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The female sexual organ in plants that produces
The male sexual organ in plants that produces sperm
A process of cell division which results in the production of two daughter cells containing sets of chromosomes identical to those of the parent call
The fusion of the sperm and egg cells
The diploid spore producing stage of the lifecycle
The fusion of the nuclei from two gametes
A mature male or gemale germ cell such as a sperm cell or egg cell
A cell or organism carrying one set of chromosomes (1N)
The cell formed from the plasmogamy and karyogamy of sperm and egg
The haploid stage of a plants lifecycle that produces gametes
The interaction between and egg and sperm leading to formation of the zygote
Nuclear division resulting in the ploidy level (chromosome number per nucleus) halving, usually from diploid (2N) to haploid (1N)
An organism that carries two sets of chromosomes (2N), one from each parent
Central tissue, usually of parenchyma cells, of stems and roots; often a storage tissue
The outermost cell layer of the plant body; usually of parenchyma cells; often covered by a protective waxy cuticle
The tissue, usually of parenchyma cells, located between the epidermis and the vascular culinder of stams and rootsl often for food stagel can be photosynthetic in young stems
The outermost layer of layers of parenchyma cells of the root sele; often becomes meristematic; origin of secondary (lateral) roots
The layer of suberised cells at the junction of epidermis and tortex of certain roots. It regulates the uptake of water, solutes and ions into the cortex.
A secondary lateral meristem from which the secondary vascular tissues (secondary xylem and phloem) develop
Innermost cell layer of the root cortex; walls of component cels often unevenly thickened and contain suberin (as Casparian strips); living protplast; implicated in selective passage of material into the vascular cylinder (stele) of the root.
A complex secondary tissue commonly called barkl derivd from the cork cambium or phellogen and replacing the epidermis; typically in woody stems and roots; provides protection
Tissue principally responsible for translocation (transport of organic products of CO2 assimilation) in vascular plants; comprises sieve elements, parenchma and sclerenchyma cells and companion cells (in angiosperms) and albuminous cells (in gymnosperms)
Tissue mainly responsible for conduction of water and inorganic salts in vascular plants; comprises vessel elements, parenchyma cells and sclerenchyma fibres; also aids as a structural of supportive tissue.
Generally green, they comprise the outermost whorl and enclose the flower as a bus. As a ring around the base of the flower, they constitute the calyx.
Comprise the whorl after the sepals and are usually the conspicuous, coloured parts in flowers pollinated by animals. As a whorl they comprise the corolla. In wind pollinated flowers, the corolla may be greatly reduced, or absent, or green and inconspicuous. The calyx and corolla are often described (collectively) as the perianth.
The term often applied to petals and sepals that are similar in shape and colour, or undifferentiated.
Form a whorl inside the corolla. Each stamen comprises a stalk (a filamient) and an anther, the pollen-forming organ at its apex.
The innermost or central structure consisting of an ovary at its base, a more or less tubular style above the overy and a pollen receptor or stigma at the apex of the style. The female (mega-) spores, megagametophyte and eff cells are formed within the ovary.
Contain the female gametophyte and eventually mature into seeds; are borne within the ovary. If more than one carpel occurs within a flower, the individual parts of each carpel may be separate or they may be fused to varying degrees. When ovaries become fused, the resulting compound structure contains a number of cavities, each of which encloses one or more ovules. Depending on the degree of fusion, the styles and stigmas may be separate of fused into a single unit
The enlarged end of the flower stalk to which the sepals, petals, stamens and carpels are attached.
What governs the type of vegetation across the globe?
Temperature and water (which both affect the length of the growing season) and nutrients.
What 3 causes of environmental problem in Australia?
- Forestry, which was extensive in the ealy days of European settlement.
- Gold mining in the 1850s-1880s.
- Vegetation clearing for agriculture post WWI and WWII.
Give 3 ways in which the Southern Hemisphere differs from the Northern Hemisphere
The balance of land and water, Evolutionary history, and glaciation
What are the 4 major components of fire?
- Time between fire (frequency) - this is critical for species that recover from fire by seed; it determines how long before that species is reproductive again
- Severity of fire (intensity) - this is the impact of the fire
- Patchiness - which areas are burnt and which aren't.
- Vegetation is not destroyed - new opportunities for plant community renewal occur
What is a population?
A number of individuals of the same species in a defined geographic area -> number, area occupied, age, structure
What is population ecology?
The dynamics of the distribution and abundance of species
Wht are abiotic factors?
The physical environment, including soils, rainfall, fire and temperature.
What are biotic factors?
Other organisms, competition, herbivory
What is a community?
A group of populations of different species living and interacting together. Communities have species diversity (species richness, alpha diversity (relative abundance) and beta diversity (div. between communities separated in space)); and structural diversity (variations in size and shape irrespective of species - projective foliage cover and the height of the foliage)
What are biomes?
Cmmunities on a global scale defined by climate
What type of vegetation would be found in a forest
>10, trees, 30-100% cover
What type of vegetation would be found in a woodland?
2-10m, trees, 10-30% cover
What type of vegetation would be found in a heath?
