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Major characteristics: Aquatic and semi-aquatic carnivores live in freshwater  lakes and rivers, marshes and the ocean. They are skilled hunters with strong senses of sight and smell, strong jaws, long canine teeth, and clawed toes to seize and hold prey. They have skeletal adaptations that efficient swimmers, streamlined bodies, four limbs adapted as flippers. Return to land to sleep and give birth, generally larger then other carnivores.

Otariidae
Galápagos sea lion- Zalophus wollebaeki
Antarctic fur seal- Arctocephalus gazella
Australian sea lion- Neophoca cinerea
California sea lion- Zalophus californianus
Steller sea lion- Eumetopias jubatus

Phocidae
Southern elephant seal- Mirounga leonina
Harp seal- Pagophilus groenlandicus
Harbor seal- Phoca vitulina
Grey seal- Halichoerus grypus
Hawaiian Monk seal- Monachus schauinslandi

Odobenidae
Pacific walrus- Odobenus rosmarus divergens
Atlantic walrus- Odobenus rosmarus rosmarus

Physical Characteristics: Pinnipeds are organized into this group because they share similar physical, functional, and genetic characteristics. Every pinniped belongs to the Order Carnivora, meat eating animals with sharp teeth. Pinnipeds have paddle-shaped feet with claws. They are similar in that they forage at sea but come to shore or on ice to give birth, mate, feed their offspring, or to molt. Externally pinnipeds share features similar to other land carnivores because they still have to be mobile on land. Sensory organs have developed to be highly functioning in water and air. All have four webbed flippers to propel the spindle-shaped bodies.  Large eyes and well-developed whiskers allow them to feed in dimly lit water, tail and external ears (if any) are small to stop drag. They have retained canine teeth, but their molars have evolved to swallow prey whole. All have fur which is annually molted, but they are primarily insulated by blubber.

Internal: comparative anatomy has presented a sister group possibility between the Ursidae and Otariidae families. All pinnipeds use blubber to minimize heat loss in water and it insulates them from the cold. The blubber is also an energy source in periods with lack of food. No erector pili muscles that would cause hair on the bodies to not lie flat. Intertwining arteries and veins in flippers, and ensure circulation to the flippers from the heart. Also allow blood to rapidly flow to skin when heat needs to be dissipated. Can also shunt blood away from skin to maintain body heat. When diving deep, they exhale their lungs and they essentially collapse so no nitrogen will form in blood stream without oxygen. Only shunt blood to essential organs while diving to reduce oxygen consumption. Kidneys are extremely efficient at accumulating urine to excrete large amounts of salt. Hear better underwater then in air. Waterborne sound waves reach the inner ear through the skull and are received in all directions. Ears have been modified to improve hearing sensitivity and directional hearing underwater. Virtually no sense of smell because of very small nostrils, and almost no sense of taste.

Obtaining food/Reproduction: Dive for a few minutes and swallow their prey whole, or bring larger catches to the surface and shake them into easier to eat pieces. Mostly sexually dimorphic mammals, and breeding females are typically gregarious. Males monopolize most of the matings. In some cases pups may die from separation from mothers, injured in fights between males, or by aggressive females. Otariid females reproduce in dense clusters, while phocid females rear their pups in small groups or in isolation.

Habitat: Pinnipeds habitats range from ice to tropics, coastal to pelagic waters and may live in migratory or sedentary existence. Live in the ocean but are able to come on land for long periods of time. Must have area on land to move from sea, where they can reproduce. Spend much of their life in water, temperature depends on the species as there are many diverse.

