<< Chapter < Page Chapter >> Page >
By the end of this section, you will be able to:
  • Describe the various types of body plans that occur in animals
  • Describe limits on animal size and shape
  • Relate bioenergetics to body size, levels of activity, and the environment

Animals vary in form and function. From a sponge to a worm to a goat, an organism has a distinct body plan that limits its size and shape. Animals’ bodies are also designed to interact with their environments, whether in the deep sea, a rainforest canopy, or the desert. Therefore, a large amount of information about the structure of an organism's body (anatomy) and the function of its cells, tissues and organs (physiology) can be learned by studying that organism's environment.

Body plans

Illustration A shows an asymmetrical sponge with a tube-like body and a growth off to one side. Illustration B shows a sea anemone with a tube-like, radial symmetrical body. Tentacles grow from the top of the tube. Three vertical planes arranged 120 degrees apart dissect the body. The half of the body on one side of each plane is a mirror image of the body on the other side. Illustration C shows a goat with a bilaterally symmetrical body. A plane runs from front to back through the middle of the goat, dissecting the body into left and right halves, which are mirror images of each other. The top part of the goat is defined as dorsal, and the bottom part is defined as ventral. The front of the goat is defined as anterior, and the back is defined as posterior.
Animals exhibit different types of body symmetry. The sponge is asymmetrical, the sea anemone has radial symmetry, and the goat has bilateral symmetry.

Animal body plans follow set patterns related to symmetry. They are asymmetrical, radial, or bilateral in form as illustrated in [link] . Asymmetrical animals are animals with no pattern or symmetry; an example of an asymmetrical animal is a sponge. Radial symmetry, as illustrated in [link] , describes when an animal has an up-and-down orientation: any plane cut along its longitudinal axis through the organism produces equal halves, but not a definite right or left side. This plan is found mostly in aquatic animals, especially organisms that attach themselves to a base, like a rock or a boat, and extract their food from the surrounding water as it flows around the organism. Bilateral symmetry is illustrated in the same figure by a goat. The goat also has an upper and lower component to it, but a plane cut from front to back separates the animal into definite right and left sides. Additional terms used when describing positions in the body are anterior (front), posterior (rear), dorsal (toward the back), and ventral (toward the stomach). Bilateral symmetry is found in both land-based and aquatic animals; it enables a high level of mobility.

Limits on animal size and shape

Animals with bilateral symmetry that live in water tend to have a fusiform    shape: this is a tubular shaped body that is tapered at both ends. This shape decreases the drag on the body as it moves through water and allows the animal to swim at high speeds. [link] lists the maximum speed of various animals. Certain types of sharks can swim at fifty kilometers an hour and some dolphins at 32 to 40 kilometers per hour. Land animals frequently travel faster, although the tortoise and snail are significantly slower than cheetahs. Another difference in the adaptations of aquatic and land-dwelling organisms is that aquatic organisms are constrained in shape by the forces of drag in the water since water has higher viscosity than air. On the other hand, land-dwelling organisms are constrained mainly by gravity, and drag is relatively unimportant. For example, most adaptations in birds are for gravity not for drag.

Maximum Speed of Assorted Land Marine Animals
Animal Speed (kmh) Speed (mph)
Cheetah 113 70
Quarter horse 77 48
Fox 68 42
Shortfin mako shark 50 31
Domestic house cat 48 30
Human 45 28
Dolphin 32–40 20–25
Mouse 13 8
Snail 0.05 0.03

Questions & Answers

breathing in reptiles
sam Reply
which molecules binds to the active site of an enzyme
Ghulam Reply
human
Haggai
what is nutrients
Patrick Reply
nutrients is substance which body use in terms of need
Haggai
yes..
Abdullahi
can I join?
Osei
substance that provides nourishment essential for the maintenance of life and for growth.
umar
right same answer as you Umar
Namuli
please remind me
Namuli
Any material that provide essential components for cell metabolisms is nutrient
Mahmood
what are the types of skeleton
Tanyi Reply
endo skeleton and exo skeleton
Faith
or types of skeletons There is exo skeleton found in class insecta Exo skeleton found in phylum chordata and lastly hydrostatic skeleton found mainly in earth worms
Daniel
and hydrostatic skeleton
Godbless
what is life?
Jerson Reply
life is when any living thing breath or respirate.
Lucky
I want to join
Patrick
me too
Favour
me two
Monday
me too
Bengazy
me too
Maggie
I here
Yahaya
Does anybody knows another biology app that brings good understand
Lucky
give an example of a phylum where all members have open circulatory
Omoro Reply
anthropoda
Daniel
phylum Anthropoda
Daniel
how do u change the unit of temperature from degree celsius to degree Fahrenheit
Maggie
what are beneficial effects in industrial
Nnamani Reply
create employment
ibrahim
provide food
ibrahim
pollution
ibrahim
dirty the environment
ibrahim
pollution and lack of knowledge about how to manage waste
Alex
what is gametophyte
Ibrahim Reply
what is biology
Basiru Reply
Biology deals with the study of living organisms and their interactions with each other and the environment.
Quartey
biology simply means the study of living and non-livingthings.
Shamstar
what is the meaning of ubiquitous
Hamziyatu Reply
Under what topic is this question
fred
three branches of biology
Alexander Reply
what is the cell
Olajide Reply
what is life
Olajide
cell is the functional and structural unit of life
Shweta
life is a problem solving entity
Atanga
what is the characteristics of plant cell
Quaku
Describe the process that results in the formation of a tetrad.
Michael Reply
what is biology
Ndukwe Reply
biology is the study of life
Oghenemine
what is biology
Jimmy Reply
the study of life
Hamziyatu

Get the best Biology course in your pocket!





Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Biology' conversation and receive update notifications?

Ask