mammalogy test
Insectivores What organisms belonged to Insectivora? Why do you think these organisms were grouped into a single group when they were clearly paraphyletic?
(Hedgehogs, shrews, moles, tenrecs, golden moles, solenodons, elephant shrews, tree shrews) all belonged to insectivora. Despite being clearly paraphyletic, these organisms were grouped Insectivores to refer to a group of small mammals. The group is now obsolete with the exception of a remaining order - Eulipotyphla
Dasyuromorphia
-4 total families -only two of which still maintain living species -mynmecobiidae has 1 living species
Afrosoricida
-55 species- Africa Tenrecs are primarily found in Madagascar Golden moles mainly live in the Namib desert Chrysochloridae- golden moles Blind and fossorial Vestigial eyes covered by skin Their name comes from the iridescent shine on their fur. Thick skin with dense, moisture resistant fur. Endemic to Sub-Saharan Africa Territorial Tenrecidae Small or medium sized and primarily found in forests of Madagascar Convergent evolution with hedgehogs, shrews, and mice. Can live in semi-aquatic, fossorial, arboreal, or terrestrial habitats Have a cloaca and low body temperatures. Insectivores what makes them Derived characters Basisphenoid bulla Zalambdodont molars Most are nocturnal and are blind or have poor eyesight. Due to their early split the two families do not have many morphological synapomorphies They have long pregnancies compared to other insectivores and can have varying litter sizes. The largest is the tailless tenrec which can have up to 32 young per litter. Golden moles "swim" through the sand and can dive down to around 50 cm. Their whiskers help them to sense slight vibrations while underground.
Paucituberculata
-Family: Caenolestidae "shrew opposums" -7 species, all caenolestids Those that live in Georgia: none Those that live in North America: none -Biogeographical location All Caenolestidae live in western South America -Unique characteristics Paired spermatozoa No marsupium Diprotodont I 4/3, C 1/1, P 3/3, M 4/4 46 total -Kill and eat the young of other mammals or other shrew opossums
Notorytcomorphia
-MARSUPIAL MOLES -One Family, Two Species Notoryctes typhlops (Itjaritjari) Notoryctes caurinus (Kakarratul) Family Notoryctidae -Both species of the marsupial mole are endemic to Australia. The Itjaritjari (N. caurinus) ranges into Western and Northern Australia. The Kakarratul (N. typhlops) ranges into Southern and the middle of Australia. They are fossorial mammals that spend most of their lives underground. Inhabit sand dunes and other places with suitable, loose sand. They are blind, their eyes are vestigial and are covered by skin. Have no external ears, only two small holes covered by hair. Short limbs with reduced digits. Their forefeet have two enlarged, spade-like, flat claws that allow them to move efficiently through sand. They are insectivores. Almost nothing is known of their reproduction.
Monotremata
-biogeography: Short-beaked echidnas are found in Australia and Tasmania Long-beaked echidnas are found in New Guinea Platypus are found in Australia and Tasmania unique traits: all members lay eggs Pectoral girdle retains reptilian features Lower body temp than other therians Sex chromosomes unique among vertebrates Sperm filiform, similar to reptiles representative species: Ornithorhynchidae-Platypus Tachyglossidae-echidna 5 none found in georgia
Phylogenies
-characters much be homologous: which is having a trait due to a common ancestor Ex: all bats have wings=shared ancestor Cant use tusks on walrus or elephant because they don't have a shared ancestor
Cingulata
20 species Armadillos are the only surviving family within this order (Family Dasypodidae) and there are only 20 living species that we know of that are still living Originated in South America, but eventually migrated to North America after the Cenozoic Only found in southern North America and South America Lumber vertebrae are "xenarthrous," or contain extra contacts, to strengthen hips and lower back Dorsal armor made of dermal bone plates Curved claws and peg-like teeth that lack enamel Carapace (body armor) is used to plug the burrow entrance or to defend against predators eats Termites, grubs, and worms Occasionally small reptiles and amphibians or bird eggs They live in burrows underground that they dig themselves Prefer moist climates and thrive in forest areas Family Dasypodidae in Georgia -Georgia's only shelled mammal Commonly found in Central and Southern Georgia Not protected in Georgia Family Dasypodidae in North America -The nine-banded armadillo is Texas's state animal Currently can be seen in large populations in Southern states Can be found as far North as Ohio Unique Facts -1 to 15 pups born at one time Not sociable animals and spend ~16 hours per day sleeping Meat is considered a delicacy in South/Central American countries
Sirenia