<2, shrubs, 30-100% cover
What type of vegetation would be found in grassland?
<1m, grasses, 10-100% cover
What are the characteristics of a temperate deciduous forest?
Growth limited to 8 months/year by frozen winter, and leaves that fall in winter to avoid the cold
What are the characteristics of savanna woodland?
Common in subtropical and Mediterranean regions, growth limited by drought, bushfires common, scattered trees with perennial grasses and herbs, supports large grazing mammals (eg. kangaroos in Aus)
What are the characteristics of a tropical rainforest?
- Little sunlight penetrates to the forest floor,
- Temperature and water availability suitable for biological activiy for >11 months per year,
- Evergreen, broad leaves foliage,
- High species richness and diversity,
- Rich in lianes (woody climbing plants) and epiphytes
- Can support large arboreal mammals
- Plants are shade tolerant with gap replacement
What are the 3 reasons why vegetation burns?
- Climate - mediterranean type, coupled with intense droughts
- Ignition sources - both natural and human
- Fuel - accumulation and flammability (oils in foliage of many australian plants promotes rapid burning). Much of the fuel is schleromorphic (hard, woody, highly lignified, slow to decay)
What are the characteristics of a desert?
Growth limited by lack of water for long and erratic periods. Dominated by widely spaced shrubs, small trees, hummock grasses and succulents.
What are some adaptations to fire?
- Thick, fibrous bark protects the stem and epicormic buds beneath
- Protection of seed – the plants may die by the seeds survive. This may be due to thick wood fruits which protect the seed and release it after fire. This allows species to regenerate in a clear seed bed, meaning there is reduced competition and herbivory. It may also be due to the burying of the seed, usually by ants. The heat from the fire stimulates germination and the cracking of the hard seed coat.
- Buds on underground swollen roots (lignotubers) of eucalypts
- Protection of underground stems (rhizomes) of bracken fern and orchids
- Underground bulbs or tubers of many native herbs
What some of the characteristics of Australian ecosystems?
- Nutrient-poor soils
- Weathering and leaching (particular phosphorus
- and nitrogen.
- Plants growing on soils poor in phosphorus, zinc, and other indispensible nutrients synthesise carbohydrates in excess of the amount that can be combined with these nutrients for metabolism and
- production of nutrient-rich foliage and reproductive tissues. They use this “expendable energy” to produce well-defended foliage, large quantities of
- lignified tissues, and readily digestible exudates. The rapid accumulation of nutrient-poor biomass, a result of low rates of herbivory, provides fuel for intense fire.
- Small, leavery leaves with thick cuticles - scleromorphy is the expression of such leaves – ‘hard leaved’.
- Fire. Adaptions to fire include resprouters (dormant
- buds protected by thick bark) and seeds (protected by woody cones, soil or hard seed coats).
- A long association with humans
- Ants – they have an important roles in the seed dispersal of plants
- Dominance by eucalypts, as they occur in all
- landscapes except rainforests and arid interior. They are unique to Australia and are also the world’s tallest flowering plants.
- Lack of winter deciduous trees – summer
- deciduous is more common.
- Plant-animal interactions: Advantages for plants include pollination and seed dispersal while advantages for animals include a source of food
- and habitat.
What are the consequences of forestry and vegetation clearing?
- Reduces plant and animal populations, which results in difficulties finding a mate (demographic processes), exposition to extreme weather events (stochastic processes), inbreeding effects (genetic processes). Small populations are thus more vulnerable to loss and extinction
- Lack of protection for soil by crops
- Dryland salinity - salt is naturally present in soil or groundwater, but out of reach of plant roots. In wet areas, rain washes salt out of soil; in dry areas, soil salinity is higher. The problem is worsened by tree removal, which reduces evapotranspiration = evaporation and transpiration. More rainwater reaches the water table, and hence the watertable rises. Ending the clearing of native vegetation and replanting recharge areas using deep-rooted species such as eucalypts
- Rural dieback – the premature and protected decline in health and vigour, dollowed by death of trees (usually eucalypts) in rural areas.
A secondary lateral meristem which produces a protective tissue (cork) which replaces the epidermis in woody stems and roots.
Cork Cambium or phellogen
The tissue, usually of parenchyma cells, located between the epidermis and the vascular cylinder of stems and roots; often for food stage; can be photosynthetic in young stems.
The outermost cell layer of the plant body; usually of parencyma cells; often covered by a protective waxy cuticle.
A layer or layers of distinctive cells immediately inside the epidermis of a stem; supportive and protective function
Radial clumps of parenchyma which link the pith and the cortex in stems, especially in wood, often gives wood its distinctive appearance when cut and dressed.
A complex secondary tissue commonly called bark derived from the cork cambium or phellogen and replacing the epidermis; typically in woody stems and roots; provides protection
PhloA group of sclerenchyma fibres associated with a vascular bundle and appearing like a cap on the phloem; provides support
Phloem or bundle cap
Central tissue, usually of parenchyma cells, of stems and roots; often a storage tissue
Radial clump of parenchyma tissue located in secondary xylem - also known as a medullary ray; gives a distinctive appearance of grain to dressed wood