Lecture Exam 3 Flashcards
What are the challenges to living in water for chordates?
- Cold temps
- High pressure
- Darkness
- Maintaining buoyancy
- Fluid resistance
- Osmoregulation
What are diffusion and osmosis?
What does it mean that these are both passive?
Passive modes of molecular movement. Passive means they don’t require ATP
What are solutes, solvents, and solutions?
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
What does it mean to be hypertonic, hypotonic, and isotonic?
Hypertonic - Having a higher [solute]
- causes organism to shrivel
Hypotonic - Having a lower [solute]
- causes organism to swell
Isotonic - Same [solute]
Be able to determine which way water will move based on solute concentrations.
from higher to lower [solute]
Why does osmosis matter?
Many organisms live in aquatic envirnoments which may be hyper or hypotonic. Important method to maintain homeostasis w/o spending ATP
What are the characteristics that unite all chordates?
- Deuterostome development
- Post-anal tail
- Notochord
- Dorsal hollow nerve cord
- Pharyngeal gill slits/pouches
- Endostyle/Thyroid gland
What traits are seen among the cephalochordates?
- 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
What traits are seen among the tunicates?
How can these animals help to combat climate change?
- 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
What does it mean to be in the subphylum Craniata?
Chordates that have a head!
What is unidirectional breathing?
How fish breath. In through mouth, over the gills, and out the body.
What is buccopharyngeal pumping?
Used to create positive pressure. Open mouth, pull water in, close mouth, push water over gills
What is ram ventilation?
Many filter-feeding species lost pumping and swim with open mouths (ram ventilation). Water flows through open mouth, across gills, and out body
How does gas exchange happen across the gills?
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
What animals are in the “Agnatha”?
Hagfish and Lampreys
What are the characteristics of hagfish?
- 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
Why do hagfish produce so much slime?
It’s a defense mechanism against predators
What are arcualia?
Rudimentary backbone, not a true vertebral column
Why is it important that hagfish can handle hypoxia?
They eat while submerged in the carcass of their prey
How do hagfishes osmoregulate?
- Are they hypertonic, hypotonic, or isotonic?
They don’t. They’re isotonic
What are the traits of the lampreys?
- Primarily in northern temperate regions
2. Larvae live sedentarily in the floor of their environment for 3-7 years
Are all lampreys parasitic?
No, only 18 species are parasitic
What is an anticoagulant?
Prevents blood clotting
How are the sea lamprey impacting the Great Lakes?
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
What animals are members of the “Gnathostomata”?
Sharks, chimeras, rays, skates, bony fish
What novel traits do we see in the gnathostomes?
o What is the importance of each of these new traits?
- Vertebral column - Provides structure for muscle attachment, increases mobility, and protects the nerve cord
- Cerebellum in the brain! - Coordination and regulation of muscle activity
- Semicircular canal of the inner ear - Balance sensory organ, essential for mobility and stability
- Myelination of neurons - Myelin sheathes insulate nervous signals and maintain speed of signal
- Paired fins (pectoral and pelvic fins) - Helps w/swimming and buoyancy
- Jaws - Allowed animals to exploit different foods
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
What are the characteristics of the Chondrichthyes?
- Cartilaginous skeleton and jaws!
- Teeth in tooth whorl and not embedded in the jaw
- Large lipid-filled liver for buoyancy
- Store urea in their tissues to make themselves hypertonic to the ocean
- Have lateral line system to detect water displacement
- (Dioecious) pelvic claspers in males assist in copulation
What are the different types of Chondrichthyes?
- Sharks
- Rays
- Skates
- Chimaeras
How do the cartilaginous fishes maintain buoyancy?
Large lipid-filled liver for buoyancy
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.
How are the pelvic claspers in male Chondrichthyes used in copulation?
Males insert clasper in females cloaca then sperm is guided by claspers
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
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
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
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.
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.
What are chimaeras?
Chimaeras are cartilaginous fish in the order Chimaeriformes known informally as ghost sharks, rat fish, spookfish, or rabbit fish
Why do males and female chimaeras stay separated most of the year?
Males stay in warmer areas which may be better for sperm production
How do chimaeras mate and reproduce?
- Sexes come together during an annual inshore spawning
- males have on cephalic clasper and two pairs of pelvic claspers
- all retractable and used to grasp female during mating
- all lay eggs - take 18-30 hours to lay one egg
- take 10-12 years to reach sexual maturity and have only a few young at once
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
What are the steps a shark goes through as it searches for, and obtains its prey?
- Olfaction first
- Lateral Line (follow wake of prey)
- Vision (when in range). If it recognizes prey, it will attack and eat quickly
- If prey is new to the shark it will circle the prey and occasionally ram it w/its rostrum
- Last moments Shark closes its (opaque) nictating membranes and then switches to electroreception and attacks
How do apex predators like tiger sharks maintain healthy ecosystems?
