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33 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Nutritional modes of animals?
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They differ from plants in that they cannot generate their own organic molecules.
Animals are heterotrophs and ingest organic molecules by eating other living organisms or nonorganic material. |
They can't perform photosynthesis.
They aren't autotrophs like plants. |
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Cell structure of animals?
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Eukaryotes; multicellular.
Supported by structural proteins (mainly collagen). Nerve cells and muscle cells unique to animals (responsible for movement and impulse). |
No cell walls like plants for structure.
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Most animals reproduce how?
What stage dominates the life cycle? |
Animals reproduce sexually; usually a flagellated sperm fertilizes a larger, nonmotile egg forming a diploid zygote.
This diploid stage dominates the life cycle. |
Easy.
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What is cleavage?
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When the zygote undergoes a succession of mitotic cell divisions without cell growth in between stages.
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Zygotes divide through mitosis.
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Cleaveage leads to?
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The formation of a multicellular stage called a blastula.
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Boom, bang, blast...
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What is a blastula?
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A hollow ball of cells.
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It's a ball of stuff.
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What is gastrulation?
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Follows the blastula stage; layers of embryonic tissues that will develop into adult body parts are produced.
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The blastula undergoes this process.
This process is seen in all animals except sponges. |
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What is a gastrula?
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The result of gastrulation, the gastrula contains an outer layer of ectoderm, and an inner layer differentiating between endoderm and mesoderm.
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What is a larva?
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Sexually immature form of an adult. Usually eats different food, and may have a different habitat than the adult (ex: tadpoles).
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Hox genes are?
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Reponsible for the regulation and development of animal embryos, controlling the expression of dozens or even hundreds of genes.
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Animals share this unique homeobox-containing family of genes.
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Studies suggest the common ancestor of living animals lived 1.2 billion - 800 million years ago.
This common ancestor may have resembled? |
Modern choanoflagellates: protists that are the closest living relatives of animals.
The common ancestor of animals was probably a colonial, flagellated protist as well. |
It's a protist.
Chrono-, but not really. |
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Edicaran fuana?
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The name of the collection of first generally accepted fossils of animals which are only 575 million years old.
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Named after the Ediacara Hills of Australia where these "things" were discovered.
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Cambrian Explosion?
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Dramatic acceleration of animal diversity occuring between 542 and 525 million years ago.
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Includes first animals with hard mineralized seletons.
Contain members of extant animal phyla-or at least close relatives. |
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Hypotheses for the Cambrian Explosion include:
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External factors: natural selection, predators vs. prey (new locomotion for predators; new defenses like shells).
Atmospheric conditions: increase of oxygen allowing for animals with larger bodies and higher metabolism. Internal factor: Hox gene complex evolves and provides developmental flexibility. |
2 external, environmental factors.
1 internal, molecular factor. |
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What is a grade?
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Levels of organizational complexity that can categorize animal species that may be grouped together in the same clade.
They differ from clades in a sense that grade-level trades are those that multiple lineages share regardless of evolutionary history. Some species may have completely evolved independently from one another but share similar characteristics. |
Clade - lineages share no evolutionary history, but similar trait(s).
Grade - all lineages share a SINGLE common ancestor. |
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What is radial symmetry?
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Any imaginary slice through the center axis divides the animal into mirror images.
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Resembles the radial structure of a pie or a flower pot.
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What is bilateral symmetry?
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Two-sided symmetry, only one plane (sagittal plane) will divide an organism into rougly two mirror images.
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Resembles the structure of a shovel.
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What is dorsal? Ventral?
What is anterior? Posterior? |
Dorsal: top side
Ventral: bottom side Anterior: head end Posterior: tail end |
Top of a door.
Bottom of a vent. Head of an ant. Tail of a post. Lame hints, but whatevs. |
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What is cephalization?
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Evolutionary trend in which a central nervous system ("brain") and other sensory equipment is concentrated at the anterior end.
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Deals with something about the head...
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What are true tissues?
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Collections of specialized cells isolated from other tissues by membranous layers.
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Sponges lack true tissues.
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As gastrulation progresses, the gastrula forms inward, filling up the open space (blastocoel) and develops layers.
What are these layers and what do they do? |
Germ layers which form the various tissues and organs of the body.
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What is the ectoderm?
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The germ layer covering the surface of the embryo.
Gives rise to the outer covering of the animal, and in some animals, the central nervous system. Skin. |
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What is the endoderm?
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The innermost germ layer. It lines the developing digestive tube, or archenteron, and gives rise to the lining of digestive tract and organs derived from it (ex: liver and lungs).
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What is diploblastic?
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Animals that have only the ectoderm and endoderm germ layers.
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What is a "true" coelom?
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A coelom formed from tissue erived from mesoderm.
Animals that have this true coelom are known as coelomates. |
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What is the mesoderm?
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A germ layer between the endoderm and the ectoderm.
It forms the muscles and most other organs between the digestive tract and the outer covering of the animal. |
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Animals that contain the mesoderm are known as?
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Triploblasts. Includes all bilaterally symmetrical animals (flatworms, arthopods, vertebrates).
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What is a pseudocoelom?
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A coelom formed from the blastocoel (fluid-filled region of blastula) rather than from mesoderm.
Animals that have a pseucoelom are known as pseudocoelomates. |
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Some triploblastic animals possess a body cavity.
What is a body cavity? |
A fluid-filled space separating the digestive tract from the outer body wall.
The more specific term for this body cavity is a COELOM. |
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What are the purposes of a body cavity/coelom?
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Its fluid cushions suspended organs, helping to prevent internal injury.
It enables the internal organs to grow and move independently of the outer body wall. Ex: the beat of one's heart would warp the body's surface without a coelom. In softbodied coelomates (earthworms), it contains noncompressible fluid that acts like a skeleton against which muscles can work. |
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What is an acoelomate?
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Triploblastic animals that lack a coelom altogether.
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What are the three features that distinguish protostome development?
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Cleavage - Spiral, determinate cleavage.
Coelom formation - The coelom forms from splits in the mesoderm (schizocoelous development). Fate of the blastopore - the mouth forms from the blastopore (opening into digestive tract). MOUTH FIRST, anus second. |
Greek "protos" - first
Greek "stoma" - mouth |
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What are the three features that distinguish deuterostome development?
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Cleavage - radial, indeterminate cleavage.
Coelom formation - forms from mesodermal outpocketings of the developing digestive tract (the archenteron). Fate of the blastopore - the anus forms from the blastopore. ANUS FIRST, mouth second. |
Greek "deuteros" - second
Greek "stoma" - mouth |
