1. Animals move in place, like a sponge, or by traveling from place to place, called locomotion. Locomotion

requires animals to expend energy to overcome 2 forces - friction and gravity.

2. Swimming is not much affected by gravity, bc water supports much of the animal’s weight. Friction is

considerable in the water.

a. we use our legs like oars to push through the water

b. other animals use jet propulsion (squids and some jellies)

c. fish swim by swishing tails from side to side

d. mammals swim moving tails up and down

e. sleek, streamlined shape is important for rapid swimming

3. Locomotion on land

a. more effect of gravity, less resistance (friction)

b. to move on land, you have to use energy to generate muscle movement that will propel you

c. hopping - large muscles in the hind legs generate a lot of power

d. muscles also contract when the animal lands, temporarily storing power, so that the stored energy is available for the next jump.

e. legs of ants or dogs and other animals also retain some energy when walking or running, reducing total amt. of energy needed for movement

4. Maintaining balance is another problem to solve for animals who live on land.

a. The kangaroo uses its 2 legs and the base of its tail as a tripod to support and stabilize itself when sitting upright.

b. Dogs and other 4 legged animals use this arrangement as well. When walking, a dog keeps 3 legs on the ground at all times.

c. Bipedal (2 legged) animals such as humans and birds are less stable on land, and generally keep one foot on the ground at all times when walking.

d. When animals run, we use momentum (similar to movement keeping a bike upright) to keep the body stable, since all feet will be off the ground at the same time.

5. Crawling animals like snakes and worms must deal with considerable friction since much of the body surface is in contact with the ground at any given time.

a. many snakes move by undulating from side to side; the snakes body pushes against the ground and it moves the snake forward.

b. other snakes, like boa constrictors and pythons have scales that are controlled by muscles. The muscles lift the scales off the ground and angle them forward, then push them back against the ground.

c. earthworms use peristalsis to crawl. An earthworm’s body has circular muscles as well as longitudinal muscles. The worm alternates contraction of these in a particular region to extend its body out, then uses bristles on the bottom surface to anchor itself while it shortens that area using circular muscles, pulling the worm forward. (Fig. 30.1D)

6. Flying animals include insects, bats, birds and reptiles. Flying reptiles died out millions of years ago, leaving birds and bats as the only flying vertebrates. (Fig. 30.1E)

a. flying requires wings that will provide what is called lift.

b. The shape that will produce lift is called an airfoil - it has a leading edge that is thicker than a trailing edge.

c. It also has an upper surface is somewhat concave relative to its lower edge.

d. air passing over the wing travels faster than air traveling under the wing.

e. air molecules under the wing are packed closer together than above it, so density of the air is lower above the wing. This greater pressure lifts the wing.

7. Similarities in all kinds of animal movement

a. at cellular level, movement is based on 2 basic contractile systems - microtubules and microfilaments

b. both require energy consuming cellular work to move protein strands against one another.

c. microfilaments are important in amoeboid movement and are the contractile elements of muscle cells.

1. An animal could not move without its skeleton; most land animals would sag without their skeletons.

2. Even water animals would be a formless mass without some form of a skeleton.

3. skeletons also provide protection for an animal’s important soft parts - for example, ribs protect hearts and lungs, and skulls protect brains.

4. there are 3 main types of skeletons- hydrostatic, exoskeletons and endoskeletons.

a. hydrostatic skeletons are fluids held under pressure in an enclosed body compartment

1. it provides protection and cushions organs or animals from shock

2. it give a body shape

3. it provides support for muscle action

4. earthworms have a coelom- a fluid-filled internal cavity. Since earthworms are segmented, they can use the separate compartments to act as a skeleton. The action of longitudinal and circular muscles produce peristaltic movement.

5. Cnidarians, like hydras and jellyfish also have hydrostatic skeletons. Hydras hold fluids in their gastrovascular cavities and alter body shape by contracting muscles in their body walls

6. When a hydra constricts circular muscles, the water cannot be compressed so the animal elongates (Fig. 30.2A)

7. hydras will sit extended for hours; if prey contact their arms, they will open their mouths, allowing water to flow out, and long muscles in its body will shorten it.

8. animals with hydrostatic skeletons are soft and flexible. Hydras can extend their bodies around prey; earthworms can maneuver through soil

9. lots of tube dwelling animals have hydrostatic skeletons

10. They work in water, but not on land, bc they can’t provide enough support for terrestrial locomotion

b. exoskeletons - rigid external skeleton possessed by many terrestrial and aquatic animals.

1. muscles attach to knobs and plates on inner surfaces of exoskeletons to produce movement

2. armorlike protection, support and flexibility of exoskeletons have helped ensure the evolutionary success of arthropods

3. these are made of materials secreted by living cells but are not themselves living and do not grow with the animal. So they must be shed periodically to provide room for growth

4. shedding = molting and most insects molt 4 - 8 times before adulthood

5. a few insects and crabs and lobsters molt all through life (Fig. 30.2b)

6. an arthropod is never with out an exoskeleton. A soft new one forms under the old hard one

7. soon after molting, an animal swallows a whole bunch of air or water, expanding the new one

8. the new skeleton hardens in the expanded state, and the animal now has room for growth.

9. animals with mantles, such as clams, secrete materials to enlarge the exoskeleton as they grow (Fig. 30.2c)

c. endoskeletons consist of hard or leathery supporting structures situated among soft tissues in animals.

1. sponges have tough protein fibers or hard needle like structures called spicules (Ca or Si).

