Animal Classification, Diversity and Behavior

the evolutionary history of a species or group of species

a discipline focused on classifying organisms and determining their evolutionary relationships; used to construct phylogenies

the first part of the binomial naming system is the genus and is where the species belongs; the second part is called the specific epithet and is unique for each species within the genus

the named taxonomic unit at any level of the hierarchy

the evolutionary history of a group of organisms can be represented in a branching diagram

a classification based entirely on evolutionary relationships; it only names groups that include a common ancestor and all of its descendants

groups of organisms that share an immediate common ancestor and are therefore each other's closest relatives

means that a branch point within the tree represents the last common ancestor of all taxa in the tree

a branch point from which more than two decendant groups emerge; indicates that evolutionary relationships among the descendant taxa are not yet clear

a similarity due to convergent evolution; a bat wing is ANALOGOUS to a bird's wing

analogous structures that arose independently (from the Greek "to mold in the same way")

shared nucleotide bases in organisms that are otherwise very different; coincidental matches

uses DNA and other molecular data to determine evolutionary relationships

biologists place species into groups called clades, each of which includes an ancestral species and all of its decendents

a taxon (group of organisms) which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group

a group which consists of an ancestral species and some, but not all, of its decendents

includes taxa with different ancestors

a character that originated in an ancestor of the taxon; (ex: in mammals, the backbone)

an evolutionary novelty unique to a particular clade (ex: in mammals, hair)

a species or group of species from an evolutionary lineage that is known to have diverged before the lineage that includes the species we are studying (ingroup)

it is important to first investigate the simplest explanation that is consistent with the facts

given certain rules about how DNA changes over time, a tree can be found that reflects the most likely sequence of evolutionary events

we can predict (using parsimony) that features shared by two groups of closely related organisms are present in their common ancestor and all of its descendants

homologous genes that are found in different species because of speciation; widespread and can extend over huge evolutionary distances

result from gene duplication, so they are found in more than one copy in the same genome

a yardstick for measuring the absolute time of evolutionary change baseed on the observation that some genes and other regions of genomes appear to evolve at constant rates

much of evolutionary change in genes and proteins ahs no effect on fitness and therefore is not influenced by Darwinian selection

the movement of genes between organisms in different domains; the process in which genes are transfered form one genome to another through mechanisms such as exchange of transposable elements and plasmids, viral infection, and PERHAPS fusion of organisms

multicellular (with tissues that develop from embryonic layers), heterotrophic eukaryotes

food is stored as Glycogen (not starch), they have cell membranes but NO cell walls, and they have intercellular junctions absent in plants (gap junctions, desmosomes and tight junctions)

diploid

a succession of mitotic cell division wihtout cell growth; occurs between division cycles

a multicellular stage (hollow ball of cells) that comes about because of cleavage

the ball of cells (blastula) forms an inpocketing, the gastrula

gut-cavity; results from the creation of the inpocketing

a sexually immature and morphologically distinct from the adult; it eventually undergoes metamorphosis

transformation that turns animals into a juvenile that resembles an adult but isn't sexually mature

1.3 million

choanoflagellates

1 Billion–524 Million Years Ago; early members of the animal fossil record include the Ediacaran biota, which dates from 565 to 550 million years ago

542–251 Million Years Ago; encompassed the Cambrian explosion = earliest fossil appearance of many major groups of living animals

• 1) new predator prey relationships
• 2) rise in atmospheric oxygen
• 3) evolution of the Hox gene complex

460 mya, and 360 mya

95%

251-65.6 mya; coral reefs emerge as important niches for other organisms; dinosaurs were dominant on land; first mammals evolved; it ended with a mass extinction

65.5 mya to present; the time period when modern mammal orders and insects diversified

such animals have oral/aboral sides; (top and bottom but no front/back or left/right)

has two axis of orientation: from to back and top to bottom; such animals have dorsal and ventral sides, anterior and posterior ends, and cephalization

germ layer covering the embryo's surface; gives rise to outer covering of animal & sometimes CNS

innermost germ layer, and lines the developing digestive tube (archenteron); also gives rise to additional organs

animals that have an ecto and endoderm (only 2 germ layers) [Cnidarians]

all bilaterally symmetrical animals; have 3 germ layers; 3rd is called the mesoderm (forms the muscles and some other organs), which separates the endo from the ectoderm [ex: flatworms, arthropods, vertebrates]

true body cavity procudes from and lined w/ mesoderm; animals that posses one are called coelomates

body cavity that is formed from the mesoderm AND endoderm

occurs during protostome development; when the planes of cell division are diagonal to the vertical axis of the embryo

occurs during protostome development; developmental fate of each embryonic cell is determined very early in development

occurs during deuterostome development; when the planes of cell division are either parallel or perpendicular to the vertical axis of the embryo; tiers are aligned

occurs during deuterostome development; each cell produced by early cleavage retains the capacity to develop into a complete embryo (what makes identical twins possible)

the splitting of solid masses of mesoderm

the mesoderm budding from the wall of the archenteron

the mouth

the anus

muscle (movement) and nerve (coordination and modification through experience) tissue

a movement or activity of a cell or an organism in response to a stimulus (Ex. increased isopod [sow bug] movement in dry conditions --- more likely to result in finding wetter enviro)

"how" a behavior occurs or is modified

"why" a behavior occurs i the context of natural selection

a sequence of unlearned acts that is unchangeable and once initiated, carried to completion; the trigger is a sign stimulus

an oriented movement toward (positive) or away from (negative) some stimulus (ex: river fish automatically orienting themselves in upward direction

smell does NOT convey directionality, but movement of the medium does; shown in moth pheromones, how they fly toward wind until they reach mate AND salmon: they imprint on native river, and in attempting to return from ocean, there is positive rheotaxis in the natal area (because of smell) and NEGATIVE rheotaxis in absence of natal area

directions of sound can be figured out based on the differences in the two ears (noctuids and arctiids use to avoid predators)

example of innate behavior; the attack itself is an FAP; the sign stimulus is anything red (or red underbelly, which only male sticklebacks have)

modification of behavior through experience