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DAT BIOLOGY > Chapter 9: Biological Diversity > Flashcards

Chapter 9: Biological Diversity Flashcards

1
Q

taxonomy

A
  1. organisms are classified into categories called taxa
  2. species name is given a name consisting of genus (closely related animal) name and species name
  3. domesticated dog in genus Canis and name Canis familiaris; Wolf is Canis lupis
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2
Q

family

A
  1. genera that share related features
  2. Species, genus, family, order, class, phyla (division for fungi and plant), kingdoms, domains (King Phil Came Over For Grape Soda)
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3
Q

systematics

A
  1. .study of evolutionary relationships among organisms (phylogeny=evolutionary relationships)
  2. All living things have: one or more cells, plasma membrane, genetic material in DNA form, and a mechanisms of using RNA and ribosomes to translate genetic material
  3. Two major divisions: eukaryotic vs prokaryotic
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4
Q

eukaryotic cell

A

chromosome contain long, linear DNA with histone; enclosed in nucleus; specialized organelles to isolate metabolic activities; p+2 microtubule array flagella and cilia

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5
Q

prokaryotic

A

single chromosome is short, circular DNA usually without histone (archae have histones); may contain plasmids, no nucleus, no organelles, flagella consist of chains of protein flegellin instead of 9+2 microtubules
*** flagella use proton motive force (electrical gradient) and NOT ATP!

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6
Q

autotrophs

A

manufacture their own organic materials; uses light or chemicals (photo vs chemo) such as H2S, NH3, NO2-, NO3-

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7
Q

heterotrophs

A

obtain energy my consuming organic substances produced by autotrophs

  • -parasites: obtain energy from living tissue of host
  • –saprobes (saprophytes): obtain energy from dead. decaying matter=> contribute to organic decay=decomposers
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8
Q

obligate aerobes

A

must have O2 to live

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9
Q

obligate anaerobes

A

require absence of O2 to live

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10
Q

facultative anaerobe

A

grows in presence of O2, but can switch to anaerobic metabolism when O2 is absent

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11
Q

Domain Archaea

A
  1. are prokaryotes but differ from bacteria, the other major category of prokaryotes
  2. archaeal cells wall contain various polysaccharide, not peptidoglycan (as in bacteria), cellulose (as in plant), or chitin (as in fungi)
  3. phospholipid components: glycerol is different (uses an isomer of the one in bacteria/ eukaryotes), and the hydrocarbon chain ( fatty acid) is branched (rather than straight chain) w/ ether linkages instead of ester linkages
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12
Q

similarity with eukaryotes

A
  1. DNA of both archaea and eukaryotes are associated with histone; not bacterial DNA
  2. ribosome activity is not inhibited by antibiotics streptomycin and chloramphenicol unlike bacteria
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13
Q

some groups of archaea

A
  1. methanogens: obligate anaerobes that produce CH4 as by product of obtaining energy from H2 to fix CO2 (mud, guts)
  2. extremophiles: live in extreme environments
    - – halophiles (salt lover): high salt environment; most are aerobic and hetertrophs; others anaerobic and photosynthetic with pigment bacteriorhodopsin
    - – thermophiles (heat lover) are sulfur based chemoautotroph in very hot places
    - –other live in high acid/base/pressure environments
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14
Q

Domain Bacteria

A

five kingdoms

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15
Q

distinct from archaea and eukaryote by these features

A
  1. cell wall (peptidoglycan=polymer of monosaccharide with amino acid)
  2. bacterial DNA is not associated with histone; ribosome activity is inhibited by above antibiotics
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16
Q

classification of bacteria

A

difficult to classify

  1. mode of nutrition/how they metabolize resources
  2. ability to produce endospore (resistant bodies that contain DNA and small amount of cytoplasm surrounded by durable wall
  3. means of motility (flagella , corkscrew motion, or gliding through slime material)
  4. shapes= Cocci (spherical), bacilli (rod), spirilla/spirochetes (spirals)
  5. thick peptidogylcan wall cell (gram positive); thin peptidogylcan covered with lipopolysaccharides (gram-negative)
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17
Q

common groups of bacteria

A
  1. cyanobacteria: photosynthetic like plants (use chloro a, slit water, release O2); contain accessory pigment phycobilins; some have specialized cells called heterocysts that produce nitrogen fixing enzyme (converts fixed inorganic nitrogen gas into NH3 that can be used to make AA’s and NT’s); known as blue green algae (not releated to other prokaryote algae groups)
  2. chemosynthetic: autotrophs; some are nitrifying bacteria NO2- to NO3-
  3. nitrogen fixing: heterotrophs that fix N2, lives in nodules of plants (mutualism)
  4. spirochetes: coiled bacteria that move with corkscrew motion, internal flagella between cell and layers
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18
Q

