quiz 4 Flashcards
What are the characteristics that define a mammal
- hair or fur (reduced in some marine mammals)
- endothermic
- mammary glands
- uterine gestation
- lungs
- 4 chambered hearts
What do marine mammals use blubber for
insulation; warmth, food reserves
what do sea otters eat
mollusks, crustaceans, and echinoderms (sea starts and urchins)
why is climate change/sea ice melting an issue for marine mammals like polar bears?
- polar bears are forced to search on land
- many pinnipeds breed on pack ice
- many species use ice as a refuge when hunting
- walruses are especially vulnerable because they cannot stay in deep water for long
- food resources are changing
What aspects of marine mammal behavior and reproduction makes them susceptible to human influence?
What is convergent evolution?
the process by which unrelated species evolve similar physical characteristics because they have similar lifestyles
how do baleen whales use their baleen to feed
rows of flexible plates hang down from the upper jaws; the inner edge of each plate consists of hair-like bristles that overlap and form a dense mat
what is baleen made of
keratin
why were whales hunted historically
commercially hunted for their meat and blubber which was processed into fuel, soaps, and other products
how do toothed whales use their teeth
only to catch and hold prey, not to chew it
how many blowholes do toothed whales have
just one
differences between dolphins and porpoises
porpoises - blunt nosed, flattened teeth
dolphins - distinctive snout, conical teeth
how do toothed whales use echolocation
emit sound waves, listen for the echoes reflected back from surrounding objects, brain analyzes the echoes
(the time it takes the echoes to return tells the animal how far away the object is)
how to toothed whales use vocalizations
to communicate to feed, reproduce, or play
sounds can be pod-specific, different sounds associated with different moods
what is cooperative feeding
when two or more individuals effectively capture more and/or bigger prey
examples of how whales engage in cooperative feeding
humpback whales - bubble net feeding
how do marine reptiles breathe and where do they reproduce
breathe air using lungs and most reproduce on land
what are some threats to cetaceans
- noise pollution
- entanglements and drownings (fishing gear)
- boat strikes
why can’t marine reptiles live in the cold?
reptiles are cold-blooded, so limited to warmer temp regions
how do reptiles deal with ridding themselves of excess salt
osmoregulation, special salt glands
in what ways are sea turtles adapted to living in the sea
They developed Paddle-shaped forelimbs, wing-like swimming, non-retractile head and limbs, completely roofed skull, backbone fused to shell (except leatherback), streamlined body, good sense of smell, good vision, salt glands near eyes, slow metabolic rate, long lifespan, return to land to lay eggs
what is the sea turtle nesting process
migrate to home beach, dig hole, lay eggs, eggs hatch, turtles find
ocean and hope to survive
How is sex determined in sea turtles
The temperature in which they are burrowed in, Cold and wet= male, hot and dry = female
why are sea turtles threatened by climate change
Why are floating plastic and balloons so harmful to sea turtles?
esophagus of a sea
turtle has barbs that face the stomach so cannot regurgitate things once swallowed
What are the challenges a sea turtle faces to survive from egg to reproductive age?
Has to hatch, then has to survive the journey from the burrow to the seashore, then has to survive and avoid all the predators in the sea. Survive the currents and harsh weather. And human pressure too. Pollution, boats ect.
What adaptations have marine reptiles evolved for living in water?
Why do sea turtles migrate such long distances?
For more better water conditions, more food, better breeding opportunities
what are Poikilotherms?
cold blooded animals
What is natal homing for sea turtles?
when they return to the same beach they were born on to lay eggs
Seabirds are usually monogamous, why is this an advantage?
it helps with heavy parental investment, defense of eggs, protect young, work together, do not lay eggs every year
What are some of the physical adaptations that marine birds have that enable them to succeed in the marine environment
Webbed feet, streamlined body, hard-shelled eggs, waterproof feathers, good eyesight and sense of smell, dense bones, increased red blood cells, salt-excreting glands.
How do marine birds feed?
Surface feeding, pursuit diving, plunge diving, adapted beaks.
Why are marine birds eating plastic?
it can resemble prey and is often mistaken for food.
what is overfishing, and why is it a problem
is a depletion of stock below sustainable levels for replenishment.
What is the Great Pacific Garbage Patch?
Collection of marine debris in the North Pacific Ocean
why is commercial fishing now a problem vs historical/subsistence fishing methods
What life history/behavioral aspects make a fish particularly vulnerable to being overfished?
Maturity time, reproductive capacity, and behavior.
What are some of the challenges of managing fisheries?
Biological, economic, and socio- aspects.
order pinnipedia
seals, sea lions, walruses
order cetacea
whales, dolphins and porpoises
order carnivora
sea otters, polar bears
order sirenia
dugongs and manatees
how do seals manage to dive for so long?
- slow heart rate to below resting
- constrict blood vessels to keep blood near major organs
- have 2x as much blood as humans
- use hemoglobin in blood an myoglobin in muscle to carry oxygen
where do walruses live
strictly arctic
what do walruses eat
benthic feeder; feeds primarily on clams
what do seals and sea lions eat
predators, feed mainly on fish and squid, crabs, penguins
where are sea otters found
only in the pacific ocean
what do sirenians eat
herbivorous; feed on seagrass and algae
what threatens sirenians
motor boat collisions, harmful algal blooms, pollution, and severe winters
what are the two groups of cetaceans
toothed whales - dolphins and porpoises
baleen whales- toothless. filter feeding whales
how are baleen whales characterized
baleen and double blowholes
What is a trait that many marine animals have that shows convergent evolution?
Ex. Shark vs. Penguin
streamlined body
how do marine reptiles breathe and reproduce
using lungs and on land
What is another reason fish are overharvested?
Fishing gear, many fish get caught accidently due to to poor fishing gear designs.
What are Biological considerations of fish that contribute to overharvesting?
Age to maturity, growth rate, size at maturity, spawning/reproductive style, Spawning location, Size/ age structure of the population, independence of stock
What is the Maximum Economic Yield (MEY)?
the sustainable catch or effort level for a commercial fishery that allows net economic returns to be maximized
What is the Maximum Sustainable Yield (MSY)?
defined as the maximum catch (in numbers or mass) that can be removed from a population over an indefinite period
What is bottom trawling? What is the issue?
Bottom trawling is when a huge net dropped onto the sea floor and dragged several miles. This catches many unwanted fish, and often scrapes up the sea floor in the process.
What is purse-seine fishing?
fishing that is used to catch surface dwelling species such as Tuna, Mackerel, Anchovies, and Hearing, which tend to feed in schools near the surface or in shallow areas, this technique requires a big net to swoop up all the fish. This often leads to a lot of bycatch.
What is longlining?
A type of commercial fishing that uses baited hooks on shorter lines connected to a long line held up with floats. This often has a lot of bycatch
What are Gillnets?
A type of woven mesh which gets dropped in the water to catch fish. This woven mesh is strong and is impossible to escape from. The holes in the mesh are big enough to swim though, but small enough to get stuck halfway. Fish cannot swim out, because the net gets caught on their dorsal fin.
