bsc2011 exam 1

vertebrates

animals with a rigid backbone

mammals

mammary glands and a body that is covered in hair

hierarchies

phylogenetic trees are another way to draw...

root

the original common ancestor for that grou[

branches

the lineages leading from an ancestor

clade

an ancestor and all its descendants (can be big or small)

sister groups

the two branches (and descendant species) that diverged from a common ancestor; each other's biologically closest relatives

relatedness

all phylogenies can be thought of as subsets of the "one true tree" and are used to show the patterns of _______________ among selected species

tree of life

it is now possible to use the pattern of homologous characters (especially from DNA sequences) among species to accurately reconstruct the history of branching in all lineages of life; the resulting tree is called the...

bacteria

domain of prokaryotes (cells without nuclei) that reproduce through spores

archaea

domain of prokaryotes (cells without nuclei) that reproduce through fission

eukarya

domain of eukaryotes (cells with nuclei)

cyanobacteria

ubiquitous photosynthetic prokaryotes (no nucleus, circular chromosomes, etc.)

oxygenic (typical carbon-fixing type prevalent today)

cyanobacteria were the first organisms to do _________ photosynthesis

amino acids (proteins); nucleic acid (DNA, RNA)

cyanobacteria can "fix" nitrogen gas from the atmosphere, which is needed for synthesis of __________ and ____________

oxygen rich atmosphere

favored organisms that could withstand and utilize oxygen

oxygenic photosynthesis

set the stage for the rise of diversification of the eukaryotes

primary endosymbiosis

produced the first photosynthetic eukaryotes; a cyanobacterium was engulfed (the chloroplast has two membranes and is now considered an "organelle" within photosynthetic eukaryotic cells)

red algae; green algae; land plants

the captured cyanobacterial cell from primary endosymbiosis gave rise to chloroplasts of _____________, _____________, and _______________

plantae

the clade of eukaryotic life with chloroplasts derived from primary endosymbiosis

algae

most of the earliest spills in the phylogenetic tree have led aquatic lineages (either marine or freshwater), like this one

red algae

plants that vary from single-celled to elaborately branched multicellular organisms; have cellulose cell walls and only have chlorophyll a (like cyanobacteria)

coralline red algae

among the oldest eukaryotic fossils, whose cell walls have calcium carbonate and are extremely important as reef-builders; are food for reef organisms, inhabit deeper waters

green plant

eukaryote with chloroplasts (chlorophyll a and b) derived from primary endosymbiosis (same as all plants); store carbs as starch which as 2 main types of polysaccharides

floridean starch

red algae make a similar compound to the ones green plants make called ______________, which lacks one of the main polysaccharides

green algae

the earliest branching green plants; mainly occur in marine or freshwater environments

streptophyta

several lineages make up this clade, including land plants, some of which are still algae-like

phragmoplasts

thought to help algae grow 3-dimensionally and create cell plates with plasmodesmata (the alternative to phycoplast)

plasmodesmata

most streptophytes have this, which are channels that penetrate the cell walls of adjacent cells

parenchyma

the basic tissue type in the streptophytes with cells linked by plasmodesmata

oogamy; plasmodesmata; apical growth

important characters that evolved in algae-like ancestors of land plants include ___________, ____________, and ____________ (not all streptophytes exhibit these three things though)

oogamy

life cycle of some green algae-like streptophytes; gametes differ in size and form

isogamy

life cycle of some green algae-like streptophytes; gametes do not differ in size and form

desmids

part of the "other green algae" called zygnematales

• had to adapt to dry, high light (xeric conditions)

• had to develop transport systems for water and nutrients

• had to develop structural support

• had to find new ways to disperse gametes and progeny

• had to have a mutually beneficial association with fungi (mycorrhizae) that promotes nutrient uptake from the soil

what are 5 key adaptations that permitted plants to colonize land?

cuticle

a waxy coating that slows water loss

stomata

closable openings that regulate gas exchange (most lineages), help plants stay hydrated

pigments

protect against UV radiation; absorb light more efficiently

spores

have thick walls containing sporopollenin, which protect spores against drying out/decaying

mycorrhizae

fungi associated with underground plant parts (roots)

ectomyocorrhizeal (EM) fungi

wrap themselves around the plant, increasing surface area for water and mineral absorption

vesicular-arbuscular mycorrhizal (VA) fungi

grow into root cells and exchange water and nutrients

chara (stonewort) life cycle

life cycle typical of many algae and other eukaryotes

alternation of generations

land plants have this in their life cycle

sporophyte

dependent on the gametophyte for nutrition at some ore all stages of development and usually remains attached; spore-producing diploid phase

gametophyte

the dominant life form in bryophytes; gamete-producing haploid phase

gametes

produced by mitosis on gametophyte plants; sperm must swim or be splashed by water to reach the egg

mitosis

gametes are produced by...

meiosis

spores are produced by...

fertilization, then mitosis, then meiosis

put the process of alternation of generations in order

reproductive organs

alternation of generations means multiple types of...

