Lecture Exam 3 Flashcards
1
Q
What are the challenges to living in water for chordates?
A
- Cold temps
- High pressure
- Darkness
- Maintaining buoyancy
- Fluid resistance
- Osmoregulation
2
Q
What are diffusion and osmosis?
What does it mean that these are both passive?
A
Passive modes of molecular movement. Passive means they don’t require ATP
3
Q
What are solutes, solvents, and solutions?
A
Solutes - Dissolved particles in a solution
- E.g. salts and sugars
Solvent - Liquid that dissolves solution
- often water
Solution - Mixture of solutes within a solvent
- salt water
4
Q
What does it mean to be hypertonic, hypotonic, and isotonic?
A
Hypertonic - Having a higher [solute]
- causes organism to shrivel
Hypotonic - Having a lower [solute]
- causes organism to swell
Isotonic - Same [solute]
5
Q
Be able to determine which way water will move based on solute concentrations.
A
from higher to lower [solute]
6
Q
Why does osmosis matter?
A
Many organisms live in aquatic envirnoments which may be hyper or hypotonic. Important method to maintain homeostasis w/o spending ATP
7
Q
What are the characteristics that unite all chordates?
A
- Deuterostome development
- Post-anal tail
- Notochord
- Dorsal hollow nerve cord
- Pharyngeal gill slits/pouches
- Endostyle/Thyroid gland
8
Q
What traits are seen among the cephalochordates?
A
- Small, elongate, flattened, and nearly transparent
- Filter-feeders that spend most of their life buried in substrate
- Finger-like projections from mouth that grab food
- Lack a true heart but have a contractile vessel
9
Q
What traits are seen among the tunicates?
How can these animals help to combat climate change?
A
- Sessile filter-feeders as adults
- Lack complex sensory organs
- Have a heart that lies at the base of animal
- Monoecious
- Free-swimming larvae (tadpoles) have a notochord
Some species digest plastic and others sequester CO2
10
Q
What does it mean to be in the subphylum Craniata?
A
Chordates that have a head!
11
Q
What is unidirectional breathing?
A
How fish breath. In through mouth, over the gills, and out the body.
12
Q
What is buccopharyngeal pumping?
A
Used to create positive pressure. Open mouth, pull water in, close mouth, push water over gills
13
Q
What is ram ventilation?
A
Many filter-feeding species lost pumping and swim with open mouths (ram ventilation). Water flows through open mouth, across gills, and out body
14
Q
How does gas exchange happen across the gills?
A
When water moves across gills, gas exchange occurs between the blood vessels and the water. 02 diffuses from water into gills. CO2 diffuses from gills into the water
15
Q
What animals are in the “Agnatha”?
A
Hagfish and Lampreys
16
Q
What are the characteristics of hagfish?
A
- Simple eyespots, one large nostril
- Four pairs of sensory tentacles on head
- Horny teeth present on tongue
- Most dioecious
- Lost their true vertebral column over time. Have simple arcualia (rudimentary backbone)
- Worldwide distribution and prefer deeper, colder, marine waters
- 90-200 mucus pores to deter predators
17
Q
Why do hagfish produce so much slime?
A
It’s a defense mechanism against predators
18
Q
What are arcualia?
A
Rudimentary backbone, not a true vertebral column
19
Q
Why is it important that hagfish can handle hypoxia?
A
They eat while submerged in the carcass of their prey
20
Q
How do hagfishes osmoregulate?
- Are they hypertonic, hypotonic, or isotonic?
A
They don’t. They’re isotonic
21
Q
What are the traits of the lampreys?
A
- Primarily in northern temperate regions
2. Larvae live sedentarily in the floor of their environment for 3-7 years
22
Q
Are all lampreys parasitic?
A
No, only 18 species are parasitic
23
Q
What is an anticoagulant?
A
Prevents blood clotting
24
Q
How are the sea lamprey impacting the Great Lakes?
A
Invasive species accidentally brought to the great lakes by humans via Erie canal system, predating native fish species that haven’t evolved to survive lamprey attacks
25
What animals are members of the “Gnathostomata”?
