Animal Tissue

1.  Adhering junction: Junction where a mass of anchored proteins help adjoining cells adhere.

2.       adipose tissue: A connective tissue having an abundance of fat-storing cells.

3.       blood: Fluid connective tissue of water, solutes, and formed elements (blood cells, platelets). Transports substances to and from cells, helps maintain internal environment.

4.       bone tissue: Of vertebrate skeleton, a tissue of osteoblast secretions hardened with minerals.

5.       cardiac muscle tissue: A contractile tissue that is present only in the heart wall.

6.       cartilage: Connective tissue with solid, pliable intercellular material that resists compression.

7.       dense, irregular connective tissue: Animal tissue with fibroblasts, many asymmetrically positioned fibers in ground substance. In skin and some capsules around organs.

8.       dense, regular connective tissue: Animal tissue with rows of fibroblasts between parallel bundles of fibers. In tendons, elastic ligaments.

9.       ectoderm: The first-formed, outermost primary tissue layer of animal embryos; gives rise to nervous system tissues and integument's outer layer.

10.   endocrine gland: Ductless gland that secretes hormones, which the bloodstream distributes.

11.   endoderm: Inner primary tissue layer of animal embryos; source of inner gut lining and derived organs.

12.   epithelium: Animal tissue that covers external surfaces and lines internal cavities and tubes. One surface is free and the other rests on a basement membrane.

13.   exocrine gland: Glandular structure that secretes products, usually through ducts or tubes, to a free epithelial surface.

14.   gap junction: Cylindrical arrays of proteins in the plasma membrane that pair up as open channels for signals between adjoining cells.

15.   gland cell: A cell that secretes products unrelated to their own metabolism for use elsewhere.

16.   homeostasis: State in which physical and chemical aspects of internal environment (blood, interstitial fluid) are being maintained within ranges suitable for cell activities.

17.   internal environment: Blood + interstitial fluid.

18.   loose connective tissue: Animal tissue with fibers, fibroblasts loosely arrayed in semifluid ground substance.

19.   mesoderm: Primary tissue layer of all large, complex animals; gives rise to many internal organs and part of the integument.

20.   nervous tissue: Connective tissue composed of neurons and often neuroglia.

21.   neuroglia: Collectively, cells that structurally and metabolically support neurons. They make up about half the volume of nervous tissue in vertebrates.

22.   neuron: Type of nerve cell; basic communication unit in most nervous systems.

23.   organ: Body structure with definite form and function that consists of more than one tissue.

24.   organ system: Organs interacting chemically, physically, or both in a common task.

25.   skeletal muscle tissue: Striated contractile tissue that is the functional partner of bone.

26.   smooth muscle tissue: Nonstriated contractile tissue found in soft internal organs.

27.   tight junction: Cell junction where strands of fibrous proteins oriented in parallel with a tissue's free surface collectively block leaks between the adjoining cells.

28.   tissue: Of multicelled organisms, a group of cells and intercellular substances that function together in one or more specialized tasks.

Evolutionary Processes #2

Allopatric Speciation: Speciation model. A physical barrier arises, separates populations or subpopulations of a species, ends gene flow, and favors divergences that end in speciation.

Anagenesis: Speciation pattern; changes in allele frequencies and morphology accumulate within an unbranched line of descent.

Archipelago: Island chain some distance away from a continent.

Biological species concept: Defines a species as one or more populations of individuals that are interbreeding under natural conditions, producing fertile offspring, and are isolated reproductively from other such populations. Applies to sexually reproducing species only.

Cladogenesis: Speciation pattern in which a lineage splits and isolated populations undergo genetic divergence.

Dosage Compensation: Any mechanism that balances gene expression between the sexes during critical early stages of development.

Evolutionary tree: Treelike diagram; a branch point means divergence from a shared ancestor and branches signify separate lines of descent.

Extinction: Irrevocable loss of a species.

Gene flow: Microevolutionary process; alleles enter and leave a population as an outcome of immigration and emigration, respectively.

Genetic divergence: Gradual accumulation of differences in gene pools of populations or subpopulations of a species after a geographic barrier arises and separates them; thereafter, microevolution occurs independently in each.

Gradual model of speciation: Idea that species arise by many small morphological changes that accumulate over great spans of time.

Hybrid zone: Where adjoining populations are interbreeding and producing hybrid offspring.

Mass extinction: Catastrophic event or phase in geologic time when entire families or other major groups are irrevocably lost.

Parapatric speciation: Idea that neighboring populations can become distinct species while maintaining contact along a common border.

Punctuation model of speciation: Idea that most morphological changes occur in a brief span when populations start to diverge; speciation is rapid, and the daughter species change little for the next 2-6 million years or so.

Reproductive isolating mechanism: Heritable feature of body form, functioning, or behavior that prevents interbreeding between two or more genetically divergent populations.

Speciation: The formation of a daughter species from a population or subpopulation of a parent species by way of microevolutionary processes. Routes vary in their details and duration.

Species: One kind of organism. Of sexually reproducing organisms, one or more natural populations in which individuals are interbreeding and are reproductively isolated from other such groups.

Sympatric speciation: A speciation event within the home range of an existing species, in the absence of a physical barrier. Such species may form instantaneously, as by polyploidy.

Evolution of Life

ANGIOSPERM: Flowering Plant.

ARCHIEBACTERIUM: Member of the prokaryotic domain Archaebacteria

ARCHEAN EON: Eon in which life arose.

BIG BANG: Model for origin of universe.

CENOZOIC ERA: The present era.

CRUST, OF EARTH: Outer zone of low-density rocks resting on the Earth's mantle.

DINOSAUR: One of a fabulous group of reptiles th

at originated in the Triassic.

EDIACARAN: One of the species with a highly flattened body that arose in the precambrian.

ENDOSYMBIOSIS THEORY: Continuing physical contact between two species, one of which lives and reproduces inside the other's body.

EUBACTERIUM: Prokaryotic cell; has a nucleoid, but no nucleus, cytoplasm, or cell membrane; most have a cell wall, some encapsulated.

EUCARYOTIC CELL:Cell having a nucleus and other membrane-bound organelles.

GLOBAL BROILING HYPOTHESIS: Theory that an asteroid impact caused the K-T mass extinction by creating a colossal fireball, the debris from which raised global air temperature by thousands of degrees.

GYMNOSPERM: Type of vascular plant in which seeds form on exposed surfaces of reproductive structures.

K-T ASTEROID IMPACT THEORY: A huge aster oid hit Earth at the K-T boundary.

MANTLE: Of Earth, a zone of intermediatedensity rocks beneath the crust.

MESOZOIC ERA: An era of spectacular expansion in the range of global diversity.

PALEOZOIC ERA: Era from Cambrian, Ordovician, Silurian, Devonian, Carboniferous, through the Permian.

PROKARYOTIC CELL: Archaebacterium or eubacterium; single-celled organism, most often walled; lacks the profusion of membranebound organelles observed in eukaryotic cells.

PROTEROZOIC EON: Period during which eukaryotic cells arose.

PROTISTAN: Photoautotroph or heterotroph unlike bacteria; some like earliest eukaryotic cells.
PROTO-CELL: Hypothetic cell-like stage between chemical evolution and the first living cell.

RNA WORLD: One model for prebiotic evolution in which RNA was the template for protein synthesis before the evolution of DNA.

STROMATOLITE: Fossilized mats of shallow-water microbial communities, mainly cyanobacteria, from Archean to precambrian.