Living Organsims 1 Flashcards
What are the ecological level structure of taxons
biome - ecosystem - community - population - organism - organ - tissue - cell - molecule
What are the taxonomic level structure of taxons?
Domain - Kingdom - phylum - Class - Order - Family - genus - Species
What are the different aspects of taxonomy?
description, identification, nomenclature, classification
What is taxonomical description?
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.
What is taxonomical identification?
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.
What is taxonomical nomenclature?
The formal naming of taxa according to some standardized system.
How to write the nomenclature?
– 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
What is taxonomical classification?
Classification is a general term referring to placing organisms into definite categories (ranks) to achieve some type of orderly study
of the entities.
What is phylageny?
The hierarchical structure through which the relationships between all living forms are described,
What are systematics?
Process of classifying living organisms according to their phylogeny
What are cladistics?
The analysis of taxa to determine similarities and differences and to use these to construct their phylogeny
What is asexual reproduction?
formation of new individuals from a single individual without the involvement of gametes.
What is sexual reproduction?
formation of new individuals (zygotes) by the fusion of female and male gametes.
What are the different kinds of asexual reproduction in algae?
- 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.
What species of algae has the different kinds of asexual reproduction?
- Autocolony formation e.g. Volvox sp.
- Sporulation - e.g. Chlamydomonas, Chlorella and Ulothrix
- Fragmentation e.g. Spirogyra
- mitosis - Euglena
What is a carbon sink?
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.
What is the phylum chlorophyta morphological forms?
- Unicellular – motile & non-motile
- Colonial – motile & non-motile
- Filamentous – branched & unbranched, 4. Thalloid – thallus, stipe & holdfast
What is terrestrialization?
the colonization of the land habitat. from the sea by plants and animals
What are the issues that plants face with terrestrialization?
- 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.
What are the stages in terrestrialization?
- 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
What are the specialised cells developed for plant terrestrialization?
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
What are the lilopholic compounds created for plant terrestrialization?
a. Cuticle
b. Suberin
c. Cork
What are examples of modification of life cycles for plant terrestrialization?
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
What are the functions of the plant root?
- Absorption
- Storage
- Anchorage
- Gaseous exchange
- Reproduction
What are the different types of plant roots?
a. Tap
b. Adventitious
c. Fibrous
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
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.
what are the similarities with chlorophyta and bryophytes?
- Simple thalloid body
- Non-vascular
- Limited tissue differentiation into flat thallus or stem-like axis, leaf-like appendages and rhizoids
- Little / no cuticle development - restricted to areas with much water
- Single, large chloroplast per cell in the simpler bryophytes
- Reproduction depends on free water - Flagellated reproductive cells, - The “amphibians of plant kingdom”
- Water and mineral absorption directly through thallus
- Anchoring rhizoids analogous to holdfast of algae
- Oogamous life cycle
- Alternation of generations with dominant gametophyte
- Protonema of the Hepatophyta resembles the filamentous green algae in form
What are the general feature of bryophytes?
- Simplest terrestrial plants
- Inhabit moist, shady habitats
- Thalloid body
o Poorly differentiated leaf-like thallus, or
o Stem-like vertical axis bearing leaf-like appendages - Anchored to substratum by rhizoids
- Non-vascular plants
- Epidermal layer with poorly developed cutin-like substance
- Pigmentation: chls. a, b & carotenoids
- Starch stored in chloroplasts
- These plants show alternation of generations with the gametophyte (n) dominating the life cycle