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Hawaiian Monk Seal: Monachus schauinslandi

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Hawaiian Monk Seal: Monachus schauinslandi

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Diurnal
Life Span: 25-30 years
Location/Habitat: Live in subtropical waters where they spend 2/3rds of their life at sea. Use water surrounding atolls, islands, and areas farther off shore such as reefs and submerged banks. They can also be found utilizing deep water coral beds as a foraging area. Need land to breed and haul-out on sand corals, and volcanic rocks. When pupping the prefered area is a shallow water in protected beaches. Can be seen resting on beaches during the day. They are distributed in six main breeding populations of Northwestern Hawaiian Islands: Kure Atoll, Midway Islands, Pearl and Hermes Reef, Lisianski Island, and French Frigate Shoals.  Smaller populations however do occur on necker island and Nihoa Island, and small but growing population is also found on Main Hawaiian Islands. Diet of fish, cephalopods, and crustaceans.

Physical Characteristics: “True seal” no ear flaps. 375-450 pounds, 7.0-7.5 feet, silver/grey backs with a lighter coloration with the underside, newborns are black, sometimes have lighter patches and green or red coloring from attached algae. They breed and haul-out on sand, corals, and volcanic rock, seen resting on beaches during the day. Part of the Phocidae or “true seal” family, they are one of the only two remaining monk seal species, one of the rarest marine mammals in the world. Females generally mature around age 5, unknown when males mature. Typically “benthic” foragers, feeding on fish, cephalopods, and crustaceans. Their diet varies by location, sex, and age. Generally hunt for food outside the immediate shoreline waters (60-300 ft), known to forage deeper then 1,000 feet where they prey on eels and other benthic organisms. Tiger sharks and Galapagos Sharks prey on monk seals.

Internal: Layer of blubber almost as thick as the blubber on an arctic and antarctic seals, this suggests a reduced amount tissue has not occurred in seals as response to exposure heat. No evidence has showed that Hawaiian monk seals become hypothermic on land. The hair coat of the seal shows that it would permit convective and conductive heat loss from the skin surface to air. The history of the sweat glands suggests that they were active. Shown to lie in depressions in the sand, may facilitate conductive heat loss. Streamlined structure to be fast and agile swimmers, layers of blubber for insulation/buoyancy. Also aided by their flippers instead of limbs. Scientists have identified that the internalization of their sensory and reproductive organs which prevents any harm while dragging to such important organs if they existed externally. Have ability to reduce heart rates to 4-15 beat per minute while diving deep into water to conserve oxygen, known as Bradycardia. Dive around 5000 ft for up to 20 minutes.

Behavior: Solitary and shy, mate in spring and summer season. Males have tendency to mate with more then one female at a time.  Monk seals mate underwater, group mobbing of “estrus” females is known to occur, sometimes causing injury or even death. The gestation period is 10-11 months, birthing rates vary with a range of 30-70% of adult females birthing in a year. Most birth rates occur in late March or early April, newborns are black and molt near the end of the nursing period. Nursing period is 5-7 weeks during which time the mother fasts and will remain with the pup. They typically spend time near shore waters, and the rest of their time on land nursing or sleeping. After this there is abrupt period when weaning occurs when the mother leaves the pup and returns to the sea and eventually resume feeding. Some females foster others offspring despite being solitary. After weaning, pups may have to lose weight to survive, but eventually regain this weight once they learn foraging. Survival rate of pups is relatively high. Do not live in large groups, become aggressive when they feel threatened by humans or animals when they get too close. Come to shore to give birth and for shelter during large storms.

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The Hawaiian Monk Seal has been impacted by both geographic isolation and reproductive isolation. The species is going through directional selection as an endangered species. The Hawaiian Monk Seal species is endangered due to people moving into the desirable habitats, hunting, fisheries and being preyed on by sharks. Despite conservation efforts the population has continued to dwindle over the years. This species along with the Mediterranean Monk Seals are the only 2 monk seal species left in the world. The species is geographically isolated to the Main and Northeastern Hawaiian Islands where they rarely migrate between the islands. This limits the gene pool of the species and created little diversity. This decreases the chances for favorable traits to result as new populations breeding, and is a cause of the endangerment of the species. They have also been reproductively isolated due to the geographic isolation and cannot interbreed within populations if groups are not migrating. The geographic and reproductive isolation along with the factors that caused the species to be endangered has negatively impacted this species, and if things continue how they have been the species may eventually be extinct like the Caribbean Monk Seal.

