SMS480 Midterm First 2 weeks (vocab, history of life on earth)

Biology

Study of life

Zoology

Branch of biology that deals with animals and animal life, including the study of the structure, physiology, development, and classification of animals

Invertebrates

-Multicellular animals without a vertebral column

-97% of all animals on the planet

Prokaryote

Single-celled organism without a nucleus, mitochondria, or other membrane-bound organelles

-Prokaryotes emerges abt 3.5 gya

Oceans formed from. . .

• Volcanic release of water vapor

• Icy comets and asteroids

• Condensation

  • Planetary cooling

  • Hot acid rain for millenia

  • Salty from rock weathering

Metazoa

Ingestive, heterotrophic, sexual, multicellular eukaryotes that undergo tissue formation

• Animalia emerged around 875-650 mya (around time of oxygen stabilization)

Late Paleozoic

• Abt 270 mya

• Pangea

• Permian Extinction (Great Dying)

  • 90% species go extinct (shallow, coastal ecosystems hit hardest)

    • 10 million year recovery for shallow systems (longer for deeper)

Post-Great Dying

• Uniformly warm

• Pangea breaks apart—> circumglobal Tethys sea (Gondwana and Laurasia)

• Rising sea level, inland water masses, atm cooling, O2 mixing

• Reef-forming corals (Sclaractinians)

• Predatory fishes and inverts increase in shallow coastal

Cenozoic Era

• Abt 66mya-present

• Cooling

• Modern continents

• Paleocene-Eocene Thermal Maxima (56 mya, greenhouse gases)

• Adaptive radiation: Opportunistic, small-bodied generalist survivors repopulate devastated niches

Monophyletic

Groups/clades 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 groups of organisms without true biological rationale/shared biological ancestor (eg. slug, microbe, etc)

Apomorphy

Evolutionary innovation present in a biological lineage, but not within its ancestral group

Synapomorphy

Shared apomorphy with 2 or more groups of organisms

Kingdoms of Life

• Bacteria: No membrane enclosed organelles or nuclei; no cytoskeleton (prokaryotic)

• Archaea: Anaerobic and aerobic, methane-producing organisms, no membrane enclosed organelles or nuclei, no cytoskeleton (prokaryotic)

• Protista: Unicellular eukaryotes, no embryological layering, have nucleus, endomembrane, cytoskeleton, and mitochondria

• Fungi: Chitinous wall around vegetative fungal cells (eukaryotic)

• Plantae: Unicellular, multicellular, photosynthetic (eukaryotic)

• Animalia: Multicellular, heterotrophic, tissue layering eukaryotes

Niche

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, grw, and reproduce if there were no interspecific interactions

Realized niche

• Actual range of environments used by a species, part of the fundamental niche

• Interspecific interactions shape habitat use

Niche partitioning

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

Continental shelf

• 0-1000km from shore

• Less than 200 m deep

• High biological productivity

Continental edge

• Rapid change in bathymetry

• Transition from shelf to slope

Continental slope

• Slope of 4—6%

• 200-3000m deep

Abyssal plain

• No light

• Over 3000m deep

• Productivity by chemosynthesis

Ocean zones/water column

• Splash/supratidal: Above mean high tide, only flooded during largest tides and storms

• Intertidal/eulittoral: Dynamic area where ocean meets the land (between high and low tide)

• Subtidal/sublittoral: Below low water, never uncovered

• Neretic: Pelagic over continental shelf

• Oceanic: Pelagic over continental shelf and beyond

Amount of light (ocean zones)

• Photic: Enough sunlight for photosynthesis (0-200m)

• Aphotic: Not enough light for photosynthesis

• Disphotic: Twilight zone, transition region between photic and euphotic

Critical depth

Depth where net photosynthesis is less than net respiration

Compensation depth

Depth where rates of respiration and photosynthesis are equal

Reynolds number (Re)

• Dimensionless term that describes fluid flow patterns in different physical situations

• Ratio of inertial to viscous forces acting on an object within a fluid

  • Greater than 1: inertial forces dominate

  • Less than 1: Viscous forces dominate

• Smaller—> lower Re—> living in a viscous world

Epifauna/epibenthic

Live on top of sediment/substrate

Infaunal

Live within sediment

• interstitial

Interstitial

Live between sand grains

• Meiofauna: Organisms less than 0.5mm

Errant

Active, motile

Sessile

Firmly attached to substrate

Sedentary (benthic)

unattached/weakly attached but do not move much

Holoplanktonic

• Holo=whole

• Organism that remain in the plankton for their entire life cycle

Meroplanktonic

• Mero=part

• Organisms are temporary members of the plankton community, typically during early development

Choanoflagellata

Likely ancestral group of Metazoa

• Near identical morphology of choanoflagellates and sponge choanocytes

• Capacity ot colonize

• DNA similarities

Cilia

Shorter, more abundant

• Useful for low Re living

• Digestion, feeding, gas exchange, reproduction

Flagella

Fewer, longer

• Useful for low Re living

• Digestion, feeding, gas exchange, reproduction

SA:V Dilemma

• diffusion needed to transport nutrients and remove waste

  • Oxygen diffusivity only 1mm into tissues before fully utilized

• Remedied through. . .

