Biology- Biological Diversity Flashcards
systematics
study of evolutionary relationships among organisms
Eukaryotic cells
- chromosomes consist of a very long, linear DNA molecule package w/ histone proteins and enclosed in a nucleus -have organelles -flagella and cilia, when present are made of the protein tubulin arranged in “9+2” microtubule arrays
Prokaryotic cells
-a single chromosome w/ short, circular DNA. Histone proteins may/may not be present. Some cells contain plasmids -no nucleus -no organelles -flagella, when present, consist of the globular protein flagellin note: flagella use proton motive force to spin
autotrophs
make their own organic molecules; uses light or chemicals such as H2S, NH3, NO2-, NO3-
photoautotrophs
use light energy
chemoautotrophs
use energy obtained from inorganic substances (as in chemosynthesis). Examples of inorganic substances that are used: hydrogen sulfide (H2S), ammonia (NH3), and other nitrogen compounds
heterotrophs
obtain energy by consuming organic substances made by autotrophs; some heterotrophic organisms are parasites, saprobes (obtain their energy from dead matter)
obligate aerobes
need oxygen to live
obligate anaerobes
can survive only in the absence of oxygen
facultative anaerobe
grows in the presence of oxygen but, when oxygen is absent, can switch to an anerobic metabolism
what are the 3 domains?
archaea, bacteria, eukarya
Archaea groups (2. Extremophiles)
live in extreme environment; Halophiles (salt lover) high [salt] environment; most are aerobic and heterotrophic; others anaerobic and photosynthetic with pigment bacteriorhodospin. Thermophiles (heat lover) are sulfur-based chemoautotroph.
Archaea groups (1. methanogens)
obligate anaerobes that produce CH4as by-product of obtaining energy from H2 to fix CO2 (mud, guts)
Archaea (similarities with eukaryotes)
- DNA of both archaea and eukaryotes are associated with histone; not bacterial DNA.
- Ribosome activity is not inhibited by antibiotics streptomycin and chloramphenicol unlike bacteria
Archaea
prokaryotes; archaeal cell walls contain various polysaccharides, not peptidoglygan (as in bacteria), cellulose (as in plant), or chitin (as fungi).
Phospholipid components such as glycerol is different (isomer of either bacteria or eukaryotes). Hydrocarbon chain is branched (straight chain for others) and ether-linkages instead of ester-linkages.
halophiles
are extremophiles; they live in environments w/ high [salt].
- Most are aerobic and heterotrophic
- others are anaerobic and photosynthetic w/ the pigment bacteriorhodopsin
thermophiles
are extremophiles that live in hot (60 to 80 C) environments such as hot springs or geysers. Most are sulfur-based chemoautotrophs.
How are bacteria distinct from archaea and eukaryotes?
- Bacterial cell walls (peptidoglycan, a polymer of a monosaccharide w/ amino acids)
- Bacterial DNA is not associated w/ histone proteins.
- Ribosome activity is inhibited by the antibiotics streptomycin and chloramphenicol.
What features have been used to categorize bacteria?
- mode of nutrition
- ability to produce endospores (resistant bodies that contain DNA and a small amount of cytoplasm surrounded by a durable cell)
- means of motility (flagella, corkscrew motion, or gliding through slimy material)
- shapes: cocci (spherical), bacilli (rod shaped) and spirilla (spirals)
- thick peptidoglycan cell wall (gram-positive), thin peptidoglycan wall (gram-negative) covered w/ a layer of lipopolysaccharides.
What are the four kingdoms in Eukarya?
Kingdom Protista
Kingdom Fungi
Kingdom Plantae
Kingdom Animalia
Kingdom Protista
consist of algaelike, animalike, funguslike, unicellular, or multicellular
Kingdom Protista (algaelike members)
all obtain energy by photosynthesis. All have chlorophyll
convergent evolution
features that arise among groups independently
charophytes
lineage of the chlorophytes are believed to be the ancestors of plants
Kingdom Protista (protozoa, or animal-like protists)
hetertrophs; 1. Rhizopoda are amoebas that move by extensions of their cell body called pseudopodia. Pseudopodia encircle food and absorb it by phagocytosis 2. Foraminifera, or forams, have tests usually made of calcium carbonate. 3. Apicomplexans are parasites of animals. 4. Ciliates are distinguished by their cilia
apicomplexans
domain: eukarya, kingdom: protista animal parasites; they are characterized by an apical complex, a complex of organelles located at an end (apex) of the cell. They have no physical means of motility. However, they form spores which are dispersed by one or more hosts that participate in the completion of their life cycles. The sporozoan that causes malaria, for example, spends part of its life cycle in mosquitos and part in humans
ciliates
distinguished by their cilia, which they use for moving and other functions. Because of specialized structures, such as mouths, anal pores, contractile vacuoles (for water balance), two kinds of nuclei (one large macronucleus and several small micronuclei), and other features, they are perhaps the most complex of all cells. Paramecium is the phylum’s most notable member
Kingdom Protista (fungus-like protists)
resemble fungi because they form either filaments or spore-bearing bodies similar to the fungi 1. cellular slime molds-exhibit both funguslike and protozoalike characteristics during their life cycle 2. Plasmodial slime molds grow as a single, spreading mass (or plasmodium) feeding on decaying vegetation 3. Oomycota include the water molds, downy mildews, and white rusts. They are either parasites or saprobes. The filaments lack septa, or they are coenocytic, containing many nuclei within a single cell.
