diversity of life Flashcards
(34 cards)
What are the three domains we have to know, and which are prokaryotic/eukaryotic?
- Archaea (prokaryotic)
- Eubacteria (prokaryotic)
- Eukarya (eukaryotic)
What are the characteristics of the domain archaea, and how does it different from the domain bacteria?
- aka “archaebacteria”
- oldest domain of life
- prokaryotic cell type
differ from domain bacteria by:
- NO peptidoglycan (have polysaccharides like bacteria)
- phospholipids with ether linkages to glycerol and hydrocarbon are branched
- histone proteins
- DNA has introns
- ribosomes are different (not inhibited by antibiotics)
- not pathogenic
note: prokaryotes that have kinda eukaryotic characteristics
3 types of archea:
1. methanogens
2. thermophiles
3. halophiles
What are the 3 types of archea, and what are their characteristics?
- methanogens
- obligate anaerobes
- produce methane (CH4) as a biproduct of their anabolic pathways
- found in GI tract of humans, cows, the mud, swamps - thermophiles
- heat lovers (eg yellow stone)
- most are sulfur based chemoautotrophs - halophiles
- salt lovers
- live in environments with a high conc of salt (eg great salt lake, dead sea)
- most are aerobic, but some are anaerobic
- some are photosynthetic and heterotrophic
What are the characteristics of eubacteria?
- prokaryotic cell type
- cell wall made up of peptidoglycan (gram + or gram -)
- no histone proteins for DNA unlike archaea or eukarya
- ribosome composition is different (70S, inhibited by antibiotics like streptomycin)
- endospores are dormant until conditions are right
2 types of bacteria:
1. nitrogen fixing and nitrifying bacteria: mutualistic relationship with plants
2. cyanobacteria (blue-green algae): photosynthetic bacteria
*NOTE ^ does NOT include eukaryotic algae
gram + vs gram -
what colours for stain?
Gram +
- thick layer of peptidoglycan
- no LPS (lipopolysaccharide) outer membrane
- teichoic acids between peptidoglycan and plasma membrane
- DARK purple when stained
Gram -
- thin layer of peptidoglycan
- LPS outer membrane, endotoxins when killed
- NO teichoic acids
- PINK when stained
What are the 4 kingdoms of eukarya and their characteristics?
- protista
- eukaryotic
- most protists are unicellular (microscopic) but some are multicellular
- auto and heterotrophs
- reproduce asexually.
- can have symbiotic relationships (eg parasites) or be free-livng
- ALL types live in MOIST environments
- 3 types: plant-like, fungus-like, animal-like - fungi
- mushrooms, mold, yeasts
- uni or multicellular
- chitin
- ALL heterotrophic
- ALL saprophytes
- hypha (plural hyphae)
- 2 types: unicellular (non-filamentous) and multicellular (filamentous) - plantae
- ALWAYS multicellular
- ALWAYS autotrophic
- photosynthetic pigments (chlorophyll)
- cellulose
- both asexual and sexual reproduction
- undergo alternation of generations
- classification based on 4 criteria: plant body, vascular system, seed formation, flowers - animalia
- ALL multicellular
- ALL heterotrophic
- most are motile during some part of their life cycle
- no cell wall
- 2 or 3 tissue layers form during embryonic development
- 10 phyla: porifera, cnidaria, platyhelminthes, nematoda, rotifera, annalida, mollusca, arthropoda, echinodermata, chordata
plant-like protists
Domain: Eukarya
Kingdom: Protista
- Contain chloroplasts and perform photosynthesis
- Not true plants –> lack plant structures (e.g. leaves, roots)
- E.g. seaweeds, dinoflagellates, euglenoids, some algae
animal-like protists
Domain: Eukarya
Kingdom: Protista
- Motile, single-celled heterotrophs that perform phagocytosis
- Categorized based on motility (have cilia or flagella)
examples:
1. Amoebas
- Use pseudopodia for movement and food capture
- Pseudopodia: transient cytoplasmic projections that emerge toward the direction of movement
- Perform phagocytosis
- Flagellates (eg. T. vaginalis)
- use flagella for movement - Ciliates (eg paramecium)
- Use cilia for movement
- Acquire genetic variation via conjugation and reproduce via binary fission. - Sporozoans (eg plasmodium)
- Gliding movement
- Parasitic
- Reproduce using spores
- eg plasmodium: an animal-like protist that causes malaria, transmitted through mosquitos
others:
foraminifera (forams)
- produce a test (shell)
- found on sea botttom (benthic) or near the surface (planktonic)
apicomplexans
- parasites of animals
fungus-like protists
- Resemble fungi –> reproduce using spores
- Do not contain chitin, unlike Kingdom Fungi
- Mostly immotile
- Heterotrophic decomposers (saprobes)
- aka “slime molds” or “water molds”
Describe the different types of algae, what kingdom are they in, and what are their characteristics?