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Atlantic Walrus, Odobenus rosmarus rosmarus

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Atlantic Walrus, Odobenus rosmarus rosmarus

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Diurnal
Life Span: up to 40 years
Habitat/Location: Very social, typically found in tight groups, can be a few individuals or thousands on land or ice. Usually travel in large sea groups. Individuals appear alone, and when they do they are typically adult males. In breeding seasons, males are often found away from females and calves. They have an ecological niche, dependant on available of large areas of shallow water, with a sustainable bottom to support a productive bivalve community, presence of reliable open water over rich feeding areas (especially in winter because of large amounts of ice), and the presence of haul-out areas in close range to feeding areas. Preferred haul-out area is sea ice, however they use terrestrial haul-out sites in the summer and fall. Live in the Atlantic, primarily in northeastern Canada and Greenland. Live in water with temperature 5-41F. Spend about two thirds of their life in the water.

Physical Characteristics: The average size of a the walrus is 7.25-11.5 ft, and up to 1.5 tons. Have a rounded, fusiform body shape. Cinnamon-brown overall coloring, appear pale in water after being in very cold water for long period of time, pink in warm weather when tiny blood vessels in the skin dilate and circulation increases, sheds excess body heat. Limbs have adapted as flippers, hairless flippers, skin on soles of walruses is thicker and rougher (traction), the foreflippers have have the major elements of forelimbs of land mammals but are shortened and modified, hold against body to steer while swimming, on land position at right angles for walking. Have triangle shaped hind flippers, bony digits, claws on three middle digits are larger then those on the outer two digits. Like sea lions, they can rotate their hind flippers under pelvic girdle, enabling them to walk on all fours. The head is a square and broad, has conspicuous tusks and whiskers. Around 400 to 700 whiskers in 13 to 15 rows on its snout, attached to muscles and supplied with blood and nerves. Have 18 teeth, two canine teeth in the upper jaw are modified into long ivory tusks, both males and females have tusks, tusks of males tend to be longer, straighter, and more stout than the females. Tusks grow in during the calf’s first summer or fall, can grow to about 39 in in males, and 31.5 in in females, grow for about 15 years, however males can continue to grow, small eyes located towards the sides of the head, ears are just behind small and there are no external ear flaps, paired nostrils are located on snout above vibrissae (whiskers), closed in resting state. Have a tail however it is hidden by a sheath of skin. A walrus’s skin is thick and tough, may be about 1.5 inches, thickest on male's shoulders and neck to protect against jabs from others tusks. Skin of males has large nodules (not in females), appear in puberty (assumed a secondary sex characteristic). Hair on body is about 0.5 in on the body, shorter on ace, and no hair on flippers. In juveniles hair is dense. Molting- annual hair shedding in June to August. Hearing- most likely sensitive, eskimos have imitated sounds and have received responses from 1 mile away. Eyesight- believed to not be as sharp as other pinnipeds because they feed on sedentary bottom-dwelling animals accurate eyesight is not necessary. Vibrissae- extremely tactile sensory organs, substantial nerve system transmits tactile info from whiskers to brain, can discover size and shape of something with whiskers. Taste- walruses prefer certain foods, however research shows they are unaware of how acute the sense is, have fewer taste buds on tongue then other mammals, but they are larger. Smell- well developed, functions for mother/calf recognition, approaching predators, and sensing others during haul-out.