Kingdom Fungi
fungi grow as filaments called hyphae. A mass of hyphae is called mycelium. Some fungi have septa, or cross walls, which divide the filament into compartments containing a single nucleus. When filaments lack septa, they are multinucleate, coenocytic. The cell walls of fungi consist of chitin, a nitrogen-containing polysaccharide
Fungi are either parasites/saprobes (decomposer) absorbing food products due to digestive enzymes.
haustoria
parasitic fungi have these hyphae that penetrate their host
Fungi sexual reproduction
- Plasmogamy- fusing of cells from 2 different fungal strains to produce single cell w/ nuclei from both strains. A pair of haploid nuclei, one from each strain, is called a dikaryon. A hypha containing a dikaryon is called a dikaryotic hypha.
- Karyogamy- fusing of 2 haploid nuclei of a dikaryon to form a single diploid nucleus.
- Meiosis- of the diploid nucleus restores the haploid condition. Daughter cells develop into haploid spores, which germinate into haploid hyphae (has 1 fungal strain) => merge into dikaryon and repeat
fragmentation
the breaking up of hyphae
budding
the pinching off of a small hyphal outgrowth
stages of asexual reproduction
**fragmentation **(breaking up hyphae), **budding **(small hyphal outgrowth), asexual spores descibed as:
- sporangiospores- produced in saclike capsules (sporangia) that are each borne on a stalk called a sporangiospore.
- conidia- formed at the tips of specialized hyphae, not enclosed inside sacs. Hyphae bearing conidia are called condiophores; asexual reproduction .
What are the six fungus groups?
- Zygomycota 2. Glomeromycota 3. Ascomycota 4. Basidiomycota 5. Deuteromycota 6. Lichens
zygomycota
lack septa, except when filaments border reproductive filaments.
- reproduce sexually by fusion of hyphae from different strains, followed by plasmogamy, karyogamy, and meiosis.
- Haploid zygospores are produced => germinate into new hyphae. Bread mold is a typical zygomycete
glomeromycota
lack septa, do not produce zygospores.
- small group that occur only in mutualistic associations w/ plant roots (mycorrhizae): plant (carbs), fungus (increases nutrient absorption, especially phosphorus)
ascomycota
septa; reproduce sexually by producing haploid ascospores. After plasmogamy of hyphae from different strains, dikaryotic hypha produces more filaments by mitosis; karyogamy and meiosis occurs in terminal hyphal => 4 haploid cells => mitosis to produce 8 haploid ascospores in a sac called ascus; grouped together into fruiting body ascocarp (yeast)
basidiomycota
septa, reproduce sexually by producing haploid basidiospores. Plasmogamy => mitosis => fruiting body (basidiocarp) such as mushroom; Karyogamy occurs in terminal hyphal cells called basidia, followed by meiosis to produce 4 haploid basidiospores.
deuteromycota
imperfect fungi, is an artificial group (no sexual reproductive cycle) has been observed. Penicillium is a deuteromycete, and produces penicillin.
lichens
mutualistic associations between fungi and algae (usually chlorophyta/cyanobacteria, provides sugar from photosynthesis); also provide Nitrogen if algae is nitrogen-fixing; fungus (ascomycete) provides water and protection (pigments from UV light, or toxic chemicals for grazers) from environment.
What characteristics do the members in Kingdom Animalia?
- multicellular 2. heterotrophic 3. dominant generation in the life cycle of animals is diploid generation 4. most are motile during at least some part of their life cycle 5. most undergo a period of embryonic development during which 2 or 3 layers of tissues form
Diversity of animals and their variations
- tissue complexity 2. body symmetry 3. cephalization 4. gastrovascular cavity 5. coelom 6. segmentation 7. protostomes and deuterostomes
acoelomate
animals that lack coelom
pseudocoelomate
animals that have a cavity that is not completely lined by mesoderm-derived tissue
taxonomy
organisms are classified into categories called taxa. A species name is given a name consisting of genus (closely related animal) name and species name.
family
genera that share related features; then Domains => Kingdoms => Phylum => Class => Order => Family => Genus => Species