Living Organsims 1 Flashcards
1
Q
What are the ecological level structure of taxons
A
biome - ecosystem - community - population - organism - organ - tissue - cell - molecule
2
Q
What are the taxonomic level structure of taxons?
A
Domain - Kingdom - phylum - Class - Order - Family - genus - Species
3
Q
What are the different aspects of taxonomy?
A
description, identification, nomenclature, classification
4
Q
What is taxonomical description?
A
Description refers to the assignment of features regarded as characters to each group (or taxon) of organisms being classified. E.g bark texture - rough/smooth. leaf shape - Elliptical, lanceolate, ovate obovate.
5
Q
What is taxonomical identification?
A
Identification of a the unknown as new to science, therefore it is then described and named by the researcher. Taxonomists utilize dichotomous keys in order to identify and describe organisms.
6
Q
What is taxonomical nomenclature?
A
The formal naming of taxa according to some standardized system.
7
Q
How to write the nomenclature?
A
– Both generic and specific names are printed in italics
– When hand-written each name is underlined with ITS OWN separate SINGLE, STRAIGHT line
– The generic name is capitalised while the specific epithet is all lower case
8
Q
What is taxonomical classification?
A
Classification is a general term referring to placing organisms into definite categories (ranks) to achieve some type of orderly study
of the entities.
9
Q
What is phylageny?
A
The hierarchical structure through which the relationships between all living forms are described,
10
Q
What are systematics?
A
Process of classifying living organisms according to their phylogeny
11
Q
What are cladistics?
A
The analysis of taxa to determine similarities and differences and to use these to construct their phylogeny
12
Q
What is asexual reproduction?
A
formation of new individuals from a single individual without the involvement of gametes.
13
Q
What is sexual reproduction?
A
formation of new individuals (zygotes) by the fusion of female and male gametes.
14
Q
What are the different kinds of asexual reproduction in algae?
A
- mitosis (eukaryotic fission) - The parent cell divides (longitudinally or transversely) into two similar parts. These two cells develop as organisms and are similar to the parent cell.
- fragmentation - the parent body breaks up into two or more fragments that grow into new organisms
- Sporulation - formation of spores (zoospores) in normal vegetative cells or specialized cells known as sporangia. The spores swim away from the parent, settle down and develop directly into new filaments.
- Autocolony Formation - These are produced inside the hollow internal space of the parent colony. New daughter colonies form from certain cells (initials) in the surface of the colony. Eventually, the parent colony will rupture and release the mature daughter colonies.
15
Q
What species of algae has the different kinds of asexual reproduction?
A
- Autocolony formation e.g. Volvox sp.
- Sporulation - e.g. Chlamydomonas, Chlorella and Ulothrix
- Fragmentation e.g. Spirogyra
- mitosis - Euglena
16
Q
What is a carbon sink?
A
A carbon sink is any reservoir, natural or otherwise, that accumulates and stores some carbon-containing chemical compound for an indefinite period and thereby lowers the concentration of CO. 2 from the atmosphere.
17
Q
What is the phylum chlorophyta morphological forms?
A
- Unicellular – motile & non-motile
- Colonial – motile & non-motile
- Filamentous – branched & unbranched, 4. Thalloid – thallus, stipe & holdfast
18
Q
What is terrestrialization?
A
the colonization of the land habitat. from the sea by plants and animals
19
Q
What are the issues that plants face with terrestrialization?
A
- Adaptation to living in a less dense medium → anchorage & support
- Relatively limited water supply → threat of desiccation 3. Relative scarcity of minerals → need for a rooting &
absorption system - Increased exposure to direct ultraviolet and cosmic rays (from the sun) → intensity & duration
- Adaptation to increased atmospheric CO2 → higher rates of photosynthesis
– [CO2] in water is 2 % that of atmospheric [CO2] - Harmful effect of Reactive Oxygen Species (ROS) due to increased [O2] in the atmosphere → increased production from faster photosynthesis
- Adaptation to pronounced fluctuations in ambient temperature
- Attacks from new and diversified microbes.
20
Q
What are the stages in terrestrialization?
A
- Development of specialized cells / organ diversification
- Accumulation of new (lipophilic) water-proofing compounds
- Modification of the life cycle
- Production of complex 2° compounds: antioxidants, antimicrobials, e.g. phenolics, terpenes, alkaloids etc.