Kingdom Protista

A

the subcategories are phylum. This is an artificial kingdom used mainly for convenience. Features shared by two or more groups may represent convergent evolution. MOST ARE UNICELLULAR

  1. Algaelike (plant-like): members of protista all obtain energy by photosynthesis. All have chlorophyll a, some have others + accessory pigments. Mainly characterized via: form of carb used to store energy. # of flagella, makeup of cell wall
  2. Protozoa (animal-like): protists are heterotrophs; consume living cells or dead organic matter; unicellular eukaryotes
  3. Fungus-like (animal like): protists resemble fungi (form filaments/spore-bearing bodies like fungi do)
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19
Q

kingdom Fungi

A
  1. fungi grow as filaments (hyphae),
  2. mycellium is a mass of hyphae;
  3. some fungi have septum which divide filament into compartments containing nucleus.
  4. Cell walls contain chitin (N-containing polysaccharide)
  5. those without septa are coenocytic (multinucleate)
  6. fungi are either parasites/saprobes (decomposer) absorbing food products due to digestive enzymes.
  7. parasitic fungi have hyphae (hasutoria) that penetrate host
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20
Q

stages of sexual reproduction

A

fungi are primarily haploid but form temporary diploid structures for sexual reprod.
a. Plasmogamy: fusing of cells from two different fungal strains to produce single cell w/ nuclei of both strains. A pair
of haploid nuclei, one from each strain is called dikaryon. Dikaryotic hypha is hypha containing dikaryon.
b. Karyogamy: fusing of two haploid nuclei of a dikaryon to form single diploid nucleus.
c. Meiosis: of diploid nucleus restores haploid condition; daughter cells develop into haploid spores which germinate
into haploid hyphae (has 1 fungal strain) => merge into dikaryon and repeat.
* Means of Asexual Reproduction: fragmentation (breaking up hyphae), budding (small hyphal outgrowth), and asexual
spores, further described as two types:
- Sporangiospores: produced in sac-like capsules (sporangia) that are each borne on a stalk called sporangiophore.
- Conidia: formed at tips of specialized hyphae, not enclosed inside sac; hyphae bearing conidia called conidiophores
Note: the above two spore types are asexual. The below spore types described are sexual. A fungi sometimes will use both (e.g. ascomycete conidia).

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21
Q

six fungus groups

A

division/classes with suffix - mycota (division) or mycete (classes) and used interchangeably

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22
Q

a. Zygomycota

A

lack septa, except filaments bordering reproductive filaments; reproduce sexually by fusion of
hyphae from different strains, followed by plasmogamy, karyogamy, meiosis; haploid zygospores are produced =>
germinate into new hyphae (e.g. bread molds).

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23
Q

b. Glomeromycota:

A

lack septa, do not produce zygospores; mutualistic associations with roots of plants
(mycorrhizae), plants provide carb, fungus increases ability of plant to absorb nutrient (especially phosphorus)

24
Q

c.Ascomycota:

A

: have 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; often grouped together into fruiting
body ascocarp (yeast). The spores release and germinate into hyphae, cycle repeats.

25
Q

d. Basidiomycota

A

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

26
Q

e. Deuteromycota:

A

: imperfect fungi, artificial group (no sexual reproductive cycle). Penicillium produces penicillin.

27
Q

f. Lichens:

A

mutualistic associations between fungi and algae (usually achlorophyta/cyanobacteria provide carbs from
photosynthesis); also provide Nitrogen if algae is nitrogen-fixing; fungus (usually ascomycete) provides water and
protection (pigments from UV light, or toxic chemicals against grazers) from environment.

