ECCB 302 Mammalogy Lecture REVIEW QUESTIONS

What are the three nonmammalian synapsids?

Pelycosaurs, Non-cynodont therapsids, and Cynodont therapsids.

Synapsids were the first amniotes to radiate in what habitats?

Terrestrial Habitats

In what era were synapsids the most abundant terrestrial vertebrates?

Permian Era

When did the synapsids begin to radiate?

Paleozoic
Late Carboniferous

When were synapsids the top carnivores?

Triassic

What kind of phyletic group is Pelycosaurs?

Not monophyletic

What are the three notable characteristics of Pelycosaurs?

Complexity of dentition, arched palate, and lower jaw flange.

When did Therapsids first appear?

Middle/Late Permian

What are the four characteristics of therapsids?

Modifications suggesting increased metabolic rate, increased neck flexibility, pectoral and pelvic girdle less massive, limbs more slender

Which of the therapsids were the dominant herbivores?

Noncynodont therapsids

What are the four characteristics of Cynodont therapsids?

More modifications for increased metabolic rate, Reduction in body size, Enlarged infraorbital foramen, and evidence of turbinates.

What are the 11 major evolutionary trends in non mammalian synapsids?

Size of temporal fenestra, Lower temporal bar, Lower jaw and jaw point, Heterodonty and Diphyodonty, Hard Secondary Palate, Parietal foramen, Position of limbs, Shape of Limb girdles, shape of feet, vertebral column and tail.

What is beneficial about having a larger temporal fenestra?

More Jaw Muscles

What is the purpose of a Hard Secondary palate?

Breathe and eat at the same time.

What is beneficial about the change in the shape of the limb girdle?

Less Weight in Limb Girdles

What does the calcaneal heel connect to?

The Achilles tendon

When the bones of the jaw decrease in size, where does the bone migrate to?

The inner ear

What is an example of a Pelycosaur?

Dimetrodon or Edaphosaurus

What are the characteristics of Amniotes?

amniotic egg, impermeable skin, costal ventilation of lungs, temporal fenestration

Which two taxa are amniotes?

Sauropsida and Mammalia

Who does the synapsid clade include?

Nonmammalian synapsids and mammals

What phyletic group are non-cynodont therapsids

Not monophyletic

How did therapsids interact with Pelycosaurs?

Therapsids possibly replaced pelycosaurs

What are the 2 major periods of mammal diversification?

Jurassic and Cretaceous periods

What is one of the oldest known mammals and when did it live?

Morganucodon from the Jurassic

What is the size of the first mammals?

Shrew sized to rat sized

What two characteristics of teeth are characteristics of mammals?

Diphyodonty (two sets of teeth) and precise occlusion (contact between teeth)

What is an important skull characteristic that defines mammals?

Derived skull features allowing for enlargement of brain and inner ear area

What two non-skeletal characteristics define mammals?

Hair and Lactation

What are the two major functions of milk?

immunity and nutrition

What is the evolutionary advantage to lactation?

Production of offspring is no longer seasonal, Not as dependent of paternal care, and young can be born at a relatively undeveloped stage

Who are the Multituberculata?

An extremely long lived lineage of rodent like animals

What are some characteristics of Multituberculata?

Coexisted with extant mammals and had rodent like bodies and incisors

When did Multituberculata live?

Late Jurassic to early Cenozoic

Who are the extinct lineages of mammals?

Multituberculata, Monotremes, Marsupials, and Placentals.

When did modern mammal orders originate?

Before the KT Boundary

How are endothermy, hair, and being nocturnal related?

The nights were cold so developing endothermy and insulative hair was beneficial for mammals

How did marsupials get to Australia?

Dispersal from South America to Antarctica to Australia in the Cenozoic

What is the Great American Interchange?

Animals migrating from North America to South America freely using what was originally Panama

How important was the Mesozoic for mammal diversification?

About 2/3 of mammalian history was here

What other groups were diversifying at the same time as mammals?

Angiosperms (Flowering plants) and a 2nd insect radiation

What are the 7 features of Monotremata?

Lay Eggs, Mammary Hairs, Shorter cochlea, no pinna, Cloaca, lack teeth as adults, and Male platypus have spurs on the hind legs that are attached to venom glands

What are the 4 major feature of Marsupials?

They continue development in the Pouch, Different tooth formula, Usually lack auditory bulla, Epipubic bones

What are the 4 major feature of Eutherians (Placentals)?

Both choriocitelline and chorioallantoic placenta, Auditory bulla, Most placentals replace all teeth except molars, some placentals have a postorbital bone

What are the 4 Eutherian Superorders?

Afrotheria, Xenarthra, Laurasiatheria, and Euarchontoglires

There are 17 shared characteristics shared by all extant mammals. What are they?

Lactation, Epiphyses on long bones, Braincase enclosed, Heterodont dentition, Dentary-squamosal articulation, Upright posture, (Crurotarsal joint and calcaneum), Pelvic Girdle arangements, (7 cervical vertebrae and unique atlas-axis complex), (Spine can be twisted lateral and dorsoventral directions), Hair, Glandular structures, (claws, nails, hooves, and horns), Adipose tissue (White and brown), Heart with complete ventricular septum and 1 systemic arch, Respiratory system, and the Urogenital system

What are the characteristics of Olfaction in mammals?

Keen sense of smell related to endothermy, Nasoturbinal and Ethmoturbinal bones, and Olfactory bulb

What are the characteristics of Vision in mammals?

