Bio Exam 4 Class 1 (Intro to Animals and Nonbilaterians) Flashcards
the first animals were found
635 mya
what was the first major radiation of animals
cambrian explosion
what was the closest ancestor to early animals
flagellated unicellular protists (choanoflagellates)
all animals…
1.lack cell walls but have extracellular matrix
2.are heterotrophs
3. move under their own power at some point in their life cycle
4. have neurons and muscle cells
what is the ECM
produces proteins used for cell to cell adhesion and communication
what do neurons do?
transit electrical signals from one cell to other
what do muscle cells do?
change the shape of the body by contracting
animals are related to….
fungi and single celled protists
what were the earliest animals to evolve
non bilaterians,, sponges and jellyfish
how are animals divided into groups?
symmetry and development
what are the two symetry groups
non bilaterians and bilaterians
what are the two development groups>
protostomes and deuterostomes
what is radial symmetry
at least two planes of symmetry
what is bilateral symmetry?
only one plane of symmetry
what is a protostome?
first mouth,, embryonic development before the anus (most snimals)
what is a deuterostome?
(second mouth),, embryonic development of the anus before the mouth (largest predators and animals)
ancestors to animals were single celled… organisms similar to…
colonial,,, choanoflagellates
although sponges look and act similarly to choanoflagellates, they
developed multicellularity and specialization
animals are sister species to
all animals
what were the key innovations to animal evolution?
- multicellularity
- multiple tissue layers
- bilateral symmetry
- cephalization
- body cavity
- segmentation
animals have multiple
embryonic tissue layers
what are the two levels of embryonic issue layers>
diploblasts and triploblasts
diploblasts have
2
triploblasts have
3
ectoderm
skin and nervous system (and the muscles in diploblasts)
endoderm
gut, digestive tract, respiratory tract, (and reproductive systems in diploblasts)
mesoderm
muscle, bone, organs, and circulatory system
what is the coelom
the empty space between the layers of tissue,, fluid filled cavity
allows for oxygen and nutrient transportation throughout the body
what are the 3 kinds of bilaterians
- acoelomates
- pseudocoelomates
- coelomates
acoelomates
do not have a coelom
pseudocoelomates
have a partially lined with muscle tissue
coelomates
coelom completely lined with muscle tissue
what are the functions of the coelom?
- circulation of o2 and nutrients
- acts as a hydrostatic skeleton
- gives bilaterians ability to move efficiently in their search for food
what does a hydrostatic skeleton do>
- gives bilaterians the ability of locomotion
- replaces the fucntions of internal skeletons and external skeletons
what types of animals have a hydrostatic skeleton?
- jellyfish
- leeches
-earthworm - other invertebrates
bilateral symmetry is coupled with the evolutionof
the central nervous system and body cavity
radial diploblasts have a
nerve nets
bilateral triploblasts have
central ervous system
what does the CNS include
a brain and ganglia
what is cephalization>
the evolution of the head
the CNS allowed for the
evolution of the head
ctenophoes and cnidarias contain,, all other animals have,,,
nerve nets, brains
segmentation
when protostome and deuterostomes evolved,, repeated body structures
segmentation allowed for
specialization of different body parts
segmentation is controlled by
hox and dpp genes
other themes in the evoution of animals
sensory organs
feeding
reproduction
CNS and specialization allowed for the…
(hint its not the evolution of the head)
evolution of specialized sensory organs
segmentation allowed for the
evolution of limbs which gave rise to better locomotion
all animals are what type of feeder?
chemoorganoheterotrophs
- can be herbivores, omnivores, detritovores, or carnivores
what are the types of animal feeders:
suspension feeders
fluid feeders
deposit feeders
mass feeders
asexual reproduction in animals
prodce diploid eggs that can mature into adults withough fertilization (pathogenesis)
sexual reproduction in animals
meiosis and fusion of gametes (most common in animals)
some species like the komodo dragon can reproduce
asexually and sexually
external sexual reproduction
- common in acquatic organisms
- both sexes release gametes into the water
internal sexual reproduction
-male sperm fertilized the eggs within females
- the zygote may or may not be retained in the female
oviparous species
lay eggs
viviparrous species
give live birth
- nourish embryo through a direct transfer of nurtients from the mother to the offspring
ovoviviparous species
retain eggs within the body and nourish by yolk, but then they give birth to a live offspring
