Biological Diversity (taxonomy) Flashcards
1
Q
What is a photoautotroph?
A
An organism that uses light as energy (as in photosynthesis)
2
Q
What are the taxonomy categories, in order from largest to smallest?
A
Domain, kingdom, phylum, class, order, family, genus, specie
3
Q
What is phylogeny?
A
Evolutionary relationships
4
Q
What is systematics?
A
The study of evolutionary relationships among organisms.
5
Q
What are saprobes/saprophytes?
A
Organisms that consume dead, decaying matter. They are called decomposers because they contribute to the decay of organic matter.
6
Q
What are the domains?
A
Archaea, bacteria, eukarya
7
Q
What are 2 major groups of archaea?
A
Methanogens and extremophiles
8
Q
What are methanogens?
A
Obligate anaerobes that produce methane as a by-product of obtaining energy from H2 to fix CO2.
9
Q
Where do methanogens live?
A
Mud, swamps, and guts of cows, humans, termites, and other animals
10
Q
What are halophiles?
A
Organisms that live in environments with high salt concentrations. Most are aerobic and heterotrophic, while others are anaerobic and photosynthetic with the pigment bacteriorhodopsin.
11
Q
What are thermophiles?
A
Organisms that live in hot (60-80C) environments such as hot springs and geysers. Most are sulfur-based chemoautotrophs.
12
Q
What are characteristics of eukaryotic cells?
A
- chromosomes are long, linear DNA w/histone proteins
- chromosomes enclosed in nucleus
- organelles
- flagella and cilia are made of the protein tubulin in “9+2” microtubule arrays
13
Q
What are characteristics of prokaryotic cells?
A
- single chromosome is short, circular DNA, and may or may not have histones
- some have plasmids, small circular DNA molecules
- no nucleus
- no organelles, although membranes might serve similar functions
- flagella are made of the globular protein flagellin
14
Q
What are chemoautotrophs?
A
organisms that obtain energy from inorganic substances (as in chemosynthesis). Examples of substances: hydrogen sulfide (H2S), ammonia, nitrite, nitrate
15
Q
What is a parasite?
A
organism that obtains energy from living tissues of a host
16
Q
What characteristics distinguish Archaea from other prokaryotes and eukaryotes?
A
1) Cell walls contain polysaccharides, but not peptidoglycan (as in bacteria), cellulose (in plants), or chitin (in fungi)
2) Plasma membranes contain different phospholipids. Glycerol is an isomer of that in bacteria and eukaryotes. Hydrocarbon chains are branched and attached with ether-linkages.
17
Q
What are similarities between Archaea and eukaryotes?
A
1) DNA are associated w/ histone proteins.
2) Ribosome activity is not inhibited by antibiotics streptomycin and chloramphenicol.
18
Q
What characteristics distinguish bacteria from archaea and eukaryotes?
A
1) Cell walls are made with peptidoglycan, a monosaccharide with amino acids.
2) DNA is not associated w/ histones.
3) Ribosome activity is inhibited by the antibiotics streptomycin and chloramphenicol.
19
Q
How many kingdoms are used to categorize all organisms?
A
5
20
Q
What features have been traditionally used to categorize bacteria?
A
1) mode of nutrition/how they metabolize resources
2) production of endospores
3) means of motility (flagella–apical/posterior/covering the cell, corkscrew motion, gliding through slime secretions)
4) shape: cocci (spherical), bacilli (rod shaped), spirilla (spirals)
5) Gram-positive vs Gram-negative
21
Q
What is the difference between Gram-positive and Gram-negative bacteria?
A
Gram-positive bacteria have a thick peptidoglycan cell wall, while Gram-negative bacteria have a thin peptidoglycan wall covered with a layer of lipopolysaccharides.
22
Q
What is an endospore?
A
A resistant body that contains genetic material and a small amount of cytoplasm within a durable wall.
23
Q
What are some common groups of bacteria?
A
1) Cyanobacteria
2) Chemosynthetic bacteria
3) Nitrogen-fixing bacteria
4) Spirochetes
24
Q
What are cyanobacteria?
A
- Photosynthetic bacteria that use chlorophyll a, split H20, and release 02, like in plants.
- They contain accessory pigments called phycobilins.
- Some have heterocysts that produce nitrogen-fixing enzymes.