Visual sensitivity important in low light, Retinas composed of rod cells sensitive to light, Fovea with cones for acute vision.

What are the characteristics of Hearing in mammals?

Complex middle ear, Long cochlea for pitch discrimination, and Pinna for sound direction

What are the 2 mammalian sub classes?

Prototheria and Theria

What is the order of evolution for hair?

1. Communication, 2. Insulation, 3. Sensory

What are the reproductive similarities between all three groups?

Lactation, Blastocysts, Trophoblast, Endometrium, Corpus luteum, Egg fertilized in the Fallopian tube

What is the reproductive differences between Prototheria and Theria?

Monotremes lay eggs and Viviparity in Theria

What reproductive characteristics are specific to Monotremes?

Oviducts remain separate, only the left oviduct is functional in the platypus, large ovaries, Egg retained in the uterus until the shell is secreted, and they possess a leathery egg shell.

What three reproductive characteristics are specific to Therians?

Placenta, Embryonic Diapause, Testes descend into scrotum.

What reproductive characteristics are specific to Marsupials?

Two lateral vaginae, Birth through a psuedo vaginal canal, Gestations time is extremely short, Young born under-developed, and the prescence

What two animals are the extreme cases of reproduction?

Naked Mole Rat and Spotted Hyena

What are bunodont teeth?

Molars found in omnivores, where cusps are low and rounded like hills

What are lophodont teeth?

Molar teeth with infoldings/cusps of enamel to create ridges for grinding; seen in odd-toed herbivores

What are selenodont teeth?

Molar teeth with crescent moon shaped cusps; seen in even-toed herbivores

What are hypsodont teeth?

High crowned teeth with enamel extending past the gum line

What are brachydont teeth?

having short crowns, well-developed roots, and only narrow canals in the roots

What are the carnassial pair of teeth?

Last Upper Premolar and First Lower Molar in Carnivores

What do animals eat with Myrmecophagous teeth?

Ants and Termites (No teeth)

Aquatic toothed mammals have what type of dentition?

Homodont dentition

What teeth modification is found in filter-feeding whales?

Baleen

Which type of gut has an enlarged large intestines and cecum?

Hindgut

Which type of gut has four chambers and chews cud?

Foregut (Ruminant)

What are the advantages and disadvantages of having a Hindgut?

partially obtain nutrients, processes food rapidly, and can survive on a low quality diet if it it's abundant.

What are the advantages and disadvantages of having a foregut?

Full breaks down cell walls, Can process plant toxins, Produce all eessential amino acids, Get the most nutrients out of their food, but they are limited in size.

What are the 7 characteristics of Cursorial locomotion?

Limbs are elongated, greater distance traveled, increased speed, energy storage in tendons, fore-aft movement of limbs, Clavicle lost, and a number of digits are reduced.

What are the 2 characteristics of Fossorial locomotion?

Burrowing and living underground, and Short and powerful limbs

How do some fossorial mammals dig? (2 Answers)

Rotating limbs through the earth and some with their incisors

What are some of the characteristics of aquatic locomotion?

All have blubber, Pinniped hindlimbs are modified, Cetaceans and Sirenians use body undulations for swimming, forelimbs are shortened and paddlelike, and hindlimbs are lost

What happened in whale evolution?

Starting with Pakicetus, they went from terrestrial environments to fully aquatic environments; Toothed and Baleen whales have distinct radiations

What are the Four social systems of primates?

female transfer systems, male transfer system, monogamous species, and solitary species

What are the three ecological factors that are important in shaping the social system of primates?

Distribution of food resources, Group size, and Predation

What are the three main groups of primates?

Plesiadapiformes
Prosimians
Anthropoids

What are the four types of social relationships among primates?

Adult/Juvenile Associations, Female Kinship Bonds, Male/Male Alliances, and Male/Female Friendships

Who are the hominid apes?

Humans, Chimps, Gorilla, Orangutans, and gibbons

Who are the 9 Major Figures in human evolution?

Homo sapiens
Homo neanderthalensis
Homo floresiensis
Homo heidelbergensis
Homo erectus
Homo habilis
Australopithecus
Kenyanthropus
Ardipithecus

Which primate genera came first?

Ardipithecus

When did bipedality evolve?

Evidence suggests 7 million years ago

What setting did bipedality evolve?

Primarily forests

What type of evidence/skeletal characteristics are there for bipedality?

S-shaped curvature of the vertebral column, modification of the pelvis and position of the hip socket, the lengthening of leg bones, and positioning as vertical columns under the body.

What is believed to be some evidence for larger brains?

Brain increased in size 3 times over time, tissue is metabolically expensive to maintain, and may have had an effect on prolonged development?

What is thought why humans needed to evolve larger brains?

Perhaps increasing ability for social interactions, conceptual complexity, tool use, dealing with rapidly changing ecological conditions, and languages

What are some thoughts about the origin of speech?

Need adaptations for controlled breathing to produce speech, need change in anatomy of pharynx and vocal tract to produce vowel sounds, and need changes in neural capacities.

What are two disadvantages of speech?

Choking and SIDS

What is an Advantage of Speech?

The ability to breathe in and out of mouth

When is it believe to be when humans lost body hair and gained pigmentation?

About 1.2 million years ago

What are some thoughts on loss of body hair and skin pigmentation?

Nakedness unique, Parasite avoidance, increase in eccrine sweat glands and use parasites to infer clothing use.