Invertebrates Definitions

Biology

the study of life

zoology

the branch of biology that deals with animals and animal life

invertebrates

without a vertebral column, 97% of animals on planet

prokaryote

single-celled organism without a nucleus, mitochondria, or other membrane-bound organelles, began ~3.5 bya

Abiogenesis

hypotheses for the advent of life, most likely an RNA world

primeval soup, deep=sea hydrothermal vents, or exoplanetary introduction

metazoa

ingestive, heterotrophic, sexual, multicellular eukaryotes that form tissues, evolved when oxygen stabilized

Ediacaran Period

worldwide invertebrate fauna, 635-541 MYA

Cambrian Explosion

541-520 MYA, rapid increase in biodiversity and abundance, Treptichnus pedum bioturbation which allowed for oxygenated sediments, rapid speciation from competition

Stromatolites

layers of microbial mats, first to preform photosynthesis, bio-accretionary structures

Primary endosymbiosis

2.5-2 BYA, alphaproteobacteria symbiosis generates mitochondria (becomes the chloroplast), first eukaryotic multicellular

Great Oxygenation

2.5-2 BYA, 1st mass extinction, oxygenation grants atmospheric protection from UV (ozone), oxygen metabolism is more efficient

Paleozoic

270 MYA, ~90% of species go extinct in Permian Extinction (Volcanic eruptions), increased: temperature and atmospheric CO2, decreased: pH and O2

Cretaceous-Tertiary Mass Extinction (K-T)

75% extinct, meteor impact and volcanism, sulfur dioxide released (decreased oceanic pH), cooling of atmosphere

Adaptive Radiation

small-bodied generalist survivors repopulating devastated environments

Monophyletic

groups/clades that include all descendants of a stem species

Paraphyletic

group that has the same evolutionary origin but does not include all the descending groups

Polyphyletic

composite groupings of organisms without true biological rationale/shared biological ancestor

Apomorphy

an evolutionary innovation present in a biological lineage but not with its ancestral group

Synapomorphy

shared apomorphy with 2 or more groups of organisms

Bacteria

no membrane enclosed organelles or nuclei, no cytoskeleton

Archaea

anaerobic and aerobic, methane-producing organisms, no membrane enclosed organelles or nuclei, no cytoskeleton

Protista

unicellular eukaryotes, have a nucleus, endomembrane, cytoskeleton, and mitochondria

Fungi

chitinous wall around vegetative fungal cells

Plantae

unicellular, multicellular, photosynthetic

Animalia

multicellular, heterotrophic, tissue layering eukaryotes

Specific heat

the amount of energy required to heat a substance, ocean is more stable since it has 5x the specific heat as the atmosphere

Carbonate buffering

carbonate ions balance excess CO2 content by re-speciating into bicarbonate and carbonic acid, resists changes in CO2 concentrations and pH

Niche

a set of all the conditions of a single species in a certain environment

Fundamental niche

complete range of environmental conditions where a species could survive, grow, and reproduce if no interspecific interactions (competition)

Realized niche

actual range of environments used by a species, part of the fundamental niche (interactions shape habitat use)

Niche partitioning

similar species evolve to use different resources or inhabit different parts within the same environment

Continental shelf

0-1,000km from shore, <200m deep, high biological productivity

Continental edge

rapid change in bathymetry, transition zone between shelf and slope

Continental slope

region with slope of 4-6%, 200-300m deep

Abyssal plain

region with no light, >3,000m deep, productivity by chemosynthesis

Supratidal (splash)

area above mean high tide, flooded by storms

Intertidal (eulittoral)

dynamic area between low and high tide

Subtidal (sublittoral)

area below low tide line, never uncovered

Neritic

pelagic region over continental shelf

Oceanic

pelagic region over continental shelf and beyond

Photic

water column with enough sunlight for photosynthesis (0-200m)

Aphotic

water column with not enough sunlight for photosynthesis

Disphotic

twilight zone, transition region between photic and aphotic zones

Compensation depth

rate of respiration = rate of photosynthesis

Critical depth

integrated rate of respiration = integrated rate of photosynthesis

Bernoulli’s principle

as the speed of a moving fluid increases, its internal pressure decreases

Reynolds number

a dimensionless term that describes the fluid flow patterns in different physical situations; the ratio of inertial to viscous forces acting on an object within a fluid (smaller organisms feel more viscous → lower Re)

how an organism feels their environment

Epifaunal

organisms that live on top of sediment/substrate

Infaunal

organisms that live within sediment

Interstitial

living between sand grains

Meiofauna

organisms living between sand grains (<0.5mm)