- green algae
- red algae
- brown algae
- blue-green algae
Algae: informal taxonomic group consisting of organisms from various kingdoms that function as primary producers.
* Prokaryotic or eukaryotic.
* Unicellular or multicellular.
* Photoautotrophs.
* Reproduce sexually or asexually.
* Other characteristics: Lack true plant structures (e.g. leaves, roots); mainly found in aquatic environments.
- Green algae (chlorophyta)
- Kingdom Plantae or Protista
- Found in freshwater habitats
- Evolutionary ancestor to terrestrial plants
- Contain chlorophyll - Red algae
- Kingdom Plantae or Protista
- Mostly multicellular
- Found in marine habitats - Brown algae (eg seaweeds, kelp)
- Kingdom Protista.
- Multicellular
- Found in marine habitats - Cyanobacteria (blue-green algae)
- Kingdom Bacteria (Gram-negative)
- Contain chlorophyll
- Precursor to chloroplasts (endosymbiotic theory)
2 types of fungi
Domain: eukarya
2 types:
1. unicellular (non-filamentous)
- “yeasts”
- facultatively anaerobic
- unicellular
- asexual reproduction by budding (similar process to mitosis, replicate genetic material and pinch off portion of cytoplasm and cell membrane to form a new cell)
- multicellular (filamentous)
- “molds” (NOT same as slime molds tho**)
- multicellular
- sexual reproduction
- aerobic
- mycelium (network of hypae (roots) that connect fungi together. muschrooms arise from mycelium)
- 2 types of mycelium: coenocytic hyphae or septate hyphae
What is coenocytic hyphae vs septate hyphae?
These are the two types of mycelium present in filamentous fungi (fungi is a kingdom of eukarya)
coenocytic hyphae:
- no division of hyphae (no cytokinesis during cell division)
- multinucleated
septate hyphae:
- have septa (cell walls that separate hypahe, “SEPerations”… but still have pores that allow transfer of nutrients)
- haustoria: specialized hyphae that penetrate cell walls of an organism (parasitic)
What are the modes of reproduction for filamentous fungi?
Asexual reproduction (budding, fragmentation, spores)
Or sexual reproduction (which will have genetic variation for increased fitness)
- plasmogamy (hyphae of two DIFF fungi grow towards each other and fuse their cytoplasms together)
- karyogamy (after plasmogamy, their nuclei fuse to make a diploid organism)
- meiosis (make haploid spores that grow into new organisms)
what does a “-mycota” or “-mycete” suffix mean?
Anything with these suffixes are part of the phylum FUNGI
eg
- zygomycota
- glomeromycota
- basidomycota
- deuteromycota
- ascomycota
Also makes sense that mycorrhiza means the mutualistic relationship between Fungi and the roots of plants
What are lichens and mycorrhiza?
Lichens:
- mutualistic relationship of Fungi and Algae (algae provides sugar via photosynthesis, fungi protects the algae)
Mycorrhiza:
- mutualistic relationship between fungi and roots of plants
What is alteration of generation in plantae?
