Mammalian Evolution and Characteristics

Flashcards from lecture notes.

Synapsids

Which of the following characterizes Synapsids?
A) Absence of temporal skull opening
B) Single temporal skull opening
C) Multiple temporal skull openings
D) No skull opening

Pelycosaurs

What are Pelycosaurs?
A) Advanced synapsids
B) Early reptiles
C) Early synapsids; precursors to mammals
D) Modern amphibians

Therapsids

Which trait is associated with Therapsids?
A) Lateral posture
B) Upright posture
C) Aquatic lifestyle
D) Arboreal lifestyle

Cynodonts

What is the significance of Cynodonts?
A) They are extinct reptiles
B) They are direct ancestors of modern birds
C) They are direct ancestors of modern mammals
D) They are a type of fish

Prototherians

What is a key characteristic of Prototherians?
A) Placental mammals
B) Marsupials
C) Egg-laying mammals (monotremes)
D) Live-bearing mammals

Metatherians

Which trait defines Metatherians?
A) Long gestation periods
B) Short gestation periods
C) Aquatic reproduction
D) Asexual reproduction

Eutherians

What is characteristic of Eutherians?
A) External pouches
B) Short gestation periods
C) Long gestation periods
D) Egg-laying

Heterodont Dentition

What does heterodont dentition refer to?
A) Uniform teeth
B) Different tooth types (incisors, canines, molars)
C) Absence of teeth
D) Continuously growing teeth

Homodont Dentition

Which of the following has Homodont Dentition?
A) Cows
B) Sharks
C) Dolphins
D) Wolves

Diphyodont

Which of the following explains diphyodont?
A) Continuous tooth replacement
B) Single set of teeth
C) Two sets of teeth (deciduous + permanent)
D) No teeth

Polyphyodont

What does Polyphyodont refer to?
A) Two sets of teeth
B) No teeth
C) Continuous tooth replacement
D) Fixed number of teeth

Incus and Malleus Origins

What are the origins of the Incus and Malleus?
A) Developed from fish bones
B) Evolved from reptilian jaw bones (quadrate and articular)
C) Modified cartilage
D) New bone structures

Hair covering

What does hair covering include?
A) Scales and feathers
B) Underhair (insulation) and guard hair (protection)
C) Exoskeleton
D) Mucus layer

Integument Functions

What are the functions of the integument?
A) Respiration and digestion
B) Protection, thermoregulation, sensation
C) Excretion and movement
D) Reproduction and circulation

Mammary Glands

What is the function of Mammary Glands?
A) Waste excretion
B) Milk production
C) Hormone secretion
D) Temperature regulation

Scent Glands

What is the primary function of Scent Glands?
A) Temperature regulation
B) Communication/marking (e.g., skunks)
C) Waste excretion
D) Sound production

Horns

Which describes horns?
A) Deciduous, bony (e.g., deer)
B) Permanent, keratinized (e.g., cows)
C) Cartilaginous
D) Spongy tissue

Antlers

Which describes antlers?
A) Permanent, keratinized (e.g., cows)
B) Deciduous, bony (e.g., deer)
C) Protective scales
D) Bony plates

Dentition of Carnivores

What is a dental characteristic of carnivores?
A) Flat molars
B) Sharp canines
C) Rounded incisors
D) Absent canines

Dentition of Herbivores

What is a dental characteristic of herbivores?
A) Sharp canines
B) Flat molars
C) Pointed incisors
D) Reduced teeth

Alimentary Canal in Herbivores

What is characteristic of the alimentary canal in herbivores?
A) Shorter guts for rapid digestion
B) Longer guts for fermentation (e.g., cows)
C) Simple stomachs
D) No alimentary canal

Diapause

Which of the following explains diapause?
A) Rapid embryo development
B) Delayed embryo implantation (e.g., kangaroos)
C) Continuous reproduction
D) External fertilization

Echolocation

Which animals use echolocation?
A) Snakes/lizards use sound waves; morphological adaptations (e.g., heat pits in snakes)
B) Bats/whales use sound

Didelphimorphia

American opossums.These mammals, like most other marsupials, are characterized by an abdominal pouch, or marsupium, in which they rear their young. Most species are in Central and South America, but one species, the Virginia opossum, Didelphis virginiana, is widespread in North America; 87 species.