5 species Family Dugongidae Dugong dugon (Dugong) Hydrodamalis gigas (Steller's Sea Cow †) Family Trichechidae Trichechus inunguis (Amazonian Manatee) Trichechus manatus (West Indian Manatee) T. m. manatus (Antillean manatee) T. m. latirostris (Florida manatee) Trichechus senegalensis (African Manatee) Paddle-like, dorso-ventrally flattened tails 2 flippers Lack hind limbs Long, thin lungs Dense pachystotic bones Brachydont & Lophodont teeth Indeterminate # of "marching molars" Lack Sagittal Crest Family Trichechidae Spooned shaped tails 3-4 nails on the second, third and fourth digits Family Dugongidae Bi-lobed Tails No nails Rostrum (muzzle) is longer and more pronounced Important Families: Family Dugongidae -Steller's Sea Cow (Hydrodamalis gigas) † Highly specialised to the sub-Arctic waters of the northern Pacific Ocean Hunted into extinction by 1768- some say this was the first historical extinction of a marine mammal at human hands Were only discovered in 1741 Could get up to 10 m in length and 11 tons in weight (data from early species descriptions of a beached sea cow) Important Families: Family Dugongidae -Dugong (Dugong dugon) Easily distinguished due to fluked tail Herbivorous diet Occurs exclusively in marine habitat Important Families: Family Trichechidae -The West Indian manatee (Trichechus manatus) is the only member of the order Sirenia that lives in the United States. Sighted in GA from April-October since GA falls in their summer range In the waters of Camden, Glynn and McIntosh counties Migrates into fresh water when temps. drop Amazonian Manatee (Trichechus inunguis) Smallest manatee species Occurs exclusively in freshwater African Manatee (Trichechus senegalensis) Show a preference for mangroves But like the W. Indian manatee, it migrates into fresh water when temps. drop Not much knowledge about them Scientists think they have a smaller pop. compared to other species Elusive behaviors
What is the sister group of Xenarthrans?
Afrotherians
What is an indel? Why is it helpful in systematic analysis?
An indel is a term for adding or removing bases in the genome. It is helpful because it helps denote differences in base pairs among different organisms which further assists with systematic analyses of creating phylogenies.
Cetartiodactyla (exact phylogenetic classification uncertain) What mammal groups comprise Cetartiodactyla?
Camelidae Suidae Tavassuidae Hyppopotamidae Cetacea Giraffidae Antilocapridae Moshidae Cervidae bovidae
Scandentia
Class Mammalia, order Scandentia, treeshrews Families Tupaiidae and Ptilocercidae Previously classified in Insectivora, not true shrews Nesting and territorial behaviors Used to be considered primitive primates based on similar morphology but were not homologous structures, now in own group Still have many studies that link to primates based on cranial anatomy Have been used as substitutes of primates in experiments because similar brain Large membranous ears Fur color can be dark brown, reddish or gray with a white to yellowish underside Long thin tail, bushy in most, few have naked scaly tails with fur at end Largest have a body about 16-21 cm long and tail length 16 cm Scent marking behavior to claim territory and communicate Terrestrial species larger than arboreal species, have claws to dig for prey Have small canine teeth and unspecialized molars Feed on insects and fruit Native to Thailand, Malaysia and islands of Indonesia Inhabit much of Southern and Southeast Asia Primarily in subtropical to tropical evergreen forests Tupaiidae Five genera, 19 species Tupaia, Anathana, Dendrogale, Lyonogale, Urogale Diurnal Partly terrestrial Most have bushy tail, can resemble squirrels Conservation status: majority of species are least concern with populations decreasing; the Golden-bellied Treeshrew is vulnerable, Nicobar Treeshrew endangered, many species status unknown Ptilocercidae One genera: Ptilocercus, one species: pen-tailed treeshrew Nocturnal Arboreal Native to Thailand, Borneo, and some Indonesian Islands Conservation status: least concern Have long thin tail with skin and tuft of fur at end Interesting facts -Pen-tailed tree shrews drink nectar from bertam palm (alcohol content up to 3.8%) without signs of intoxication Drink amount equivalent to 10-12 glasses of wine per night Process ethanol differently, benefit of adaptation not understood Tree shrews are the only mammals besides humans that seek spicy foods Less sensitive to spicy foods due to mutation in pain receptors in their mouths Said to be adaptation to expand diet
Hyracoidea
Composed of a single family, Procaviidae, 5 species. Procaviidae= Before the caviids (guinea pigs) Central and Southern Africa >Algeria >Libya >Egypt Middle East: >Israel >Syria >Southern Saudi Arabia Herbivorous, feed on vegetation Digestive system: One large cecum and a pair of ceca on the ascending colon Adult female hyraxes have testosterone levels equal to or greater than males Poor thermoregulators Prominent middorsal gland about 15 mm long surrounded by lighter colored hair Specialized elastic, rubbery pads on the soles of the feet Toes have a short, hoof like nails except second digit of the hind feet Molariform dentition in hyraxes is not replaced horizontally >Only one extant family and it only found in Africa and Middle East. -Lives in colonies with up to 25-35 a group. Rock hyraxes form social hierarchies with cooperative breeding. Very vocal and make a variety of sounds; whistles, screams, croaks, and chatter >'singing' can identify individual rock hyraxes (by their body weight, reproductive condition, and social status
phylogenetic tree
Consists of a diagram that represents patterns of ancestry among organisms Ex: This image is an example of the placental mammal phylogenetic tree.