25
What is a heterocyst?
A specialized cell that produces nitrogen-fixing enzymes.
26
What happens when nitrogen is fixed?
Inorganic, unreactive nitrogen gas is converted to ammonia, which can be used for nitrogen-containing amino acids and nucleotides.
27
What are chemosynthetic bacteria?
Autotrophic bacteria that use inorganic materials. Some are called nitrifying bacteria because they convert nitrite to nitrate.
28
What are nitrogen-fixing bacteria?
Heterotrophs that fix nitrogen. Many establish mutualistic relationships with plants (both benefit from interdependent relationship). The bacteria live in nodules in plant roots.
29
What is a mutualistic relationship?
When both parties benefit from an interdependent relationship.
30
What is a spirochete?
Coiled bacteria that moves with a corkscrew motion. They have internal flagella that is position within layers of the cell wall.
31
What are the kingdoms in the domain Eukarya?
1) Protista
2) Fungi
3) Plantae
4) Animalia
32
What is convergent evolution?
When features shared by two or more groups arose independently.
33
What are characteristics of organisms in the kingdom protista? What domain does this belong in?
Organisms may be algaelike, animallike, fungus like, unicellular, or multicellular. This kingdom is artificial and used mainly for convenience because in many cases, the evolutionary relationships are weak and/or poorly understood. Many features represent convergent evolution. Belongs to the domain Eukarya.
34
What are characteristics of algaelike (or plant-like) members of the Protista?
- All are photosynthetic.
- All have chlorophyll a, but may have others in addition.
- Different accessory pigments
- Categorized by: chlorophylls and accessory pigments, form of carb used for energy storage, # of flagella, makeup of cell walls
35
What are important algaelike taxa?
1) Euglenoids
2) Dinoflagellates
3) Diatoms
4) Brown algae
5) Rhodophyta (red algae)
6) Chlorophyta (green algae)
36
What are euglenoids?
Algaelike protist that have:
- 1-3 flagella at apical (leading) end
- thin protein strips called pellicles wrapped over cell membranes instead of cellulose cell wall
- can become heterotrophic in absence of light
- some have eyespot that permits phototaxis (the ability to move in response to light)
37
What is phototaxis?
The ability to move in response to light.
38
What are dinoflagellates?
Algaelike protists that have:
- 2 flagella (1 posterior, 1 transverse and rests in encircling midgroove perpendicular to 1st)
- some are bioluminescent
- others produce nerve toxins that concentrate in filter-feeding shellfish, which causes illness in humans when eaten
39
What are diatoms?
Algaelike protists that have tests (shells) consisting of silica (SiO2) that fit together like a box with lid.
40
What are brown algae?
Algaelike protists that are multicellular and have flagellated sperm cells. Some are giant seaweeds (kelps).
41
What are rhodophyta?
```
AKA red algae
Algaelike protists that:
-contain red accessory pigments called phycobilins
-are multicellular
-gametes do not have flagella
```
42
What are chlorophyta?
AKA green algae
Algaelike protists that:
-have both chlorophyll a and b
-cellulose cell walls
-store carbs as starch
-gametes can be isogamous, anisogamous, or oogamous
Trends towards multicellularity:
-unicellular (Chlamydomonas)
-colonies of 4-32 cells (Gonium and Pandorina)
-colonies of 100s cells (Volvox)
Charophytes (a lineage of Chlorophytes) are believed to be the ancestors of plants.
43
What are isogamous gametes?
Sperm and eggs are motile and equal in size.
44
What are anisogamous gametes?
Sperm and egg differ in size.
45
What are oogamous gametes>
Large egg cell remains with parent and is fertilized by small, motile sperm.
46
What are characteristics of protozoa (animal-like) protists?
Heterotrophs that consume living cells (i.e. are predatory or parasitic) or dead organic matter.
47
What are important protozoa taxa?
1) Rhizopoda
2) Foraminifera
3) Apicomplexans
4) Ciliates
48
What are rhizopods?
Protozoa that are amoebas, moving by extension of their cell body called pseudopodia. Pseudopodia encircle and absorb food through phagocytosis.
49
What are foraminifera?
AKA forams
| Protozoa that have tests made of calcium carbonate.
50
What are apicomplexans?
Protozoa parasites of animals.
