Diversity of Life

archaea

single celled prokaryotes

eubacteria

single celled prokaryotes

eukarya

can be single or multicellular, contain membrane-bound organelles

domains

broadest classification of living organisms

order of taxonomy

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six kingdoms

archaea, eubacteria, protista, plantae, fungi, animalia

kingdom monera

outdated classification that grouped archaea and eubacteria together based on their lack of membrane-bound organelles

prokaryotes

organisms that do not have membrane bound organelles

• genetic material housed in nucleoid region

• either archaea or eubacteria

cell walls: archaea vs eubacteria

archaea lack peptidoglycan, ether linkages

eubacteria contain peptidoglycan, ester linkages

ribosomes: archaea vs eubacteria

both 70S size

DNA organization: archaea vs eubacteria

archaea: circular with introns and histones

eubacteria: circular, no introns nor histones

structural features: archaea vs eubacteria

both have flagella and pili

reproduction: archaea and eubacteria

both utilize binary fission

prokaryotic membranes do not posesss…

steroids

steroids

lipids with four hydrocarbon rings including cholesterol and the steroid hormones

endospores

non-reproductive, non-ubiquitous protective structure that can preserve genetic material during times of extreme stress

extremophiles

organisms, often archaea, which thrive in extreme environments where most other organisms would not survive

ex: extreme heat/cold, salinity, pH level, available water

peptidoglycan

large, mesh-like molecule whose scaffolding serves as the principle component of bacterial cell wall

• made of sugars and amino acids

• all bacteria contain some degree of this in their cell wall, but the amount varies

capsule

protective coating which encapsulates the cell’s wall

• acts as a virulence factor by preventing desiccation

• all bacteria invariably possess capsules

gram staining

staining method used to differentiate bacteria based on cell walls

gram-positive

thick peptidoglycan layer

stain dark purple

no outer membrane

minor periplasm

no lipopolysaccharides (LPS)

secrete exotoxins

contain teichoic acids

teichoic acids

polysaccharide that connects the peptidoglycan layer to the plasma membrane

provides rigidity and support

exotoxins

class of toxic proteins that are produced and released by both gram positive and gram negative bacteria

gram-positive bacteria characteristics mnemonic

PPT

Purple

Peptidoglycan (thick)

Teichoic acid

gram negative bacteria

thin peptidoglycan layer in the cell

stain pink

periplasm between inner and outer membranes

lipopolysaccharides (LPS) present

secrete exotoxins

no teichoic acids

lipopolysaccharides

endotoxins released by gram-negative bacteria only

• released when bacteria is destroyed

gram negative bacteria characteristics mnemonic

LONG

Lipopolysaccharides

Outer membrane

Negative

Gram

prokaryotes

organisms without membrane bound organelles

eukaryotes

organisms with membrane bound organelles

cell size: pro vs eu

pros are smaller (1um)

eus are larger (10-100 um)

cell wall: pro vs eu

pros have cell wall

eu cell walls are only present in plants, fungi, and some protists

steroids in membrane: pro vs eu

absent in pro

present in eu

chromosome location: pro vs eu

pro: nucleoid region

eu: nucleus

introns and histones: pro vs eu

pro: absent in eubacteria, present in archaea

eu: present

plasmids: pro vs eu

Pro: frequent in eubacteria, sometimes in archaea

eu: rare

origin of replication: pro vs eu

pro: one in eubacteria, many in archaea

eu: many

DNA replication speed: pro vs eu

pro: slow

eu: slow

ribosome: pro vs eu

pro: 70S (50S and 30S)

eu: 80S (60S and 40S)

transcription and translation: pro vs eu

Pro: occur simultaneously in cytoplasms

eu: transcription first in nucleus, translation second in cytoplasm

post-transcriptional modification to RNA: pro vs eu

pro: no

eu: yes

cell cycle length: pro vs eu

pro: short, divide by binary fission

eu: long, divide by mitosis

cilia: pro vs eu

pro: absent

eu: present

flagella: pro vs eu

present in both

cellular respiration location: pro vs eu

Pro:

glycolysis - cytosol

pyruvate oxidation - cytosol

Krebs cycle - cytosol

ETC - cell membrane

eu:

glycolysis: cytosol

pyruvate oxidation: mitochondrial matrix

Krebs cycle: mitochondrial matrix

ETC: mitochondrial inner membrane, and thylakoid membrane for plants

protista

kingdom of (mostly unicellular) eukaryotic organisms

3 types of protists

fungus-like, plant0like, animal-like

fungus-like protists

lack a cell wall made of chitin

can move via cilia or flagella

saprophytic: feed on decaying organic materials

feed vis phagocytosis

reproduce via asexual reproduction and sporulation

plant-like protists

among the most important primary producers

algae encompasses a large variety

• have chloroplast and photosynthetic abilities

include diatoms and dinoflagellates

animal-ike protists

known as protozoa

contain food vacuoles

include amoeba and paramecium

heterotrophic: gain energy from food

move via flagella and cilia

often parasitic pathogens

fungi

eukaryotic organisms

includes mushrooms, molds, and yeast

heterotrophic

saprophytic (eat decaying organic matter)