Macroscelidea
Consists of only one Family (The Macroscelididae) 20 living species Elephant Shrews aka Sengis Found in Northern, Southern, Eastern, and Central Africa Lives in diverse habitat including desert, brushland, plains, forests, and rocky areas. Long, flexible, highly sensitive snout Large eyes and ears Longer hind legs that allow for hopping Forelimbs are pentadactyl Hind limbs can have 4 or 5 toes Tail is slightly shorter than head and body length Alert with fast reflexes Sleep and hide in burrows May live alone, as monogamous pairs, or in small groups Scent-mark stones and twigs to maintain elaborate trails Some species sunbathe; others "sand-bathe"
Is Ameridelphia considered a monophyletic group? Why?
Currently, Ameridelphia is considered a paraphyletic group because it includes all marsupials living in the Americas, except for Monito del monte.
Currently, what is the thinking about the evolutionary relationships between monotremes, marsupials, and placental mammals?
Currently, the evolutionary relationship between monotremes with marsupials and placental mammals are represented as sister groups within the monophyletic prototheria clade in the modern phylogeny.
Superorder Xenarthra What mammal groups comprise Xenarthra?
Dasypodidae Myrmecophagidae bradypodidae
derived vs ancestral traits
Derived :a trait that is present in an organism, but was absent in the last common ancestor of the group Ancestral: trait originally present in the ancestor of a given group
What differences do you note?
Despite the modern phylogenetic tree containing more detailed information due to the discovery of more species and advancement of technology, the biggest difference is visual depiction. In other words, Simpson's classic phylogeny is less visually oriented with a more chronologically-based listing of mammal species whereas the modern phylogeny is more visually oriented with a depiction of a descending lineages of mammals containing nodes and common ancestors.
I. Why has the classification of mammals changed over time? Be specific in terms of both knowledge and techniques. Another way to ask the same question is "What do we know now or have available know that was unavailable to Simpson?"
Due to the age of science during Simpon's life, information was not readily available, therefore, crafting phylogenies were very direct and classification ranged by listing subclasses into infraclasses, cohorts and orders (respectively), chronologically all via paper, journals, notes, and books. In the current age of science, technology has dramatically shaped the way we process and store scientific information which has allowed a lot of records and data be not only logged, but shared with other evolutionary biologists to actually map out lineages between mammals and related species.
Superorder Laurasiatheria What mammalian groups comprise Laurasiatheria?
Eulipotyphia Pholidota Carnivora Chiroptera Perissodactyla Cetartiodactyla
Eutheria includes many orders:
Eutheria includes many orders: Artiodactyla are herbivores with an even number of toes. This includes moose, hogs, camels, goats etc Carnivora includes dog family, cat family, bears, raccoons etc. Their jaws move only up and down and most have sharp canine teeth; all but some are meat eaters Insectivora members eat insects and include shrews, moles and hedgehogs Lagomorpha members are herbivores with sharp teeth and most have long ears, short tails and strong hind legs. This includes hares and rabbits. Primates have opposable thumbs and claws are replaced by flat nails on fingers and toes Rodentia include rodents and are mainly herbivores with long sharp teeth
Who was G. G. Simpson? Why is his the classic phylogeny?