Characterized by apical complex (complex of organelles located at end (apex) of cell. They have no physical means of motility, so they form spores that are dispersed by hosts.
51
What are ciliates?
Protozoa distinguished by their cilia, which is used for moving and other function. Most complex cell because of specialized structures: mouths, anal pores, contractile vacuoles (for water balance), 2 kinds of nuclei (1 large macronucleus, several small micronuclei). Paramecium is this phylum's most notable member.
52
What are characteristics of fungus-like protists?
They form filaments or spore-bearing bodies similar to fungi.
53
What are important fungus-like protist taxa?
1) cellular slime molds
2) plasmodial slime molds
3) oomycota
54
What are cellular slime molds?
Protists that exhibit funguslike and protozoalike characteristics.
1) Spores germinate into amoebas that feed on bacteria.
2) cAMP secreted by amoebas that experience food deprivation to signal aggregation into single unit that migrates as a slug.
3) Individual cells of slug mobilize to form a stalk with capsule at top, similar to spore-bearing bodies of fungi.
4) Spores are released, and cycle repeats.
55
What are plasmodial slime molds?
Protists that grow as a single, spreading mass (plasmodium) that feeds on decaying vegetation. When food runs out or the environment dries up, stalks bearing spore capsules form. Haploid spores are released and germinate into haploid amoeboid or flagellated cells, which fuse to form a diploid cell and grows into the plasmodium.
56
What are oomycota?
Protists that include water molds, downy mildews, and white rusts.
- They are either parasites or sap robes.
- Like fungi, they form filaments (hyphae) that secrete enzymes that digest surrounding substances. The products are then absorbed.
- They are coenocytic, containing many nuclei within a single cell, because the filaments lack septa (cross walls) that partition it into compartments.
- Cell walls are made of cellulose, rather than chitin (in true fungi).
57
What is a coenocytic cell?
A cell with many nuclei.
58
What are characteristics of organisms in Kingdom Fungi? What domain do they belong in?
- Domain Eukarya
- Grow as filaments called hyphae (s: hypha)
- Mass of hyphae called mycelium (p: mycelia)
- Some have septa (s: septum), or cross walls, that divide the filament into compartments containing a single nucleus.
- Filaments lacking septa are multinucleate (or coenocytic)
- Cell walls consist of chitin, a nitrogen-containing polysaccharide
- Can be parasites or saprobes that absorb products broken down by digestive enzymes they secrete.
- Many parasitic fungi have hyphae called haustoria that penetrate their host.
- Dominantly haploid, but most form dipoid structures for sexual reproduction.
59
What are haustoria?
Hyphae of parasitic fungi that penetrate host.
60
What are the stages of fungi sexual reproduction?
1) Plasmogamy
2) Karyogamy
3) Meiosis
61
What is plasmogamy?
- 1st stage of fungi sexual reproduction.
- Fusion of cells from two different fungal strains to produce a single cell with nuclei from both strains.
- A pair of haploid nuclei (one from each strain) is called a dikaryon, and a hypha containing a dikaryon is called a dikaryotic hypha.
62
What is karyogamy?
- 2nd stage of fungi sexual reproduction
| - Fusion of two haploid nuclei of a dikaryon to form a single diploid nucleus.
63
What is a dikaryotic hypha?
A hypha containing a dikaryon (a pair of haploid nuclei, one from each strain of fungi).
64
Describe meiosis in fungi.
- 3rd stage of fungi sexual reproduction
- Diploid nucleus restores haploid condition
- Daughter cells develop into haploid spores, which germinate and form haploid hyphae
65
What are asexual means of fungi reproduction?
1) Fragmentation (breaking up of hyphae)
2) Budding (pinching off of small hyphal outgrowth)
3) Asexual spores (sporangiospores and conidia)
66
What are two kinds of asexual spores in fungi?
1) Sporangiospores
| 2) Conidia
67
What are sporangiospores?
Asexual fungi spores that are produced in saclike capsules called sporangia (s: sporangium), each of which are made on a stalk called a sporangiosphore.
68
What are conidia (s: conidium)?
Asexual fungi spores that are formed at the tips of specialized hyphae called conidiophores and are not enclosed in sacs.
69
What are the suffixes for fungus divisions and classes?
