This document summarizes the major modes of animal locomotion and components of the skeletal system. It discusses how animals move through swimming, walking, running, hopping, crawling, and flying. It then describes the three main types of skeletons: hydrostatic skeletons, exoskeletons, and endoskeletons. Finally, it focuses on the vertebrate skeleton, bones, joints, and muscle contraction.

1. How
Animals
Move
BIO 14 General Biology 2

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.

3. 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

4. Major Modes of Animal
Locomotion
 Walking and Running- A walking animal
moves each leg in turn, overcoming friction
between the foot and the ground with each step.
- To maintain balance, a four-legged animal usually
keeps three feet on the ground at all times when walking
slowly

5. Major Modes of Animal
Locomotion
 Hopping- a specialized mode of locomotion
that has also evolved independently in several
rodents.

6. 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

7. Major Modes of Animal
Locomotion
 Flying- few animal groups:
insects, reptiles (including
birds), and, among the
mammals, bats.

8. Skeletons function in support, movement, and
protection
3 main types of skeletons:
1. Hydrostatic skeletons
2. Exoskeletons
3. Endoskeletons

9. Hydrostatic Skeletons
- consists of fluid held
under pressure in a closed
body compartment.
- helps protect other
body parts by cushioning
them from shocks. And it
also gives the body shape
and provides support for
muscle action.

10. 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.

11. Endoskeletons
- consists of hard
or leathery supporting
elements situated
among the soft tissues
of an animal

12. The Vertebrate
Skeleton

13.  All vertebrates have an axial skeleton
supporting the axis, or trunk, of the body.
- consists of skull, vertebral column
(backbone) and in most vertebrates, rib cage.

14. 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.

15.  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.

16. Bones are complex
living organs
-bones are actually
complex organs consisting
of several kinds of moist,
living tissues.

18. What causes the colors of yellow
and red bone marrow?
Yellow bone marrow stores fat
while red bone marrow develops red
blood

19. 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.

21. 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.

22.  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.

23. 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

24.  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

25. Muscle Contraction and Movement
 The skeleton and muscles interact in movement
Muscles are connected to bones by tendons.

26.  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.

27. 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.

28.  Thin filaments-
composed primarily of
actin molecules.
 Thick filaments-
which are made up of
myosin molecules

29. 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