George Gaylor Simpson was an American paleontologist who was an Influential mind in "new synthesis" his mammalian taxonomy was based on phylogeny and shared characteristics
What are the closest living relatives of whales?
Hippos
homology vs homoplasy
Homology: similarity of the structure, physiology, or development of different species of organisms based upon their descent from a common evolutionary ancestor Ex:The structure of the vertebrates in these different mammals is considered to Homoplasy: Traits shared due to convergent evolution and did not arise from a common ancestor Ex: The similar shape of both the shark and killer whale is an example of homoplasy
What is the sister group of Glires?
Lagomorpha
Thus, what are the four deep lineages of eutherian mammals?
Laurasiatheria Euarchontoglire Xenarthra Afrotheria
Who's is the current phylogeny?
Meredith et al 2011 is the current phylogeny.
Proboscidea
One extant family: Elephantidae - -3 species -Elephas maximus (Asian Elephant) -Loxodonta africana (African Elephant) -found everywhere Trunks Enlarged Incisors, Tusks Lophodont teeth Mammuthus, The American Mastodon Mammoth fossils found in Glynn County, Ga
Didelphimophia
One family - Didelphidae 111 species* - All in South or Central America except one -Biogeographic Location with Map south america eastern range of usa Polyprotodont: four or more upper incisors on each side of the jaw. five upper and four lower incisors, tritubercular molars. 50 teeth total. Small to medium Opposable 5th digit on hind feet Prehensile tail, usually long and scaly Long rostrums, small braincase, and prominent sagittal crest -Water Opossum -Grey Short-tailed Opossum -Common Opossum -Four-eyed Opossum Those that live in Georgia: One! - Didelphidae Those that live in North America: One! - Didelphidae Species that are unique: Grey Short-tailed Opossum doesn't have a true pouch. Water Opossum is the most aquatic marsupial. Playing dead or hissing when threatened Most teeth of any land mammal in the U.S. Carry young on the back when too large for the pouch Some are immune to the venom of pit vipers Virginia opossum is estimated to eat up to 5,000 ticks annually and have a body temperature (usually) too cold to harbor rabies.
Microbiotheria
Only 1 Family (Microbiotheridae) with only 1 living species (Dromiciops australis) >known as monito del monte- 'little monkey of the mountains' 3 species Southern South American: >Southern and Central Chile >Southwestern Argentina >50 teeth >nocturnal >greatly inflated auditory bulla >cloaca under the tail >Ankle joints similar to those of Australian marsupials >eat insects and fruits >mostly consumer beetles, grasshoppers, and crickets >construct nests that are about 20 mm in diameter >lined with waterproof bamboo leaves and moss in tree cavities, fallen logs, and thickets
Monotremes and Prototheria What is the difference between "monotremes" and "prototheria"?
Prototheria is a subclass, while monotremata is an order.
Are there any groups in prototheria, either extinct or extant, besides prototheria? Why or why not?
Prototheria is linked into two clades (Marsupialia and Placentalia), both containing extant and extinct species of mammals. For instance, extinct mammals are marked on the modern phylogeny with dots and extant mammals' lineages continue.
Four clades of Eutherians Superorder Euarchotoglires What mammal groups comprise Eurachontoglires?
Scandentia Lagomorpha Rodentia Dermoptera Primates
What similarities do you note? (be specific--mark-up your handouts)
Similarities between the modern phylogenetic tree and the classic phylogenetic tree include a "precendence" layout format that goes in order between the subclasses (Prototheria, Theria e.g.), infraclasses and orders.
Why was the scientific debate about whether or not the rodents are in a single monophyletic group important to systematics as a whole?
Since systematics involve the process of differentiating base pairs among organisms to classify them taxonomically, controversy in naming and classifying all rodent species within a single monophyletic group was difficult due to the large range of genetic differences in all rodents overall.
