Flash Exam Flashcards
symmetry
correspondence of size, shape of parts on opposite sides of median plane, like other features, has evolved
asymmetry
no symmetry, no planes divide into equal halves
spherical symmetry
•any plane through center divides body into mirrored halves
•suited for floating, rolling
•earth’s are aquatic
•some unicellular forms
•rare in animals
•protozoan—volvox
radial symmetry
(tire) divided into similar halves by 2 or more planes passing through longitudinal axis
biradial symmetry
•2 planes passing through longitudinal axis mirrored halves, usually sessile, freely floating, or weakly swimming animals
•no anterior or posterior end
sagittal plane
•two mirror portions (left and right)
•much better fitted for directional (forward) movement
cephalization
•concentration of nervous tissue & sense organs (head)
•advantageous to an animal moving through its environment head first
•most recent and successful
taxonomy
•formal system for naming & classifying species
•~1.5 million species of animals named
•probably less than 20% of extant animals and 1% of extinct
systematics
•broader science of classifying organisms based on similarity, biogeography, descent
•goals: to discover all species of animals, reconstruct their evolutionary relationships, to classify according to their evolutionary relationships
binomen
•Homo sapiens- “thinking man”
•Aedes albopictus- “white painted unpleasant”
3 domains
eukarya, achaea, bacteria
common descent
same pattern of ancestry
smallest distinct groupings
share patterns of ancestry and descent
reproductive community
•excluded members of other species distribution in space and time
•cosmopolitan: wide
•endemic: narrow
typological species concept
•pre-darwin, distinct, immutable entity
•a type specimen: labeled, deposited in a museum
•an ideal form- still have type specimen but variation is not considered deviation from type
biological species concept
•a species is a reproductive community of populations that occupies a specific niche in nature
•interbreeding central
•boundaries between species may be difficult to locate
•does not address asexual organisms
evolutionary species concept
•adds evolutionary time to the BSC
•a single lineage of ancestry-descendant populations that maintains its own identity from other such lineages and that has its own evolutionary tendencies and historical fate
•considers sexual, asexual, time
cohesion species concept
•the most inclusive population of individuals having the potential for phenotypic cohesion through intrinsic cohesion mechanisms
•definition includes genetic changes (gene flow, genetic drift, natural selection)
phylogenetic species concept
•an irreducible (basal) grouping of organisms diagnosable distinct from other such groupings & within which there is a parental pattern of ancestry and descent
•asexual, sexual
•phylogenetic species is the smallest single population lineage with no detectable branching
systematics major goal
•infer the evolutionary tree (phylogeny) that relates all extant & extinct species
•organismal features that vary among species
•common: morphological, chromosomal, molecular
•less common: behavioral, ecological
homology
•character similarly resulting from common ancestry
•similarity does not always reflect common ancestry
•fur in bats and mice
homoplasy
•character similarity that misrepresents common descent (wings)… birds, bats, insect
•wings in birds and bats, thumbs in primates and pandas
who proposed 3 domains
woese, kandler, and wheelis
who proposed 5-kingdom system
R.H. Whittaker
developmental patterns
•reflects evolutionary advantage
•all animals have a blastula (hollow ball) of cells during development
•can produce 3 layers
3 layers of development
ectoderm, endoderm, mesoderm
ectoderm
epithelium and nervous system
endoderm
epithelial lining of digestive tube, liver, and pharynx
mesoderm
muscular system, reproductive system, peritoneum
what animals are diploblastic?
ectoderm and endoderm
what animals are triploblastic?
protostomes and deuterostomes
lophophore
whirl of tentacles
trochopore
larvae
ecdysozoan
shedding of the cuticle
protostome
mouth to anus
deuterostome
anus to moth (humans)
acoelomate
•no cavity
•flatworms
pseudocoelom
•false coelom
•fluid-filled cavity around gut
•mesoderm lines outer side of blastocoel
•endoderm lines inner side
coelom
•mesoderm lines both sides
•deuterostomes are truly coelomic
choanoflagellates
•”sister” to animals, but different origin
•solitary or colonial aquatic
•each cell has flagellum surrounded by collar of microvilli
•flagella draws water in collar
•microvilli collect mostly bacteria
•strongly resemble sponge feeding cells
phylum porifera
pore bearing, most marine
asconoids
•flagellated spongocoels
•simplest form
•water enters a large cavity
•lined with choanocytes
•all calcarea= asconoids
syconoids
•flagellated canals
•like asconoids, larger and thicker
•choanocyte-lined canals, empty into spongocoel
•class calcarea, hexactinellida
leuconoids
•flagellated chambers
•most complex, larger, many ostia
•clusters of flagellated chambers
•increases surfaced compared to volume
•large sponges filter 1500 L water per day
•most sponges leuconoid
choanocytes
•one end in mesohyl
•exposed end: flagellum surrounded by collar
•collar consist of microvilli filtering device to strain food
•particles too large for collar: trapped in mucous
•moved to choanocyte, phagocytized
•food engulfed by choanocytes is passed to archaeocytes for digestion
archaeocytes
•free moving within mesohyl
•phagocytize particles
•can differentiate into any other type of cell
•sclerocytes secret spicules
•spongocytes secrete spongin
•collencytes secrete fibrillar collagen
•lophocytes secrete collagen
pinacocytes
•form pinacoderm (inner layer cells)
•regulate water flow