Sharks, chimeras, rays, skates, bony fish
26
What novel traits do we see in the gnathostomes?
| o What is the importance of each of these new traits?
1. Vertebral column - Provides structure for muscle attachment, increases mobility, and protects the nerve cord
2. Cerebellum in the brain! - Coordination and regulation of muscle activity
3. Semicircular canal of the inner ear - Balance sensory organ, essential for mobility and stability
4. Myelination of neurons - Myelin sheathes insulate nervous signals and maintain speed of signal
5. Paired fins (pectoral and pelvic fins) - Helps w/swimming and buoyancy
6. Jaws - Allowed animals to exploit different foods
27
Know the basic external anatomy of fishes.
```
o Pectoral fins
o Pelvic fins
o Dorsal fins
o Anal fin
o Caudal fin
o Adipose fin
o Lateral line
o Gill openings
o Operculum
```
28
What are the characteristics of the Chondrichthyes?
1. Cartilaginous skeleton and jaws!
2. Teeth in tooth whorl and not embedded in the jaw
3. Large lipid-filled liver for buoyancy
4. Store urea in their tissues to make themselves hypertonic to the ocean
5. Have lateral line system to detect water displacement
6. (Dioecious) pelvic claspers in males assist in copulation
29
What are the different types of Chondrichthyes?
1. Sharks
2. Rays
3. Skates
4. Chimaeras
30
How do the cartilaginous fishes maintain buoyancy?
Large lipid-filled liver for buoyancy
31
How do cartilaginous fishes osmoregulate?
| o Are they hypertonic, hypotonic, or isotonic?
Store urea in their tissues to make themselves hypertonic to the ocean, water moves into the animal.
32
How are the pelvic claspers in male Chondrichthyes used in copulation?
Males insert clasper in females cloaca then sperm is guided by claspers
33
What is a lateral line? How does it help fishes in their aquatic environment?
It's an adaptation to detect water displacement and it allows them to find prey and sense predators stalking them
34
How does electroreception work in cartilaginous fishes?
Electroreceptors (“Ampullae of Lorenzini”) are located on the heads and fins. Canals (non-conductive) connect nerves to the surface. Canals are filled w/conductive gel that transmits electricity to the nerve
35
What is biofluorescence and its significance in the Chondrichthyes?
It's the ability to glow using biological processes. They absorb blue light and emit green light and the ability is used to recognize different species in low-light situations
36
How do rays and skates breathe?
Through spiracles, which allows them to rest on the ocean bottom and receive oxygenated water through openings in their heads, rather than breathing in water and sand from the ocean bottom.
37
What is the difference between rays and skates?
skates have circular bodies and their pelvic fin has two lobes. Rays are kite shaped and their pelvic fins have only one lobe.
38
What are chimaeras?
Chimaeras are cartilaginous fish in the order Chimaeriformes known informally as ghost sharks, rat fish, spookfish, or rabbit fish
39
Why do males and female chimaeras stay separated most of the year?
Males stay in warmer areas which may be better for sperm production
40
How do chimaeras mate and reproduce?
1. Sexes come together during an annual inshore spawning
2. males have on cephalic clasper and two pairs of pelvic claspers
3. all retractable and used to grasp female during mating
4. all lay eggs - take 18-30 hours to lay one egg
5. take 10-12 years to reach sexual maturity and have only a few young at once
41
What is a tapetum lucidum? How does it help animals see in dark environments?
Eyeshine, it reflects light like a mirror back through the retina. It gives cone and rod cells a second chance to pick up the light stimulus
42
What are the steps a shark goes through as it searches for, and obtains its prey?
1. Olfaction first
2. Lateral Line (follow wake of prey)
3. Vision (when in range). If it recognizes prey, it will attack and eat quickly
4. If prey is new to the shark it will circle the prey and occasionally ram it w/its rostrum
5. Last moments Shark closes its (opaque) nictating membranes and then switches to electroreception and attacks
43
How do apex predators like tiger sharks maintain healthy ecosystems?
Top-down regulators for communities. Keep prey populations in check
44
Why are shark populations so slow to rebound after they have been decreased?