- Establishment of mutualistic associations: pollination, dispersal mechanisms
- Removal of dependence on free water: for support and reproduction
21
Q
What are the specialised cells developed for plant terrestrialization?
A
a. Epidermis – maintain internal integrity, cuticle secretion, guard
cells & stomata, light transmission, root hairs
b. Mesophyll cells: more chloroplasts per cell, bilateral symmetry
(palisade cf. spongy)
c. Support:fibres,sclerenchyma,
d. Vascularization: water- and food-conducting cells, support
e. Storagetissue:roots,stems,leaves
f. Reproductive organs: perennating organs, gametangia, sporangia, flowers, seed habit
22
Q
What are the lilopholic compounds created for plant terrestrialization?
A
a. Cuticle
b. Suberin
c. Cork
23
Q
What are examples of modification of life cycles for plant terrestrialization?
A
a. Restriction to moist areas → low-lying habit → followed by radiation to other areas as
tissues develop
b. Heteromorphic alternation of generations – increasing size/dominance of the sporophyte
c. Annuals, biennials, perennials
24
Q
What are the functions of the plant root?
A
- Absorption
- Storage
- Anchorage
- Gaseous exchange
- Reproduction
25
What are the different types of plant roots?
a. Tap
b. Adventitious
c. Fibrous
26
What are meristematic tissue?
These are specific parts of the plant that growth takes place e.g root apical meristem, lateral meristem, Shoot apical meristem
27
What is the heteromorphic generations?
Heteromorphic alternation of generations means that there is a sporophyte version of the plant and a gametophyte version of the plant that each participate in that plant species's life cycle.
28
what are the similarities with chlorophyta and bryophytes?
1. Simple thalloid body
2. Non-vascular
3. Limited tissue differentiation into flat thallus or stem-like axis, leaf-like appendages and rhizoids
4. Little / no cuticle development - restricted to areas with much water
5. Single, large chloroplast per cell in the simpler bryophytes
6. Reproduction depends on free water - Flagellated reproductive cells, - The “amphibians of plant kingdom”
7. Water and mineral absorption directly through thallus
8. Anchoring rhizoids analogous to holdfast of algae
9. Oogamous life cycle
10. Alternation of generations with dominant gametophyte
11. Protonema of the Hepatophyta resembles the filamentous green algae in form
29
What are the general feature of bryophytes?
1. Simplest terrestrial plants
2. Inhabit moist, shady habitats
3. Thalloid body
o Poorly differentiated leaf-like thallus, or
o Stem-like vertical axis bearing leaf-like appendages
4. Anchored to substratum by rhizoids
5. Non-vascular plants
6. Epidermal layer with poorly developed cutin-like substance
7. Pigmentation: chls. a, b & carotenoids
8. Starch stored in chloroplasts
9. These plants show alternation of generations with the gametophyte (n) dominating the life cycle
30
What are the similarities with bryophytes and higher plants?
1. Terrestrial (amphibious)
2. All macroscopic, except for the protonema (young gametophyte)
3. Greater support mechanism in less dense medium of air
4. Greater level of development of the gametophyte now with a differentiated epidermal layer
5. Tissues produced through activity of apical meristem
6. Development of water-absorbing rhizoids in more complex bryophytes
7.Multicellular gametangia with sterile, protective
jacket of sterile cells: o Antheridia:male
o Archegonia:female
8. Multicellular sporophyte, producing many more
spores in sporogenous tissue.
o Gametophyte is still the dominant phase of the life cycle
9. no zoospores produced
10. Meiosporeswithsporopollenincovering
11. Spore dispersal by wind and water
12. Many small chloroplasts per ce
31
What are th different evolutionary lineages of bryophytes?
1. Liverworts: Phylum Hepatophyta or Marchantiophyta
2. Hornworts: Phylum Anthocerophyta
3. Mosses: Phylum Bryophyta
32
Describe What are hydroids?
• Located within a central strand – hadrom
• Resemble tracheids & vessels:
i. Lacking living protoplasm at maturity
ii. Elongate cells with
iii. Slanting thin cross-walls permeable to water
iv. No lignin however
33
What are the special conducting cells that possess have?
1. for water (hydroids)
| 2. for food (leptoids)
34
What are leptoids?