(haploid multicellular) gametophytes

spores grow to produce these, which make gametes by mitosis in gametangia

diploid zygotes; embryo

eggs are fertilized by sperm to form ____________, which develops by mitosis into a multicellular ___________, and this eventually grows into a mature diploid plant

haploid spores

cells in sporangia produce ______________ by meiosis

gametangia

organs that enclose gametes and prevent them from drying out

archegonium

a type of gametangia that forms and produces egg cells and a pollen chamber

antheridium

a type of gametandia that produces motile sperm

embyro

young plant contained within a protective structure

liverworts, hornworts, mosses

nonvascular land plants have what three bryophyte lineages?

bryophytes

have no true roots, stems, or leaves, they obtain and move water around in a relatively undirected fashion via osmosis, and typically live in moist habitats

support tissue plant body; desiccation tolerance; sperm

bryophytes have no strong _______________, they have signaling proteins that are typically involved in _______________, and have swimming ___________ (2 flagella)

size is restricted (small enough that minerals can be distributed throughout their bodies by diffusion)

bryophytes have no vascular system to transport water, so...

liverworts

green, leaf-like gametophytes, most of which can reproduce sexually and asexually

apical growth

growth occurs at growing points at the apex of the plant (green tissue is all the gametophyte stage)

larger

in liverworts, sporophyte remains attached to the (smaller/larger) gametophyte

internal water conduction; stomata

liverworts have no ____________ or true ______________

stalk; capsule (sporangium)

sporophytes of liverwort have a ____________ and ____________, and is attached to the gametophyte and physiologically depends on it

valves

sporophytes usually split into these to release spores and elaters

elaters

assist in disperal, flex in response to changes in humidity

mosses

erect, leafy gametophytes that have cells called hydroids

hydroids

cells that die and leave a channel through which water can move

water and most sugars

sporophytes in mosses are attached to the gametophyte, dependent for ______________, and they are unbranched, producing (one/multiple) capsule(s)

capsules

many mosses have stomata on their...

peristome teeth

teeth surrounding the opening of the bryophyte spore capsule; these structures are hygroscopic and allow gradual spore disperal

hygroscopic

shape changes (flex) with humidity

sphagnum (peat) moss

a moss with unusual ecological significance; acidic and cold, so resist decay, storing gigatons of carbon

hornworts

bryophytes whose cells contain one chloroplast; sporophytes look like small horns and grow from a basal region capable of indefinite cell division

cyanobacterium

hornworts have a symbiotic relationship relationship with ______________ that live in internal cavities and fix nitrogen

vascular plants (tracheophytes)

the major clade of land plants that have a dominant sporophyte generation (branched sporophyte is independent of the gametophyte at maturity)

• light can make glucose (photosynthesis) and convert it to sucrose, but water is limiting

• water is abundant in the soil, but there is no light in soil, and tissues require food (new transport methods are necessary)

consequences of having a large/tall sporophyte in a heterogenous environment are...

cooksonia paranensis (devonian)

oldest known "megafossils" of land plants that represent branched sporophytes (unclear whether photosynthetic or dependent on non-fossilized gametophytes; some species have vascular tissue)

branched sporophyte

sporangia with stomata and containing spores in tetrads with sporopollenin

vascular tissue

specialized system of pipes that run through the plant (xylem and phloem)

xylem

conduct water and minerals from the roots up to the plant (enables plants to get large, which solves problem of hydrating leaves and feeding roots); controlled by stomata

phloem

conduct sugars from the leaves to the lower part of the plant

devonian

earliest fossils of vascular plants date to the early _____________ period (around 400 mya)

carboniferous

major diversification (and high O2) does not happen until the ___________ period (between 360 and 300 mya)

forests

once lineages with vascular tissue began to diversify, __________ became possible for the first time

coal

_________ forests of large trees exist; original deposition of these major deposits around the world occurred in the carboniferous

fossil record

fern, horetails, and lycophytes have a long _____________, and were dominant organisms in the carboniferous

global cooling (climate change)

burial of organic carbon caused...

lycophytes

club mosses with independent sporophyte and gametophyte generations; true dichotomous branching roots, have leaflike structures (microphylls), arranged spirally on stem

are not (they have evolved microphylls)

lycophyte leaves (are/are not) true leaves

microphylls

small leaves with a single midvein

true roots (or leaves, etc.)

developed from the radical of embryos

false roots (or leaves, etc.)

not developed from the radical of embryos

sporangia

spore-forming structures

strobili

sporangia are in many species in these club-like clusters (sporangia clustered at tips of branches)

vascular tissues

led to rapid diversification of plants

heterosporous

most vascular plants are...