Midterm 2 (Ch. 29-34) - Lecture Slides Flashcards
Characteristics of Archaea and Bacteria (4)
Prokaryotic, single-celled (nearly all), lack nuclear envelope and membrane-bound organelles, circular DNA
Are prokaryotes a natural taxon?
No (archaea more closely related to us)
Metagenomics
study of genetic material recovered directly from environmental samples
Microbiome
microorganisms in a particular environment
These groups are not protists
Plants, animals, fungi
Synapomorphy for eukaryotes
nuclear envelope
Stages of reproduction for malaria parasite
Asexual reproduction in humans, sexual reproduction in mosquitoes
Uni- vs. bikonta
One vs. two flagella
Protist characteristics (4)
Eukaryotic, have mitochondria (or genes for them), nucleus and endomembrane system, cytoskeleton
Endosymbiosis theory
membrane-bound organelles (chloroplast, mitochondria) were protobacteria that protists engulfed
Evidence for endosymbiosis theory (4); specific to mitochondria - similar for chloroplasts
Mitochondria:
- are size of protobacteria
- replicate by fission
- have double membranes
- have own genomes (circular)
How many membranes do chloroplasts in members of Plantae have?
2
Haploid (n)
one set of chromosomes (23 total)
Diploid (2n)
two sets of chromosomes (23 pairs, 46 total)
Bacteria and archaea are always ____ (n or 2n).
haploid (n)
Protists are ____ (n or 2n).
Depends; they can have asexual and sexual reproduction
Alternation of generations
organisms have multicellular haploid phase and multicellular diploid phase
Gametophyte
multicellular haploid form; specialized cells produce gametes
Sporophyte
multicellular diploid form; specialized cells undergo meiosis and produce spores
Spore
single haploid cell that divides (mitosis) to form multicellular gametophyte
How green algae are related to land plants (3)
same photosynthetic pigments (chlorophyll a and b), similar internal cellular structures, chloroplasts make starch as sugar storage product
Nonvascular plants (definition and example)
no vascular tissue to conduct water and provide support; e.g., mosses
Seedless vascular plants
vascular tissue but don’t make seeds; e.g., ferns
Seed plants
have vascular tissue and make seeds; e.g., angiosperms (flowering plants)
Green algae (3)
ulvophytes, coleochates, stoneworts
Nonvascular plants (bryophytes) (3)
liverworts, mosses, hornworts
Seedless vascular plants (4)
lycophytes, whisk ferns, ferns, horsetails
Gymnosperms (seed plants) (5)
ginkgos, cycads, redwoods, pines, gnetophytes
Angiosperms (def.)
flowering plants
Synapomorphy for land plants
pores
Adaptations to land for plants
cuticle, pores (with stomata and guard cells), vascular tissue
Why did plants move to land? (5)
- more sunlight
- more carbon dioxide
- escape predators (certain herbivores)
- more room to grow
- get away from competitors (new environment, new niches)
Synapomorphy for seedless vascular plants
vascular tissue
Gametangia
specialized reproductive organs in land plants
Male gametangium
antheridium
Female gametangium
archegonium
Homosporous
produces a single type of spore
Heterosporous
produces two kinds of spores (male and female)
Microsporangia make ___.
sperm
Megasporangia make ___.
eggs
First photosynthetic organisms
cyanobacteria
What makes fungi important?
they can digest cellulose, and some can digest lignin - important in recycling carbon
Two basic fungi morphologies
yeasts and mycelium/mycelia
Yeasts (def. and importance)
single-celled fungi; important to fermentation
Mycelium/mycelia (def.)
filamentous structures
Symbiosis
close relationship between species
Mutualism
both species benefit
Commensalism
one species benefits, the other is not affected either way
Parasitism
one species benefits at the expense of the other
Mycorrhizal fungi (location and role)
- grow on roots of plants
- mutualistic symbiosis
- aid in transfer of mineral, water, and sugar between soil and plants
- increase growth
Importance of fungi in nitrogen cycle
mycorrhizal fungi aid in nitrogen uptake in plants
Ectomycorrhizal fungi (EMF)
extracellular digestion of polypeptides and proteins with peptidases; form film on outside of roots
Arbuscular mycorrhizal fungi (AMF)
intracellular (penetrate cell); common in grasslands and tropical forests
Why are hyphae so branchy?