Generally can be submerged for about 10 minutes with 1 minute breathing in between. Usually dives no deeper then 262 ft. Research has shown walruses to dive about 299 feet, or even 371 feet and be submerged for 25 minutes. Conserve oxygen when diving- heart rate slows, blood is shunted away from tissues tolerant of low oxygen levels and pushed near heart and brain, muscles have high content of protein myglobin, which transports and stores oxygen, Pharyngeal muscles prevent water from entering trachea when mouth opens underwater. Thermoregulation- heat gradient throughout blubber to skin, core body temp s 97.9 F, skin stays about 1.8-5.4 F than water, from -4 to -59 F the metabolism does not change and temperature does not affect behavior. In cold water, blood is shunted inward, skin appears almost white. When warm skin vessels dilate, appears pink. Blubber reinforced by fibrous connective tissue, insulates and streamlines body.

Behavior: Social- all year round, congregate by hundreds, haul out in herds, seldom haul out alone. Males and females form separate herds, The largest walruses with the longest tusks are the most aggressive and generate threat displays most often. Smaller walruses, and those with smaller or broken tusks, have a lower social ranking. Use tusks as dominance displays and weapons, males will fight another male if he intrudes during a courtship display- physical injury. Individuals frequently compete for most favorable haul-out sites. Male produce bell-like sounds and other vocalizations as courtship. Hauling out- haul out on ice or land to rest and care for young, use tusks as aid. Males don't sexually mature until 8-10, not 15 until they can compete for females based off size. Most females are sexually mature about 5-6, successful reproduction begins around 10. Only a portion of females mate a year, Non-pregnant females may go into estrus sometime between December and June and ovulate in February. Most mating occurs in March, when mature males produce viable sperm. Mating takes place off the pack ice, underwater and remote from shore, inaccessible for observation. Each herd of estrous females is attended by one or more large male adults, ratio is 1 to 23. Bulls either maintain distance of 23-33 ft, or they violently fight. Displaying males are present so subadult males are scarce or absent. Females leave ice to join a displaying male in water, copulation takes place. After mating, mature males return to all-male herds. Gestation- 15 to 16 months, includes period of delayed implantation, fertilized egg divides in a hollow ball of cells on layer thick, stops growing and remains free-floating in uterus for four to five months, blastocysts then implant on uterine wall and continue development. Delayed implantation allows the mother time to recover from last pregnancy and allow her energy to go to raising and nursing the calf, and ensures calf will be born in safe conditions.

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California Sea Lion, Zalophus californianus:

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California Sea Lion, Zalophus californianus:

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Diurnal
Life Span: 20-30 years=
Location/Habitat: They live along the rocky Pacific Ocean coastlines of western North America. Huge colonies are typically gathered along seaside rocks, and sometimes man made structures for breeding and birthing. Males gather in harems and females gather to sides in competition to sire young pups who are born on land. Found on top of rocks, floating docks and beams under fishing piers, and sometimes balancing on floating buoys. Highly social animals, can group in several hundred to several thousand animals in colonies onshore. Generally more juvenile and male sea lions in the Monterey Bay area, and mature females typically stay closer to breeding colonies of southern California. North Pacific from the Japanese coast to California, Mexico and Galapagos Islands.

Physical Characteristics: The ancestors lived on land, and gradually adapted to an aquatic environment. The streamlined body and powerful flippers which rotate forward allow for efficient movement on the land and in the water. When they dive into deep waters, they allow their heart rates to slow to allow them to stay underwater up to 10 minutes. This allows them to efficiently hunt fish, squid, and shellfish that primarily make up their diet. Males can be up to 8 ft. long, 750 lbs, and females can be no larger 220 lbs.

Social Behavior: Diurnal. Aggregate in protected areas near shore. In water they may form a raft: small mass of sea lions on the surface in very close proximity. Juvenile and nonbreeding are typically the most playful; often riding the surf, chase each other, push and shove each other off rocks, and practice territorial battles. As a response to sudden noise or rapid movement, one or a few individuals begin to move towards the water, and the herd rushes to follow. Males establish dominance by vocalization and open-mouth threats, pushing, and shoving. closely associates with mating behavior in males, and with the start of the breeding season, the sea lions establish breeding territories. Dominant males maintain territories from May through August, behavior is most intense between late June and early July. Territory borders extend to the water, can be seen in tide pools and reefs. Males establish their territory by incessant barking, pushing chest-to-chest, grappling, and even biting. Fights may break out and result in injury and are almost never fatal. Territories only exist where and when females are present, but females move freely between territories and males do not make attempts to herd them.