Note: plantae is a kingdom of eukarya
Alteration of generations is when each subsequent generation of new individuals alternates between haploid and diploid states
- plants either prefer the gametophyte state OR the sporophyte state
Describe the classification of different plantae
In this order ask whether:
1. Plant body? (whether the plant has differentiated body parts or not)
2. Vascular system?
3. Seed formation?
4. Flowers?
If a plantae has no plant body (no body differentiation)?
Domain: eukarya
Kingdom: Plantae
it is a thallophyte (think algae, but algae also includes plant-like protists (kingdom protista))
- simplest form of plant
- lacks a differentiated body structure
- no specialized vascular system, roots, leaves, etc
- AQUATIC
If a plantae DOES have differentiated body parts?
Either a tracheophyte or a bryophyte
Ask next… does it have a vascular system?
NO: bryophyte
- differentiated plant body
- lacks a vascular system for transportation of substances; they do not grow vertically, have rhizoids that absorb water
- found in LAND and AQUATIC habitats
- EG mosses, liverworts, hornworts
- dominant GAMETOPHYTE (haploid (n)) stage
————————————————-
YES: tracheophyte
(think “trachea” = tube, they have tubes)
- differentiated plant body
- vascular system; grow vertically and tall, xylem and phloem
- dominant sporophyte ((2n) diploid) stage
Ask next for tracheophytes… seed formation?
NO: seedless tracheophtytes (eg horsetail, fern, club moss)
YES: seedbearing tracheophytes
Ask next for seedbearing tracheophytes…flowers?
NO: gymnosperms
- bear naked seeds
- no flowering, no fruit
- dorminant sporophyte ((2n) diploid) stage
- eg conifers
YES: angiosperms
- bears seeds inside FRUITS
- produces flowers, which house reproductive organs
- can undergo double-fertilization (unique to angiosperms
angiosperms are either:
1. monocotyledons (monocots)
- one cotyledon
- parallel veins
- scattered vascular
- flower parts in multiples of three
2. dicotyledons (dicots)
- two cotyledons
- net-like veins
- ringed vascular
- flower parts in multiples of 4 or 5
What is double fertilization?
One male gamete (1n) fuses with the female egg gamete (1n) to form an embryo (2n) and ANOTHER male gamete fuses with polar nuclei to form endosperm
- UNIQUE TO ANGIOSPERMS
Xylem and phloem
Xylem: transports only minerals and water from the roots (bottom)
- x at bottom of alphabet
Phloem: transports the food produced from Photosynthesis
- p for photosynthesis
What are monocotyledons (monocots) vs dicotyledons (dicots)?
angiosperms are either:
1. monocotyledons (monocots)
- one cotyledon
- parallel veins
- scattered vascular
- flower parts in multiples of three
2. dicotyledons (dicots)
- two cotyledons
- net-like veins
- ringed vascular
- flower parts in multiples of 4 or 5
What are the 10 phyla of animalia, and what are the ways that we can distinguish these?
- porifera
- cnidaria
- platyhelminthes
- nematoda
- rotifera
- annalida
- mollusca
- arthropoda
- echinodermata
- chordata
Easiest ways to distinguish between these phyla:
- body symmetry (bilateral, radial, assymetric)
- tissues and germ layers (diplo vs triploblastic)
- coelom (acoelomates, pseudocoelomates, coelomates)
- embryonic development (protosome vs deuterosome)
- digestive tract (complete vs incomplete)
Other ways, but variable even within phyla:
- reproduction
- respiratory system
- circulatory system
- excretory system
What are the different types of body symmetry in animalia?
- bilateral symmetry (left/right)
- sagittal plane divides body into left and right planes
- head and tail
- most have cephalization (collection of nervous tissue in the front of an animal; brain) - radial symmetry
- circular arrangement around a central axis
- oral side and aboral side (w/mouth) - assymetry (no symmetry)
Note: some animals show diff body plans at diff stages in development