higher surface area to volume ratio makes transfer more efficient
Heterokaryotic
genetically distinct haploid nuclei in cells
Dikaryotic
type of heterokaryosis where there are two distinct haploid nuclei in cells (n+n)
Plasmogamy
fusion of cytoplasm from two individuals
Karyogamy
fusion of nuclei
Batrachochytrium dendrobatidis
fungus causing chytridiomycosis in amphibians
Pseudogymnoascus destructans
fungus causing white nose syndrome (deadly) in North American bats
What are mushrooms?
sexual reproduction structures
Characteristics of all animals (4)
- extracellular matrix (proteins and other molecules that allow cell-cell adhesion and communication)
- heterotrophs (get compounds from other organisms)
- move under own power at some point in their lives
- have neurons and muscle cells (except sponges)
Are porifera a natural taxon?
No
Characteristics of sponges (4)
- suspension feeders
- have specialized cells
- have extracellular matrix
- develop from single cell layer
Tissues
similar cells organized into functional units
Blastula
hollow ball of cells that forms from fertilized cells
Gastrula
multilayered structure that develops from blastula
Diploblast
has two embryonic tissue layers: endoderm and ectoderm
Triploblast
has three embryonic tissue layers: endoderm, mesoderm, ectoderm
What does each tissue layer form in a diploblast?
- ectoderm: skin, nerves, muscle
- endoderm: digestive tract, reproductive organs
What does each tissue layer form in a triploblast?
- ectoderm: skin, nerves
- mesoderm: circulatory system, muscles, bones, organs
- endoderm: lining of digestive system
Radial symmetry
can divide organism along more than one plane and get mirror images
Bilateral symmetry
can only divide organism along one plane and get mirror images
How are nerves arranged in animals with radial symmetry?
nerve nets; not centrally organized
How are nerves arranged in animals with bilateral symmetry?
central nervous system, organized around ganglia, head, and brains
Cephalization
localizing of certain organs in the “head” area
“Tube within a tube”
in triploblasts, in-folding continues until a “tube within a tube” develops
What tube is what in “tube within a tube”?
- inside tube: gut
- outside tube: skin and nervous system
Coelom (def. and function)
fluid-filled cavity between inner and outer tubes that allows internal organs to move independently and provides space for circulation
Acoelomates (def. and example organism)
lack coelom; flatworms
Pseudocoelomates (def. and example organism)
have coelom without mesodermal lining; roundworms
True coelomates (def. and 5 examples)
have coelem completely lined with mesodermal lining; mollusks, annelids, arthropods, echinoderms, chordates
Hydrostatic skeleton
fluid-filled chamber that allows wormlike animals to squeeze and extend
Metamorphosis
different life stages differ radically
Protostome
first pore becomes mouth
Deuterostome
first pore becomes butt
How does coelom develop in protostomes?
blocks of solid mesoderm split off to form coelom
How does coelom develop in deuterostomes?
mesoderm pockets pinch off of gut to form coelom
Lophotochozoan groups (protostomes)
RPAM: rotifera, platyhelminthes, annelida, mollusca
Ecdysozoan groups (protostomes)
NOTA: nematoda, onychophora, tardigrada, arthropoda
Most speciose group of protostomes
arthropods (insects are most of these)
Challenges in transitioning to land (3)
gas exchange, reproduction, desiccation
Lophophore
specialized structure for suspension feeding; ciliated tentacles around the mouth
Trochophore
specific kind of larvae with ring of cilia around its middle
Traits of lophotrochozoans (3)
- lophophore
- trochophore larvae
- spiral cleavage
Traits of platyhelminthes (flatworms) (3)
- lack coelom and specialized structures for gas exchange
- lack circulatory system
- gas exchange happens directly across skin
Traits of mollusks (4)
- muscular “foot” used in movement
- visceral mass containing internal organs
- mantle covering visceral mass
- radula
Radula
rasping mouth parts used to feed (in mollusks)
How do mollusks like squid and octopi move?
jet propulsion (squirting water)
What did the “foot” become in squid/octopi?
Head and tentacles
Semelparous
reproduce once and die
Iteroparous
can mate and reproduce several times
