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All together, Roots (Concept (taproots pic (are found in (carrots,…
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Roots
Concept
taproots pic
as roots of willows, sorrels and other plants spread horizontally, they produce shoot buds that grow out and act as a new plant
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selective advantage for a plant to control the size of its shoot,so that transpiration by its leaves do not exceed absorption by its roots
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Even a light porus soil can be most easily and thoroughly penetrated by narrow cylinders rather than thin sheets
roots do not need to adapt for light, but to absorb and conserve water
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has absorption factors like the leaf, but two different functions. the roots collect the water and minerals
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without proper root attachment, trees and shrubs could not remain upright, and epiphytes would be blown away
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Zone of elongation pic
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between the provascular tissues and the protoderm is a ground tissue, a rather uniform parenchyma that differentiates into root cortex
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center is vascular tissues, become xylem and phloem
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Root caps pic
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cells appear to extend around the sides of the root, the root is actually growing through the edges of the root cap
Simultaneously, cells on the edges of this group grow toward the side and proliferate
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storage root
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perennial plants with permanent shoots that do not die back also store significant amounts of nutrients within themselves during winter
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Carbohydrates stored in the root are used to produce a new shoot in the spring, when photosynthesis is impossible owing to the lack of leaves
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storage roots pic
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roots frequently provide long-term storage for carbohydrates that accumulate during the summer photosynthesis
Prop roots pic
Buttress roots
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roots on certain tropical trees become tall, plate like, their upper side grows more rapidly than other parts of the roots
if a root undergoes secondary growth and becomes woody, they can be extremely strong supports
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Prop roots
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Root apical meristem pic
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the root is more orderly than the shoot because it experiences no disruptions because of leaf primordia, leaf traces or axillary buds
regular files of cells can be seen to originate in the meristem and extend in to the regions of the mature root tissues
is examined in relationship to the root tissues it produces,
Mycorrhizae
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roots of most species of seed plants have a symbiotic relationship with soil fungi in which both organisms benefit
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Contractile Roots
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because the root is firmly fixed in the soil, the stem is pulled downward so that the base of the shoot is either kept at soil level or, in the case of bulbs
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After extending through the soil and becoming firmly anchored, the uppermost portions slowly contract.
External Structure of roots #
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Transportation
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water Potential
Matric potential
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water adhesion to dissolved structures such as the cells walls, membranes and soil particles
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most liquids can not be stretched very much, because water is cohesive
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water potential
if water is under pressure, the pressure potential increases an does water potential
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because water is so important in botany, its chemical potential is usually referred as water potential
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Like any other chemical, water has a free energy, a capacity to do work
Concepts
Isolation mechanisms
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vascular tissues make it advantageous for shoots to grow upright, elevating leaves into the sunlight above competing plants
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this elevation is feasible because photosynthetically produced sugars can be transported downward to other plants parts.
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Specific transportation occurs at virtually every level of the biological organization: Enzymes transport electrons, protons and acetyl groups
transportation processes consume energy and many are driven by the exergonic breaking of ATP's high energy phosphate bonding orbitals
Diffusion also occurs during life but proceeds more slowly that the controlled and oriented transport processes that tend to increase the order within the plant or animal body
after death occurs atoms, ions and molecules diffuse moving from regions of higher concentration to regions of lower concentration #
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one fundamental aspect of life itself is the ability to transport specific substances to particular sits
Diffusion, osmosis and active transport
Intracellular transport
during fusion, the membranes merge and the vesicle content are transferred into the organelle
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the molucule pump which in a protein, binds to both the molecule and ATP, then ATP splits into ADP and Phospate
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molecular pumps
use energy of ATP to force molecules across the across the membrane, even if that type of molecules is extremely concentrated on the receiving side this is active transport
Aquaporins
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water molecules, even through highly polar, pass through all memebrane
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Hydrophobic molecules diffuse easily through any cell membrane,
where as polar, hydrophilic molecules can cross differentially permeable membrane only if the membrane have special protein channels through which the molecules can diffuse
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diffusion
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Osmosis
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which random movement of particles in solutions causes them to move from areas where they are in relatively high concentration to areas where they are low concentrations
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the first thing to consider is the mechanism by which materiel moves through a solution and crosses a membrane.
