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39 Cards in this Set
- Front
- Back
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Animal Kingdom |
1.3 million spp identified
15 – 150 million spp yet to be identified |
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Heterotrophic
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ability to ingest and digest food with enzymes; self-feeders |
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Food
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living organisms or non-living organic material
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Cell Structure
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Specific cell structure with specialization
Cells held together by proteins (collagen) Intracellular junctions keep cells in close contact with each other |
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Two cell types unique to animals
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Muscle cells
Nerve cells |
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Most animals reproduce sexually
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The diploid stage (2n) is dominant
Haploid sperm (n) + haploid egg (n) = diploid zygote (2n) |
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Cleavage
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series of mitotic divisions with-out cell growth between cycles
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Blastula
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hollow ball of cells
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Gastrula
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solid ball of cells that gives rise to embryonic tissues
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Larva
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sexually immature form of an animal, morphologically distinct from the adult
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Larva
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Different diet
Different habitat |
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Metamorphosis
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resurgence of develop-ment transforming the larva into an adult
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Homeobox (hox) genes
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180 nucleotide gene sequence within homeotic & developmental genes; widely conserved in animals
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Homeotic genes
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any of master regulatory genes that control placement and spatial organization of body parts in animals, plants, and fungi by controlling the development fate of groups of cells
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Characteristics of Hox genes
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Evolved in eukaryotic line
Play a role in embryonic development Control expression of 100’s of genes Control cell division & differentiation |
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Characteristics of Hox genes
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Regulate the formation of water channels in sponges
Regulate the patterning of the anterior and posterior axis |
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The Cambrian Explosion
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Dramatic acceleration of animal diversifica-tion 542 – 525 mya
Oldest fossils of approximately half the ex-tant animal spp occurred at this time |
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Predator v. prey relationships developed
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Locomotion v. defense
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An increase in atmospheric oxygen occurred
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More oxygen resulted in more metabolism
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Reasons for the Cambrian Explosion
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Evolution of the Hox gene complex resulted in greater flexibility in evolution of new spp
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Grades
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group of animal spp that share the same level of organizational complexity
Examples: pachyderms (extinct and extant) |
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Body plan
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set of morphological traits that define a grade, integrated into a functional whole (organism)
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Asymmetry
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absence of a body plan
Example: poriferans (sponges) |
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Radial symmetry
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body plan in which arms radiate from a central axis
Example: cnidarians (jellyfish) |
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Bilateral symmetry
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body plan in which a sagittal plane divides the organism into left and right halves which are mirror images
Example: most invertebrates, all vertebrates |
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Cephalization
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concentration of sensory or-gans and central nervous system in anterior region
Example: most invertebrates, all vertebrates |
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Tissues
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collection of isolated cells, kept separate by membranous layers; arise during embryonic development by gastrulation
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Ectoderm
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outer layer giving rise to outer coverings and nervous system
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Endoderm
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inner layer giving rise to lining of digestive tract and organs (liver, lungs, etc.)
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Mesoderm
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middle layer giving rise to blood, bones, and muscle
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Diploblasts
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animals consisting of only 2 germ layers, ectoderm and endoderm
Example: cnidarians |
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Triploblasts
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animals consisting of 3 germ layers, ectoderm, endoderm, and mesoderm
Example: bilaterians |
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Coelom (body cavity)
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fluid-filled sac sepa- rating the digestive tract from the outer body wall; develops from mesoderm
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Coelomate
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animals that form a true body cavity
Examples: mollusks, annelids, arthropods, echinoderms, chordates |
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Pseudocoelomate
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animals that form a false body cavity; from blastocoel, not mesoderm
Examples: roundworms |
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Acoelomate
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animals with no body cavity
Examples: flatworms |
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Functions of Body Cavities
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Cushion suspended organs in fluid
Provide shape & support in invertebrates Allow internal organs to move indepen-dently of outer wall |
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Protostome Development
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Mouth arises from blastopore
Spiral cleavage of embryo occurs Body cavity splits between solid mass of mesoderm Examples: mollusks, annelids, arthropods |
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Deuterostome Development
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Anus arises from blastopore
Radial cleavage of embryo occurs Body cavity forms from outpockets of mesoderm Examples: echinoderms and chordates |