Pilosa
Sloths & Anteaters Sloths and anteaters are only found in Central and South America, extending into Mexico. Presence of at least 2 accessory "xenarthrous" intervertebral articulations or xenarthrales (strange joint), located primarily on the lumbar and some posterior thoracic vertebrae Loss of incisors & canines, and cheekteeth (if present) that are single-rooted and without enamel Acromion & coracoid processes of the scapula are separate and well developed to enhance muscle attachment for digging Dermal ossicles in the skin Transverse processes of the anterior caudal vertebrae and the ischia are fused (except the silky anteater) Secondary scapular spine Infraorbital canal position Significant amounts of HAIR & absence of armor found in armadillos All sloths and anteaters have a litter size of 1 Myrmecophagidae -Giant Anteater (Myrmecophaga tridactyla) Northern Tamandua (Tamandua mexicana) Southern Tamandua (Tamandua tetradactyla) Characteristics: Long tapered skulls, elongated rostrums, long tongues, & tiny mouths Giant Anteater tongues can be extended up up 600 mm and are covered with a viscous secretion produced from the submaxillary glands, and small, barb-like spines which both help with trapping ants. Tamanduas forage on the ground and in trees, with a prehensile tail that aids with climbing. They also have large, powerful claws for foraging and the middle claw is typically enlarged. Cyclopedidae Silky Anteater (Cyclopes didactylus) The Silky or Pygmy Anteater gets its name from its fine, soft fur. They are tiny compared to the Giant Anteater and Tamanduas, weighing only 230 grams with a total length of 430 millimeters. They are nocturnal and entirely arboreal. They also have a prehensile tail. Megalonychidae Hoffman's Two-toed Sloth (Choloepus hoffmanni) Linnaeus's Two-toed Sloth (Choloepus didactylus) Two-toed sloths have 2 toes on the forefeet, each with a long sharp claw, and 3 toes on the hind feet. May have 5, 6, or even 8 cervical vertebrae (most mammals have 7). They are almost entirely arboreal and folivorous, moving to a different tree each day, only coming to the ground to defecate. They are also good swimmers. Bradypolidae Pygmy Three-toed Sloth (Bradypus pygmaeus) Maned Three-toed Sloth (Bradypus torquatus) Pale-throated Sloth (Bradypus tridactylus) Brown-throated Sloth (Bradypus variegatus) They have three well clawed toes on the forefeet and five toes on the hind feet. They have 8 or 9 cervical vertebrae, which allows for greater flexibility in the neck - they can rotate their heads in a 270° arc. They are also arboreal folivores, and typically spend a prolonged periods in the same tree. Vulnerable Maned Three-Toed Sloth Giant Anteater Critically Endangered Pygmy Three-Toed Sloth
What are some examples of parallel evolution in Afrotheria and Laurasiatheria?
Some examples of parallel evolution in Afrotheria and Laurasiatheria involve traits among convergent evolution within the orders of these groups. Furthermore, these deep lineages are related via Laurasiatheria and Euarchontogilire as a sister group to Xenarthra and Afrotheria within the entire Placentalia clade. An example would include an aquatic basis between cetacean and sirenian organisms.
Diprotodontia
Species: 155 total -All are Diprotodont and Syndactylous Arboreal members of Diprotodontia are often schizodactylous and the hallux (big toe) is opposable -Phascolarctidae The Koala is the only extant species Found in Eucalyptus forests in S and SE Australia Their diet is composed solely of eucalyptus which isn't very nutritious Because of their diet they have the largest cecum relative to body size of any mammal, move slowly, and sleep 20 hours a day Marsupium opens posteriorly Vestigial tail Schizodactylous with opposable hallux Dental Lacks first 2 premolars Closed rooted dentition Dentary isn't inflected Petauridae Genus: 3 Species: 11 Monophyly not well supported Found in forested areas in Australia, New Guinea, and surrounding islands Nocturnal and arboreal Herbivorous and insectivorous Patagium extends from wrist to ankle Dark dorsal stripe Fur covered prehensile tails Schizodactylous with opposable hallux Marsupium opens anteriorly Dental 40 teeth Lower incisors long and sharp Bunodont molars Macropodidae Genera: 11 Species: 50 extant Largest marsupial family Can be found in a wide range of environments from deserts to rainforests macropodids= big footed Strong well developed hind limbs and large feet Marsupium opens anteriorly Large sacculate stomach with microorganism aided digestion Dental Upper and lower incisors don't occlude Canines small or absent No diastema Hypsodont (high crowned) molars Mesial drift (like elephant and manatee teeth Currently found in Australia where they evolved in the late oligocene
Synapomorphies
Taxa that is grouped based on shared derived characteristics that can be traced back to the most recent ancestor that both the groups evolved from Ex: The characteristic of humans having the ability to move and use their thumbs, while most animals can't, is a synapomorphy we share with chimpanzees, monkeys, and other primates.
