Chapter 3 Flashcards
What is a bauplan, and what does it do?
- a structural plan or design
- establishes capabilities and limits
What do animals require to survive and reproduce (2)?
- obtain oxygen for respiration
- acquire, digest, metabolize, and distribute food
What is symmetry? (2)
- regular arrangement of body structures relative to a particular axis
- can be bisected at a point to have similar halves
What is asymmetry, and what is it found in?
- no body axis or plane of symmetry
- some sponges and placozoans
What is spherical symmetry (2), and what is it found in?
- body lacks an axis and has a spherical shape, radiating from a central point
- infinite number of planes
- rare- found in some protists and sponges
How is spherical symmetry similar to asymmetry?
lacks polarity
What is radial symmetry (2), and what is it found in?
cylindrical form, with any plane of sectioning along the central axis resulting in similar halves
no front or back ends
common in sessile and sedentary animals, or free-drifting pegalic species
- sponges, starfish, aea anemones
What is a benefit of radial symmetry?
allows animal to confront environment equally from all directions
What is perfect radial symmetry found in?
some sponges and cnidarians
What is biradial symmetry, adn what is it found in?
- The organism can be divided into two symmetrical halves in one plane, but this plane is restricted to only one or a few axes.
- sea anemones and ctenophores
What is rotational symmetry?
shape that looks precisely the same after some rotation of 180 degrees or less
What is multiradiality found in?
- quadriradial symmetry in some jellyfish
- pantaradial symmetry in some echinoderm
What is bilateral symmetry, and what is it found in?
oriented on an axis passing through the anterior through the posterior
found in highly directional mobile animals
What is the midsagittal plane?
separates left and right
What is the frontal plane?
separates dorsal and ventral
What is the transverse plane?
perpendicular to the midsagittal plane
Lateral vs medial
- lateral- sides of the body away from the midsagittal plane
- medial- midline body, near the midsagittal plane
What does the anterior end do?
confront environment, with feeding and sensory structures
What is cephalization?
specialized head containing nervous tissues, sensory structures, and feeding structures
Dorsal vs ventral end role
- dorsal end is used for locomotion
- ventral end is used for protection
What is secondary bilateral, and what is it found in?
- bilateral animals with radial structures
- spiral coiling of snails
