exam 2 Bio 122: Phylogenies, intro to plants, invertebrates

Phylogeny

evolutionary history of a species or group of species

ex) phylogeny shows that legless lizards and snakes evolved from different lineages of legged lizards

Systematics

classifies organism and determines their evolutionary relationships

recognize only groups that include a common ancestor and all its descendants

gather info about morphologies, genes, and biochem of living organisms

- used in computer programs and math tools to analyzed DNA

What is Carolus Linnaeus known for

taxonomy based on resemblances

two key features of binomial nomenclature are two-part name system for species and hierarchical classification

first is genus, second is epithet

1st letter capitalized and entire name italicized

both together name species

Linnaeus introduced taxonomic groups from broad to narrow

domain, kingdom, phylum, class, order, family, genus, species

taxon

taxonomic unit at any level

note- broader taxa are not comparable btw lineages (snails has less genetic diversity than order of mammals

phylogenetic tree

* Evolutionary history of a group of organisms is represented in branching

* Represent hypothesis about evolutionary relationships

branch point represents divergence of two evolutionary lineages form common ancestor

* Pattern of descent not phenotypic similarity

* doesn't indicate when species evolved or how much change occurred in lineage

* should not be assumed that a taxon evolved from taxon next to it

sister taxa

groups that share immediate common ancestor that is not shared by any other group

rooted tree

includes branch to represent the most recent common ancestor of all taxa in the tree

basal taxon

diverges early in history of a group and originates near common ancestor of the group

Homologies

phenotypic and genetic similarities due to shared ancestry

organisms w similar morphologies or DNA sequences are likely closely related than organisms with different structures or sequences

- infer phylogeny

applying phylogenies

phylogeny provides important info about similar characteristics in closely related species

used to identify the species of whale form which "whale meat" originated to discover if the whale was harvested illegally

analogy

similarity due to convergent evolution

convergent evolution

when similar environmental pressures and natural selection produce similar (analogous) adaptations in organisms from different evolutionary lineages

difference between homology and analogy

comparing fossil evidence and degree of complexity

- more elements that are similar in two complex structures the more likely are homologous

-if genes in two organisms share portions of nucleotide sequence; homologous

cladistics

group of organisms by common ancestry

clade

group of species that includes ancestral species and all its descendants

-can be nested in larger, but not all grouping of organisms qualify as it

polyphyletic

grouping includes distantly related species but does not include their most recent common ancestor

distinguished from paraphyletic by the fact they don't include recent common ancestor

paraphyletic

grouping consists of an ancestral species and some, but not all, of the descendants

monophyletic

signifies that it consists of ancestor species and all its descendants

shared derived characteristics

evolutionary novelty unique to particular clade

shared ancestral characteristics

originated in an ancestor of the taxon

ingroup

the various species being studied

outgroup

diverged before ingroup- closely related to ingroup

maximum parsimony

assumes that the tree that requires the fewest evolutionary events (appearances of shared derived characters) is the most likely

maximum likelihood

based on probability rules about how DNA changes over time and assumes a tree can be found that reflects the most likely sequence of evolutionary events

orthologous genes

found in single copy in the genome and are homologous between species

widespread and extend across many widely varied species

paralogous genes

result from gene duplication found in more than one copy in the genome

diverge within the species that carries them and often evolve new functions

why are algae not included in plant kingdom

they are photosynthetic protist

dont have embryos

green algae

called charophytes (predominately freshwater) are closest relatives of plants

traits plants share only with charophytes

* Rings of cellulose-synthesizing proteins

* Structure of flagellated sperm

* Formation of phragmoplast (guides cell division during cytokinesis)

- plants are not descended form modern charophytes but share common ancestor with modern charophytes

sporopollenin

in charophytes, a layer of durable polymer- prevents exposed zygotes form drying out

- found in plant spore walls

plant to land benefits

unfiltered sunlight, more CO2, and nutrient rich soil

challenges of plants to land

scarcity of water, lack of structural support against gravity

-plants are embryophytes (plants with embryos)

key traits in plants but not charophytes

* Alternation of generations

* Multicellular, dependent embryos

* Walled spores produced in sporangia

* Multicellular gametangia (produces gametes)

* Apical meristems (drives vertical growth)

Alternation of generations

plants alt btw two multicellular generations, reproductive cycle

gametophyte

haploid and produces haploid gametes by mitosis

diploid sporophyte

fusion of sperm and egg- produces haploid spores by meiosis, spores develop into gametophytes

multicellular, dependent embryos

diploid embryo is retained within the tissue of female gametophyte

nutrients are transferred from parent to embryo through placental transfer cells

plants are embryophytes because of dependency of the embryo of the parent

walled spores produced in sporangia

the sporophyte produces spores in organs called sporangia

diploid cells called sporocytes undergo meiosis to generate haploid spores

spore walls contain sporopollenin which makes them resistant to harsh environments

multicellular gametangia

gamestes are produced within organs called gametangia

female gametangia= archegonia-single nonmotile egg

male gametangia= antheridia- produce and release sperm

egg is fertilized within an archegonium

apical meristems

plants sustain continual growth in length by repeated cell division within the apical meristems

