Studied by 7 peopleProtists are ____.
eukaryotes
Are eukaryotic organelles more or less complex than prokaryotic cell?
more complex
What is the organism that is in most eukaryotic lineages?
protists (unicellular)
Name these protists from left to right.
Slime mold, amoeba, euglena, dinoflagellate, paramecium, diatom, macroalga
Photoautotroups
contain chloroplasts
Heterotrophs
absorb organic molecules or ingest food
Mixotrophs
combine photosynthesis and heterotrophism
How do protists reproduce?
sexually and asexually
What four groups are all eukaryotes (including) protists separated into?
excavata, SAR (stramenopiles, alveolates, and rhizarians), archaeplastida, unikonta
Endosymbiosis
a relationship between two species in which one organism lives inside the cell or cells of the other organism (the host)
What is derived from prokaryotes and how?
mitochondria and plastids, prokaryotes were engulfed by ancestors of early eukaryotic cells
What specifically did mitochondria evolve from?
endosymbiosis of an alpha proteobacterium
What specifically did plastids evolve from?
endosymbiosis of a photosynthetic cyanobacteria
Excavata
diplomonads, parabasalids, euglenozoans
Why was this group given the name excavata?
some members have an “excavated” feeding grove on one side of the body
What is unique about diplomonads and parabasalids?
they lack plastids and have modified mitochondria; most live in aerobic environments
Diplomonads
mitochondria called mitosomes, derive energy from anaerobic biochemical pathways, are often parasites
Parabasalids
have a reduced mitochondria called hydrogenosomes, generate some energy anaerobically
Trichomonas vaginalis
a sexually transmitted parasite
Name these from left to right.
“textbook” mitochondrion, anaerobic mitochondrion, hydrogenosome, mitosome
What is unique about euglenozoans?
they have a spiral or crystalline rode inside their flagella
Euglenozoans
predatory heterotrophs, photosynthetic autotrophs, mixotrophs, and parasites
What is unique about kinetoplastids?
have a single mitochondrion with an organized mass of DNA called kintoplast
Trypanosomes
evade host immune responses by producing cell-surface proteins with different molecular structures in each generation
Euglenids
can be autotrophic or heterotrophic
SAR
stramenopiles, alveolates, rhizarians
Stramenopiles
photosynthetic organisms, examples are diatoms, golden algae, and brown algae
Diatoms
unicellular algae
Brown algae
largest and most complex algae; multicellular and often marine (seaweed)
Alveolates
dinoflagellates, apicomplexans, ciliates
Dinoflagellates
aquatic phototrophs, mixotrophs, and heterotrophs (“red tides”)
Apicomplexans
parasites of animals, spread as sporozoites (Plasmodium causes malaria)
Ciliates
a large varied group of protists
Rhizarians
many are amoebas, protists
What do rhizarians consist of?
radiolarians, forams, cerrozoans
Radiolarians
mostly marine protists
Forams
named for their porous shells called “tests”, made of calcium carbonate (seashells)
Archaeplastida
red algae, green algae, and plants
Unikonta
animals, fungi, and some protists; includes two clades (amoebozoans and opisthokonts)
Amoebozoans
lobe or tube-shaped amoebas (slime molds, tubulinids, and entamoebas)
Slime mold A
Plasmodial slime molds (unicellular)
Slime mold B
Cellular slime molds (motile)
Tubulinids
unicellular protists, heterotrophic
Entamoebas
parasites of vertebrates and some invertebrates
Symbiotic protists
some benefit their host and some are parasitic
Photosynthetic producer protists
convert CO2 to organic compounds
When did cyanobacteria and protists likely exist on land?
1.2 million years ago
When did small plants, fungi, and animals emerge on Earth?
within the last 500 years
Where does Earth’s oxygen come from?
marine microbes, land plants, and macro algae (kelp)
Which plant species produces the most oxygen?
snake plant
What are the closest relatives to plants?
green algae (charophytes); rings of cellulose synthesizing proteins, structure of flagellated sperm, and formation of a phragmoplast
Sporopollenin
a durable polymer layer that prevents zygotes from drying out
What are the benefits for charophytes moving to land?
unfiltered sunlight, more plentiful CO2, and nutrient rich soil
What were the challenges for charophytes moving to land?
scarcity of water and lack of structural support against algae
Alteration of Generations
gametophyte generation (haploid and produces haploid gametes by mitosis) and fusion (diploid sporophyte which produces haploid spores by meiosis)
Label this picture
meiosis, fertilization, spore, gametophyte, mitosis, gamete from another plant, spore, gamete, fertilization, zygote, mitosis, sporophyte
How are nutrients transferred from parent to embryo?
placental transfer cells
Why are plants called embryophytes?
because of the dependency of the embryo on the parent
Spoeocytes
diploid cells that undergo meiosis to generate haploid spores
Archegonia
female gametangia, produce a single non-motile egg
Antheridia
male gametangia, produce and release sperm
Apical Meristems
within this plants sustain continual growth in length by repeated cell division
Cuticle
a waxy covering of the epidermis
Stomata and Guard cells
specialized cells that allow for gas exchange between the outside air and the plant
What do the appearance of plant spores in the fossil record indicate?
that plants colonized land at least 470 million years ago
Vascular tissue
cells joined into tubes for the transport of water and nutrients
Bryophytes
nonvascular plants
Seedless vascular plants
lycophytes (club mosses and their relatives) and monilophytes (ferns and their relatives)
Seed
an embryo and nutrients surrounded by a protective coat
Seeded vascular plants
gymnosperms ('“naked seeds, not in chambers) and angiosperms (“enclosed seeds”, develop inside chambers)
Bryophytes
liverworts, mosses, and hornworts
Rhizoids
anchor gametophytes to substrate
Sporophyte vs. Gametophyte
What does a sporophyte consist of?
a foot, a seta (stalk), and a sporangium (capsule)
What were the prominent types of vegetation during the first 100 million years of plant evolution
bryophytes
What do the earliest fossils of vascular plants date to?
425 million years ago
Xylem
conducts most of the water and minerals and includes tube-shaped cells called tracheids
Lignin
strengthens water conducting cells and provides structural support
Phloem
has cells arranged into tubes that distribute sugars, amino acids, and other organic compounds
Roots
organs that anchor vascular plants, absorb water and nutrients from soil
Leaves
organs that increase the surface area of vascular plants, maximizing photosynthesis
Microphylls
small leaves with a single vein
Megaphylls
larger leaves with a highly branched vascular system
Sporophylls
modified leaves with sporangia
Sori
sporangia clusters on sporophyll undersides
Strobili
cone-like structures formed from groups of sporophylls
Homosporous
producing one type of spore that develops into bisexual gametophyte
Megaspores
produced by heterosporous species, give rise to female gametophytes
Microspores
give rise to male gametophytes
Lycophyta
club mosses, spike mosses, and quillworms
Monilophyta
ferns, horsetails, and whisk ferns and their relatives
When did seed plants originate?
360 million years ago
Reduced gametophytes
develop within the walls of spores that are retained with tissues of the parent sporophyte, protects the developing gametophyte
Ovule
consists of megasporangium, megaspore, and one or more protective integuments
How many integuments do gymnosperm megasporangia and angiosperm megasporangia usually have
gymnosperm megasporangia have 1 and angiosperm megasporangia have 2
Pollen grain
what a microspore develops into, consists of a male gametophyte enclosed within the pollen wall
Pollination
the transfer of pollen to the part of a seed plant containing the ovules
Pollen tube
discharges sperm into the female gametophyte within the ovule
What does gymnosperm mean?
“naked seed”
Note
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