Midterm 1 Flashcards
What are the 6 basic characteristics of animals?
1) Multicellular
2) Heterotrophic
3) Eukaryotic
4) Motile
5) No cell wall
6) Go through blastula
How can animals characterized?
By body plans
How many identified living species of animals are there?
1.3 Million
What are heterotrophs?
Obtain organic molecules from their food that they ingest and digest within their bodies
What are 2 defining characteristics of animals?
1) Nervous tissue
2) Muscle tissues
Definition of tissues
Groups of cells that act as a functional unit
What do parazoans lack?
They have no true tissue
What is the group called for all animals?
Metazoa
What does the group eumetazoa mean?
Animals w/ specialized tissues
How do zoologists sometimes categorize animals by?
Body plan: a set of morphological and developmental traits
How long has the molecular control of gastrulation remained unchanged?
More than 500 million years
What are the 4 characteristics of bilaterally symmetrical animals?
1) Dorsal and ventral (top and bottom)
2) right and left
3) Anterior and posterior (front and back)
4) cephalization: brain
True or False: Bilateral animals are triploblasts and Radial animals are diploblasts?
TRUE
What are the 5 stages of early embryonic development in animals?
1) zygote
2) 8-cell stage
3) Blastula
4) Gastrulation
5) Gastrula
What stage usually dominates the life cycle (diploid or haploid)?
Diploid stage
What are the 3 layers in tissue from outermost to innermost (triploblastic)?
1) Ectoderm
2) Mesoderm
3) Endoderm
What layer of tissue do diploblasts lack?
Mesoderm
Which animal is considered to be the simplest?
Trichoplax adhaerens (TP); used to be th only living species in the phylum placozoa (now there are 4)
What is a pseudocoelom?
A body cavity derived from mesoderm and endoderm (only triploblasts). Animals that possess these are called pseudocoelomates
Triploblastic animals that lack a body cavity are called what?
Acoelomates
What are triploblasts that contain a true coelom called?
Coelomates
True or false: radial cleavage leads to protostomes and spirall cleavage leads to deuterostomes
False: spiral cleavage = protostomes & radial cleavage = deuterostomes
What are ecdysozoans?
Invertebrates that shed their exoskeleton through a process called ecdysis
What does arthropod mean?
Jointed feet