cells from apical meristems differentiate into various tissues

additional derived traits

cuticle- waxy covering of epidermis

stomata- specialized cells that allow for gas exchange btw the outside air and plant

mycorrhizae- symbiotic associations btw fungi and plants, may have helped plants without true roots obtain nutrients

vascular tissue

cells joined into tubes for transport of water and nutrients; these constitute the vascular plants

nonvascular plants

bryophytes

seedless vascular plants clades

lycophytes and monilophytes

seeless vascular plants dont form a clade

organisms that are grouped based on shared key bio features rather than shared ancestry, can be referred to as a grade

lycophytes ex

club mosses and relatives

monilophytes examples

ferns and relatives

seed

embryo and nutrients surrounded by a protective coat

seed plant clades

gymnosperms and angiosperms

gymnosperms

produce seeds that are not enclosed in chambers

angiosperms

produce seeds that develop inside chambers that originate within flowers

bryophyte examples

- rep by three phyla of small, herbaceous (nonwoody) plants

* liverworts, phylum hepatophyta

* mosses, phylum bryophyta

* hornworts, phylum anthocerophyta

bryophyte gametophytes

all three bryophyte phyla, gametophytes are larger and longer-living than sporophytes

sporophytes are typically present only part of the time

their height of this is constrained by lack of vascular tissues

in mature ___ produce flagellated sperm in antheridia and an egg in each archegonium

sperm swim through a film of water to reach and fertilize the egg

protonema

a spore germinates into a gametophyte composed of this

and one or more gamete producing (gametophores)

rhizoids

anchor gametophytes to substrate

bryophytes can reproduce asexually

some mosses produce brood bodies small plantlets that detach from the parent plant and grow into genetically identical copies of their parent

sporophyte

consists of a foot, seta (stalk), and sporangium, also called capsule, which discharges spores through a peristome

byrophyte sporophytes

never live independently of gametophyte; they are the smallest and simplest sporophytes of all extant plant groups

difference in liverworts from hornwort and moss sporophytes

hornwort and moss sporophytes have stomata; liverworts dont

ecological and economic importance of mosses

mosses inhabit diverse and extreme environments but common in moist forests and wetlands. colonize bare, sandy soil to help reduce nitrogen loss form soil; other harbor nitrogen fixing cyanobacteria

Peat- moss

or Sphagnum forms extensive deposits of partially decayed organic material known as this-

used for fuel

low temp, pH, and oxygen level of these in abundancy inhibit decay of moss and other organisms

ferns and other seedless vascular plants

- first to grow tall

-vascular tissue allow plants to grow tall

-like bryophytes seedless vascular plants have flagellated sperm and are usually restricted to moist environments

vascular plants

- early had independent branching sporophytes

-lifecycles w dominant sporophytes

-well developed roots and leaves

-spore bearing leaves called sporophylls

-in contrast with bryophytes, sporophytes of seedless vascular plants are the larger, more complex generation

types of vascular tissue in vascular plants

xylem and phloem

xylem

conducts most of the water and minerals and included tube- shaped cells called tracheids

water conducting cells are strengthened by lignin and provide structural support

phloem

has cells arranged into tubes that distribute sugars, amino acids, and other organic products

roots

organs that anchor vascular plants

enable vascular plants to absorb water and nutrients from the soil

evolved from subterranean stems

leaves

organs that increase the surface area of the vascular plants, thereby capturing more solar energy that is used for photosynthesis

two types: microphylls and megaphylls

microphylls

type of leaf that is small spine shaped leaves with a single vein

megaphylls

leaf- larger with a highly branched vascular system

sporophylls

modified leaves with sporangia

sori

clusters of sporangia on the undersides of sporophylls

strobili

cone like structures formed from groups of sporophylls

homosporous vs heterosporous

most seedless vascular plants are homosporous, producing one type of spore that develops into a bisexual gametophyte

all seed plants and some seedless vascular plants are heterosporous

heterosporous species produce megaspores which give rise to female gametophytes and microspores which give rise to male gametophytes

Phylum Lycophyta

one of two clades of seedless vascular plants

includes club mosses, spike mosses, and quillworts

-moist swamps but diversity declines when climate is drier

- small herbaceous plants

club and spike mosses have vascular tissue and not true mosses

phylum monilophyta

one of two clades of seedless vascular plants, included ferns, horsetails, and whisk ferns and their relatives

-fern is most widespread seedless vascular

-most diverse in tropics but thrive in temperate forests

-horsetails were diverse during carboniferous- now genus equisetum

-whist ferns resemble ancestral vascular plants but are closely related to modern ferns

what happened to seedless vascular plants

time pressure and heat makes - peat to lignite to coal

invertebrate

animals lack backbone, 95% of known animal species

Phylum Porifera

sponges- sessile and have porous body and choanocytes/ flagellated collar cells (generate water currents through sponge and ingest suspended food)

live in fresh and marine

lack true tissues and organs

suspension feeders- capture food particles suspended in the water that passes through their body

most sponges are hermaphrodites (both male and female)

all animals except sponges belong to clade Eumetazoa, animals with true tissues.