Many sharks grow slowly, mature late, and have few offspring
45
In what ways are humans negatively impacting shark populations?
Fishing
46
What type of animals belong to the Actinopterygii? How many species are there?
ray-finned fish, many many species. Make up 99% of bony fishes and 50% of vertebrates.
47
What characteristics are novel to the bony fishes?
1. Ossified skeleton
2. Teeth embedded in jaw bones
3. Swim bladder
48
How do marine fishes osmoregulate?
Most marine fishes live in hypertonic environment, so they lose water and gain ions across body.
1. Drink lots of salt water
2. Specialized cells on gills excrete excess Na+ and Cl-
3. Takes ATP to do b/c solute is higher in the ocean
4. Urine highly concentrated (lots of solutes)
49
How do freshwater fishes osmoregulate?
Freshwater fishes live in a hypotonic environment, meaning that they gain water and lose salts
1. Drink very little water
2. Produce large quantities of dilute urine, which gets rid of excess water in body
3. Salts are obtained from food and/or cells on gills that absorb Na+ and Cl- from the water
50
How do archerfishes obtain their food?
Spit water at insects
51
How do moray eels eat?
have a second set of jaws that move independently of the primary jaws
52
How do anglerfish reproduce?
1. Immature males bite females and fuse circulatory systems
2. He acts as a parasite until maturation when he makes sperm
3. Male then atrophies until all that is left are his gonads, which fertilize the female’s egg
53
Describe the lives of mudskippers.
1. Marine fish that construct burrows on land
2. Hide in burrows during high tide
3. Forage in mud during low tide
4. Eggs are laid inside burrow
5. Up-turned chamber w/constant air pocket
54
How do seahorses reproduce?
1. During copulation male and female put their abdomens together
2. Eggs are released into male’s pouch which closes tightly as he releases sperm
3. Any unfertilized eggs are absorbed by the male for nutrition
4. Eggs develop in male for 2-4 weeks
5. Young expelled through muscle contractions
55
What percent of fish follow the XX/XY pattern of sex determination?
About 10%
56
Describe the sex lives of clown fish.
1. Largest in group is female, second is reproductive male
2. Others in group are immature males
3. If female dies, reproductive male changes to female
4. Largest immature male becomes the new mature reproductive male
57
What type of fishes belong to the Sarcopterygii?
1. Lungfishes
| 2. Coelacanths
58
What are the characteristics of coelacanths?
1. Paired fins move in diagonal pairs
2. fins have thicker bones than ray-finned fish
3. Swim bladder filled with fat for buoyancy
4. Marine and nocturnal
5. Dioecious and give live birth
59
How do lungfishes survive long periods of drought?
1. When water recedes, it burrows in the mud for estivation
2. Drop metabolism down to 1/60th normal rate
3. Mucus secretions form a protective envelope/cocoon around the fish
60
How do lungfishes breathe?
Have both gills and functioning lungs, just like lungs of tetrapods
61
Why are coelacanths considered a Lazarus taxon?
They were thought to be extinct until 1938
62
Why are coelacanths considered a living fossil?
Body hasn't changed in ~400 mil years
63
How are humans impacting populations of fishes?
Climate change, habitat loss, pollution, disease, invasive species, etc.
64
What is the biggest threat to fishes?
overfishing, climate change
65
What is bioaccumulation?
Heavy metals accumulate in tissues of fish
66
How do fish farms impact wild populations of fishes?
1. Fish at these farms are highly concentrated and produce large volumes of waste that promote blooms of algae and bacteria in the water which lowers o2 concentration in water
2. Sea lice are common in farm salmon and are transmitted to wild salmon as they swim near the farms
3. Fishmeal is made from catching small fish and invertebrates, depleting the food base of wild fish
67
What is an amphibian?
Four-legged vertebrates that have made it onto land
68
What are the three different orders of amphibians?
| ▪ Which group have the greatest number of species?
1. Urodela - Salamanders
2. Anura - Frogs and Toads (most species)
3. Apoda - Caecilians
69
What is the difference between ectothermy and endothermy? Which type of animals have which type of heat regulation?
