chap 32 Flashcards
(25 cards)
animal characteristics
6
-Heterotrophic
-Multicellular
-Absorptive nutrition
-No cell walls
-Usually have nerves, muscles, and the ability to move
-Tissues develop from embryonic layers
reasons why the cambrian period led to a rapid increase in animal diversity
3
-Predators acquired adaptations that caused prey to adapt with defensive adaptations, such as shells
-An increase in atmospheric O2 enabled animals with higher metabolic rates and larger bodies to thrive
-Genetic change, such as Hox genes, and microRNAs developed, causing evolution in many new body forms/complexity
how did bilateral symmetry allow for more active lifestyles in animals
It allowed for a stream-lining and a central nervous system, which coordinates complex movements.
diploblastic vs tripoblastic
Diploblasts have only two germ layers (jellyfish)
triploblasts have all three (most animals)
What do the embryonic tissue layers grow into
-Endoderm
1. Lining of the digestive tract
2. Most organs
-Ectoderm
1. Outer covering of animal
2. In some phyla, the central nervous system
gametic life cycle
sperm and egg (n) –> fertilization –> diploid zygote (2n) –> mitosis –> living thing (2n) –> meiosis –> sperm and egg (n)
protostome vs deuterostome development
cleavage + blastopore
protostomes (mollusks, annelids, and arthropods)
- cleavage – 8 cell stage, spiral and determinate
- blastopore – mouth
deuterostome (echinoderms, chordates)
- cleavage – 8 cell stage, radial and indeterminate
- blastopore – anus
tissue
groups of similar cells that act as a functional unit
radial symmetry
can be cut in different parts and will look the same in all
(stars, flowers etc)
dorsal
top side
ventral
bottom side
anterior
front side
posterior
back side/end
diploblastic
two germ layers (cnidarians)
triploblastic
three germ layers (most animals)
endoderm
innermost germ layer
ectoderm
outermost germ layer covering the surface of the embryo
mesoderm
3rd germ layer
fills space btw the ecto- and endoderm
coelom
true body cavity that is lined by the mesoderm (thick)
in the eucoelomate body tissue
pseudocoelom
fluid-filled false body cavity – invertebrates
helps with movement
in the pseudocoelomate
spiral cleavage
The planes of cell division of an embryo are diagonal to the vertical axis
creates spiral arrangement
radial cleavage
they are parallel or perpendicular to each other
they look more organized
determinate cleavage
the fate of the embryonic cell is set early on
losing a cell would cause damage to the embryo
indeterminate cleavage
each cell has the ability to develop into a complete embryo
if a cell is lost, another can take its place
