Multicellular, eukaryotic heterotrophs that ingest their food; no cell walls;; nerve and muscle cells; sexual reproduction and life cycles with unique embryonic stages; unique developmental genes
hydrostatic skeleton
In soft-bodied animals, a noncompressible fluid in the body cavity provides a rigid structure against which muscles contract, moving the animal.
Why are sponges thought to represent the earliest branch of animals?
Sponges lack symmetry and true tissue, and their choanocyte resemble certain flagelleta protists. They also do not have muscles and nerves.
A gastrovascular cavity?
A gastrovascular cavity is a digestive sac with only a single opening. It helps in digestion, gas exchange, circulation, movement, body support, waste disposal
Flatworms are thin, flat, ACOLEOMATES (body has no cavities) animals that can be free-living or parasitic.
true
T or F Flatworms and roundworms both have bilateral symmetry.
true
What evolutionary progress does bilateral symmetry allow?
t allows parts of the body to evolve different organs....and animals with bilateral have more efficient movement than animals with radial symmetry.
T or F Flatworms resemble a ribbon and have a definite head region and body organs, unlike sponges and cnidarians.
true
How do flatworms move?
cilia and contracting body muscles
T or F Flatworms are hermaphrodies...why
because they produce both eggs and sperm
T or F A planarian that is cut in half horizontally can grow a new head on the tail end and a new tail on the head end, forming 2 new organisms.
true
T or F They also have sensory cells that help them detect chemical and water movement.
true
What does bilateral symmetry allow animals from flatworms on up to do?
Bilateral symmetry means that one plane passing through the longitudinal axis of an organism divides it into right and left halves that are mirror images. It is characteristic of active, crawling, or swimming organisms and usually results in the formation of a distinct head (cephalization) where accumulation of nervous tissue and sensory structures occurs. This reflects the importance to the organism of monitoring the environment it is meeting- rather than that through which it has just passed
Contrast the skeleton of an echinoderm with that of an arthropod. Why aren’t echinoderms considered more closely related to other radially symmetrical animals like the cnidarians?
An echinoderm has an endoskeleton; an arthropod has an exoskeleton.Also the larva of echinoderms have bilateral symmetry while cnidarians show radial symmetry.
What are the four features of Chordates? Which are the invertebrate chordates?
chordates possess 4 features: (1) a dorsal, hollow nerve cord (2) a notochord (3) pharyngeal slits (4) post-anal tail
Eg., of invertebrate chordates: tunicate and a lancelet
What is the evolutionary source of the jaw bones?
Vertebrate jaws evolved from skeletal supports of the pharyngeal slits
Contrast the respiratory system of a typical ray finned fish, and the hypothesized respiratory strategies of the fossil Acanthostega.
Ray finned fish, have gills as respiratory system. Acanthostega was hypothesized to be the first tetrapods that were fish with lungs that had gradually evolved legs as they dragged themselves from pool to pool in search of water.
What is the advantage of the amniotic egg? Adaptations for flight in birds?
the amniotic egg is a shelled egg in which an embryo develops within a fluid-filled amniotic sac and is nourished by yolk.
Adaptations for flight in birds:-Reduced weight, endothermic with high metabolism, efficient respiratory and circulatory systems, feathered wings shaped like airfoils, good eyesight
Which groups of amniotes are/were ectothermic and which are/were endothermic?
ectothermic: bearded dragon of the Australian outback
endothermic: Deinonychus and other small dinosaurs and birds.
How does this character affect an animals lifestyle?
Ectothermic( EX): The bearded dragon of the Australian outback commonly warms up in the morning by sitting on warm rocks and basking in the sun. If the lizard gets too hot, it seeks shade. Because nonbird reptiles absorb the external heat rather than generating much of their own, they are said to be ectothermic
Endothermic: using heat generated by metabolism to maintain a warm, steady body temperature.
What is the difference between monotremes, marsupials, and eutherians?
monotremes: egg-laying mammal, such as the duck-billed platypus.
marsupials:
A pouched mammal, such as a kangaroo give birth to embryonic offspring that complete development while housed in a pouch and attached to nipples on the mother’s abdomen.
eutherians: Placental mammal; mammal whose young complete their embryonic development within the uterus, joined to the mother by the placenta.
Types of arthropods
1. crusteacean
2. Arachnid
3. insects
Author
smaraya
ID
152982
Card Set
animals5
Description
study guide-reece and campbell 6th edition chp 18 and 19