Located within a central strand of tissue called the leptom
Surround the hydroids within the central cylinder of the stem
Resemble the phloem vessels:
i. Elongate cells
ii. Living protoplasm at maturity
iii. Degenerate nuclei (cf. sieve tube cell)
iv. Inclined end walls with perforations
These conducting cells help to suggest the Bryophytes to be the ancestors of the tracheophytes
35
What are the differences between hydroids/leptoids and xylem/phylem?
They are similar to xylem and phloem except they lack specialized, lignin-containing wall thickenings. Their cell walls are much thinner and yet very permeable to water and solutes.
36
What are the difference with hornworts and liverworts?
1. no dichotomous branching of the thallus occurs
2. lobes of the thallus overlap
3. guarded mucilaginous pore, connected with internal
mucilaginous cavities in the thallus
4. only one large, algal-like chloroplast in each cell of the thallus
5. colonies of the mutualistic cyanobacterium Nostoc fill small cavities that are scattered throughout the ventral part of the hornwort thallus
6. The gametangia are sunken in pits within the thallus no antheridiophores or archegoniophores
7. The capsule forms the major and conspicuous part of the sporophyte:
8. Meristematic region located at the foot of the sporophyte (‘horn’)
37
What is secondary growth vs primary growth?
secondary growth is the growth that results from cell division in the cambia or lateral meristems and that causes the stems and roots to thicken, while primary growth is growth that occurs as a result of cell division at the tips of stems and roots, causing them to elongate, and gives rise to primary tissue.
38
what are the various phyla of ferns?
1. Psilophyta:
2. Equisetophyta:
3. Lycopodiophyta:
4. Polypodiophyta:
39
Describe the types of sporangia?
– Leptosporangia
• Arise from divisions of a superficial epidermal cell
initial
• Sporangial wall made up of one cell layer
– Eusporangia
• Arise from divisions of many epidermal cell initials • Sporangial wall made up of >1 cell layer
• Hold many more spores
40
What are the different vascular arrangements?
a. Protostele
b. Siphonostele
c. Eustele
41
What re the defining features in leaves?
1. vascularization
2. determinate growth
3. bilateral symmetry(adaxial–abaxial polarity
4. definite arrangement (phyllotaxy)
42
What influences leaf size?
1. Altitude – solar radiation
2. Rainfall
3. Day and night temperatures
4. Soil nutrient content
5. Inherent genetic factors
43
What is parallel venation?
When veins (or the nerves) are arranged parallel to one another all over the leaf blade or lamina is called as parallel venation
44
what is reticulate venation?
When veins (or the nerves) shows network or web-like arrangement all over the leaf blade or lamina, it is called as reticulate venation
45
what is Heterospory?
Heterospory is the production of spores of two different sizes and sexes by the sporophytes of land plants.
46
Similarities with gymnosperms and pteridophytes
1. Dominance of complex sporophyte in the life cycle and - smaller simpler gametophyte
2. Heterospory like some Lycopodiophyta genera, e.g.
Selaginella (but not like Polypodiophyta)
- with megaspores and microspores produced in
strobili/cones
3. Vascular tissue:
- tracheids only in xylem
- sieve cells only in the phloem
4. Some have pinnately compound leaves (e.g. cycads)
47
Differences with gymnosperms and pteridophytes
1. Sporophyte structure better adapted to terrestrial habitat: - development of tap root system
- development of thick cuticle, etc.
- all have megaphylls
- upright thickened stem: vascular and cork cambia produce secondary growth
2. More advanced cone structure:
- with ovules and integuments
- offers greater protection to megaspore
3. No free water required for sperm transfer in gymnosperms
- male spore/gametophyte is a POLLEN grain, which carries male gamete/sperm to egg (pollination and pollen tube)
4. Female megaspore and megagametophyte retained on sporophyte for complete development -
gametophyte matures and is fertilized on parent sporophyte.
5. Development of the SEED
- fertilized gametophyte (ovule) forms the seed which contains embryo of new sporophyte generation
- the most important advance of gymnosperms over pteridophytes
Instead of spores being dispersal units (as in bryophytes & pteridophytes), seeds are dispersed (more effective as they can directly form new sporophyte plant)
48
What are angiosperm features?
flowers
ovules & seeds enclosed (ovary & fruit, resp.)
double fertilization
endosperm in seed (triploid nutritive tissue)
xylem with vessel elements & fibres as well as tracheids
phloem with companion cells as well as sieve tubes
49
What is Entomophily?