Phylogenetic tree:
Terninal branch: living or extinct species for which relationships have been inferred Node- a past speciation event Internal branch: a hypothesized ancestral species Root-the most recent common ancestor of all species on the human Monophyletic- all shares a common ancestor
What are the living orders of marsupials? Where are they found?
The 8 extant orders of marsupials and their locations are as follows: Didelphimorphia (North America) Paucituberculata (South America) Microbiotheria (South America) Dasyuromorphia (Australia) Peramelemorphia (Australia) Notoryctemorphia (Australia) Diprotodontia (Australia)
How are the American and Australasian taxa of marsupials related? What was the "smoking gun" that supported
The American and Australasian taxa of marsupials are related because they both descended from a common marsupial ancestor. The "smoking gun" that supported this was when ancient continents were breaking apart.
Is Australidelphia considered a monophyletic group? What orders does it include and where are they found geographically?
The Australidelphia is not considered a monophyletic group and taxa within it are geographically found within Australia.
How are mammals defined?
The Merriam-Webster dictionary defines mammals as; Warm-blooded higher vertebrates Animals that nourish their young with milk produced by their mammary glands Skin at least partially covered by hair Members of the class Mammalia
In Australidelphia, how do the carnivorous orders differ from the herbivorous order? (Know which orders are in each group).
The difference between the carnivorous orders and herbivorous orders within Australidelphia is the food sources within the order. Carnivorous orders rely on meat food sources, while herbivorous orders rely on plant food sources.
Which of these traits are unique to mammals?
The middle ear bones Hammer (malleus), anvil (incus), and stirrup (stapes) Neocortex Segment of the brain that involves sensory perception, movement, and spatial reasoning
Dermoptera
The order Dermoptera contains only ONE family: Cynocephalidae This family has only TWO species: Malayan flying lemur Philippine flying lemur This order is found in southeast Asia and on some of the Philippine islands. "Skin-wings" Well developed stomachs with long intestines Comb-like incisor teeth Webbed fingers/toes Cynocephalidae The only family in the order Dermoptera. More commonly known as 'Colugos' Characteristics: Herbivores Mothers give birth to a single baby Called flying lemurs, but are not related to lemurs About the size of a domestic ca
What trait initially prompted scientists to hypothesize the relationship between Cetaceans and Artiodacytla?
The whales hind foot led for scientists to hypothesize the relationship.
Why study mammals?
There are a variety of reasons why studying mammals is important: Mammals are a huge resource food for humans. Food, clothes, etc. This aids greatly in the survival of humans. Mammals play a role in our ecosystems, so it's important to know the relationships between them. They are often kept as pets, including cats, dogs, hamsters, rabbits, etc. This has helped scientists to study more diseases and even finding cures for them.
Which of these traits are unique to mammals?
There are certain characteristics that are unique to mammals, and they include: Mammary glands Hair or fur Sweat glands These are absent in some mammals, but only occur in mammal species
How are mammals classified?
There are three subdivisions of mammals: Prototheria- only has one order: monotremata Metatheria- mainly marsupials Eutheria- the largest division with 19 orders Prototheria- Monotremes lay eggs and do not have teeth. These include the platypus and echidnas. Metatheria includes marsupials: koalas, kangaroos, etc., which give birth to underdeveloped young and carry them in a pouch.
Tubulidentata
There is only one family in this order: Orycteropodidae -One living species: aardvark -Those that live in Georgia: none -Those that live in North America: none Biogeographic location Throughout Africa, south of Sahara desert -ranges from Savannah to rainforest -their distribution is closely associated with ant and termite mounds Unique characteristics -More turbinate bones (scroll -like bones in nasal passages) -Very rough hide -Long sticky tongue -Nocturnal -Adult dentition is I 0/0, C 0/0, P 2/2, M 3/2-3=18, rootless -Teeth have no enamel, columns of dentine in a figure 8 shape
Where do these groups fall on the mammalian family tree? Why are they difficult to place on the mammalian tree?
They are under placentalia. Their anatomy is unusual making it difficult to compare to others.
Superorder Afrotheria What mammalian groups comprise Afrotheria?