Ectothermic - energy used to maintain body temp comes from the environment
Endothermic - Maintain body heat internally
70
Why are the smallest endotherms significantly larger than the smallest ectotherms?
Small things have high SA:Vol, thus exchange heat quickly
71
What are the four ways in which animals exchange heat with their environment?
1. Conduction - Touching something
2. Convection - Water or air moving past animal
3. Radiation - Heat energy from sun or other objects
4. Evaporation - Removal of water (and heat) by air
72
What is a salamander?
The most basic body plan of all amphibians
73
Where in the world is the greatest biodiversity of salamanders?
Smokey Mountains of Tennessee
74
How do salamanders move?
Use lateral bending of trunk and limbs for movement
75
Which type of salamanders have the greatest number of species? Why is this groups of salamanders so successful? What is the significance of the tongue bone in these salamanders?
Lungless salamanders. They can catch prey from great distance with their extra longue tongue which shoots out of their mouth incredibly quickly
76
How do salamanders court each other and reproduce? Where do they lay their eggs? What do their larvae look like?
1. Pheromones stimulate the receptivity of females. Male wipes pheromones from his chin onto the nostrils of the female. Some species bite the females then slather the wounds with pheromones.
2. If female is interested she will touch his tail w/her snout. Male lays down his sperm packet. Female picks it up w/her cloaca
3. Most salamander eggs are laid in water either singly or in mass and hatch into gilled larvae.
4. Some lungless salamanders lay eggs under logs and leaf litter. Gills of larvae are absorbed before hatching. Hatch as mini adults!
77
What are the characteristics of frogs that make them modified for jumping?
1. Fused tibia and fibula (leg bones) to withstand the force needed to jump
2. Fused tail bone (urostyle) and pelvis fastened to spine which acts as springboard to generate force for jump
3. Strong fused radius and ulna (arm bones) to withstand the force needed to catch the frog as it lands
4. Large binocular eyes to be able to see depth/where they are jumping
78
What is a urostyle?
a fused tailbone
79
What is the significance of the fusion of the leg bones in frogs?
They can withstand the force needed to jump
80
What is ecomorphology?
How the morphology of an organism is explained by its interactions w/its environment
81
What are the different ways in which frogs move?
| o Which type of frogs use each kind of movement?
```
Hopping - Terrestrial
Jumping - Semi-aquatic
Climbing - Tree
Swimming - Aquatic
Digging - Burrowing frogs
```
82
How does the type of locomotion vary by the type of environment in which the frog lives?
83
Which types of frogs are often toxic?
Fully-terrestrial frogs and Toads
84
Which types of frogs are often camouflaged?
Tree frogs
85
What is a parotoid gland? Which kind of frogs have these?
Located behind the eyes to secrete poison. Toads.
86
How does the morphology vary by terrestrial, semi-aquatic, burrowing, tree-dwelling, and aquatic frogs?
87
What is amplexus? How does fertilization happen in frogs?
Amplexus - male mounts and grabs female.
| o Eggs and sperm released for external fertilization
88
What are the different types of parental care seen among frogs?
1. Guardian frog - Carries his eggs until they hatch, then he drops them at a pond
2. Strawberry Poison Frogs - Feeds unfertilized eggs to tadpoles in water
3. Darwin’s frog - Males hold eggs in vocal sacs (that extend into pelvis) until babies metamorphose
4. Surinam Toad - Carries eggs in her back until metamorphosed juveniles emerge
5. African bullfrog - Guards eggs and digs channels to guide tadpoles to pools of water
89
What are the characteristics of caecilians?
1. All legless, burrow underground, or are aquatic
2. Eyes are greatly reduced
3. retractable sensory tentacles on each side of the snout
4. Internal fertilization
90
Where do caecilians live?
Mostly in S. America, but also Africa, India, and SE Asia
91
Describe the eyes of caecilians.
1. Eyes are greatly reduced, often covered in skin or bone.
2. Some species have lost eyes entirely.
3. See shadows, but not colors
4. Can’t form images
92
What is the significance of caecilian protrusible tentacles?