life cycle is predominantly haploid

cell wall made of chitin

hyphae

long, branching filaments of fungi

mycelium

fungal network created by interconnected hyphae

• can be used as feeding network

fungi reproduction

alternate between sexual and asexual

fungi asexual reproduction

occurs during favorable conditions

budding: bud (outgrowth) forms on organism, receives DNA, and buds off

sporulation by mitosis: reproductive spores form via mitosis

create offspring identical to parent

fungi sexual reproduction

fungi alternate between diploid and haploid

occurs during unfavorable conditions

produce genetically diverse daughter cells to increase likelihood of survival

lichens

symbiotic autotrophs where a fungus is paried with either an algae or a cyanobacteria

fungus role in lichen

protects algae/cyanobacteria and provides it with water/nutrients

algae/cyanobacteria role in lichen

photosynthesize to provide fungi with food

animalia characteristics

eukaryotic

diploid

multicellular

heterotrophic

aerobic

animal phylum

Porifera

Cnidaria

Platyhelminthes

Nematoda

Rotifera

Annelida

Mollusca

Arthropoda

Echinodermata

Chordata

coelomates

organisms possessing fluid filled cavity called a coelom, where the mesoderm surrounds the coelom on all sides

acoelomates

do not possess a coelom

pseudocoelomates

coelom is only partially surrounded

acoelomate phylum

platyhelminthes

pseudocoelomate phylum

nematoda and rotifera

coelomate phylum

annelida, mollusca, arthropoda, echinodermata, and chordata

schizocoelomates

coelom begins and splits within the mesoderm

• holoblastic cleavage: cleavage throughout the entire embryo, evenly dividing it

• occurs in animals with little yolk

spiral cleavage

misaligned cells deviate from their axes, taking on a final spiral orientation

determinate cleavage

blastomeres have a decided fate

protostomes

organisms where the mouth develops first, prior to the anus

usually schizocoelomates

enterocoelomates

coelom begins as lateral out-pockets of the archenteron

radial cleavage

cells align in a vertical axis

indeterminate cleavage

blastomeres do not have a pre-set fat, resulting cells are totipotent

deuterostomes

organisms where the anus develops first, prior to the mouth

porifera

simple, multicellular, porous sponges

thought to be the earliest animals

porifera characteristics

body asymmetry

parazoan: no true tissue organization

• cannot be classified by coelom type

sessile: non-motile

aquatic habitats

cnidaria

jellyfish, hydra, corals

cnidaria characteristics

radial body symmetry

diploblastic: two cellular layers present (endoderm and ectoderm)

aquatic habitats

platyhelminthes

non-segmented, parasitic worms with organs

• flatworms, tapeworms, etc

platyhelminthes characteristics

bilateral body symmetry

cephalization: concentration of nervous/sensory organs in the head (no full brain tho)

• associated with bilateral symmetry

triploblastic (ectoderm, mesoderm, endoderm)

acoelomate

protostomes

nematoda

non-segmented, parasitic worms

roundworm

nematoda characteristics

bilateral body symmetry

triploblastic

pseudocoelomates

protostomes

rotifera

non-segmented, aquatic zooplankton

include rotifers

rotifera characteristics

bilateral body symmetry

triploblastic

pseudocoelomates

protostomes

annelida

segmented worms

earthworms and leeches

annelida characteristics

body segmentation

closed circulatory system: blood pumps through vessels via pressure from the heart

• system has multiple aortic arches as well as distinct arteries and veins

bilateral body symmetry

triploblastic

coelomate

protostomes

mollusca

soft-bodied organisms, some have hard shells

snails, squids, octopus

mollusca characteristics

mostly aquatic

bilateral body symmetry

triploblastic

coelomates

protostomes

arthropoda

organisms with segmented bodies and jointed appendages

the most diverse set of organisms within a phylum!

crab, scorpion, grasshopper

arthropoda classes

insecta: ants, grasshoppers, etc

arachnida: spiders, scorpions, etc

crustacea: lobsters, crayfish, crabs, etc

arthropoda characteristics

bilateral body symmetry

triploblastic

coelomates

protostomes

exoskeleton of chitin

body segmentation

jointed appendages

open circulatory system: fluid does not stay within closed vasculature throughout entire system

• hemolymph replaces blood

• hemolymph flows between: the heart w its connected vessels, an open cavity called the hemocoel, and body tissue

echinodermata

closest related phylum to chordates

starfish and sea urchin

echinodermata characteristics

radial body symmetry

triploblastic

coelomates

deuterostomes

chordata

segmented bodied organisms

includes vertebrate and invertebrate organisms

chordata characteristics

bilaterial body symmetry

triploblastic

coelomate

deuterostome

dorsal hollow nerve cord

notochord

pharyngeal pouch (slits)

post-anal tail

dorsal hollow nerve cord

develops in the central nervous system

notochord

cartilaginous rod derived from the mesoderm

• forms primitive axial skeleton

• supports the body during embryonic development

• develops into the spinal bones

pharyngeal pouch (slits)

forms pharynx, gills, feeding strucutres, head/neck structures

post-anal tail

lost during embryological development in humans and many other chordates

types of chordates

vertebrates and invertebrates