28
Q

adaptations for survival on land

A

a. Dominant generation is diploid sporophyte generation (except primitive bryophytes-mosses, liverworts, and
hornworts); provide two copies against genetic damage that plants were more susceptible to once out of water.
b. Cuticle: waxy covering that reduces desiccation (drying up/water loss)
c. Vascular system reduces dependency on water (cells no longer need to be close to water) => formation of
specialized tissues: true leaves (centers for photosynthesis, true stems (support leaves), true roots (acquire water/anchor
plant. Two groups of vascular tissues evolved: Xylem (water transport), phloem (sugar transport).
d. In primitive plant divisions (flagellated sperm require water to swim to eggs). In advanced division (coniferophyta
and anthophyta), sperm is packaged as pollen (wind).
e. Anthophyta: gametophytes are enclosed (protected) inside an ovary.
f. Adaptations (in coniferophyta + anthophyta) of seasonal variations in availability of water and light. Some are
deciduous (shed leaves to prevent water loss through slow-growing seasons). Others like desert plants will germinate,
grow, flower, and produce seeds rapidly in brief periods of rain.

29
Q

major plant divisions

A

*** note that each has increasingly greater adaptation to survive on land

30
Q

a. bryophytes

A

mosses, liverworts, and hornworts. Gametes are produced in gametangia (protective structures) on
gametophytes, dominant haploid stage of life cycle of bryophytes. Antheridium (male gametangium) produces flagellated
sperm that swim through water. Archegonium (female) produces egg. Zygote grows into diploid structure (still connected
to gametophyte). They are anchored by rhizoids rather than roots.
- In mosses, this structure is a stalk bearing capsule which contains haploid spores produced by meiosis => spores
dispersed by wind and germinate grow into haploid gametophytes which produces antheridium + archegonium.
- Lacks true root, true leaves, true stems (lack vascular tissues); so must remain in/near water.
* The following are vascular plants (tracheophytes): true root, leaves, and stems; germination of antheridium +
archegonium (swim) produces diploid zygote into sporophyte (dominant generation)

31
Q

b. lycophyta

A

club mosses, spike mosses, and quillworts (herbaceous plants); club and spike mosses produce
clusters of spore-bearing sporangia in conelike structure strobili. Resurrection plant (recover from dead-appearance after
watered, is a spike moss).

32
Q

c. pterophyta

A

3 groups. (note the life cycle here pictured is for ferns but they are very similar for lycophyta as well:
primary difference is that the lycophyta use a prominent cone-like strobili, but ferns use the sori on undersurface of leaves.)
- Ferns: produce cluster of sporangia called sori that develop on undersurface of fern fronds (meiosis => spores).
- Horsetails: include extinct woody trees; hollow, ribbed stems that are jointed at nodes; strobili bear spores.
Stems, branches, and leaves are green (photosynthetic) and have rough texture due to silica (SiO2).
- Whisk ferns: branching stems without roots. Leaves reduced to small appendages or absent. Absence of
roots/leaves is considered secondary loss; lost as whisk ferns diverged from ancestors.

33
Q

production of seeds

A

male spores and female spores; microsporangia produces microspores
(male spores) and macrosporangia produce the macrospores (female spores). Summary of seed plant reproduction:
- Microsporangium: produces numerous microspore mother cell, which divide by meiosis to produce 4 haploid
cells (microspores-male) => mature into pollen grains (represent gametophyte generation) which divides into 3 cells (in
flowering plants) or 4 cells (in conifers). One is vegetative (tube) cell that controls growth of pollen tube, others = sperms.
- Megasporangium: called nucellus produces megaspore mother cell  (meiosis)  4 haploid cells, one survives
to become megaspore (female gametophyte generation). Megaspore  (mitosis)  one egg (in flowering plants) or two
eggs (in conifers). One/two tissue layers (integuments) surround megasporangium. Ovule (integument + nucellus +
megaspore daughter cells); Micropyle is opening through integuments for pollen access to egg.
- Once pollen grain contacts megasporangium, tube cell (of sperm) directs growth of pollen tube through the
micropyle and toward egg => fertilization (zygote) => embryo (beginning of sporophyte gen.); integuments => seed coat.