Transfer cells
cells are found in areas where rapid S.D.T is expected to occur. in glands that secrete salt , in areas that pass nutrients to embryos and in regions where sugar is loaded into or out of phloem #
the plasma membrane is pressed firmly against all of the convolutions and thus has consequently, the room is available for many molecular pumps and high-volume transport can occur across these transfer walls
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the walls are smooth on the outer surface but have numerous finger-like and ridge-like outgrowths on the inner surface
he rate which material can be actively transported depends on the number of molecules pumps present.
which in turn depends on the surface area of the plasma membrane: the larger the membrane, the more molecular pumps it can hold.
guard cells
when they must open, potassium are actively transported from surrounding cells into the guard cells
the extra water and potassium causes the guard cell to swell bend and push apart opening opening the stomatal pore
the loss of potassium causes the water potential in adjacent cells to become less negative whereas absorption of potassium causes water potential in guard cells to become more negative. adjacent cells and guards cells are thrown out the hydraulic equilibrium #
once inside the G. Cells, the potassium cannot leave because the plasma membrane is impermeable to it
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the opening and closing of stomata pores are based on the S.D.I.T #
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cell and water movement
growing regions, such as the stem and roots
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immature growing cells have weak, deform able walls and cannot generate enough pressure to stop water absorption.
with such a large influx of water, solutes in the cell may become significantly diluted
under these conditions, the cell may increase greatly in size
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even the thinnest most delicate walls of mature parenchyma cells can exert enough pressure on the protoplast to raise the pressure potential high enough to counterbalance osmotic potential #
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lysis
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motor cells
motor cells
are similar to guard cells: they can either accumulate or expel potassium and thus adjust their water potential and turgidity
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the location of flexure is either the entire midrib or the point at which the petiole attaches to the lamina or stem
the leaves of sensitive plants move slowly and reorient themselves by flexing and folding in response t a variety of stimuli
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Short distance Intracellular Transport #
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Most plants communicate with their neighboring cells, transferring water, sugar, minerals and hormones
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Community Ecology
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Diversity
communities consist of more than one species,but how many more?
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some are obviously more diverse than others, but that is often easier to see than to measure
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Diversity and scale
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as an alternative, we can plot number of species in each abundance class and obtain a species abundance distribution
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the relationship between area and species richness is called the species -area relationship and is expressed by the formula
in which the S is the number of species, A is the area, and c and z are constants that must be discovered by studying individuals communities
once c and z are known for various communities, they can be used compare the diversity of those communities
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during a disturbance such as a drought or fire, larger populations are less likely to die out than smaller ones
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whichever aspect of community diversity we might be studying a common observation is the scale matters.
Concept
Community
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community restoration
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climax community
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the disturbed patch undergoes succession until it becomes spruce-fir forest again #
Succession
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Even if climate and geology remain the same throughout the lifetime of a community,
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many factors such as fires, volcanic eruptions, erosion, hurricanes and other disturbances alter patches of territory
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community ecology might be examine that same species but would take into consideration its interactions with other species #
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is a group of species that occur together at the same time and place #
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Genetics
Monohybrid Crosses
Multiple alleles
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within population of plants, as many types of gametes can be produced as there are different types of alleles
certain mutations still result in the production of a protein with the normal sequence, but most lead to altered protein structure
when genes are polymorphic, hahving multiple alleles, numbers such as X1,X2,X3,X4 ans so on are used rather than capital and lowercase letters
the gene is therefore at least 900 sites exist at which point mutations can occur, and of course, any mutation may involve several nucleotide
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a protein of average size consist of about 300 amino acids, so the coding portion of its mRNA must have about 300 codons, each containing three nucleotide.
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test crossing
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after the actual genotypes pf plants are known, those that are homozygous dominant can be gathered and planted in special areas,
kept free of all natural pollinators, and allowed to breed among only themselves
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all gametes produced by homozygous recessive parents carry the recessive allele, which is unable to mask the homologous allele in resulting F1 zygote
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if traits has Complete Dominance, it is difficult to know what genotype of any particular plant is unless the plant shows the recessive trait.
