Download Animal Evolution and Diversity | BIOL 1108 - PRINCIPLES OF BIOLOGY II and more Quizzes Biology in PDF only on Docsity!
4 Defining Characteristics of all Animals
- Comprised of eukaryotic cells 2. Contain cells that lack cell walls 3. Are multicellular 4. Are heterotrophic TERM 2
Heterotrophic
DEFINITION 2 Ingest energy in the form of food, rather than producing it from a non-organic source, as plants do through photosynthesis TERM 3
In addition to the 4 defining characteristics,
MOST animals also share these
characteristics:
DEFINITION 3
- Reproduce sexually 2. Capable of independent movement
- Body plans are symmetrical 4. Bodies contain tissues 5. Undergo unique embryonic developmental stages not shared by all invertebrates, beginning with the formation of a blastula TERM 4
Tissues
DEFINITION 4 Groups of cells contained in a membrane. They carry out vital functions in the body, provide protection and structural support for the animal, and combine with other tissues to form complex organs TERM 5
Blastula
DEFINITION 5 A hollow ball of cells that develops from the zygote
Zygote
Fertilized egg TERM 7
Monophyletic
DEFINITION 7 Meaning that all animals descended from a single common ancestor, likely a colonial protist. TERM 8
The Key Innovations in Animal Evolution
DEFINITION 8
- Tissues 2. Structural Symmetry 3. Body Cavity 4. Embryonic developmental plans 5. Segmented bodies TERM 9
Structural Symmetry
DEFINITION 9 describes the form an animal's body takes. Most animals are either radial or bilateral. TERM 10
Radial Symmetry
DEFINITION 10 Describes a circular structure developed around a point in the center of the body
Eumetazoa
"true animals" possess tissues that carry out particular functions TERM 17
Radiata
DEFINITION 17 Radially symmetrical animals. They are symmetrical around the center point of the body. Example: Jellyfish TERM 18
Bilateria
DEFINITION 18 Bilaterally symmetrical animals, they are symmetrical along a single central axis. Most Eumetazoans such as: fish, birds, and mammals, exhibit this bilateral symmetry. TERM 19
Dorsal
DEFINITION 19 Top TERM 20
Ventral
DEFINITION 20 Bottom
Anterior
Front TERM 22
Posterior
DEFINITION 22 Back TERM 23
Advantages of Bilateral Symmetry over Radial
Symmetry
DEFINITION 23
- Allowed different, specialized tissue organs to develop in different parts of the body 2. It led to the development of sensory organs in more strategic locations on the body 3. Provided a means for greater and more efficient mobility in the environment, where radial animals tend to be sessile TERM 24
Sessile
DEFINITION 24 Attached to a base or passively floating TERM 25
Acoelomates
DEFINITION 25 have no body cavity. This group contains the radiata
