plants and shi

formation of the planet

first event in history of life on earth

evolution of prokaryotic cells

second event in history of life on earth

oxygen revolution

third event in history of life on earth

evolution of multicellular life

fourth event in history of life on earth

evolution of mammals

fifth and last event in history of life on earth

mass extinction and adaptive radiation

what are the two themes in the history of life on earth

mass extinction

the rapid extinction of a large number of diverse species around the world, at least 60% within 1MY

background extinction

species disappear naturally over time, independent of catastrophic events

adaptive radiation

rapid production of many descendant species in a single lineage

adaptive radiation

extinction, evolution of a key trait, and dispersal to a new environment are all triggers of

end-cretaceous

which of the recognized mass extinctions wiped out the dinosaurs, along with 60-80% of multicellular life (aka k-pg)

paraphyletic group

prokaryotes make what kind of group on a phylogenetic tree

metabolic and ecological diversity

mechanisms that generate genetic variation that aren’t sexual reproduction

rapid reproduction, mutation, genetic recombination

genetic variability in bacterial populations comes from

genetic recombination

combining of DNA from 2 sources, contributes to diversity, can be the same or different species

vertical gene transfer

the process of passing genetic material from parent organisms to their offspring during reproduction, ensuring the inheritance of traits within a species

horizontal gene transfer

the process of transferring genetic material between organisms in a manner other than traditional reproduction (3 different ones)

conjugation

horizontal gene transfer that involves direct contact

plasmid

a small, usually circular chromosome that exists independently of bacterial cells’ main chromosome, plays a role in conjugation

transduction

HGT that involves viruses

transformation

HGT that involves taking up foreign DNA from the environment

microbe

microscopic organism that plays a role in energy/carbon source, nitrogen metabolism, and presence of oxygen

chemoheterotroph

breaks chemical bonds as energy source, uses organic compounds as carbon source

photoautotroph

uses light as energy source, uses CO2 as carbon source

extremophiles

live in extreme habitats (pH < 1, 0 celsius)

microbiome

community of microbes that naturally inhabit a body or parts of a body, key roles in nutrition, metabolism, and immune system function

rhizobia

an ecologically and economically important species that fix nitrogen in the roots of legumes

bacteria

all known pathogenic prokaryotes belong to what family (that cause around ½ of all human diseases)

exotoxins

proteins secreted by bacteria that can cause disease

endotoxins

lipopolysaccharide components of the outer membrane of gram-negative bacteria, released when bacteria die and their cell walls break down

endotoxin

salmonella, a result of food poisoning, is an example of what kind of toxin

peptidoglycan

many antibiotics target what molecule, which human cells also lack

gram-negative

bacteria with thin peptidoglycan walls and an outer membrane that tend to be more resistant to antibiotics

gram-positive

bacteria with thick peptidoglycan walls that stain a darker color and are more affected/damaged by antibiotics

eukaryotes, unicellular

protists are a paraphyletic group, most _________ are protists and most protists are __________

endosymbiosis

relationship between 2 species in which one organism lives inside the cell of the other organism (the host)

plastid

membrane bound organelle found in algae, plants, and other eukaryotes diversified into mostly chloroplasts

euglenozoans

taxonomy: excavates

euglenozoans

defining characteristic: single celled and flagellated

euglenozoans

habitat: freshwater and marine environments, can be free living or parasitic

euglenozoans

feeding: diverse clade including predatory heterotrophs, photosynthetic autotrophs, mixotrophs and parasites

cercozoans

taxonomy: rhizaria

cercozoans

defining characteristic: amoeboid and flagellated protists that feed using threadlike pseudopodia

cercozoans

habitat: marine, freshwater, and soil

cercozoans

feeding: heterotrophic parasites or predators (most)

chloroarchniophyte

a photosynthesizing heterotroph that acquired chloroplasts via secondary endosynbiosis

apicomplexans

taxonomy: alveolates

apicomplexans

defining characteristic: unicellular and spore forming

apicomplexans

habitat: mostly obligate endoparasites of animals

apicomplexans

feeding: obligately parasitic at some point in their life cycle

diatoms

taxonomy: stramenophiles

diatoms

defining characteristic: unicellular, photosynthetic, glass-like wall made of silicon dioxide

diatoms

habitat: mostly aquatic (marine and fresh), called phytoplankton

diatoms

feeding: photosynthetic autotrophs, generate 20-50% of oxygen produced on the planet each year

protected embryo, cuticle, thick-walled spores, alternation of generations

first evolutionary change on phylogenetic tree that is also the (4) synapomorphies of all land plants, excludes only green algae

stomata

second evolutionary change on phylogenetic tree that becomes common from mosses down (diverges after liverworts)

vascular tissue

third change on phylogenetic tree that is common from lycophytes down

megaphylls

fourth change on phylogenetic tree that is common from ferns down

seeds

fifth change on phylogenetic tree that is common from gymnosperms down

flowers

sixth and last change on phylogenetic tree that appears only in angiosperms

precambrian

3500 MYA - plant ancestors

green algae

evolutionary outgroup to plants, contain chlorophyll a+b, includes chlorophytes, coleochaetophytes, and stoneworts

UV radiation, gravity, water stress, dispersal, nutrients

stressors that exist on land that wouldn’t have existed in aquatic environments

makes spores via meiosis

sporophyte

makes gametes via mitosis

gametophyte

protected embryo

synapomorphy - the diploid embryo is retained within the tissue of the gametophyte and nutrients are transferred from parent to embryo through placental transfer cells

embryophyte

term for plants because of the dependency of the embryo on the parent

gametangia

structures that produce gametes

female gametangia

produce a single nonmotile egg

antheridia

male gametangia, produce many motile sperm

cuticle

waxy covering of the epidermis that reduces water loss

spores

small, single-celled reproductive structures that can grow into new individuals without needing to fuse with another cell (unlike gametes, which require fertilization)

sporopollenin

tough plant spores

nonvascular plants

ground hugging - include liverworts, mosses, and hornworts - water moves by capillary action, gametophyte dominant, thin cuticle, fully protected embryo

liverworts

9000 species, leaflike gametophytes lie close to the ground, root-like filaments on the undersurface, sporophyte remains attached to the larger gametophyte

mosses

15000 species, form thick mats on damp ground, stomata, sporophyte grows off the larger gametophyte

stomata

a microscopic pore that allows gas exchange and prevents water loss on the surface of plant leaves and stems

hornworts

100 species, persistently green sporophyte that does not have limited growth, marks the transition to sporophyte dominated life cycle