ORGANIZATION OF LIVING THINGS

Levels of Organization of Living Things

Cell

tissue

organ

organ system organism

Types of Tissues

Epithelial

Connective

Muscular

Nervous

INTEGUMENTARY SYSTEM

Integumentary System

Organisms outer covering

Varies in form but same basic function

Made up of skin and its derivatives (scales, hair, nails, etc.)

Largest organ

Function of the Integumentary System

Protection Thermoregulation Sensory Water regulation Excretion

Thermoregulation

Maintain homeostasis – stable internal environment – through regulating temperature

Endothermic

Ectothermic

Three Main Parts of Skin

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)

Accessory Structures

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

Differences in Vertebrate Skin

Scales Fish (Placoid, Dermal, Cosmoid, Ganoid,

Cycloid/Ctenoid) Reptiles Birds

Horns and antlers Feathers

Skin of Jawless Fishes

Relatively thick skinEpidermal glandular cells: secretes protective cuticleMulticellular slime glands secrete large amount of mucous to cover the body surface for protection

Skin of Cartilaginous Fishes

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

Skin of Bony Fishes

ScalesScales are not shed

they grow at the margins and over the lower surface

Skin is permeable and can be used in gas exchangeMucus help in fighting off bacterial and fungal infection

Skin of Amphibians

Transitional between aquatic and terrestrial vertebratesStratified epidermis and a dermis containing mucus and serous glands plus pigmentation cellsThe earliest amphibians were covered by bone scales

SKIN MICROSCOPE LAB

Skin of a Frog

Skin of a Frog

Skin of Reptiles

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

Skin of Birds

Epidermis is usually thin and only two or three layers thickThe 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

Feathers 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

Skin of Mammals

Mammalian skin’s notable features include:HairA variety of epidermal glandsAnd 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

Skin of Mammals

Barrier to prevent harmful microorganisms and chemicals from entering the bodyPrevents the loss of life-sustaining body fluidsProtects the vital structures inside the body from injury and potentially damaging ultraviolet rays of the sunContains various types of specialized nerve cells responsible for the sense of touch

BLUBBER LABAND

BODY ATLAS: SKIN

Skin Cladogram

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

Fish Amphibians Reptiles Birds Mammals

Glands Yes, some

Yes, some No Yes, some

Yes, many

Skin Thickness

Thin Thin Thick Thin Thick

Hair? No No No No Yes

Skeletal System

Goal: provide protection, support of body and organs Provide attachment for muscles to allow for

movement Origin Insertion

Ligaments Connect bone to bone

Skeletal System

Bones have different shapes Long bones (femur/humerus)

Spongy bone and compact bone Short bones (hands and feet) Flat bones (skull) Irregular bones (vertebrae)

Muscular System Goal: allow for movement, heat 3 types: skeletal, smooth, cardiac Tendons: connect muscle to bone

Skeletal Muscle

Usually attached to bone Voluntary movement Threadlike structure Multinucleated Striated – alternating light and dark

bands Because of the contractile unit within the

muscle

Smooth Muscle

Line organs and blood vessels Involuntary movement No striations

Cardiac Muscle

Heart Cells are striated and branched

Intercalated discs: directly connect each cell to the next

Involuntary movement

CHICKEN WING DISSECTION

• Goal: use enzymes to break down food to make energy

• Starts at the mouth and ends with the anus

• Various accessory organs

Digestive System

Respiratory System

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

Circulatory System Goal: transport blood throughout body

Blood carries nutrients, oxygen, waste Includes heart, blood vessels

Nervous System Goal: regulate

and coordinate all body systems, detect external stimuli, respond to stimuli

Includes brain, spinal cord and associated nerves

Urogenital System

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

Reproductive Systems

Internal vs. External fertilization Placental animals Egg laying animals

Post-fertilization differences (fertilized eggs left to hatch alone, cared for, etc.)

Hatching, birth