Errant

active, motile organism

Sessile

organism firmly attached to the substrate

Sedentary

unattached/weakly attached organism, do not move much

Holoplankton

organisms that remain in plankton for whole life

Meroplankton

organisms that are temporary members of plankton community

Choanocyte

collar cell in sponge reminiscent of choanoflagellate

Cilia

shorter more abundant cell structure for movement, feeding, digestion

Flagella

longer, fewer cell structure for movement, digestion, gas exchange, reproduction

Oxygen diffusivity

only 1 mm into tissues until fully utilized, causes a problem with getting bigger (diffuses too fast)

Solutions to diffusion problem

fold cell surface, flatten, become thread like to increase SA, or become multicellular

Ontogeny

unicellular zygotes transform into multicellular individuals and eventually into reproducing adults (embryogenesis is an example)

Embryogenesis

the growth and development of embryo

Vitellogenesis

yolk production

Zygote

fertilized egg

Blastomeres

cells resulting from initial division (cleavage) of a zygote

Holoblastic

cleavage planes pass completely through cell, blastomeres fully separated by thin membrane, normally in isolecithal (evenly distributed yolk, small)

Meroblastic

cleavage planes do not pass completely through cell, blastomeres are not separate, typically in telolecithal (yolk concentrated on one end)

Macromeres

larger cells at vegetal pole, unequal cleavage

Micromeres

smaller cells at animal pole, unequal cleavage

Radial cleavage

longitudinal and transverse divisions arrange blastomere in rows perpendicular or parallel to A-V axis

Spiral cleavage

successive diagonal division of cells, during transition from 4 to 8 blastomeres, spiral arrangement around A-V axis

Blastula

embryonic stage preceding the formation of the embryonic germ (tissue) layers

Blastocoel

space within the blastula/primary body cavity

Coeloblastula

hollow ball of cells, usually 1 cell layer thick, has blastocoel in middle

Steroblastula

solid ball of blastomeres

Discoblastula

cap of cells at the animal pole

Periblastula

hollow ball of cells retaining a non-cellular yolk

Coelom

true body cavity

Protostome

mouth formed first during gastrulation, spiralia and ecdysozoa

Deuterostome

anus formed first during gastrulation

Gastrulation

formation of the embryonic germ layers and resulting embryo, process that separates the Metazoa from the Protists, forms initial sheets of cells

Ectoderm

outer layer, nervous system, outer skin

Mesoderm/Coelom

middle layer, coelomic lining, circulatory systems, internal support, musculature

Allows for locomotion (muscles and skeletons), feeding and digestion, excretion and osmoregulation, circulation and gas exchange, nervous system and sense organs, and reproduction

Triploblastic Metazoa

acoelomate: no cavity, mesoderm in solid mass of tissue

blastocoelomate/pseudocoelomate: fluid-filled body cavity, not fully lined by mesodermal tissue

coelomate/eucoelomate: fluid=filled body cavity fully lined with mesoderm, attaches to organs

Coelomate

true mesoderm is derived from the endoderm, others are from the ectoderm (not true mesoderm)

Endoderm

inner layer, gut

Osmoregulator

maintains ion/water balance independent of environment

Osmoconformer

ion/water balance varies with environmental salt content

Protogynous hermaphrodite

female transition to male

Protoandrous hermaphrodite

male transition to female

Propioceptor

senses self orientation to environment

Geoceptor

detects the pull of gravity, gives orientation

Hermaphroditic

each animal contains both ovaries and testes, can be simultaneous or sequential

Gonochoristic

having only testes or ovaries, separate sexes

Gastrula

embryonic stage where germ/tissue layers develop

Monophyletic

groups/clades that include all descendants of a stem species

Metamorphosis

process of transformation from an immature form to an adult form

Metameres

repeated sections in annelids, serial homology from teloblastic development

Proglottids

repeated sections of tapeworms, mature toward anus, gravid proglottids closer to scolex