Mammal Anatomy Quiz

Mammal Anatomy

• Tissues are composed of cells with a similar structure and function
• Similar cells form tissues
• Organs are made up of tissues
• Organs are part of organ systems (e.g., nervous/digestive)
• Epithelial tissue is arranged in continuous sheets of closely packed cells
• It covers external body surfaces and lines body cavities
• Connective tissue connects organs, protects, supports, fills spaces, produces blood cells, and stores fat
• The cells are usually surrounded by a matrix of acellular material
• Connective tissue includes cartilage, bone, blood, fat, and other tissues
• Muscular tissue is composed of long cells called muscle fibers
• It consists mostly of proteins and includes skeletal, cardiac, and smooth muscle
• Nervous tissue consists of neurons and glial cells
• Glial cells have many support and service functions

Mammal Anatomy Postures

• Plantigrade: entire foot on the ground (e.g., humans)
• Digitigrade: up on the digits (e.g., cats, dogs)
• Unguligrade: on the tips of toes with hoofs (e.g., ungulates like horses, donkeys)

Mammal Anatomy Antlers and Horns

• Antlers: branched, shed every year, usually found in male deer, elk, and moose
• Horns: not branched, permanent, consist of a keratin sheath over bone, found in both sexes of some animals, rhinoceros horns are composed of hair-like keratinized filaments, and skin-covered bone ossicones are found in giraffes.

Mammal Anatomy Hair

• Hair is a key feature of mammals
• It grows out of hair follicles and is composed of a tough protein called keratin

Mammal Anatomy Glands

• Sweat glands are only found in mammals, with two types: eccrine and apocrine
• Eccrine glands secrete watery sweat for evaporative cooling
• Apocrine glands secrete a white or yellow sweat at puberty, primarily in armpits, pubic areas, breasts
• Scent glands are present in most mammals and used to attract mates, mark territories, communicate, and warn others (e.g., skunks)
• Sebaceous glands secrete sebum, oils the skin and hair, and keeps them pliable. Has antibacterial properties, and most are associated with hair follicles.
• Mammary glands produce milk and are unique to mammals, probably modified sweat glands

Mammal Ecology

• Environment: everything an organism is exposed to( abiotic components: weather, light, nutrients, and water; biotic components: all the organisms that live in an organism's environment)
• Population: members of a specific species in an area
• Community: all populations in a particular area
• Ecosystem: the abiotic and biotic factors in an area
• Biosphere: global ecosystem
• Abiotic factors: temperature, water, sunlight, wind, rocks, soil, periodic disturbances
• Biomes: aquatic (oceans, wetlands, estuaries- cover 75% of Earth's surface) and terrestrial biomes (temperate deciduous forests cover 25% of Earth's surface)

Mammal Ecology Density and Dispersion

• Density: number of individuals per unit area
• Dispersion: pattern of spacing of individuals in a population
• Factors influencing population growth:
• Intraspecific competition: competition within species
• Density-dependent factors: competition for resources increases with population density
• Density-independent factors: weather, natural disasters
• Patterns of dispersion:
• Clumped
• Uniform
• Random
• Carrying capacity: maximum stable population an environment can support
• Species diversity includes species richness (number of species) and relative abundance (proportion of each species)

Mammal Ecology Stability and Disturbances

• Stability: constant state (equilibrium) a community may reach
• Disturbances: have major effects on communities
• Ecological succession: replacement of species over time (primary succession begins in lifeless areas like volcanic islands; secondary succession begins after a disturbance such as forestry)
• Biogeography: study of the distribution of species and communities
• Trophic levels: different feeding levels in an ecosystem
• Primary producers: base trophic level, support other levels, usually photosynthetic organisms (plants, phytoplankton)
• Primary consumers: herbivores that eat primary producers
• Secondary consumers: carnivores that eat primary consumers Food chains and webs form from trophic levels.

Mammal Ecology Behavioral Ecology

• Proximate causes of behavior: how questions about behavior (e.g., how bats use sonar)
• Ultimate causes of behavior: why questions about behavior's evolutionary basis (e.g., why do birds migrate?)
• Fitness: ability of individuals to reproduce and have offspring that survive
• Primates: mostly arboreal (tree dwelling), grasping hands, flexible limbs, well-developed brains, binocular vision.
• Two groups of primates (Traditional): prosimians (lemurs, tarsiers) and simians (monkeys, apes).

Mammal Ecology Primates

• New world monkeys: found in South America, many have prehensile tails
• Old world monkeys: found in Africa and Asia, lack prehensile tails
• Apes: first appear in fossil record 22 million years ago, generally no tails, longer arms than monkeys, proportionally larger brains.
• Gibbons/siamangs: small, social, noisy primates that move by brachiation, found in SE Asia, endangered
• Orangutans: large, red, arboreal apes in SE Asia
• Great apes: include orangutans, chimpanzees, gorillas, bonobos; all are endangered

Mammal Ecology Human Evolution

• Humans belong to the group of primates called hominins.
• Upright bipedal posture freed up hands
• Upright posture also important for predator vision
• Ahelanthropus Tchadenis: oldest known hominin
• Ardipithecus Ramidus: bipedal hominin
• Early hominins: sahelanthropus, ardipithecus, orrorin (some may not be considered true hominins)