Individual: Sleep on land and in the water, may raise a flipper out of water to regulate body temperature. Often “porpoise” or jump out of water while swimming and enter head first.

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California Sea Lion
Animalia
Chordata
Mammalia
Carnivora
Otariidae
Zalophus
californianus

Hawaiian Monk Seal
Animalia
Chordata
Mammalia
Carnivora
Phocidae
Monachus
schauinslandi

Atlantic Walrus
Animalia
Chordata
Mammalia
Carnivora
Odebnidae
Odobenus
osmarus rosmarus

The taxonomic classification the three species shows the relatedness of the organisms. All of the classifications are the same until the family, which are the three families that are apart of the pinniped group. They split at the family because that is where the major differences are that classify them as different families. These are all of the characteristics (external and internal) researched. If the animals share a similar taxonomy it shows they are related today, but share a common ancestor and have evolved into different families, genus and species from that ancestor. It gives anyone basic insight into the relatedness of animals to each other. Taxonomy can be used to determine this because they all have similar characteristics in anatomy, embryology, DNA/ran, etc. All of this shows how the animals have evolved into three different families from one common ancestor.

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Biochemistry- Proteins
Pinnipeds have the protein apoA-IV is a plasma protein. This protein is also present in humans, and is the product of the APOA4 gene. This protein was found in the pinniped group, and shows the evolutionary link between the three families of this group. By sharing a protein it shows how they received it from a common ancestor, and it has passed down between the three families.This is an important link in evolution of pinnipeds because it shows the relatedness of the three families and the species that are classified as pinnipeds.

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Fossil Record
Fossil #1 (upper left): Enaliarctos mealsi, one of oldest known enaliarctine seals- (30-16 million years ago)
Fossil #2(upper right): Skull of Allodesmus kernensis, gigantic desmatophocid seal- (9-23 million years ago)
Fossil #3(Middle left): Gomphotaria pugnax- (7.246 to 5.332 Ma)
Fossil #4(Middle right): unknown vertebrae, 20-12 million years

Fossil #5(Lower left): Allodesmus gracilus (12-16 million years old)
Fossil #6(Lower right): Acrophoca longirostris, one of the best-known fossil earless seals- (7.246 to 5.332 Ma)

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Embryology
These three embryos are the polar bear, walrus, and seal. These embryos show the similarities in the ursidae family, and the pinniped family. The pinniped family evolved from the ursidae family and the two groups show similarities in the embryos linking the two in evolution. In the polar bear embryo to structure of the skull is similar to the seal and walrus. All three have a slimmer nostril area that widens towards the back. On the face the there are similarities in the the shape of the mouth, and nose which have a similar triangle-like shape. The shape of the bodies shows evolution because the walrus shows are larger size, and they are the largest of the pinniped families. The seal body shape is more streamlined which has evolved over time to make them faster swimmers. The forelimbs on all embryos show how the animals have evolved over time to aid what they use them for. The bear has more defined paws and digits, with longer arms that are the same length as the hind-limbs because they walk and run on land efficiently. The forelimbs of the walrus have evolved into a more webbed shape, which are more effective for swimming. Digits on the animal can still be seen however, and are used to hunt and move on land when they are mating, hauling-out, or resting. In seals, the forelimbs have almost completely evolved to flipper, with very closely joined digits. This evolution helps the seal be a faster swimmer, with little traction and drag because of the shape of their flippers. Lastly, the hind-limbs of the embryos shows evolution and relatedness of the three animals. In the polar bear, the hindlimbs are the same length as the forelimbs and are used to move on land. In the walrus, the hindlimbs are shorter in length and have a similar shape to the forelimbs. The forelimbs have evolved into a flipper shape, which make for more effective swimming, but they are still used in movement on land. In the seal, the forelimbs have also evolved to a shorter, and closer shape, similar to the walrus. The flippers allow for fast and effective swimming. All of these changes can be seen in the embryos and show the relatedness of the families. This shows how through evolution some ursidae have evolved into pinnipeds.