34
Q

d. coniferophyta (gymnosperms)

A 
aka gymnosperms (naked-seeds): cone-bearing (pines, firs, spruces, junipers, redwoods, cedars);
pollen-bearing male + ovule-bearing female cones; seeds produced in unprotected megaspores near surface of reproductive
structure. Fertilization and seed development are lengthy (requires one to three years).
35
Q

e. Anthophyta (angiosperms)

A

flowering plants, dominant land plant form. The major parts of flower:
1. Pistil: female reproductive structure (three-parts: ovary (egg-bearing), style, and stigma).
2. Stamen: male reproductive structure (pollen-bearing anther and stalk, filament).
3. Petals: (and sometimes the sepals too) function to attract pollinators.
- Major evolutionary advancements: attracts pollinators (insects + birds); ovule protected inside ovary which
develops into fruit => dispersal of seeds by wind or other animals.

36
Q

process of fertilization

A
  1. Pollen lands on sticky stigma (female). Pollen tube (elongating cell) that contains vegetative nucleus grows
    down the style toward an ovule; two sperm cells inside pollen tube.
  2. Ovule within ovary (consist of megaspore mother cell surrounded by nucellus + integuments). Megaspore
    mother cell => (meiosis) 4 haploid megaspores; one survives => (mitosis x 3) 8 nuclei => 6 nuclei undergoes cytokinesis
    and form plasma membranes (embryo sac). At the micropyle of embryo sac are 3 cells (egg + 2 synergids). At the other
    end of micropyle are 3 antipodal cells. In the middle are polar nuclei (2 haploid cells).
  3. Pollen tube (2 sperm cells) enters embryo sac through micropyle; 1 sperm cell fertilizes egg (form diploid
    zygote); nucleus of 2nd sperm fuses with both polar nuclei => triploid (3N) nucleus  (mitosis)  endosperm (provide
    nutrient). Double fertilization is fertilization of the egg and polar nuclei each by a separate sperm
37
Q

kingdom animalia

A
  • Variations in
    -characteristics: (diverse kingdom, but its members share these characteristics: multicellular; heterotrophic;
    dominant diploid generation; *motile at some part of life cycle; *2-3
    layers of tissues form during embryonic development.)
    ** 7 variations that allow diversity of animals
38
Q

a. Tissue complexity

A

eumetazoa (functioning cells organized
into tissues). Diplobasltic/triploblastic layers of tissue (ecto, meso,
endoderm); another group is parazoa (cells not organized into true
tissues => organs do not develop.)

39
Q

b. body symmetry

A 
radial symmetry (one orientation-front
and back) w/ circular body pattern; bilateral symmetry (dorsal-top,
ventral-bottom, head-anterior, tail-posterior)
40
Q

c. cephalization

A

in animals with bilateral symmetry (greater
nerve tissue cxn at anterior end as organisms increase in complexity).
E.g. brains have developed + sensory organs

41
Q

d. gastrovascular cavity

A

guts (digestion of food). One opening
– sacline, limited processes. Two openings (digestive tract),
specialized activities as food travels through

42
Q

e. coelom

A

Coelom: more advanced animals develop this cavity derived
from mesoderm; fluid-filled coelom cushions internal organs.
Acoelomate animals lack coelom; pseudocoelomate animals have a
cavity (but not completely lined by mesoderm-derived tissue).

43
Q

f. segmentation

A

sometimes repetitive and sometimes

specialized (seen in: arthropods, annelids, chordates)

44
Q

g. protostomes and deuterostomes

A

cleavages (cell divisions in
zygote’s early development); Archenteron (The primitive gut that forms during gastrulation in the developing blastula. It
develops into the digestive tract of an animal; its opening will either be mouth or anus). Coelom will either develop from
splitting of mesodermal tissue at side of archenteron or directly from outpouching in archenteron wall. Know this img

45
Q

List of Animal Phyla

A

major evolutionary trend are summarized

46
Q

a. porifera

A

sponges; feed by filtering water
through sponge wall of flagellated cells (choanocytes-flagella
creates a flow of water for feed-filter). Water exits through
osculum opening. Choanocytes pass food to amoebocytes
(digesting + distribute nutrients); sponge wall contains spicules
(skeletal needles made from CaCO3 or SiO2. Sessile (fixed). Used
in development + research of antibiotics.