Tubulidentata Afrosoricida Macroscelidea Sirenia Proboscidea Hyracoidea
sister groups
Two descendents that split from the same node and are considered to be each other's closest relatives Ex: The Lion and the Leopard would be considered a sister group, and the Tiger and Snow Leopard would also be considered a sister group in this cladogram.
parsimony
Utilized to reduce potential conflicts in the data set involves grouping taxa together in ways that minimize the number of evolutionary changes that had to have occurred in the characters Ex: In this example Tree 1's length was 7 and Tree's 2 length was 10. Since the shortest possible tree that explains the data is considered as the best tree, Tree 1 is the best choice based on Parsimony.
Basic characteristics mammals share:
Vertebrates Have mammary glands and produce milk Control internal temperature (usually with fur or blubber) Give birth to live young Have middle ear bones Have embryo in placenta
Marsupials Are marsupials monophyletic?
Yes, marsupials represent a monophyletic clade.
Is the order Chiroptera monophyletic? What evidence supports your answer?
Yes, they are monophyletic. One origin of powered flight in mammals, making them monophyletic.
Crown groups
a phylogenetically defined group that is composed of all the descendants of the last common ancestor of the living members of the group. Ex: A crown group in this example is human beings - Homo sapiens.
Stem group
a phylogenetically defined group that is composed of all the taxa that are more closely related to the living members of the group than to the living members of other groups . Ex: The stem group would be anything more closely related to humans than to the crown group composed of chimps and bonobos.:
Outgroups
a taxon outside the group of interest, but is related to it ex:The turtle would be an example of the outgroup in this cladogram because it is not a mammal, so it is outside of the group of interest.
Peramelemorphia
bandicoots and bilbies Terrestrial, ground-dwelling marsupials 23 Species across 3 different families -Marsupium (pouch) that opens to the rear -Omnivores; opportunistic feeders -Nocturnal, except for the Southern Brown Bandicoot -Most are semifossorial -Have an accelerated breeding cycle -Shorter gestation period -Chorioallantoic placenta -Does not attach to wall of mother's uterus -They can be found in Australia, Tasmania, New Guinea, and the surrounding islands. -They occupy a large range of habitats -Deserts -Grasslands -Tropical Lowland -Rainforests -Peramelidae: The Bandicoots and Echymiperas -19 species -The Giant Bandicoot (Peroryctes broadbenti) -Long-nosed Echymipera (Echymipera rufescens) -Found in Australia, Tasmania, and New Guinea -Long hind limbs for running and hopping -Still maintain traits related to digging -Embryos form a placenta -Very brief gestation period however (12.5 days) -Thylacomyidae: The Bilbies -Rabbit-eared bandicoots Rabbit + rat = bilby -Two species: Lesser Bilby (Macrotis leucura) (extinct) Greater Bilby (Macrotis lagotis) -Used to be found all over, but now in the desert areas of Central Australia -Build burrows using powerful front claws Get most of their water from food -Chaeropodidae: The Pig-Footed Bandicoots -Two extinct species: -Chaeropus ecaudatus (Southern Pig-footed Bandicoot) -Chaeropus yirratji (Northern Pig-footed Bandicoot) -Were found in the plains of Australia -Unusually long and thin legs -Only 2 functioning toes on front paws -Last collected in 1901; extinct since the 1950s -Only 29 specimens worldwide
homologous characters
different organisms contain characters that are similar because they were inherited from a common ancestor that also had that character Ex: An example of a homologous character includes how the higher vertebrates have a similar skeletal structure of their forelimbs
characters (as referred to in phylogenetics)
heritable traits that can be compared across organisms Ex: bobbed tail, uniform coat, and stripes are examples of characters in this
What features make these a monophyletic group?
includes the common ancestor and all of its descendents
monophyletic group
includes the most recent common ancestor of a group of organisms, and all of its descendents Ex :the yellow portion of the cladogram is the monophyletic group
convergent evolution
is the process where non monophyletic organisms independently evolve similar traits as a result of having to adapt to similar environments or ecological niches
Phylogeny
the study of relationships among different groups of organisms and their evolutionary development Ex: Phylogeny is occuring by utilizing this cladogram to describe the evolutionary relationships between the great apes
Constructing phylogenies:
· A variety of types of characters can be used -morphological (traditional) -molecular analysis of both proteins and dna sequences
What is phylogenetics?
· How do we know who is related to who? · Phylogenetics: study of evolutionary relationships among groups of organisms. No the same as naming and classifying organisms
Homoplasy
· Traits shared due to convergent evolution