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Sexual reproduction between two individuals is called cross #
within a population, mutation produce new alleles and genotypes of individuals within the population differ. of the plants that grow in an area and that can interact sexually,
many may have the same allele of a particular gene but other individuals any have other alleles, other versions of the gene
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each sex cell- that is , each sperm cell and egg cell- contains one complete set of genes.
each sperm cell contains all the genes necessary to construct a new plant; the same is true of each egg cell
the meiotic divisions that precede a cross reduce the number of sets the chromosomes per cell from the diploid number to the haploid number
Replication of DNA
replication fork
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as DNA uncoils and seperates, it has a forked appearance
Next, one strand of DNA double helix is cut and the two strands separate from each other in a short region, forming a small "Bubble" called a replicon pic
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these are ribonucleotides, not deoxyribonucleotides, and they are pomerized into short pieces of Primer RNA Pic
with the helix opened, free nucleotides diffuse to regions of single-stranded DNA and pair with its bases along both strands
as replication begins
DNA does not release histones; instead, Nucleosomes structure remains intact.
chromatin first becomes less compact, opening sufficiently to allow entry of the necessary replicating factors
replication doubles the amount of DNA and each gene exists in at least two copies,
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one on each of the two chromatids,
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before a cell undergoes nuclear division, either mitosis or meiosis
Mutation
Mutations
a Mutation is any change, however large or small, in DNA
Inversion
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Under some conditions a piece of DNA becomes tangled and breaks and during repair, it puts in backwards
Insertion
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Deletion
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Point Mutation
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the smallest mutation, affecting the least amount of DNA
DNA Repair Processes
mutations occur in the genes that code for repair enzymes, resulting in serious problems
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certain mechanisms recognize base mismatches, loops or other problems; other enzymes minimize the number of errors that occur in the first place
because most mutations are deleterious and occur frequently enough to be significant problems, it is selectively advantageous for organisms to have DNA repair mechanisms that recognize and remove mutations
Somatic Mutations
the mutation may occur in a leaf cell nucleus, but in gene that is inactive in leaves, such as a gene that affects root hair growth or bark information
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when a leaf falls off in the fall, the mutated gene decomposes along with the rest of the leaf.
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the same is true of any mutation in roots, wood or bark
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Mutations can occur at any time in any cell, but if they happen in cells that never lead to sex cells they are called somatic cells
Effects of mutation
Statistically, Mutation are almost always harmful
any mutation that changes the structure of proteins, rRNA, or tRNA is more likely to produce a less useful than more useful forms
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enzymes tend to be approximately 300 to 400 amnion acids long and hundreds of trillions of proteins could possibly exist
Within exons, a small mutation may not be important if it only changes a codon into another codon that specifies the same or a similar amino acid.
a mutation in an exon may cause the gene to code for proteins whose active sit is disrupted and the proteins cannot function
changing codons to ones that specify very different amino acids may not matter if they are located in a part that is not critical to the proteins' functioning
point mutation and small insertion and deletion in introns appear to be unimportant generally- they change portions of hnRNA that will not be incorporated into mRNA #
if it occurs in spacers DNA between two genes, it may have no effect whatsoever.
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Causes of mutations
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if a small piece of foreign DNA is present after cutting, it may accidentally be incorporated into the Chromosomal DNA by DNA ligase
can be caused by many methods, because a variety of enzymes cut and rejoin DNA as part of repair processes.
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as DNA unwinds ahead of the DNA Polymerase,
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Concepts
Selective advantageous
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in asexual reproduction, each offspring is identical to its parents and siblings
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even though this seems like the most safe mechanism for producing offspring to carry the parents genes into future generation,
the progeny are never more fit than the parent and no progeny is adapted to any environment other than the parents environment
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alleles
Genotypes
and the expression of those alleles in the individual size, shape, or metabolism is its Phenotype pic
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as a result of mutation, the population of individuals has varying genotypes and phenotypes
not identical, as is apparent from considering humans
Mutation can occur in any gene in any individual, and thus, gradually a population of separate plants comes to have a variety of alleles
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if all plants of a species had exactly identical nucleotide sequences in their DNA, then all those plants would be identical physically
the chemical basis of genetic inheritance is the gene,
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Dihybrid Crosses
Gene on Separate chromosomes: independent Assortment #
after the possible types of gametes are known, the punnet square can be set up #
During meiosis 2 , the two chromoatids of each chromosomes separate from each other resulting in four types of haploid cells in equal numbers; SY, sY, Sy, sy
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During anaphase 1, homologous chromosomes separate from each other and both Y alleles move to one pole because they are on the two chromatids of one chromosome
both y alleles, located on the two chromatids of the homologous chromosomes
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the chromosomes have duplicated during S phase and each has two copies of each allele; all chromosomes align on the metaphase plate during the metaphase 1.
