bis 2c final (moore)

what are phylogenetic trees comprised of?

branches and nodes

what are the two different types of nodes and what does each indicate?

internal nodes indicate speciation events

terminal nodes indicate species or groups of species

what do the branch lengths in a cladogram represent?

literally nothing they’re random

what do the branch lengths in a chronogram represent?

they are proportional to time so they show evolutionary history on a weird timeline

can you tell whether a species is advanced/derived or primitive/ancestral?

no, these terms can be used to describe character states but even then not really so nope!

what are the diagnostic features of embryophytes aka land plants?

protected embryo

sporic life cycle aka alternation of generations

what are the diagnostic features of tracheophytes aka vascular plants?

tracheid cells (these make up the xylem)

xylem

phloem

what are the diagnostic features of euphyllophytes aka true-leaved plants?

megaphyllous leaves

overtopping growth form (which allows for the growth of megaphyllous leaves)

what are the diagnostic features of seed plants aka spermatophytes?

seeds

pollen

vascular cambium (which allows for secondary growth)

what are the diagnostic features of flowering plants aka angiosperms?

flowers

fruit

what does the secondary phloem give rise to? how does this relate to where it is located?

secondary phloem is in between vascular cambium and primary phloem → thus giving rise to bark

what are the adaptive significances of the vascular cambium?

* secondary vascular tissues renews the vascular system as the plant ages
* increase in girth = rigid structural support → allows for plants to grow taller and therefore compete for effectively for sunlight

what is the adaptive significance of pollen?

allows for the delivery of sperm without the need for water → allows colonization of more fully terrestrial habitats

what is pollen?

flying microgametophyte

what is the adaptive significance of the seed?

dormancy -- sporophyte embryo can rest for a while, resuming development when conditions are favorable

seedling survival -- contains nutrients that help the young plant become established

what is the adaptive significance of the flower?

entices animals to serve as efficient pollination vectors

how are gymnosperms fertilized?

sperm reaches egg via wind dispersed pollen grains therefore produce hella pollen

what is the adaptive significance of the fruit?

facilitates dispersal of the seed

what features are inferred to have evolved in the mrca of ecdysozoans?

ecdysis

what is the major group of ecdysozoans?

arthropoda

what features are inferred to have evolved in the mrca of arthropoda?

paired, jointed appendages

tagmosis

compound eyes

what is tagmosis?

fusion of segments into specialized regions

what are compound eyes?

group of light sensing structures (ommatidia)

during gastrulation, where does segmentation from annelids and arthropods form from and where does it come from in chordates? what does this say about segmentation in terms of its placement on the phylogeny?

annelids and arthropods -- ectoderm

chordates -- mesoderm (and not fully divided)

segmentation is not homologous

what are the major arthropod groups? and examples?

myriapods (centipedes)

chelicerates (spiders)

malacostraca (lobster)

hexapods (bee)

what are the diagnostic features of myriapods?

body with one tagma (head)

many segments, each with one or two pairs of legs per segment

what are the diagnostic features of chelicerates

body with two tagma

head and thorax fused into a carapace

chelicerae (claw/pincher thingys)

what are the diagnostic features of malacostracans?

body with three tagma (head, thorax, abdomen)

head and thorax fused into a carapace

two pairs of antennae

what are the diagnostic features of hexapods?

body with three tagma (head, thorax, abdomen)

one pair of antennae

three pairs of legs

flight

what’s a little funny about flight and insect wings?

it evolved once within insects and has been lost many times independently

wings are used to determine what kind of insect

what are the different groups within hexapoda? and examples?

hymenoptera (wasps)

coleoptera (beetles)

diptera (flies)

what is the diagnostic feature of hymenoptera?

two pairs of wings connected by hooks (hamuli)

what are the diagnostic features of coleoptera?

two pairs of wings

forewings are modified into protective coverings (elytra)

what are the diagnostic features of diptera?

one pair of wings

hind wings are modified into stabilizers (halteres)

what features are inferred to have evolved in the mrca of echinoderms?

pentaradial symmetry

water vascular system

calcareous endoskeleton with catch collagen

what are the groups of echinoderms? examples?

echinoids (sea urchins and sand dollars)

holothuroids (sea cucumbers)

what is something funky about the sand dollar’s symmetry?

its secondarily bilateral

what is something funky about the sea cucumber’s symmetry?

they are secondarily bilateral

what features are inferred to have evolved in the mrca of chordates?

notochord

dorsal hollow nerve cord

post anal tail

how is the dorsal hollow nerve cord formed?

via neurulation, which is initiated by the notochord

what are the major lineages of chordates? and what does each one introduce?

vertebrates (hagfish, lamprey, +) -- vertebrae cranium

gnathostomes (chondrichthyes, +) -- jaws, teeth

tetrapods (amphibians, +) -- 4 jointed limbs

amniotes

what are the diagnostic features of amniotes?

amniotic egg -- allowed embryo to develop in contained aqueous environment

impermeable skin

efficient kidneys

what features are inferred to have evolved in the mrca of mammals?

mammary glands

hair/fur

four-chambered heart

\*\*all innovations have to do with high metabolic rate

what are the amniotic homoplasies? what other group are they seen in besides mammals?

4 - chambered heart, endothermy

reptiles → birds