2. sea urchins and sea stars have hard plates beneath their skin

3. vertebrates have skeletons of cartilage, or cartilage and bone

4. sharks have cartilaginous skeletons

5. most other vertebrates have skeletons of cartilage and bone (Fig. 30.2E)

1. our human skeletons are adapted for life in an upright position, but nothing is perfect. Our S shaped spinal column helps us keep balance, but is subject to stress over our lifetimes especially in our lower backs which support the weight of our hanging internal organs.

2. keep your lower back fit by strength and stretching exercises, especially abdominal exercises and lower back and hamstring stretching exercises

3. Arthritis is inflammation of the joints - it affects one out of 7 people in the U.S.

a. age related - cartilage wears down, bone becomes thickened and restrict movement. Moderate exercise, rest and over the counter meds can relieve symptoms

b. rheumatoid arthritis - autoimmune disease - joints become highly inflamed, tissues destroyed by body’s immune system. Begins btn ages 30 - 40, may be triggered by stress or infection or genetic factors. Anti-inflammatory drugs may help, but no cures; artificial joints may help

c. osteoporosis - serious bone disorder related to hormonal changes that accompany aging. Most common in older women after menopause. Estrogen contributes to normal bone maintenance. With lower estrogen production, bones may become more brittle, thinner and more porous. Insufficient exercise, inadequate protein and calcium and diabetes may also contribute to this disease. Prevention is the best way to beat this disease.

1. Bones consist of several types of moist, living tissue, amply supplied with blood (Fig. 30.5)

2. sheet of connective tissue surrounds most of the outside of the bone (pink); this tissue can form new bone cells in the event of a fracture

3. At each end of the bone, a thin sheet of cartilage (blue), also living tissue, replaces connective tissue. This sheet forms a cushionlike surface for joints

4. Bone itself contains living cells that secrete surrounding material or matrix. Bone matrix = protein collagen (flexible material) embedded in hard calcium salts, more or less like rebar in concrete; the collagen resists cracking, the calcium salts resist compression

5. Shaft of long bone is made up of compact bone, which has a dense matrix

6. Compact bone surrounds a central cavity which contains yellow bone marrow. Yellow bone marrow is stored fat brought into the bone by blood. The ends, or heads of the bones have outer layer of compact bone and an inner layer of spongy bone, honeycombed w/small cavities.

7. Cavities contain red bone marrow, a specialized tissue that produces blood cells

8. Tissues in bone require servicing, as does any tissue

9. blood vessels course through channels in bone transporting nutrients and hormones to its cells

10. nerves parallel the blood vessels to regulate the flow of materials between blood and bone.

1. skeletal muscle is attached to the skeleton and produces movement is made up of a hierarchy of smaller and smaller parallel strands.

2. A muscle consists of bundles of parallel muscle fibers. Each muscle fiber is single cell with many nuclei.

3. each muscle fiber consists of many parallel, smaller myofibrils. Skeletal muscle is also called striated muscle bc of the alternating dark and light bands in myofibrils.

4. Myofibrils consist of repeating units called sarcomeres.

a. sarcomeres are the regions btn dark, thin lines called z lines = proteins that connect the thin filaments

b. functionally, the sarcomere is the contractile unit of the myofibril - a muscle fiber’s unit of action

c. myofibrils are composed of regular arrangement of 2 kinds of filaments

d. thin filaments (blue) = double strand of protein actin and 1 strand of regulatory protein coiled together

e. thick filament (pink) = number of strands of protein myosin

1. sliding filament model of muscle contraction - A.F. Huxley (1950)

2. sarcomeres contract when thin filaments slide across thick filaments

3. Fig. 30.9A shows filaments in relaxed, contracting and contracted muscle.

4. filaments themselves don’t change shape, they over lap.

5. a whole muscle can contract to about .5 resting length

6. what makes filaments slide in muscle contraction?

a. heads of myosin (thick) bind with specific sites on actin.

b. 1) ATP binds to a myosin head, causing it to detach from actin (Fig. 30.9B)

c. 2) ATP is hydrolyzed to ADP and P releasing energy; these remain attached to myosin head. Head gains some of the energy and takes a cocked position, ready to bind with another actin binding site

d. 3) Ca2+ (calcium ion) opens a binding site on actin,

e. 4) power stroke - ADP and P released from head, bending it down to bind with new site on actin. The bending pulls the thin filament toward the center of the sarcomere

f. a typical thin filament has 350 heads and this process occurs again and again in a contracting muscle

g. each can bind and unbind to an actin filament 5x/sec.

h. some myosin hold the actin to prevent backsliding, other myosin reach forward to new binding sites

I. process continues till muscle is fully contracted

1. Sarcomeres are stimulated to contract by motor neurons

2. typical motor neuron can stimulate more than one muscle fiber; each neuron has many branches (Fig. 30.10)

3. motor unit = neuron and all the muscle fibers it controls (2 or 3 in this case)

4. motor unit has dendrites and cell bodies in the cns

5. axons form synapses, called neuromuscular junctions in muscle fibers

6. when motor neuron sends out action potential, synaptic knobs release acetylcholine; it diffuses across neuromuscular junctions to muscle fibers, making all fibers of a motor unit contract simultaneously

7. Depending on how many motor units your brain commands to function, you have either a weak or a forceful contraction

8. As in a synapse, an action potential carried by a change in electrical charge inside the muscle cell causes contraction of the sarcomeres.

9. Ca2+ is used as a "pump"