)

9. Explain how birds navigate during migration, and understand how this ability is evaluated experimentally

Migration:

• Many species in northern latitudes migrate bc of season change

• Physiological changes

  • Cues to migrate: circannual rhythm and day light

  • Substantial increases in fat stores

Migration and Navigation:

• Straightest path not always taken

  • Route determined by landmarks, prevailing winds, need to rest at feeding grounds

Naviagtional Cues:

• Position of sun, stars, requires internal circadian rhythm to calibrate expected positions

• Earth’s magnetic field

• Landmarks

• Possibly sound, odors

Bird Conservation:

• 1,500 of 11,000 bird species are threatened

Many threats:

• Loss of habitat

• Loss of food resources

• Light pollution

• Pesticides

• Building collisions

• Roadway fatalities

Estimated 3 billion fewer birds in North America now than there were in 1970

Early Synapsids and Mammals

1. Describe the evolutionary changes in non-mammalian synapsids that contributed to increased activity/metabolism

2. Place mammals in a phylogenetic context

3. List and describe the functional & evolutionary significance of mammalian synapomorphies

• Dentary squamosal jaw articulation

  • Relatively small dentary

  • Articulation: quadrate on cranium, articular on mandible, conflict between chewing and breathing

  • Dentary, now entire lower jaw

  • Articulation: dentary

• Mammalian Hair:

  • Only a few living cells at the base of the hair

  • As cells are moved upward from the living base, they become keratinized and pigmented with melanin

  • Fur keeps warm

  • Whiskers: sensory

  • Skunk: white streak, communication 

  • Toxic or sexual 

  • Hair types:

    • Pelage: fur coat

    • Vibrissae: whiskers

  • Mammalian Teeth:

    • Mastication: better when food fit together well

    • Occulsion: match up well so teeth don’t grind up together

    • Jaw movements change from up and down to more circular when chewing

    • Rounded multi cusp cheek teeth

  • Lactation: evolved, coincidence with diphyodonty and occlusion

  • Mammary glands: derived from apocrine sweat glands

    • Apocrine sweat glands secrete odors often associated with sweating, often associated with communication

  • Suckling: Note 2 lost in post-infant humans because larynx shifted ventrally to accommodate speech, we are prone to choking because of this

  • Differentiated Facial Musculature:

    • Initial adaptation of suckling

  • Cardiovascular System Supports High Activity

    • Annucleated Red Blood Cells

      • As they mature, they shed their nucleas, very few organelles

      • Packed with hemoglobin for maximum energy support