clade eumetazoa: phylum cnidaria

oldest groups in clade

radial symmetry, gastrovascular cavity, and cnidocytes

sessile and floating forms; jelly corals and hydras

-simple diploblastic (ectoderm and endoderm)

-sac with central digestive compartment, gastrovascular cavity

single opening- mouth and anus

two body plants polyp (mouth up) or medusa (mouth down)

-carnivores - use tentacles to capture prey- armed with cnidocytes function as defense as well

phylum cnidaria: class hydroza

portuguese man of war, hydras, corals- most marine few freshwater, polyp and medusa stages, in most species; polyp is colonial

phylum cnidaria: class scyphozoa

jellies, sea nettles- all marine, polyp stage reduces; free swimming, medusae up to 2 m in diameter

phylum cnidaria; class cubozoa

box jellie, sea wasp- all marine; box shaped, medusae; complex eyes

phylum cnidaria: class Anthozoa

sea anemones, most corals, sea fans: all marine, medusa stage completely absent, most sessile: many colonial

Clade Bilateria

most animals have this symmetry, triploblastic developments

3 layers: ectoderm, mesoderm, endoderm

Phylum Platyhelminthes

flatworms, live in marine, freshwater, damp terrestrial

-flattened dorsoventrally and have gastrovascular cavity

-undergo triploblastic development

-acoelomates: lack fluid filled body cavity between body wall and digestive track

Phylum Platyhelminthes, Class Trematoda

trematodes, flukes; parasites, always vertebrates: two suckers attach to host: most life cycles include intermediate hosts

monogeneans and treatodes live as parasites in or on other animals parasitize a wide range of hosts

Phylum Platyhelminthes, Class Turbellaria

mostly free-living flatworms- marine, some freshwater, few terrestrial; predators and scavengers; body surface ciliated

turbellarians/ planarians - have light sensitive eyespots and centralized nerve nets

Phylum Platyhelminthes: class Monogensea

marine and freshwater parasites: most infect exteranl surfaces of fishes; life history simple; ciliated larva starts infection on host

Phylum Platyhelminthes, Class Cestoda

tapeworms; parasites of vertebrates;scolex attaches to host; proglottids produce eggs and break off after fertiliztion; no head or digestive system; life cycle with one or more intermediate hosts

tapeworms- lack digestive system

Phylum Rotifer

are tiny animals that inhabit fresh water the ocean, and damp soil

smaller than many protist

multicellular and have specialized organ systems

- alimentary canal-digestive tybe with seperate mouth and anus that lies within a fluid-filled pseudocoelom: only partially lined by tissue derived from mesoderm

rotifers reproduce by parthenogenesis- in which females produce more females from unfertilized eggs

phylum nemertea

proboscis worms or ribbon worms

anatomy- nemerteans unique proboscis is used for defense and prey capture, extended by a fluid filled sac

-closed circulatory system

-blood is contained i vessels distinct from body cavity fluid

-coelomic: fluid filled body cavity to protect organs (54 meters length)

Phylum Mollusca

muscular foot, visceral mass, and a mantle

-includes snails, slugs, oysters clams, octopi and squids

most are marine some fresh and some terrestrial

soft bodied animals most protected by shell

-separate sexes w gonats located in visceral mass

-life cycle included ciliated larval stage called trochophore

Phylum Mollusca, Class Polyplacophora

chitons, oval shaped mairne animals encased in armor of eight dorsal plates; marine, shell with eight plates; foot used for locomotion; radula; no head

Phylum Mollusca, Class Gastropoda

marine, freshwater, or terestrial, snails/slugs, assymetrical, body w coiled shell, shell reduced or apbset in somel foot for locomotionl radula

-torsion, which causes animals anus and mantle to end up above head (most distic)

Phylum Mollusca, Class Bivalvia

clams, mussels, scallops, oysters, marine and freshwater, flattened shell w two valves, head reduced; paired gills; no radulal most suspension feeders, mantle forms siphons

- gills used for feeding as well as gas exchange

Phylum Mollusca, Class Cephalopoda

squids, octopus, cuttlefish, chambered nautiluses, marine, head surrounded by grasping tentacles, usually suckers, shell external, internal or absent; mouth with or without radula; locomotion by jet propulsion using siphon made from foot

-carnivores with beak like jaws

- octopuse creep along sea floor for prey

-squid use siphon; fire jet of water, which allows fast swimming

- nautilus shelled; survies today

phylum annelida

segmented worms

bodies composed of series of fused rings

Phylum Annelida, Class Oligochaeta

freshwater, marine, and terrestrial segmented wors; earthworms; reduced head, no parapodia, chaetae present

-sparse chaetae, or bristles made of chitin

-earthworms and variety of aquatic species

-earthworms eat way thrugh soil, extracting nutrients, as soil moves through alimentary canal

-helps till the earth making worm valuable to farmers

Phylum Annelida, Class Polychaeta

mostly marine, segmented worms, well developed head, each segment usually has parapodia with chaetae; tube dwelling and free living

-possess paddlelike parapodia that function as gills and aid in locomotion