Divisions bear "-mycota" suffix
Classes bear "-mycete" suffix
They are often used interchangeably, depending on the classification scheme.
70
What are major groups of fungi?
1) Zygomycota
2) Glomeromycota
3) Ascomycota
4) Basidiomycota
5) Deuteromycota
6) Lichens
71
What are zygomycota?
-Fungi that lack septa, except when filaments border reproductive filaments.
-Sexual reproduction by fusion of hyphae, followed by plasmogamy, karyogamy, and meiosis.
-Haploid zygospores are produced, which germinate into new hyphae.
Ex: bread mold
72
What are glomeromycota?
- Fungi that lack septa and do not produce zygospores.
- Only occur in mutualistic associations with plant roots (called mycorrhizae).
- Plant provides carbs, fungus increases ability of plant roots to absorb nutrients, especially phosphorus.
73
What are mycorrhizae?
Fungus that grows in association with plant roots.
74
What are ascomycota?
-Fungi with septa that reproduce sexually by producing haploid ascospores.
-After plasmogamy of hyphae, a dikaryotic hypha produces more filaments by mitosis.
-Karyogamy and meiosis occur in terminal hyphal cells to produce 4 haploid cells, which divide by mitosis to make 8 haploid ascospores in a sac called an ascus (p: asci).
-Asci can be grouped into a specialized fruiting body called the ascocarp.
Ex: yeasts, powdery mildews, truffles
75
What are basidiomycota?
- Fungi with septa and reproduce sexually by producing haploid basidiospores.
- Plasmogamy of hyphae is followed by mitosis and growth of dikaryotic heptae to form fruiting body called basidiocarp. (Ex: mushroom)
- Karyogamy occurs in hyphal cells called basidia (s: basidium), followed by meiosis and production of 4 haploid basidiospores.
76
What are deuteromycota?
AKA imperfect fungi
An artificial group comprising of fungi for which no sexual reproductive cycle has been observed.
Ex: Penicillium
77
What are lichens?
Mutualistic associations between fungi and algae.
-Algae (usually chlorophyta or cyanobacteria) provide sugar from photosynthesis and nitrogen if nitrogen-fixing.
Fungus (usually ascomycete) provides water and protection from environment. Some produce pigments that shield algae from UV radiation or excess light, or toxic substances that discourage algae consumption by grazers.
78
What are the major plant adaptations for living on land?
1) Dominant generation in all plants (but primitive bryophytes) is a diploid saprophyte
2) All plants possess a cuticle
3) Development of a vascular system (xylem and phloem)
4) Pollen
5) In the most advanced division, the Anthophyta, gametophytes are enclosed in an ovary
6) Adaptations to seasonal variations in availability of water and light
79
What is the advantage of plants having a dominate diploid sporophyte generation?
A greater ability to survive genetic damage because the recessive mutation to be masked.
80
What is the advantage of plants having a cuticle?
The cuticle, a waxy covering on aerial parts, reduces desiccation.
81
What is the advantage of plants developing a vascular system?
By reducing dependency on water, specialized tissues could form because water is distributed throughout the plant.
-True leaves as centers of photosynthesis
-True stems as framework to support leaves
-True roots to obtain water and anchor plant
Vascular tissues: xylem and phloem
82
What are xylem?
Vascular tissues in plants that are specialized for water transport
83
What are phloem?
Vascular tissues in plants that are specialized for sugar transport
84
What is the advantage of plants developing pollen?
Sperm packaged as pollen allows it to be delivered by wind or animals, rather than swim to eggs in water, which occurs in primitive plant divisions.
85
What is the advantage of plants developing ovaries?
In the most advanced plant division, the Anthophyta, gametophytes are enclosed and protected inside an ovary.
86
What is the advantage of plant adaptations to seasonal variations in water and light?
Plants of the Coniferophyta and Anthophyta have adapted to variation in water and light. For example, some plants are deciduous (shed leaves to minimize water loss during slow-growing/dormant seasons. Desert annuals germinate, grow, flower, and produce seeds within brief growing periods in response to a spring rain.
87
What are deciduous plants?
Plants that shed their leaves to minimize water loss during slow-growing/dormant seasons
88
What are the major plant divisions?
1) Bryophytes
2) Lycophyta
3) Pterohyta
4) Coniferophyta
5) Anthophyta (or angiosperms)
89
What are bryophytes?