  • Folding, flattening, thread-like (increase SA)

  • Keep important things near cell surface

  • Multicellularity

Multicellularity

Solves SA:V dilemma by bringing environment closer to cell:

• folded cell and tissue layers

• Internal transport mechanisms

• Organs

Ontogeny

Process by which unicellular zygotes transform themselves into multicellular individuals and eventually into reproducing adults

Embryogenesis

Growth and development of the embryo

Animal-vegetal axis

How egg cells are polarized

• Animal: future head/dorsal side, fewer/smaller yolk cells

• Vegetal: Future posterior/ventral side, more abundant/larger yolk cells

Egg types

• Isolecithal

• Telolecithal

• Centrolecithal

Isolecithal

Small yolk, evenly distributed

Telolecithal

Yolk concentrated in one end

Centrolecithal

Yolk concentrated at the center

Vitellogenesis

Yolk production

• Longest phase of egg production

• High energy deman

Zygote

Fertilized egg

Blastomeres

Resulting cells of initial division of zygote (cleavage)

Cleavage types

• Holoblastic

• Meroblastic

Holoblastic

Cleavage planes pass completely thru cell, blastomeres fully separated by thin membrane

• Isolecithal

• Weak-moderate telolecithal

Meroblastic

Cleavage planes do not pass completely through the cell, blastomeres are not separate

• Strongly telolecithal

Cleavage plane types

• Longitudinal: Pass thru or parallel to A-V axis

• Transverse: Passes at right angles to A-V axis

Macromeres

Name for the larger cells at vegetal pole during spiral cleavage

Micromeres

Name for the smaller cells at animal pole during spiral cleavage

Dextrotropic

New cells displaced clockwise during spiral cleavage

Levotropic

New cells displaced counterclockwise during spiral cleavage

Radial cleavage

Strictly longitudinal and transverse divisions, blastomeres arranged in rows either perpendicular or parallel to the A-V axis

Spiral cleavage

During transition from 4 to 8 blastomeres, embryonic cell division generates successive blastomeres diagonally, creating a ‘spiral’ arrangement around A-V axis

• Dextrotopic

• Levotropic

Cell fates

• Determinate cleavage

• Indeterminate cleavage

Fate maps

By about 104 cells, terminal tissues are assigned to distinct ‘regions’ of cells

Determinate cleavage

Cell fates established very early in development

• Early as 2-4 cells

• Mosaic ova: Cell removal leads to abnormal development

Indeterminate cleavage

Cell fates not established until late in development

• Regulated ova: Cells can “regulate” for lost cells and normally develop

Blastula

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

• Coeloblastula

• Steroblastula

• Discoblastula

• Periblastula

Coeloblasula

Hollow ball of cells, usually 1 cell layer thick

• Blastocoel

Blastocoel

Space within blastula/primary body cavity

Steroblastula

Solid ball of blastomeres

Discoblastula

Cap/disc of cells at the animal pole

Periblastula

‘Hollow’ ball of cells retaining a non-cellular yolk

Gastrulation

Formation of embryonic germ layers and the resulting embryo—> forms initial sheet of cells

• Process that separates Metazoa from Protista

Germ layers

• Ectoderm

• Mesoderm

• Endoderm

Ectoderm

Outer layer

• Nervous system

• Outer skin and derivatives

Mesoderm

Middle layer

• Coelomic lining

• Circulatory structures

• Internal support structures

• musculature

Endoderm

Inner layer

• Gut and associated structures

Forms of gastrulation

• Invagination

• Ingression

• Delamination

• Epiboly

• Involution

Invagination

Formation of internal pouch near vegetal pole as a sac within blastocoel

• Forms archenteron and blastopore

Archenteron

Embryonic gut

Blastopore

Opening to outside of gastrula

Ingression

Cells detach from internal wall into blastocoel, cells divide until full

Delamination

Forms a layer of endoderm surrounded by a layer of ectoderm

Epiboly

Layering on cellular layers (like an onion)

Involution

Discoblastula cap forms a layer of cells underneath original

Germ layers

Embryonic tissues that form the framework upon which the Metazoan body plans are constructed

• Interdependent, specialized, coordinated, and orchestrate tissue layering during embryogeny

Diploblastic

2 germ layers (endo and ecto)

Triploblastic

3 layers (endo, ecto, meso)

Grades of triploblastic Metazoa

• Acoelomate

• Blastoceolomate/Pseudocoelomate

• Coelomate/eucoelomate

Acoelomate

• No cavity

• Mesoderm forms solid mass of tissues

  • Sometimes with small open spaces

Blastocoelomate/Psuedocoelomate

• Fluid-filled body cavity (psuedocoel)

  • Not fully lined by mesodermal tissue

  • Internal organs float freely

Coelomate/Eucoelomate

• Fluid-filled body cavity lined with mesoderm

• Gut lining (peritoneum) attaches to organs and separates them from coelomic space

Coelom formation

• True mesoderm derived from endoderm

• Schizocoely

• Entercoely

Schizocoely

Internally-aired packets split

• schizo=to split

Enterocoely

“Pouching”

• Entero=intestine

Mesoderm body plan innovations

• Locomotion

  • Muscles and skeletons

• Feeding and digestion

• Excretion and osmoregulation

• Circulation and gas exchange

• Nervous system and sense organs

• Reproduction

Types of locomotion

• Ameboid

• Ciliary/flagellar

• Hydrostatic propulsion

• Locomotor limb movement

Ameboid

Change cellular shape to generate asymmetrical movement

Ciliary/flagellar

Hair-like organelles move to generate fluid currents

Hydrostatic propulsion 

Soft-bodied, fluid-filled cavities move using pressure

Locomotor limb movement

Muscles to move