Tentacles pull in chemical cues to the vomeronasal organ
93
What is the vomeronasal gland?
The vomeronasal organ (VNO), or Jacobson's organ, is the paired auxiliary olfactory (smell) sense organ
94
How do caecilians reproduce?
Internal fertilization and males have an intromittent organ. 75% have live birth
95
What is dermatophagy?
Young feed on mother’s thickened skin. She regrows it and feeds them again
96
How do amphibians breathe? When do they depend on their lungs?
1. Water and gas diffuse across the skin of amphibians
2. During low activity they use cutaneous respiration. Lungs are bypassed, but three-chambered heart continuously pumps oxygenated blood.
3. As temp and/or activity level increases, amphibians depend heavily on lungs. Increased metabolic rate needs more oxygen
97
How many chambers are in the amphibian heart? How does it work?
3 chambers
98
What are the different ways in which amphibian reduce water loss?
1. Cutaneous glands that secrete mucus
2. Estivate while waiting for rain
3. Semi-aquatic frogs have a pelvic patch
99
What is a pelvic patch?
Highly vascularized region near the hind legs where water is rapidly absorbed. Only need their rear end in the water!
100
What is metamorphosis?
Transformation from larvae to mini adults
101
What anatomical structure regulates metamorphosis?
Thyroid gland
102
What environmental factors increase the rate of metamorphosis?
1. Overcrowding
2. Reduced food or oxygen
3. Decreased water availability
4. Increased predation, etc.
103
How does amphibian metamorphosis differ from that of insects?
Unlike insects, amphibians stay active during metamorphosis
104
How do salamander larvae differ from frog larvae (tadpoles)?
1. Salamander larvae have external gills
| 2. Frog gills become covered w/operculum
105
What is pedomorphosis?
Retention of juvenile traits into adulthood
106
How is the pedomorphosis in mudpuppies different from that of axolotls?
Mudpuppies retain childlike traits (gills) when they reach sexual maturity, but axolotls may develop further if their pond dries up
107
What are some of the cool/interesting characteristics of the axolotl?
1. Axolotl will remain gilled its entire life unless its pond dries up
2. Walk onto land to find a new pond
3. Can regenerate limbs, spinal cord, and tail
108
What percentage of amphibians are at risk of extinction?
40%
109
What are the primary ways in which amphibian populations are being negatively impacted? Which is the largest impact?
1. Habitat destruction***
2. Pollution
3. Climate change
4. Diseases
110
What is chytrid fungus and how does it impact the skin of amphibians? What is keratinization?
It's a water fungus w/motile spores. It increases the keratinization of the skin, limiting water and gas exchange
111
Describe the salamander-eating fungus. How was this fungus introduced into Europe? How are North American governments trying to prevent this disease?
A disease that has skin-digesting enzymes, immunosuppressing properties, and its spores are dispersed by the feet of birds. Genetics revealed that it originated in Asia and was brought to Europe through the pet trade. Canada and the US both heavily restrict the trade of salamanders.
112
What are some of the challenges to living on land?
1. Overcoming gravity
2. Less stable temperatures
3. Dealing w/water loss
113
What is the amniotic egg? What is the significance of this adaptation? Which type of animals have this trait?
1. Limits water loss for embryo
2. Leathery calcified shell
3. Eggs must be laid on land (and in dry areas)
4. They are larger than non-amniotic eggs
5. More nutrition = larger babies = better fitness
6. Reptiles (including birds) and mammals
114
What are the other traits that are new to the amniotes, and what is their significance?
1. Longer necks - increased mobility
2. Rib ventilation
3. Desiccation-resistant skin
4. Kidneys that conserve more water
5. Larger brains and sensory structures
115
How is breathing different in amphibians and amniotes?
```
Negative-pressure breathing in amniotes
Positive pressure (buccal pumping) in amphibians
```
116
What is a tuatara, and how are they different from lizards?
1. Lack earholes
2. Have third eye
3. Skull is akinetic and robust
4. Have two rows of teeth on top, one on bottom
5. Beak-like extension on skull
6. Prefer cool temperatures
117
What is decreasing the tuatara populations?