• Order Monotremata

egg-laying (oviparous) mammals: duck-billed platypus, echidnas. Five species in this order are from Australia, Tasmania, and New Guinea. The most noted member of the order is the duck-billed platypus, Ornithorhynchus anatinus.Echidnas, Zaoglossus and Tachyglossus, have a long, narrow snout adapted for feeding on ants, their chief food.

Primates

First among animals in brain development, with especially large cerebral cortex. Most species are arboreal, with large eyes, binocular vision, grasping hands, and five digits (usually with flat nails) on both forelimbs and hindlimbs. There are two suborders; 376 species.

Order Rodentia

gnawing mammals: squirrels, rats, mice, marmots. Most numerous of all mammals in both numbers and species. Characterized by two pairs of chisel-like incisors that grow throughout life and are adapted for gnawing. With their impressive reproductive rate, adaptability, and capacity to invade nearly all terrestrial habitats, they are of great ecological importance. Important families of this order are Sciuridae (squirrels and marmots), Muridae (rats and house mice), Castoridae(beavers), Erethizontidae(porcupines), Geomyidae(pocket gophers), and

Order Pholidota

• pangolins. Pangolins are ant- and termite-eaters whose bodies are covered with overlapping keratinized scales formed from fused bundles of hair. Their home is in tropical Asia and Africa; eight species.

Order Carnivora

flesh-eating mammals: dogs, wolves, cats, bears, weasels, seals, sea lions, walruses. All except the giant panda have predatory habits, and their teeth are especially adapted for consuming flesh. Among more familiar families are Canidae(dogs), containing wolves, foxes, and coyotes; Felidae(cats), whose members include tigers, lions, cougars, and lynxes; Ursidae (bears); Procyonidae (raccoons); Mustelidae (weasels), containing martens, skunks, weasels, otters, badgers, minks, and wolverines (Figure 28.40); and Otariidae (eared seals), containing fur seals and sea lions (Figure 28.41). Worldwide in distribution but Australia only has seals and the dingo (Canis); 286 species.

• Order Artiodactyla

even-toed hoofed mammals: swine, camels, deer, giraffes, hippopotamuses, antelopes, cattle, sheep, goats. Most have two toes, although the hippopotamus and some others have four (Figure 28.42). Each toe is sheathed in a keratinized hoof. Many, such as cattle, deer, and sheep, have horns or antlers. Many are ruminants. Most are strictly herbivores, but some species, such as pigs, are omnivores. The group includes some of the most valuable domestic animals; 240 species.

Order Cetacea

whales,dolphins, porpoises.Anterior limbs of cetaceans are modified into broad flippers; posterior limbs are absent. Some have a fleshy dorsal fin and the tail is divided into transverse fleshy flukes. Nostrils are represented by a single or double blowhole on top of the head. Hairs are limited to a few on the muzzle, and skin glands are absent except for those of the mammary and the eye. The order is divided into toothed whales (suborder Odontoceti), represented by dolphins, porpoises, and sperm whales; and baleen whales(suborder Mysticeti) (Figure 28.43), represented by rorquals, right whales, and gray whales. The blue whale, a rorqual, is the heaviest animal that has ever lived. Rather than teeth, baleen whales have a straining device made of keratin, called baleen, used to filter plankton. Cetaceans are the sister group to hippos; thus, some taxonomists place cetaceans within the order Artiodactyla; 84 species.

• Order Sirenia

• sea cows, manatees. Large, aquatic mammals with a large head, no hindlimbs, and forelimbs modified into flippers. The sea cow (dugong) of tropical coastlines of East Africa, Asia, and Australia and three species of manatees of the Caribbean area and Florida, Amazon River, and West Africa are the only living species. A fifth species, the large Steller’s sea cow, was hunted to extinction by humans in the mid-eighteenth century; four species.