Top-down regulators for communities. Keep prey populations in check
Why are shark populations so slow to rebound after they have been decreased?
Many sharks grow slowly, mature late, and have few offspring
In what ways are humans negatively impacting shark populations?
Fishing
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.
What characteristics are novel to the bony fishes?
- Ossified skeleton
- Teeth embedded in jaw bones
- Swim bladder
How do marine fishes osmoregulate?
Most marine fishes live in hypertonic environment, so they lose water and gain ions across body.
- Drink lots of salt water
- Specialized cells on gills excrete excess Na+ and Cl-
- Takes ATP to do b/c solute is higher in the ocean
- Urine highly concentrated (lots of solutes)
How do freshwater fishes osmoregulate?
Freshwater fishes live in a hypotonic environment, meaning that they gain water and lose salts
- Drink very little water
- Produce large quantities of dilute urine, which gets rid of excess water in body
- Salts are obtained from food and/or cells on gills that absorb Na+ and Cl- from the water
How do archerfishes obtain their food?
Spit water at insects
How do moray eels eat?
have a second set of jaws that move independently of the primary jaws
How do anglerfish reproduce?
- Immature males bite females and fuse circulatory systems
- He acts as a parasite until maturation when he makes sperm
- Male then atrophies until all that is left are his gonads, which fertilize the female’s egg
Describe the lives of mudskippers.
- Marine fish that construct burrows on land
- Hide in burrows during high tide
- Forage in mud during low tide
- Eggs are laid inside burrow
- Up-turned chamber w/constant air pocket
How do seahorses reproduce?
- During copulation male and female put their abdomens together
- Eggs are released into male’s pouch which closes tightly as he releases sperm
- Any unfertilized eggs are absorbed by the male for nutrition
- Eggs develop in male for 2-4 weeks
- Young expelled through muscle contractions
What percent of fish follow the XX/XY pattern of sex determination?
About 10%
Describe the sex lives of clown fish.
- Largest in group is female, second is reproductive male
- Others in group are immature males
- If female dies, reproductive male changes to female
- Largest immature male becomes the new mature reproductive male
What type of fishes belong to the Sarcopterygii?
- Lungfishes
2. Coelacanths
What are the characteristics of coelacanths?
- Paired fins move in diagonal pairs
- fins have thicker bones than ray-finned fish
- Swim bladder filled with fat for buoyancy
- Marine and nocturnal
- Dioecious and give live birth
How do lungfishes survive long periods of drought?
- When water recedes, it burrows in the mud for estivation
- Drop metabolism down to 1/60th normal rate
- Mucus secretions form a protective envelope/cocoon around the fish
How do lungfishes breathe?
Have both gills and functioning lungs, just like lungs of tetrapods
Why are coelacanths considered a Lazarus taxon?
They were thought to be extinct until 1938
Why are coelacanths considered a living fossil?
Body hasn’t changed in ~400 mil years
How are humans impacting populations of fishes?
Climate change, habitat loss, pollution, disease, invasive species, etc.
What is the biggest threat to fishes?
overfishing, climate change
What is bioaccumulation?
Heavy metals accumulate in tissues of fish
How do fish farms impact wild populations of fishes?
- 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
- Sea lice are common in farm salmon and are transmitted to wild salmon as they swim near the farms
- Fishmeal is made from catching small fish and invertebrates, depleting the food base of wild fish
What is an amphibian?
Four-legged vertebrates that have made it onto land
What are the three different orders of amphibians?
▪ Which group have the greatest number of species?
- Urodela - Salamanders
- Anura - Frogs and Toads (most species)
- Apoda - Caecilians
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
Why are the smallest endotherms significantly larger than the smallest ectotherms?
Small things have high SA:Vol, thus exchange heat quickly
What are the four ways in which animals exchange heat with their environment?
- Conduction - Touching something
- Convection - Water or air moving past animal
- Radiation - Heat energy from sun or other objects
- Evaporation - Removal of water (and heat) by air
What is a salamander?
The most basic body plan of all amphibians
Where in the world is the greatest biodiversity of salamanders?
Smokey Mountains of Tennessee
How do salamanders move?
Use lateral bending of trunk and limbs for movement
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
How do salamanders court each other and reproduce? Where do they lay their eggs? What do their larvae look like?
- 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.
- 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
- Most salamander eggs are laid in water either singly or in mass and hatch into gilled larvae.
- Some lungless salamanders lay eggs under logs and leaf litter. Gills of larvae are absorbed before hatching. Hatch as mini adults!
What are the characteristics of frogs that make them modified for jumping?
- Fused tibia and fibula (leg bones) to withstand the force needed to jump
- Fused tail bone (urostyle) and pelvis fastened to spine which acts as springboard to generate force for jump
- Strong fused radius and ulna (arm bones) to withstand the force needed to catch the frog as it lands
- Large binocular eyes to be able to see depth/where they are jumping