Pictures (left to right): Polar bear, Walrus, Seal

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Chromosome 15 of the walrus, 17 of the sea lion, and 15 of the seal are the same. The left chromosome in these pairs follows the banding pattern of 19,16 and the right chromosome of the pair has the banding pattern 1,2,5. This evidence supports the evolutionary relationship of pinnipeds because it shows that they share a chromosome, which shows their relatedness. If they were not related they would not have similar chromosomes and have an identical one. This shows how all of the families of pinnipeds evolved from one common ancestor, and this chromosome stayed with the families, and it is a link of evolution.

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Anatomy and Physiology
Anatomical similarities in pinnipeds can be seen in the structure of the flippers, seen in links 1 and 4. They all share two fore-flippers that share a similar structure. All flippers of the pinnipeds get gradually wider towards the bottom with 5 digits at the end. All pinnipeds share the same basic anatomical make-up with a streamlined body, fore flippers, one or two hind flippers in the animals. All share swimming muscles such as pectoralis (sea lion) and longissimus dorsi (seal) . These are used to aid swimming in the pinnipeds and make them faster and more efficient. In the hindlimb non swimming muscles were found in the sea lion, and non swimming muscles were found in the pectoralis of seals. This shows how they share the same basic structure, but they use the muscles in different ways to benefit them. In seals the non swimming muscle is the pectoralis of the sal because they have only one hind flipper, so having stronger swimming muscles there is more important. They can support themselves with larger muscles where the larger flipper is and this allows them to be faster and efficient. In the seal lion, the non swimming muscle is in the hind limbs most likely because the fore flippers are larger so it is more important to have stronger muscles there were the focus of swimming is.
A homologous structure found across the animalia kingdom is the structure of the forelimb. In almost all members of the animalia kingdom, the forelimb shares a similar structure, with all of the same bones (vary in size) including digits. The makeup of this structure varies from animal to animal because they have adapted overtime to meet the needs of the animal. This basic structure is: acromion-humerus-olecranon-radius-ulna-carpals-metacarpals-phalanges (digits). This is observable in almost all members of the animalia kingdom and shows how over time the same structure of the forelimb has adapted to many species to fit their needs. This structure was originally used for movement of the animal, and is still used for that purpose. In aquatic and terrestrial species, the forelimb is used to move the animal across land or through water, or to eat/catch prey. In domestic dogs it can be used for the animal to walk or run, where in whales it has adapted to a fin shape to make it easier to move through water. In pinnipeds this structure is observed in the species and is used for movement. The pinnipeds have all adapted the structure to benefit them most. The structure varies in size and shape depending on the species but they all share the similar structure. In otariidae, the structure is slimmer and more compact then the other pinniped families. The digits are very similar is size, and gradually increase in size from front to back, however they are not drastically different. In the phocidae family, the forelimb structure is more widespread, the bones are slightly farther apart, with longer digits. The outermost digits are longer than the inner ones, and are more webbed together than the otariidae. The odobenidae is similar at the top of the structure to the otariidae, but the digits are further apart. The digits are almost all the same size/length, and are the most webbed out of all three families. In the pinniped family the forelimb structure is very similar, and is used to mobilize the animals, and allow them to swim effectively.

