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phylogeny

true evolutionary history between organisms

node on phylogeny tree

where two lineages (branches) diverge

root of phylogeny tree

common ancestor

tips of phylogeny tree

extant (now living) organisms

taxon

any group of species designated with a name

monophyletic clades

groups of taxa that include an ancestor AND all of its descendants

outgroup

reference point because it has the ancestral traits

in-group

has at least one characteristic that is different from the outgroup

derived trait

a trait that is different from the outgroup

has evolved from an earlier condition

Synapomorphy

shared, derived traits that provide evidence for a common ancestry

a homology that allows us to describe the characteristic of monophyletic clades

sister taxa

groups that are more closely related to each other than any other group

sister taxon

a lineage's closest relative

sister groups

paired lineages that result from evolutionary splits

maximum parsimony

applying the simplest, most obvious way with the least number of steps

homologous traits / homologies

heritable trait shared by more than one species AND inherited from the common ancestor

Difference between synapomorphy and homology

All synapomorphies are homologies, but not all homologies are synapomorphies

homoplasies

traits that are shared NOT due to a common evolutionary history - but because of convergent evolution or evolutionary reversals

Ex. wings of bats and birds evolved independently (do not share common ancestor)

convergent evolution

occurs when similar traits evolve in different lineages due to common evolutionary pressures (ex. environment)

evolutionary reversals

occurs when a character reverts from a derived state back to an ancestral state

Ex. loss of flight in penguins and ostriches

paraphyletic grouping

contains an ancestor but only some of its descendants

polyphyletic grouping

does not contain the common ancestor

when two members from unrelated lineages are grouped together, a polyphyletic linkage occurs

photosynthetic organisms

Organisms that can produce their own food by performing photosynthesis.

Photoheterotrophs

An organism that uses sunlight to generate ATP but that must obtain carbon in organic form (not from CO2) and do not generate oxygen as a byproduct

Ex. purple, non-sulfur bacteria and hablobacteria (live in salty environments)

Photoautotrophs

Organisms that use light to create ATP to synthesize organic substances (through the process of carbon fixation)

carbon fixation

turning gaseous carbon dioxide into glucose and other complex organic molecules

stromatolites

layers of fossilized cyanobacteria

mitochondria

evolutionary advantage after the Earth became oxygen rich to eukaryotes which require oxygen for cellular respiration

endosymbiotic theory and endosymbiosis

how two of these organelles - mitochondria and chloroplast - were integrated into the early eukaryotic cell

primary endosymbiosis

a pro-eukaryotic cell engulfed a specialized prokaryotic cell and the prokaryotic cell was integrated into the eukaryotic cell's body as an organelle

symbiotic relationship - mutual benefit

chloroplasts with 2 membranes

shared characteristics between mitochondria and chloroplasts

1) they have their own DNA which replicates independently

2) their DNA consists of a singular, circular chromosome

3) they have 2 membranes

All ____ cells have mitochondria, whereas only some have _______

eukaryotic, chlorplasts

What do scientist believe about the endosymbiotic event that led to mitochondria and chloroplasts?

That the endosymbiotic event that led to the earliest mitochondria occurred before the endosymbiotic event that led to the earliest chloroplasts

secondary endosymbiosis

A larger eukaryotic cell engulfs a smaller EUKARYOTIC cell but is not digested

secondary endosymbiosis in green algae led to euglenoids

secondary endosymbiosis in red algae led to dinoflagellates and stramenopiles

chloroplasts with 3 membranes

tertiary endosymbiosis

a cell engulfed another cell that was itself a product of secondary endosymbiosis

tertiary endosymbiosis led to emergence of some dinoflagellates

chloroplasts with 4 membranes

Euglena

members of a group that are heterotrophic

result of secondary endosymbiosis

also considered mixotrophic - can switch back and forth between producing ATP through photosynthesis and acquiring ATP by consuming other cells

Stramenopiles

diatoms and brown algae

result of endosymbiotic event with red algae

Dinoflagellates

result of secondary and tertiary endosymbiosis

red pigment from red algae in sec. endosymbiosis

acquired but not fully assimilated chloroplasts from brown algae in ter. endosymbiosis

produce toxic compounds

Glaucophytes

microscopic freshwater algae; thought to be similar in general form to the ancestor of Plantae because it contains a small amount of peptidoglycan between its inner and outer membranes

Distinguishing feature - huge chloroplasts (containing chlorophyll a) have retained their peptidoglycan cell walls