• Order Chiroptera (kī-ropˊter-ə) (Gr. cheir, hand, + pteron, wing):

• bats. Wings of bats, the only true flying mammals, are modified forelimbs in which the second to fifth digits are elongated to support a thin integumental membrane for flying. Most bats, including all North American species, are nocturnal insect-eaters and navigate by echolocation. In Old World tropics, fruit bats, or “flying foxes,” live chiefly on fruits and usually lack echolocation abilities; 1116 species.

Synapsids

Which of the following describes Synapsids?

A) Absence of temporal skull opening

B) Single temporal skull opening

C) Multiple temporal skull openings

D) No skull opening

Migratory Animals (Examples)

Migratory Animals (Examples)
Caribou, monarch butterflies, gray whales.

Causality Behind Migration

Causality Behind Migration
Seasonal resource availability, breeding needs, climate avoidance.

Energetic Demands of Migration

Energetic Demands of Migration
High energy cost; requires fat storage (e.g., Arctic tern’s long-distance flights).

Territory

Territory
Defended area for resources (e.g., wolves marking boundaries).

Home Range

Home Range
Undefended area where an animal regularly travels (e.g., deer foraging).

Density-Dependent Factors

Density-Dependent Factors
Impact populations as density increases (e.g., disease, competition).

Density-Independent Factors

Density-Independent Factors
Affect populations regardless of density (e.g., hurricanes, droughts).

Monestrous vs. Polyestrous

Monestrous: One breeding cycle/year (e.g., bears).
Polyestrous: Multiple cycles/year (e.g., mice).

Choriovitelline Placenta

Simple placenta in marsupials; short gestation.

Umbilical Cord/Navel Origin

Forms from fetal connection to chorioallantoic placenta (eutherians).

True Flyers vs. Gliders

Flyers: Active flight (bats, birds).
Gliders: Passive descent (flying squirrels, sugar gliders).

Domestication Criteria

Selective breeding for traits (tameness, coat color), e.g., dogs vs. wolves.

Cattle (artiodactyls), cats (carnivores), rabbits (

Migratory Animals (Examples)

Which of the following is an example of a migratory animal?
A) Lion
B) Caribou
C) Elephant
D) Giraffe

Causality Behind Migration

What is a primary driver behind animal migration?
A) Constant food supply
B) Year-round warmth
C) Seasonal resource availability
D) Lack of predators

Energetic Demands of Migration

What is a significant energetic adaptation for long-distance migration?
A) Small body size
B) Limited fat storage
C) High energy cost
D) Rapid metabolism

Territory

Which of the following is true of a territory?
A) It is undefended
B) It is used for foraging
C) It is a defended area for resources
D) It is only used during migration

Home Range

Which of the following describes a home range?
A) A defended area
B) An area where animals regularly travel
C) An area only used for breeding
D) A fixed location

Density-Dependent Factors

Which of the following is a density-dependent factor?
A) Hurricane
B) Drought
C) Disease
D) Flood

Density-Independent Factors

Which of the following is a density-independent factor?
A) Competition
B) Predation
C) Disease
D) Drought

Monestrous vs. Polyestrous

Which animal typically has one breeding cycle per year (monestrous)?
A) Mouse
B) Bear
C) Rabbit
D) Cat

Choriovitelline Placenta

Which type of animal has a simple placenta and short gestation?
A) Eutherians
B) Marsupials
C) Primates
D) Cetaceans

Umbilical Cord/Navel Origin

From which placental connection does the umbilical cord form?
A) Choriovitelline
B) Chorioallantoic
C) Allantoic
D) Vitelline

True Flyers vs. Gliders

Which of the following animals is a true flyer?
A) Flying squirrel
B) Sugar glider
C) Bat
D) All of the above

Domestication Criteria

What is a primary criterion for domesticating animals?
A) Aggressiveness
B) Wildness
C) Selective breeding for tameness
D) Large size

Examples of Domesticated Mammals

Which of the following is a domesticated mammal from the order Artiodactyla?
A) Cats
B) Rabbits
C) Cattle
D) Dogs