test 2: diversity Flashcards
domains
bacteria, archae, eukarya
bacteria
- most common prokaryotes
- important in ecosystem (chemical recycling, ecological interactions)
archaea
extreme environements
- extreme halophiles
- extreme thermophiles
- methanogens (anaerobic)
big picture evolution for organisms
- bacteria first
- single celled organisms + incorporation of chlorplasts and mitochondrias
- multicellular organisms
- animal group radiates
- verterbrates evolve and move onto land
eukarya kingdoms
protists, plants, fungi, animals
cell walls
bacteria/archaea: peptidoglycan
protists/animals: none
plants: cellulose (can’t digest)
fungi: chitin (digest a little)
capsule
sticky layer of polysaccharides on cell wall
- prokaryotes to stick to surface
- extra layer against desiccation
fimbrae
hair like projections that help stick
flagella
some species have them for movement, analogous structures
nucleoid region
no nucleus, DNA clumped in one area of the cell
aerobic
must use o2 for cellular respiration
anaerobic
poisoned by o2
facultative anaerobes
use o2 if present
animals
heterophobic (ingest/breakdown) multicellular eukaryotic but no cell wall muscle/nerve cells sexual reproduction
cephalization
sensory equipment concentrated at anterior end and a central nervous system
segmentation
replicated organs and divisions (insects)
radial symmetry
multiple planes (like pie)
bilateral symmetry
1 plan with 2 equal halves
appendage
limbs
verterbrates - phylum cordata
1- notochord: dorsal, flexible supportive rod (spinal chord)
2- pharyngeal slits/pouches
3- dorsal hollow nerve cord
4- post-anal tail
cambrian explosion
- animals diversified suddenly
- 535 million yrs ago
- before, all large animals were soft bodied herbivores
ie: appearance of agressive predators
big explosion of mutations
important steps of vertebrate evolution
mineralized skeleton, paired fins, jaws, lungs, internal fertilization, tetrapod limbs, amniotic egg, flight
urochordates and cephalochordates
tunicates and lancelets: very primitive members of chordata
class myxini
hagfish, no real jaws/vertebrae, skull of cartilage, ratin notochord as flexible cartilage support
class pretromyzontida
lampreys, jawless, no paired fins, cartilage skeleton, gill pouches
class gnathostomes
subgroups: pacoderms, chondrichthyes, osteichthyes
placoderms
- oldest
- hinge structures and teeth
- evolved from skeletal rods in gill slits
- retained paired fins and gained a rudimentary tail
chondrichthyes
- sharks, rays, marine predators
- cartilage
- some degree of parental care
- true tail
- internal fertilization
- electrical field detection
osteichthyes
subclass: actinopterygii and sarcopterygii
actinopterygii
traditional body fish
- lungs to breath air and gills, swim bladder, parental care
sarcopterygii
from here evolved animals with limbs
actinista
coelacanth, believed to be extinct
dipnoi
lungfish, gulp air at surface into lungs but have gills
tetratops evolved from here (animals on all 4s, fins strong enough to crawl in mud, pectoral and pelvic fins replaced with feet and digits)
amphibia
frogs, salamanders, caecilians, reproduce aquatically
reptilia
1st fully terrestrial verterbrate
- amniotic egg
- internal fertilization
- waterproof skin
- flight
- leg position
amniotic egg
- no need for water to reproduce
- full development on land
yolk sac, amnion, allantois, chorion
yolk sac
found in fishes, bigger, yolk enclosed in membrane
stockpile of nutrients for the embryo
amnion
water filled sac around embryo, protects embryo from mechanical shocks (cushions)
allantois
extension of urinary system (waste striage); blood vessels late in development allow for oxygen exchange
chorion and shell
protective and waterproof, also allows exchange of gases between embryo and air (o2, co2)
internal fertilization
- egg develops in mom and is laid
- no more need for water
- eggs not subject to predation in water, reptiles able to out compete amphibians
waterproof skin
better heart and lungs, no need for external eater supply, better able to compete on land
flight
dinosaurs gave rise to birds, birds grouped under theropods, feather may have enabled small dinosaurs to gain extra lift while running1gliding
earliest known bird fossil
archaeopteryx
adaptations for flight
no bladder, females have one ovary, no teeth, light porous bones, wings and feathers
leg position
higher repitles are more efficient, legs more underneath
weight supportedly mostly on bone
movement faster and longer
(crocodile limb position analogous)
mammalia
hair, breasts, larger brain, 4 chamber heart, heterdont (different teeth)
small early on, not diverse until dinosaurs died
groups of mammals
monotremes, marsupials, placentals
monotremes
platypus and spiny anteater (australia), evolved apart from other mammals, not ancestors of other mammals, lay shelled eggs and nurse young
marsupials
australia (american ones went extinct), 3 week gestation then embryo crawls to pouch and nurses on mammary glands; outcompete by placentals