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Speciation: Evolution follows gradualism because of the evidence found in research of pinnipeds. The changes from the ursidae family into the odobenidae, phocidae, and otariidae. These animals that can be observed today show similarities to their ancestors such as torso shape, bone structure, and fossils show the evolution of pinnipeds. The animals gradually evolved from terrestrial carnivores of the ursidae family into the aquatic carnivores that we see today. The animals have gradually changed over time become more and more adapted to the aquatic environment. It was not a quick change to become adapted to the aquatic environment and has resulted in 33 extant species of pinnipeds, and more than 50 extinct species that have been discovered by fossil evidence. From evidence found from the pinniped evolution, the belief of gradual evolution is shown is how many millions of years it took terrestrial carnivores to evolve into aquatic carnivores.

Co-evolution: After research, the evolution of pinnipeds follows coevoultion. As the different genus's within the pinnpeds group began to evolve from the believed ancestor of the ursidae, they have most likely evolved together. Throughout time, the three different genus's developed as a result of mutations and adaptations to new environments being explored. So as the animals evolved they still shared similar characteristics, but as they became more widespread they adapted to the new environment. These can be observed today in the similarities and differences in the pinniped group.

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California Sea Lion: Breed around May to June, males and females reach sexual maturity around 4-5 years of age. Non-random mating- males establish territory for success in mating. Males often participate in Postural displays, fighting (result in injury, sometimes death) and barking or growling is common as males (bulls) compete for females (cows). Males will create a harem of females and young to protect them in breeding season. Mating and birthing takes place in remote “rookery” locations, which are safe from humans and predators.

Hawaiian Monk Seal: monk seal mating is rarely observed because they mate at sea. They most likely use non-random mating, and males compete for females such as the California Sea Lions do. After mating the pregnant females haul out on shore to give birth, generally to a single pup. Birthing takes place at various times of the year, highest in March and April. Pups are nursed for five to six weeks.
Atlantic Walrus: Nonrandom mating- Only a portion of females mate each year, as some are still pregnant from the year before. Nonpregnant females go into estrus between December and June and most ovulate in February. Most mating occurs from December through March, when most sexually mature males produce viable sperm. Mating takes place off the pack ice, underwater and remote from shore. Every heard of estrous females is accompanied by large male adults, 1 to 23 ratio. Males visually and vocally display from water while the females rest. Include clanging bell-like sounds, pulses, and clicks under water. Bulls may violently fight with each other, and when displaying males are present the rest are scarce or absent. After mating season, mature bulls return to all male herds.

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California Sea Lion:  As a whole populations do not migrate over 200 km, which could lead to immigration into a new population or emigration from a previous one. However, males tend to migrate after the breeding season (August-September) north, sometimes as far north as British Columbia. They then return south in March-May. Males from Baja California arrive in Southern California in December-January. It appears that females and young tend to not migrate but it is unclear. This movement of males could introduce males into new species if they do not migrate back south after the breeding season. The males with different traits from the south may mate with females in the north, and introduce new traits into that population's gene pool. These males may have emigrated from there old population and immigrated into a new population in their migration. Also some males may mate as they travel back south within different females, introducing new traits.
Hawaiian Monk Seal

Monk seals tend to return to the same location each year, and it is not typical of the species to migrate between the Hawaiian islands. However, about 10-15% of the species migrate along the northwestern Hawaiian Islands. This migration may cause emigration from old populations and immigration into new populations. This will introduce different traits and genes into populations, and may cause genetic diversity within the species. These traits may than be continued to be passed down, or they may end up disappearing from populations.

Atlantic Walrus: Atlantic walruses inhabit coastal areas from northeastern Canada to Greenland. The animals may migrate in this area. Some may emigrate their population and immigrate to new populations. This may cause new genetic migration in a population, where traits may be introduced into a population that were not there before. This could introduce genes into the gene pool that were not there before, and if they are beneficial they may begin to reappear more and more within that population.

