How

Animals

MoveBIO 14 General Biology 2

Movement and Locomotion

Movement - a distinguishing characteristics of

animals.

(In muscle cell contraction and amoeboid

movement, the cellular system is based on

microfilaments. Microtubules are the main components of

cilia and flagella)

Locomotion- active travel from place to

place—requires energy to overcome two forces

that tend to keep an animal stationary: friction

and gravity.

Major Modes of Animal

Locomotion Swimming- Animals

swim in diverse ways.Ex. 1. Insects- use their legs as

oars to push against the water.

2. Squids, scallops, and some

jellies are jetpropelled, taking in

water and squirting it out in bursts.

3. Fishes swim by moving their

body and tail from side to side

Major Modes of Animal

Locomotion Walking and Running- A walking animal

moves each leg in turn, overcoming frictionbetween the foot and the ground with each step.

- To maintain balance, a four-legged animal usuallykeeps three feet on the ground at all times when walkingslowly

Major Modes of Animal

Locomotion Hopping- a specialized mode of locomotion

that has also evolved independently in several

rodents.

Major Modes of Animal

Locomotion Crawling- Animals that

have no limbs, or very short

limbs, drag their bodies along

the ground in a crawling

movement.

- Because much of the

animal’s body is in contact with

the ground, its energy is mainly

expended to overcome friction

rather than gravity

Major Modes of Animal

Locomotion Flying- few animal groups:

insects, reptiles (including

birds), and, among the

mammals, bats.

Skeletons function in support, movement, and

protection

3 main types of skeletons:

1. Hydrostatic skeletons

2. Exoskeletons

3. Endoskeletons

Hydrostatic Skeletons

- consists of fluid heldunder pressure in a closedbody compartment.

- helps protect otherbody parts by cushioningthem from shocks. And italso gives the body shapeand provides support formuscle action.

Exoskeletons

- rigid external skeleton

-characteristic of the

phylum Arthropoda, a group

that includes insects, spiders,

and crustaceans such as

crabs.

- characteristic of the

phylum Arthropoda, a group

that includes insects, spiders,

and crustaceans such as

crabs.

Endoskeletons

- consists of hard

or leathery supporting

elements situated

among the soft tissues

of an animal

The Vertebrate

Skeleton

All vertebrates have an axial skeletonsupporting the axis, or trunk, of the body.

- consists of skull, vertebral column

(backbone) and in most vertebrates, rib cage.

Backbone

- the definitive

characteristic of vertebrates,

consists of a series of

individual bones, the

vertebrae, joined by pads of

tough cartilage known as

discs.

- number of vertebrae

varies among species.

Pythons have 400, while an

adult human has 24.

Most vertebrates also

have an

appendicular

skeleton, which is

made up of the bones

of the appendages

and the bones that

anchor the

appendages to the

axial skeleton.

Bones are complex

living organs

-bones are actually

complex organs consisting

of several kinds of moist,

living tissues.

What causes the colors of yellow

and red bone marrow?

Yellow bone marrow stores fat

while red bone marrow develops red

blood

Healthy bones resist stress and heal from

injuries

Excessive bone fatigue can lead to so-called

stress fractures, hairline cracks in the bone, just

as the accumulation of small amounts of stress

on metals can cause a break.

bone is composed of living, dynamic tissue.

Cells continually remove old bone matrix and

replace it with new material.

The risk of bone fracture increases if bones

are porous and weak.

Osteoporosis is

characterized by low

bone mass and

structural

deterioration of bone

tissue.

Other lifestyle habits, such as smoking, may

also contribute to osteoporosis. There is a

strong genetic component as well;

young women whose mothers or

grandmothers suffer from osteoporosis

should be especially concerned with

maintaining good bone health.

Treatments for osteoporosis include calcium

and vitamin D supplements and drugs that

slow bone loss.

Joints permit different types of movement

- the versatility of the vertebrate skeleton

comes from its joints.

Ligaments- Bands of strong fibrous

connective tissue

3 kinds of Joints:

Ball –and-socket joints

Hinge joints

Pivot joints

Ball –and-socket joints

- are found where the

humerus joins the pectoral

girdle

- enable us to rotate

our arms and legs and move

them in several planes.

Hinge Joints

- permit movement in a

single plane, just as the

hinge on a door enables it to

open and close.

Pivot joint- enables us to rotate the

forearm at the elbow

- pivot joint between

the first and second cervical

vertebrae allows movement

of the head from side to side

Muscle Contraction and Movement

The skeleton and muscles interact in movement

Muscles are connected to bones by tendons.

Each muscle cell has its

own contractile

apparatus

A muscle consists of

many bundles of muscle

fibers—roughly 250,000

in a typical human biceps

muscle—oriented

parallel to each other.

Myofibrils - discrete bundles of

proteins that include the

contractile proteins actin and

myosin.

Sarcomere- is the region

between two dark, narrow lines,

called Z lines, in the myofibril.

Each myofibril consists of a long

series of sarcomeres.

Functionally, the

sarcomere is the contractile

apparatus in a myofibril—the

muscle fiber’s fundamental unit

of action.

Thin filaments-

composed primarily of

actin molecules.

Thick filaments-

which are made up of

myosin molecules

A muscle contracts when thin filaments slide

along thick filaments

Sliding-filament model of muscle contraction

- a sarcomere contracts (shortens) when

its thin filaments slide along its thick filaments