Over-hunting and invasive species of cats, rats, and dogs
118
What traits make tuataras different from lizards?
119
Where do tuataras sleep, and what do they eat?
Share burrows w/sea birds. Eat wetas and invertebrates attracted to bird guano, occasionally eat chicks and adult birds
120
What type of temperatures do tuataras prefer?
Cool temps
121
Why do tuataras evolve so slowly?
Takes them 10-20 years to reach sexual maturity
122
How do tuataras reproduce?
1. Females mate once every 4 years
2. Male courts female by changing color, lifting chest, & parading around her in circles
3. She either runs to burrow or submits
4. Lost their ancestral penis and now have a rudimentary intromittent organ so sperm transfer through cloacal kiss
5. Eggs are soft w/long gestation (12-15 months)
123
What is a cloacal kiss?
The male and female press their cloacals together for a few moments to transfer sperm to the female.
124
Who is Henry, and why did he not reproduce until he was 111 years old?
Henry is the tuatara on the NZ 5-cent, sired his first offspring at 111 because he had a tumor on his cloaca which kept him from wanting to mate
125
What animals are within the order Squamata?
Lizards and snakes
126
How do squamates reproduce?
Males hemipenes (paired penis) emerge during copulation and insert into females cloaca
127
What are hemipenes?
paired penis
128
How are sexes determined in squamates?
1. Many species have genetic sex determination, males are heterogametic (xy)
2. Temperature sex determination occurs in skinks, geckos, and bearded dragons
129
What types of parental care are seen among the squamates?
1. Guarding their eggs (skinks)
2. Incubating their eggs (some pythons)
3. Watching neonates until first shedding (rattlesnakes)
130
What characteristics are seen among the lizards?
1. Have eyelids and external ears
2. Most have 4 legs
2. Most have keen color vision
3. Often active hunters
4. Use lateral undulation like salamanders
131
How do lizards move?
Use lateral undulation like salamanders
132
How does lateral undulation affect lizards' breathing?
Compresses lungs side-to-side while running, unable to breathe in and out. Can only run for short distances
133
What type of adaptations do we seen among geckos, monitors, and chameleons?
Monitors are highly predaceous - Long necks and legs; less undulation > breathe easier
Chameleons have prehensile tails, long tongues, independently moving eyes, zygodactylous feet
Gecko feet allow them to cling to surfaces using Setae
134
How does the Gila monster conserve water in the deserts of Mexico?
Gila monsters store fat in tails for metabolic water
135
What senses do lizards in different environments depend on?
Fossorial - Depend on olfaction and touch
Arboreal - Acute vision for hunting and judging distance
Terrestrial - vision, hearing, olfaction
Semi-aquatic - Rare in lizards; Eat red and green algae in ocean; Water anole brings air bubble w/itself underwater
136
What are the ecomorphological features seen among lizards in different environments?
137
What are the characteristics of snakes?
1. Limbless
2. No eyelids
3. No external ears
4. Extreme elongation of body
5. Left lung reduced
6. Eyes covered w/transparent membrane
7. Skull specializations for swallowing large prey
8. Most snakes have poor vision
9. Primarily depend on chemosensation
138
How do snakes perceive their environment with poor vision?
1. Primarily depend on chemosensation
2. Use tongue to pick-up chemicals
3. Wipe tongue on vomeronasal organ on roof of mouth
4. Smell their environment!
139
What are the different ways snakes move?
1. Serpentine - Slithering
2. Concertina - Inch-worming
3. Rectilinear - Rib-walking
4. Sidewinding
140
What type of adaptations are seen among arboreal snakes?
1. Long and thin
| 2. Binocular vision
141
What type of adaptations are seen among Burrowing snakes?
smooth shiny scales w/short tails
142
What type of adaptations are seen among Aquatic snakes?
laterally flattened w/valves in nostrils
143
What are the three main ways snakes consume their prey?
