2. Cell  tissue  organ  organ system  organism

3.  Epithelial  Connective  Muscular  Nervous

5.  Organisms outer covering  Varies in form but same basic function  Made up of skin and its derivatives (scales, hair, nails, etc.)  Largest organ

6.  Protection  Thermoregulation  Sensory  Water regulation  Excretion

7.  Maintain homeostasis – stable internal environment – through regulating temperature  Endothermic  Ectothermic

8.  Epidermis – outermost layer of epithelial tissue  Dermis – under the epidermis  Contains blood vessels, nerves, glands  Hypodermis/ Subcutaneous layer – lowest layer of skin, mostly loose connective tissue and adipose cells (fat)

9.  Nails  Hair  Glands:  Sebaceous – sebum  Sweat  Eccrine – “normal” sweat, most numerous, exit skin at a pore  Apocrine – activated by stress, associated with hair follicles  Specialized Sweat Glands: secrete ear wax (ceruminous fluid), mammary glands

10.  Scales  Fish (Placoid, Dermal, Cosmoid, Ganoid, Cycloid/Ctenoid)  Reptiles  Birds  Horns and antlers  Feathers

11. Relatively thick skin Epidermal glandular cells: secretes protective cuticle Multicellular slime glands secrete large amount of mucous to cover the body surface for protection

12.  Multilayered and contains mucus and sensory cells  The dermis contains placoid scales called denticles  Denticles contain blood vessels and nerves and is very similar to vertebrate teeth

13. Scales Scales are not shed they grow at the margins and over the lower surface Skin is permeable and can be used in gas exchange Mucus help in fighting off bacterial and fungal infection

14. Transitional between aquatic and terrestrial vertebrates Stratified epidermis and a dermis containing mucus and serous glands plus pigmentation cells The earliest amphibians were covered by bone scales

18.  Terrestrial  The outer layer of the epidermis is thick, lacks glands, and is modified into keratinized scales, scutes, plaques and beaks  The thick keratinized layer resists abrasion, inhibits dehydration and protects

19. Epidermis is usually thin and only two or three layers thick The most prominent part of the epidermis are the feathers Feathers are derived from the scales of reptilian ancestors and are the most complex of all derivatives of the vertebrate skin

20.  Provides the strong, lightweight surface area needed for powered, aerodynamic flight.  Insulation: trap pockets of air to help birds conserve their body heat.  The varied patterns, colors, textures, and shapes of feathers help birds to signal their age, sex, social status, and species identity to one another.  Camouflage

21. Mammalian skin’s notable features include: Hair A variety of epidermal glands And a dermis many times thicker than the epidermis The prevention of dehydration is one of the evolutionary reasons mammals and other animals have been able to colonize terrestrial environment

22. Barrier to prevent harmful microorganisms and chemicals from entering the body Prevents the loss of life-sustaining body fluids Protects the vital structures inside the body from injury and potentially damaging ultraviolet rays of the sun Contains various types of specialized nerve cells responsible for the sense of touch

24.  3 part assignment  Start with a chart of any relevant skin characteristics (ex: glands, skin thickness/layers, hair, etc.)  Construct a cladogram using your chart  Summarize conclusions of skin evolution over time using your cladogram.  This will be counted as a quiz grade FishAmphibiansReptilesBirdsMammals GlandsYes, some NoYes, someYes, many Skin Thickness Thin ThickThinThick Hair?No Yes

25.  Goal: provide protection, support of body and organs  Provide attachment for muscles to allow for movement  Origin  Insertion  Ligaments  Connect bone to bone

26.  Bones have different shapes  Long bones (femur/humerus)  Spongy bone and compact bone  Short bones (hands and feet)  Flat bones (skull)  Irregular bones (vertebrae)

28.  Goal: allow for movement, heat  3 types: skeletal, smooth, cardiac  Tendons: connect muscle to bone

29.  Usually attached to bone  Voluntary movement  Threadlike structure  Multinucleated  Striated – alternating light and dark bands  Because of the contractile unit within the muscle

30.  Line organs and blood vessels  Involuntary movement  No striations

31.  Heart  Cells are striated and branched  Intercalated discs: directly connect each cell to the next  Involuntary movement

34. Goal: use enzymes to break down food to make energy Starts at the mouth and ends with the anus Various accessory organs

35.  Goal: bring oxygen into the body so cellular respiration can occur  Rid body of excess carbon dioxide (waste product of cellular respiration)  Includes lungs, gills

36.  Goal: transport blood throughout body  Blood carries nutrients, oxygen, waste  Includes heart, blood vessels

37.  Goal: regulate and coordinate all body systems, detect external stimuli, respond to stimuli  Includes brain, spinal cord and associated nerves

38.  Goal: rid body of waste  Includes kidneys, ureter, bladder, urethra

39.  Internal vs. External fertilization  Placental animals  Egg laying animals  Post-fertilization differences (fertilized eggs left to hatch alone, cared for, etc.)  Hatching, birth