47
Q

b. cnidaria

A

hydrozoans, jellyfish, sea anemones, corals;
two body forms (medusa-floating, umbrella-shaped body with
tentacles; polyp-sessile cylinder-shaped with rising tentacles);
some alternate between during medusa/polyp their life cycle.
cnidoblasts – specialized cells located in the tentacles and bodywalls of cnidaria;
interior of cnidoblasts filled with stinging organelles (nematocysts)

48
Q

c. platyhemithes

A

three types of acoelomate flatworms;
Free-living flatworms (planarians-carnivores in marine or
freshwater). Flukes are internal animal parasites/external parasites
31
that suck tissue fluids/blood. Tapeworms are internal parasites that often live in digestive tract of vertebrates; appear
segmented (but these segments [proglottids] only develop secondarily for reproduction  not considered true segmented
animal). Tapeworms do not have digestive tract, only need to absorb predigested food around them. Other Platyhelminthes
have saclike gut.

49
Q

d. nematoda

A

roundworms: pseudocoelomate with complete digestive tract; free-living soil dwellers help decompose
and recycle nutrients (causes trichinosis in human, when ingested via incompletely cooked meat).

50
Q

e.rotifera

A

multicellular with specialized organs enclosed in pseudocoelom, complete digestive tract; filter-feeder

51
Q

f. mollusca

A

snail, octopus (highly developed NS w/ complex brain), squids (most have shells), bivalves (2 part
shells e.g. clams and mussels); no shell in octopus, small and internal shell in squid. Mollusks have coelomate bodies,
complete digestive tract, usually open circulatory system w/ internal cavity called hemocoel. Exoskeletons are CaCO3
- Class Gastropoda – largest Molluscan class; ex. slugs & snails; characterized by single shell
- Class Cephalopoda – octopus and squid; have high O2 demand, giant nerve fibers, closed circulatory system
- Class Bivalvia - clams, mussels, scallops, oysters

52
Q

g. annelida

A 
segmented worms (Leeches – have suckers at both ends for attachment and movement and are
predators of small animals/blood parasites; earthworms;and polychaete worms – mostly marine, exhibit variety lifestyles).
Septa divide the coelom into separate compartments.
53
Q

h. arthropoda

A

piders, insects, crustaceans; jointed appendages, well-developed nervous system; specialized body
segments, exoskeleton (chitin). Two kinds of life cycles: Nymphs (small version of adult, change shape as growth
proceeds). Larvae are maggots specialized for eating; when they reach certain size => enclose themselves within pupa
(cocoon) to undergo metamorphosis into adults (specialized to disperse and reproduce). Classes include:
- Insects – three pairs of legs, spiracles, tracheal tubes for breathing. More species than any other class on earth.
- Arachnids – four pair of legs and “book lungs” (spiders & scorpions)
- Crustaceans (subphylum)– segmented body with variable number of appendages and have gills. Crab, shrimp, lobster, crayfish, and barnacles

54
Q

i. echinodermata

A

sea stars, urchin, sand dollars; coelomate deuterostomes; complete digestive tract; adults have
radial symmetry but are bilateral when young; some features are bilateral (ancestors are believed to have been bilateral)

55
Q

j. chordata

A

Chordata: 4 main features (sometimes just temporary during embryonic development)
- Notochord provides dorsal, flexible rod that functions as support; replaced by bone during development in most
vertebrates, it becomes nucleus pulposus of intervertebral disc; arrived from mesoderm. Defines primitive axis of embryo.
- Dorsal hollow nerve cord forms basis of nervous system. In some chordates, beomes brain and spinal cord.
- Pharyngeal gill slits provide channels across pharynx to outside body; slits become gills for O2 or filter-feeding;
slit disappear during embryonic development in others. In fish, gill pouch  fish gils. In mammals, gill pouch  Eustachian tubes in the ears
- Muscular tail: such tail is lost during embryonic development in humans and many other chordates
- Two groups of chordates: invertebrate chordates (lancelets, tunicates) and vertebrate (sharks, fish, amphibians,
reptiles, birds, and mammals) have vertebrae that enclose the spinal cord.
Note: Reptiles have leathery eggs

DAT BIOLOGY (14 decks)

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