there are two Y alleles, two y alleles , two S alleles and two s alleles at the metaphase plate
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if the twp genes are on separate chromosomes, the alleles of one gene move independently of alleles of other gene, Independent assortment
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Crossing-over
if the two genes are close together on a chromosome, however, crossing over may occur and the two alleles may move together during meiosis 1,
most chromosomes are so long that crossing over occurs several tomes within each chromosome during prophase 1
because no preferential sites for crossing-over seem to exist, the farther apart two genes are the greater the possibility that crossing over will occur between them
Independent assortment can also occur if two genes are located far apart on the same chromosome such that crossing-over occurs between them during prophase 1, after homologous chromosomes have paired and a synaptonemal complex is formed
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Leaves
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Concepts
The shoot system
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Almost all leaves contain only primary tissues; secondary production of wood and bark in leaves in extremely rare.
Stems
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Maximum conduction and support with minimum expenditure of construction material require a cylindrical stem
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Leaves
most tissues should be alive and differentiated into chorophyll-rich chlorenchyma for photosynthesis
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Respiration
Types of Respiration
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Aerobic
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Electron acceptors
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Oxygen-not needy, Cheap, not toxic
Citric acid Cycle
Glycolysis
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Facultatively
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Fungi, Tissues in animals
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Anaerobic
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Facultatively
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Fungi, Tissues in animals
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No Oxygen
Occurs, plants, Fungi in mud or still water
Acetaldehyde- Expensive, needy, toxic #
Pyruvate-expensive, needy, toxic #
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Ancient, Metabolism, happens everywhere
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Fermentation
Beer
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grains
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barely, Wheat , corn , rice
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Flowers and reproduction
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Sexual reproduction
fruit development
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the entire fruit wall, whether composed of one, two, or all three layers is the pericap
the exocarp is the outer layer-the skin or peel; the middle layer is the mesocarp or flesh and the innermost layer endocarp, may be tough like the stones or pit of a cherry
as the ovule develops into a seed, the ovary matures into a fruit
Embryo and seed development #
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the end of the embryo farther from the suspensor initiates two primordia that grow into two cotyledons
the zygote grows into small cluster of cells part of which later becomes the embryo proper and the other part becomes a short stalk-like structure the suspensor
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all of this tissues, both coenocytic and cellular is called endosperm and it nourishes the development of the zygote
because both sperm nuclei undergo fusions-one with one egg nucleus and the other with the polar nuclei- the process is called double fertilization
it undergoes karyogamy with both polar nuclei est. large endosperm nucleus that is triploid containing three full sets of genes
Syngamy of sperm and egg involves both plasmogamy, fusion of the protoplasts of the gametes, and karyogamy fusion of the nuclei
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Megagametophyte
the seven cells are one large central cell with two polar nuclei, three small antipodal cells and an egg apparatus consisting of two synergids and an egg
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Mircogametophyte
after a pollen grain lands on a stigma, it germinates by producing a pollen tube that penetrates in to the loose open tissues of the stigma
there it divides mitotically, producing a large vegataitve cell and a small Len-shaped generative cell
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it is not uncommon for flowers of certain species species to lack one or two of the four basic floral appendages thus being called incomplete flowers
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the flower like stalk is a pedicel and the very end of the axis where the other parts are attached is the receptacle
the plant life cycle
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because gametophytes do not resemble sporophytes at all this is an alternation of heteromorphic generation
the two types of gametophytes have grown from two types of spores: mircrogametophytes from microspores
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a life cycle like this, with two generations-sporophyte and gametophyte is said to be an alternation of generation
in oogamous plants, just as in of individual and eggs by different type of individuals hence, there are "male" or microgametophytes
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Mammalian gametes are of two types: small sperm cells (microgametes) that swim and large eggs (megagametes) that do not
they cannot undergo syngamy, but each undergoes mitosis and grows into an entire haploid plant called a gametophyte
Gametes can fuse with other gametes in a process called syngamy or fertilization, thereby producing the diploid zygote
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sexual reproduction in angiosperms involves flowers which produce the necessary cells and structures
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Concepts
which are produced by sexual reproduction, often have a means of long distance dispersal
with asexual reproduction, progeny are never more fit than the parent, but during sexual reproduction sex cells of one plant
combine with those of one or several others, resulting in many new gene combinations
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if the environment is stable during several lifetimes it is selectively advantageous for an organism to reproduce asexually by budding or sending out runners #
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Biomes
The Current World Biomes #
Tropical Biomes
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Tropical Rain forest
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the morning may be cool and fresh, but clouds develop rapidly and rain almost invariably falls by noon
occur close to the equator, rain fall is high typically over 200 cm/yr and often much more
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Dry temperature Biomes
Desert
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Shrubland and woodland
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If grass grows between the trees, the biome is known as a Savanna instead
A woodland is similar to a forest except that trees are widely spaced and do not form a closed canopy.