Red algae

almost all multicellular

red color from phycoerythrin - an accessory pigment found in chloroplasts that absorbs green light and extends photosynthesis

chloroplasts contain carotenoids and chlorophyll a

Distinguishing features:

- retain cellulose in cell walls

- no centrioles

- lack flagellated cells

- store sugars in cytosol

Green plants

green algae and land plants

include chlorophytes, coleochaetophytes, charophytes

Distinguishing features:

- Chlorophyll b

- Starch which is stored in chloroplasts

chlorphyll a vs. chlorophyll b

similar, but they differentiations by a single methyl group in the upper right carbon

green plant characteristics

1) chloroplasts developed from primary endosymbiosis

2) chloroplasts consist of both chlorophyll a and chlorophyll b

3) they store carbohydrates as true starch

Green algae

include chlorophytes, coleochaetophytes, charophytes and other green algae

grouping is NOT monophyletic

chlorophytes

range from unicellular organisms to large, branched seaweeds that exist in salt water, fresh water, or even moist soil

can be unicellular, multicellular or colonial

sexual reproduction = isogamy

spirogyra

charophyte that arranges its chloroplasts in a beautiful spiral pattern that gives the organism's fibers tensile strength

Streptophytes

subset of green plants that consists of two groups of green algae and land plants

What is class is most closely related to green plants?

streptophytes

Characteristics of streptophytes

Oogamy - sexual reproduction involving sperm (carries genetic material) and large egg (genetic material + everything else)

Plasmodesmata - channels that join cytoplasm to adjacent cells

Parenchyma - primary tissue type in streptophytes

Isogamy

sexual reproduction by the fusion of similar gametes

Oogamy

sexual reproduction in which one of the gametes (the egg) is large and nonmotile and the other gamete (the sperm) is smaller and motile

Plasmodesmata

definition - channels through cell walls that connect the cytoplasms of adjacent cells

function - communicate with one another through material exchange in cytoplasm

characteristic of streptophytes

Parenchyma

primary tissue in streptophytes, link plasmodesmata and parenchyma together

What is class is most closely related to land plants?

charophytes

synapomorphies:

- plasmodesmata

- branching apical growth

- similar peroxisome contents, chloroplast structure, processes for mitosis and cytokinesis

- parenchymal tissue consisting of roughly spherical (isodiametric) parenchyma cells

Land plants (embryophytes)

Distinguishing feature: enclose their eggs in a protective embryo

"invaded" land 450 million years ago

cuticle

waxy coating that prevents water loss and protects against UV rays

found on bottom or top of leaves

stomata

Small openings on the underside of a leaf through which oxygen and carbon dioxide can move

multicellular gametangia

Gametes are produced within organs called gametangia

Female gametangia, called archegonia, produce eggs and are the site of fertilization

Male gametangia, called antheridia, produce and release sperm

Advantageous - keeps egg and sperm from drying out

embryos

tiny diploid plants initially surrounded and nourished by cells of the gametophyte

syngamy

gametes fuse together and form a zygote that will eventually divide and become the embryo

UV absorptive compounds

UV absorptive pigments that protect against ultraviolet radiation

pigments work in conjunction with chlorophyll a

accessory pigments

energy absorbing plant pigments other than chlorophyll

ex. carotenoids, xanthophyll, and flavonoids

thick spore walls

land plants developed spores with thick walls containing sporopollenin (resists decay and spore tryout)

sporopollenin

resists decay and spore tryout

symbiotic associations with fungi

helped land plants acquire water and minerals needed to survive on land through use of mycorrhizae (symbiotic associations between fungi and underground plant structures)

mycorrhizae

symbiotic associations between fungi and underground plant structures

Ectomycorrhizae

A type of mycorrhizae in which the mycelium forms a dense sheath, or mantle, over the surface of the root.

arbuscular mycorrhizae

extend hyphae through the root cell walls and into the cortex.

arbuscules - branches that increase the surface area and promote nutrient transfer

ex. Glomalean

alternation of generations

a universal synapomorphy of all land pants

there is a multicellular diploid (2n) form (aka the sporophyte) and a multicellular haploid (n) form (aka the gametophyte)

Bryophytes

first land plant to evolve

incude liverworts, mosses, and hornworts

Characteristics:

- lack true roots, stems, leaves, vascular tissure

- rely on osmosis and absorption to get water

Bryophyte reproduction

most time in in haploid, gametophyte stage (dominant stage)

gametophytes are larger and live longer than sporophytes

sporophytes short lived and dependent on gametophyte for nutrition

Life cycle of bryophytes

1) release of a spore from the sporangium

2) sporangium forms a capsule that will cause spore to split and be thrown from palnt

3) Spore comes into contact w water and germinates

4) turns into a multicellular haploid male or female gametophyte - anchored by specialized root-like tissue called rhizoids

5) will form gametes for mitosis and fertilization begins between archegonia and archegonium

rhizoids

A thin, rootlike structure that anchors a moss and absorbs water and nutrients.