1. Biting and swallowing whole - Smaller foods (insects, worms, etc.)
2. Constrict and swallow whole - Larger foods (mammals and birds)
3. Envenomate and swallow whole - Larger foods (mammals and birds)
144
How are the jaws of snakes adapted for eating larger prey items?
1. Snake jaws do not come unhinged, but an extra joint allows for the jaws to open wider
2. Stretchy ligament connects the left and right halves of lower jaw
3. Lower jaw can widen horizontally
4. Prey is “walked” into mouth
145
What are the four different types of dentition/fang types seen among the snakes?
1, Fangless
2. Rear-fanged
3. Front-fanged
4. Folding-fanged
146
What are example snakes that have each type of teeth?
1, Fangless - Boas, pythons, garters
2. Rear-fanged - Hognose, boomslang
3. Front-fanged - Corals, cobras, mambas
4. Folding-fanged - Rattlesnakes, vipers
147
What are venom glands, and how do they help snakes?
Modified salivary glands used to subdue prey
148
How does each type of snake venom impact its prey/victims?
1. Neurotoxins often impact the ability of nerves and muscles to interact (corals, cobras, mambas). Causes paralysis, heart, and respiratory failure
2. Cytotoxins kill cells and cause necrosis (e.g. puff adder)
3. Hemotoxins disrupt blood-clotting cascades (e.g. vipers)
149
What type of snakes have which type of venom?
1. Neurotoxins - Corals, Cobras, Mambas
2. Cytotoxins - Puff Adder
3. Hemotoxins - Vipers
150
How is snake venom in a coevolutionary arms race with prey species?
between venom toxicity and prey resistance
o Honey badger and cobras
o Virginia opossums and rattlesnakes
151
What is LD50, and how does it relate to the toxicity of venoms?
Concentration of toxin needed to kill half of the sampling population. The lower the LD50 the more deadly the venom.
152
What is an anti-venom, and how much do they cost?
Venom antidote. $9-119/dose elsewhere.
| $2300 per dose in the US for CroFab
153
What are the human benefits of snake venoms?
Snake venoms are extracted to treat human diseases
154
What are some examples of venomous lizards?
1. Beaded lizard
2. Gila Monster
3. Komodo Dragon
155
What disease are treated with venoms of snakes and/or lizards?
1. Cancers
2. chronic pain
3. Alzheimer’s
4. Clotting disorders
156
How many people die each year from snake bites in the US and worldwide?
Worldwide at least 20k people die from snakebites each year
157
How do lizards and snakes avoid predation?
1. Camouflage
2. Venom
3. Eavesdropping
4. Autotomy
5. Poisonous from prey they eat
158
What is unique about the regal horned lizard?
o Squirts blood from its eyes!
159
What are the major conservation threats for lizards and snakes?
1. Habitat loss
2. Direct persecution
3. Climate change
4. Disease, over-harvesting, invasive species, pollution
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What is the difference between turtles and tortoises?
Turtle/terrapin are more associated w/water
| Tortoises are land specialized turtles
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What senses are strong and weak in turtles?
Poor hearing but good olfaction and vision
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How do turtle skulls differ from those of snakes, lizards, and tuataras?
Turtle skulls are not flexible like snakes and lizards. Lack teeth but their jaws have sharp beaks
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What are the two parts to a turtle shell?
Carapace and plastron
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What is the turtle's shell made of?
Keratin
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How are the plastron and carapace formed?
Carapace (top) - Formed by expansion of ribs and covered by large keratin scales (scutes)
Plastron (bottom) is formed from ossified skin
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How does the height of the carapace vary between environments?
Aquatic - Flattened, softer carapace
Semi-aquatic - Carapace intermediately domed
Terrestrial - Domed carapaces
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How do turtles pull their heads into their shells?
Side-necked turtles retract their head by bending neck sideways. Leaving the side of neck exposed
Straight-necked turtles have special vertebrae in neck to bend it in s-shape
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How do the feet and shell of turtles vary among different environments (ecomorphology)?
Aquatic - Flattened, softer carapace. o Plastron often reduced. Webbed-feet or flippers
Semi-aquatic - Carapace intermediately domed. Feet partially webbed w/claws
Terrestrial - Domed carapaces. Column-like limbs w/toenails.