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In the Subantartic fur seals that are breeding on Amsterdam Island the length of the seals appears to be under selection. This research has proved that pups are gradually becoming longer, and that more females that are longer appear to be selected over others to mate. This is an example of microevolution because this change is observable, and is most likely going to stay this way until being longer is no longer beneficial to the species. This change is a form of microevolution because the change is what is reappearing in new generations, and is not a major change, but the species may eventually evolve to be much larger and this is the beginning.
By comparing the bone structure in the paw of a black bear, and the bone structure in the flipper of  any seal we can see how divergent evolution has occurred. In the bear paw, there are 5 digits with 3 parts, and the claws attached to the base. The digits of the bear vary in size, with the inner 3 very similar in size, and the outermost 2 are smaller. In the seal, there are 5 digits, with 4 parts, and they all vary in size. In the fore flipper, the digits gradually increase in size, while in the hind flipper they are longer on the outside, and shorter on the inside. These comparisons show how divergent evolution has occurred in these species over time. The differences show how over time some members of the ursidae family gradually became more and more involved in the water. They then eventually formed a new species, and adapted into flippers to be more effective for swimming.

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Evolution follows gradualism because of the evidence found in research of pinnipeds. The changes from the ursidae family into the odobenidae, phocidae, and otariidae. These animals that can be observed today show similarities to their ancestors such as torso shape, bone structure, and fossils show the evolution of pinnipeds. The animals gradually evolved from terrestrial carnivores of the ursidae family into the aquatic carnivores that we see today. The animals have gradually changed over time become more and more adapted to the aquatic environment. It was not a quick change to become adapted to the aquatic environment and has resulted in 33 extant species of pinnipeds, and more than 50 extinct species that have been discovered by fossil evidence. Throughout millions of years the Atlantic walrus, Hawaiian Monk seal, and California sea lion have been evolving through decent with modification. These organisms have slowly changed from there ancestors into the animals we can observe today. From evidence found from the pinniped evolution, the belief of gradual evolution is shown is how many millions of years it took terrestrial carnivores to evolve into aquatic carnivores.
The California Sea Lion most likely goes through stabilizing natural selection. This is because the species is not endangered and is living healthy in their habitat. Stabilizing selection is when the population stabilized on a particular non-extreme trait value. The species is not facing extreme loss which may result in disruptive or directional selection. They are balanced in hunting and being hunted, so their traits are not extreme because most California Sea Lions are living to their life expectancy, and reproducing. So they are a stable species where the observable traits are the typical and non-extreme traits of the species.

This Hawaiian monk seal is very endangered so the species is most likely experiencing directional selection. As many individuals in the species are dying either from natural causes or being/were hunted for specific traits. So the traits that were not hunted for or were able to survive the natural causes are most likely observed in the species today. So over time the traits that were once present in the species are now the only extreme available in the endangered species.

The Atlantic Walrus is not an endangered species and most likely goes through stabilizing selection. The species is able to survive and reproduce in their habitat, so there are no extreme traits being shown in the species. The traits that are favorable at a certain point will show, and they will change as the species remains stable. The species is not facing extreme loss, so it is not going through disruptive or directional selection. They are a stable species where the non-extreme version of traits are observable.

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The phyologenetic tree shows how the groups of pinnipeds (otariidae, odobenidae, and phocidae) have evolved over time from the ursidae. As evolution continued the animals slowly became more adapted to aquatic environments. This phylogenetic tree shows how flippers evolved in pinnipeds over time, to meet the needs of the animal as the aquatic carnivores. The ursidae have normal legs that they use to move across land, and to hunt. Starting with the otariidae, they developed flippers which are used to move in water and hunt in the water. This trait is observable in the otariidae, odobenidae, and phocidae family because they have evolved into aquatic carnivores. This gives insight to how the Atlantic walrus, Hawaiian monk seal, and California sea lion have evolved from the believed ancestor of the ursidae and arctoids. familyThis phylogenetic tree not only shows how the pinniped family evolved from the ursidae, but the trait of having flippers instead of normal legs distinguishes them from their ancestors.

# data[].attributes.body
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