Grasslands
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This part of North America has no mountains being too far from the various continental collision zones; it is remarkably flat with at most low, roiling hills
the entire plains of north America extending from the Texas coast to and beyond the Canadian border is or more accurately, was grasslands
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Temperate Deciduous
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the foliage of these angiosperms trees contains fewer defensive chemicals than do the needles and scale leaves of a conifer
dominate trees vary geographically, but tall broad leaf tress are more frequent everywhere
in the united states occupies lower, warmer regions, where as higher cooler elevations support the Subalpine vegetation of the Appalachians and Adirondacks
the climate that produces the temperate Deciduous forest Biome is one with cold winters and warm but not hot summers #
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Moist Temperate Biomes
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rains are reliable present through fall,winter and spring, with only a brief period of summer dryness.
Winter are mild, and only rarely is there frost; northern California to Alaska, but they end at the summit of the Coastal Range 200 kn form the coast
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The northwest coast of the united sates is formed by a series of mountain ranges that force westerly winds from the Pacific Oceans
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as a result of the continental drift, the United States is currently located almost exclusively in the north temperate zone
Much of Alaska is situated in the polar zone, whereas Hawaii, Puerto Rico and Guam lie in the tropical waters
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Concepts
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the geographic locations of the earths biomes are determined by many factors but #
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at all sites, the physiognomy-the appearance-of a biome is similar,
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a particular type of biome.such as grassland or temperate deciduous forest, #
may occur in various regions of earth because the same set of climatic and soil factors occurs in various regions
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biomes vary from extremely simple, as in tundra, to more complex grasslands, temperature forest and tropical rain forests. #
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Atmospheric Distribution of heat #
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land areas below this descending air contain the worlds hot,dry desert biomes #
air radiates heat to space, cooling it even more
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by the time it reaches about 30 degrees Nor S it has cooled contracted and become dense enough to sink
after rising, the air is pulled northward and southward by the rising of more tropical air below it
much of the tropical zones is occupied by the pacific, Atlantic and Indian oceans
throughout the year, water and air receive solar heat, causing tremendous amounts of evaporation.
as it flows upward, the surrounding air pressure decreases and the moist rising air expands even more
this expansion causes the air to cool, decreasing its ability to hold moisture. water vapor condenses into rain and falls back
tot he surface in torrential storms, producing tropical rain forest in Central America, northern south America, central Africa and southeast Asia
the air warms, expands, then rises high into the atmosphere
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the atmosphere and oceans, being fluids, develop convection currents and massive flows when heated in one area and cooled in another
Effects of Earth's tilt
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the most intense solar heating moves seasonally northward, then southward.
all parts of the plants experience seasonally, although in the region between 23.5 degree N between summer and winter as in the temp regions outside this band
as earth contuines it orbit, the axis of rotation point less towards the sun
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if there was no atmosphere or oceans, heat could be transferred from the equator gradient between those regions
at all sites not on the equator, 70 degree N, the sun would never be overhead
maximum heating would be at the equator; all other regions would always receive only obliqued lighting and would be much cooler
everyday it would rise in the southeast, pass low in the sky and set in the south west
at the equator, the sun would rise exactly in the east every day of the year
there would be no change, no seasons
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earths climatic conditions are the results of its tilted axis of the rotation and the presence of the atmosphere and oceans
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