What plant was most likely the first land plant?

liverworts

evidence - pattern of parallel ridging that matches those of modern liverworts, lack stomata

Liverworts

oldest bryophyte

sporophyte is dependent on larger gametophyte

Characteristics:

- rhizoids

- no vascular tissue

- cannot conduct water

- reproduce sexually and asexually

elater

cell that grows alongside the spores in the sporophyte

assist in dispersal of the spores

hygroscopic - move in response to water and are sensitive to humidity changes

gemma cups

tiny pieces of thalloid and leafy liverworts

method of asexual reproduction and dispersion

Process --> rain drop splashes in cup --> gamma splash out --> land somewhere around plant --> grow

Mosses

soft, small, green and nonvascular and are found on the ground near water

Characteristics:

- Transport water externally by capillary action = must live in moist habitats

- Some have hydroids

-

Hydroids

water conducting cells in bryophytes

Mosses reproduction

sporophytes depend on gametophytes for protection and nutrition

and uses capsule to disperse gametes through use of peristome teeth (increase efficiency of spore dispersal)

Sphagnum moss

Peat moss-

branches grow in whorls, found in swampy areas,

acidify water which slows down rate of decay of dead life forms that fall in bogs

carbon storage

Hornworts

closest relative to vascular plants

sporophytes look like small horns

largest and most independent sporophyte

contain only one chloroplast

very green

capable of indefinite cell division

Alternation of generations life cycle

LAND PLANTS:

diploid sporophyte makes spore through meiosis

haploid gametophyte makes gametes in gametangia (protective structures) through mitosis

Different from human reproduction (gametes produced through meiosis)

Sporophyte characteristics

- multicellular, diploid (2n)

- synapomorphy of all land plants

- produce spores through meiosis

- genetically different because of crossing over and independent assortment

gametophyte characteristics

- haploid (n)

- produced through mitosis

- genetically identical due to mitosis

genetic advantages of diploidy in a large multicellular sporophyte

diploid individuals can hide a recessive deleterious gene, where as haploid individuals cannot

advantage in genetic variation in a large multicellular sporophyte

diploid sporophyte can produce sporangia that can produce millions of genetically unique spores

advantageous in a changing environment

cards for pg.57 start here

angiosperms

flowering plants, have seeds surrounded by an ovary, closest existing relatives are gymnosperms

synapomorphies of angiosperms

- flowers: highly visual, characteristic reproductive parts of angiosperm

- fruits: a mature ovary with embryonic seeds called ovules

- reduced gametophytes: female gametophyte is extremely reduced, allowing it to develop rapidly

- double fertilization: one sperm fertilizes egg to form zygote, one sperm fuses with two polar bodies to form endosperm

- production of triploid endosperm: nourishes sporophyte during early development

- ovules and seeds enclosed in carpel: carpel consists of ovary, stigma, and style

- germination of pollen on a stigma: stigma is sticky, with lots of fine hairs that trap pollen grains

typical parts of a flower

sepals, carpels, stamens, and petals

stamen

male reproductive unit, holds microsporangia, contains filament and an anther (produces pollen)

ovary, style, stigma

female parts of plant (collectively called carpel) holds megasporangia

-stigma is sticky to trap pollen

-ovary develops into fruit when mature

sepals and petals

the non-reproductive parts of a flower

-sepals have protective function (collectively form a whorl called calyx)

-petals function to attract pollinators (collectively form whorl called corolla)

-calyx and corolla form perianth

receptacle

portion of flower where floral organs are attached

pollination

transfer of pollen from anther to stigma, can be achieved by:

-abiotic agents (wind, water, etc)

-biotic agents (animals)

fruit

A mature ovary of a flower that protects dormant seeds and aids in their dispersal.

types of fruit

berries (simple fruits), drupes (simple), aggregate fruits, accessory fruits, multiple fruits

angiosperm phylogeny

magnoliids

trees and shrubs with net-veined, aromatic leaves, monosulcate pollen with a singular linear, thinned furrow-like area on the grain

monocots

develop from seeds that have single cotyledons, parallel venation, fibrous root system, scattered vascular bundles, secondary growth is not common, pollen grains with single germination aperture, subterranean germination, flower parts in groups of 3