Entomophily or insect pollination is a form of pollination whereby pollen of plants, especially but not only of flowering plants, is distributed by insects.
50
What is Ornithophily
Ornithophily or bird pollination is the pollination of flowering plants by birds.
51
What is Zoophily
pollination by animals such as birds, bats, insects,
52
What is Anemophily
pollination by wind
53
What is Hydrophily
Pollination by water
54
What is pollination syndromes
The specialized adaptations of a flower for a pollinator type are collectively known as pollination syndromes or systems.
55
What are the primitive flower traits?
* Flower parts many
* Flower parts of indefinite number
* Flower parts free
* Flower parts spirally arranged
* All types of parts present
* Flowers bisexual
* Ovary superior
* Flower of regular symmetry
* Flowers conspicuous
56
What are the advanced flower traits?
* Flower parts few
* Flower parts of definite number
* Flower parts fused
* Flower parts whorled
* Some whorl(s) missing
* Flowers unisexual
* Ovary inferior
* Flower of bilateral or irregular symmetry
* Flowers inconspicuous
57
What is a simple fruit?
from one flower with one carpel or fused carpels, e.g. mango, apple, tomato.
58
What is a multiple fruit?
from inflorescence: several fruits develop, merging and fusing into a single fruit body, e.g. pineapple, noni, breadfruit.
59
What is aggregate fruit?
from one flower with several unfused carpels, each carpel becoming a ‘fruitlet’, which fuse together (partially or mostly) e.g. sweetsop, soursop, raspberry
60
what is true fruit?
Develops from nothing but ovary wall – most fruits
| – after pollination, all other parts of flower fall off receptacle; style and stigma abscise.
61
What is accessory fruit?
Develops from other parts of flower as well as ovary wall
– Receptacle often becomes the accessory tissue, e.g. temperate (Golden Delicious, etc.) apple, temperate (Bosch, etc.) pear, strawberry.
62
What is succulence?
Fruits may also be described on basis of whether mature fruit is
- fleshy/succulent (juicy) or
- dry (stony, papery, woody, etc.).
63
What is dehiscent or indehiscent?
opens to release seeds: dehiscent or
| • remains closed: indehiscent; seeds are retained & dispersed within fruit.
64
What is the purpose of the seed being in a dormant state?
- unit of dispersal
| - unit of perennation (survival from one growing season to next)
65
What are epigeal seeds?
seeds germinate with cotyledons being raised above ground level as the hypocotyl elongates, e.g. Phaseolus
66
What is hypogeal seeds?
seeds germinate with cotyledon(s) remaining below ground level as the epicotyl elongates, e.g. Cajanus, Zea
67
What are ground tissues in plants?
Ground cortex & pith, some plants cortex only: parenchyma, strengthening tissues (sclerenchyma, collenchyma), sometimes chlorenchyma.
68
What are dermal tissues in plants?
epidermis
69
What are vascular tissues in plants?
eustele i.e. several separate bundles, with phloem (towards periphery) & xylem (towards centre).
70
What are lenticels?
one of many raised pores in the stem of a woody plant that allows gas exchange between the atmosphere and the internal tissues.
71
What are the types of tropical rainforest?
a. Lowland tropical rainforests: They receive the most rain per year
b. Highland tropical rainforests: These kinds of rainforests are situated on the high peaks and tablelands
c. Monsoon rainforests: This kind of tropical rainforest occurs in areas that experience strong seasonal wet and dry climate. Climbers are usually the biggest feature of Monsoon tropical rainforests.
d. Subtropical rainforest: similar to tropical rainforests only that it harbors a lesser number of species. Climbers and epiphytes are common here & most of the trees are buttressed
72
What are lianas?
long-stemmed woody vines rooted in the soil.
73
What are epiphytes?
plants that grow on host plants or objects for physical support only esp. to gain access to light in forests
74
What are the types of deserts?
1. Hot deserts:
Sahara, Kalahari, Arabian, Australian, Australia, Arabian, Peninsula, Mexico/ S.W. USA
2. Coastal deserts: Peru and Chile
3. Cold deserts: China,Mongolia,Iran,Afghanistan,S.WAfrica,W.China,
Argentina, South America, Middle East, Antarctica and USA
4. Semi-arid deserts / Steppes: USA, Canada, Ukraine and China