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How do turtles breathe?
1. To inhale shoulder girdle moves forward. Creates more space inside shell. Guts fall, pulling the lungs down w/them, makes lungs expand, pulling in air.
2. To exhale shoulders move backward, muscles push the guts back upward, pushes air out of the lungs and out the body
170
How do pond turtles find and court their mates?
1. Many pond turtles have bright patches (e.g. red ears). Allow them to recognize species and sexes underwater
2. Males vibrate their claws to tickle the sides of female’s head
3. Larger species often less romantic and bite the female and hold her under water
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How do tortoises court one another?
1. Many tortoises have glands on chins that produce pheromones
2. Wipe pheromones on their forelimbs
3. Lift forelimbs toward each other to sniff before mating
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How do turtles reproduce?
Internal fertilization and eggs are laid on land.
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What is temperature-dependent sex determination?
a type of environmental sex determination in which the temperatures experienced during embryonic/larval development determine the sex of the offspring.
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What is indeterminate growth?
Growth that is not terminated in contrast to determinate growth that stops once a genetically pre-determined structure has completely formed.
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What are the major threats to baby and adult turtles?
1. Predation (babies)
| 2. Human hunting
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What are the various ways in which sea turtles are being impacted by humans?
1. by-catch in fishing nets
2. Plastics
3. Climate change
4. Light pollution
5. Oil spills
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How have sea turtles been impacted by COVID-19?
Sea turtle nesting has increased during covid-19
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How have humans impacted populations of giant tortoises?
1. Loss of large trees for shade
2. Livestock over consume the tortoises food
3. Dogs, cats, and rats eat eggs & hatchlings
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Why are so many turtles imported out of the United States?
Sold as foods and medicines in Asian countries
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What are the traits of the crocodilians?
1. Semi-aquatic predators w/muscular jaws that close quickly and forcefully
2. Four-chambered heart
3. Thick scales w/bony plates
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What are the three families of crocodilians? What are the characteristics of each family?
Alligatoridae - Shorter broader snout w/lower tooth hidden when their mouth is closed
Crocodylidae - Longer less broad snouts, lower tooth exposed w/mouth closed. Most aggressive
Gavialidae - Long slender snouts
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What are the different ways in which crocodilians move?
Belly crawl – legs extend to the sides of the body, belly rubs on ground
High walk – legs are moved underneath and lift-up the organism. Used for moving far, but it’s slow
Gallop – moving of both sets of legs synchronously, while flexing the vertebral column
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What is the adaptive significance of the secondary palate?
Allows them to breathe w/only their nostrils and eyes above water
184
What are the different ways in which crocodilians capture and eat their prey?
1. Sneak up on their prey which are often pulled under water until dead
2. “Death roll” - Croc bites the prey and rotates itself along it’s long axis
3. Can wedge dead prey into shrubbery
4. American alligators lure birds by stacking sticks on their snouts
5. Wait along trails to ambush runners and pet dogs
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How do crocodilians lure their prey?
by stacking sticks on their snouts
186
What are the different sounds produced by crocodilians, and what do they mean?
Vocalizations and head slaps, used to signal location, proximity, and size of males
187
What is the “water dance”?
Created by males producing subsonic vocalizations to communicate his size
188
What do head slaps signal?
location and proximity to others
189
What is play?
activity that consumes time and energy w/no gain in reproduction or survival
190
What are the different types of play seen among the crocodilians?
1. Solitary locomotor play
2. Object play
3. Social play
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How do crocodilians reproduce?
1. All crocodilians are oviparous
| 2. Internal fertilization w/male’s penis
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What forms of parental care are seen among the crocodilians?
1. Females guard eggs
2. Build mound nests or excavate holes
3. Often guarded by several adults
4. Gharials form creches of 1k young
5. Contact calls and distress calls are used by the young for food sharing and protection
193
What is a crèche?
A group of young gharials
194
What are the major threats to crocodilians?
1. Habitat Loss
2. Invasive species
3. Hunting
4. Alligator and Crocodile farms