The plant division consisting of mosses, liverworts, and hornworts.
- Gametes produced by protective structures called gametangia on the surface of gametophytes, the dominant haploid stage of the life cycle of bryophytes.
- The male gametangium, or antheridium (p: antheridia) produces flagellated sperm that swims through water to fertilize eggs produced by the female gametangium, or archegonium (p: archegonia).
- The zygote grows into a diploid structure, still connected to the gametophyte. In mosses, this structure is a stalk bearing a capsule which contains haploid spores produced by meiosis. The spores are dispersed by wind, germinate, and grow into haploid gametophytes.
- Lack xylem and phloem, so they must remain small and water must absorb through surface tissues and be used as a medium for sperm transport.
90
What are tracheophytes?
AKA vascular plants
| They possess xylem and phloem, and as result, have true roots, true stems, and true leaves.
91
What are lycophyta?
A plant division that includes club mosses, spike mosses, and quillworts.
- Herbaceous plants, usually less than 30 cm tall.
- club mosses and spike mosses produce clusters of spore-bearing sporangia in cone like structures called strobili.
- spores germinate into small gametophytes that produce antheridia and archegonia that produce sperm and eggs.
- flagellated sperm swim to archegonia to fertilize eggs
- zygotes are diploid and grow into sporophytes, which are the dominant generation
92
What are pterophyta?
A plant division that includes three groups:
1) Ferns
2) Horsetails
3) Whisk ferns
- spores germinate into small gametophytes that produce antheridia and archegonia that produce sperm and eggs.
- flagellated sperm swim to archegonia to fertilize eggs
- zygotes are diploid and grow into sporophytes, which are the dominant generation
93
What are ferns?
Part of the plant division pterophyta
-Produce clusters of sporangia called sori (s: sorus) that develop on the undersurface of fern fronds. The sporangia undergo meiosis to produce spores.
94
What are horsetails?
Part of the plant division pterophyta
- include woody trees common during Carboniferous period and extant herbaceous plants
- have hallow, ribbed stems jointed at nodes, which occur at intervals along the stem and produce small, scalelike leaves, and in some species, branches (bushy branches give appearance of a horsetail)
- stems, branches, and leaves are green and photosynthetic, and have a rough texture due to the presence of silica (silicon dioxide)
- strobili bear the spores
95
What are strobili?
Clusters of spore-bearing sporangia in cone like structures
96
What are whisk ferns?
Part of the plant division pterophyta
- consist of branching stems without roots
- leaves are reduced to small appendages or are absent
- absence of roots and leaves is considered a secondary loss (structures that were lost as a whisk fern diverged from ancestors)
97
What is a secondary loss?
Structures that were lost as a plant diverged from ancestors
98
What are microsporangia?
Plant structures that produce microspores (male spores).
- produce numerous microspore mother cells, which divide by meiosis to produce 4 haploid cells (microspores)
- microspores mature into pollen grains (male gametophyte generation)
- pollen grain divides into 3 cells (flower plants) or 4 cells (in conifers), one cell is a vegetative, or tube, cell that controls growth of pollen tube, and the others become sperm cells
99
What are macrosporangia?
Plant structures that produce macrospores (female spores)
AKA nucellus
-produces a megaspore mother cell, which divides by meiosis into 4 haploid cells, one of which survives to become the megaspore and represent the female gametophyte generation
-megaspore divides by mitosis to produce one egg (flowering plants) or two eggs (conifers)
-other accessory cells may also be produced
-one or two tissue layers called integuments surround the megasporangium
-collectively, integuments, nucellus, and megaspore daughter cells are called the ovule
-micropyle: opening through the integuments for pollen access to egg
100
What are microspores?
Male spores
101
What are macrospores?
female spores
102
What is a micropyle?
An opening through integuments for pollen to access egg
103
What is an ovule?
The collective of integuments, nucellus/megasporangia, and megaspore daughter cells
104
What occurs when a pollen grain contacts the megasporangium?
- tube cell directs growth of a pollen tube through the micropyle toward egg
- after fertilization, zygote divides to form an embryo, beginning the sporophyte generation
- integuments develop into seed coat
105
Which two plant divisions produce seeds?
Coniferophyta and Anthophyta/Angiosperms
