General Characteristics
1. multicellular (many specialized tissues -- leaf, root, flower, stem, some develop seeds -- protection)
2. eukaryotic
-- have a nucleus
-- DNA inside nucleus (in the form of chromosomes)
3. have cell wall with cellulose
4. aerobic
5. autotrophic (photosynthesize - have chlorophyll)
6. large (compared to bacteria)
Photosynthesis Plants (an other photosyntesizing organisms -- autotrophs), produce the oxygen in the atmosphere through the process of photosynthesis. It can be simply written as the reaction formula below, but it is a much more complex process consisting of two reactions -- the light-dependent reaction (or just light reaction) and the ligh-independent reaction (or the "dark reaction" or the Calvin cycle).
Light energy + 6CO2 + 6H2O ---> C6H12O6 + 6O2
Sometimes written with "n" instead of numbers, where n = 6.
Photons + nCO2 + nH2O ---> (CH2O)n + nO2
Need something simple to help you remember the photosynthesis, here is the "photosynthesis song".
Movement to land
-- Plants invaded land about 430 mya (430 - 410 mya)
(seedless vascular plants)
Early plant forms lived in the oceans
1. no problem with dehydration
2. no problem with rapid temperature changes
3. no problem with extreme temperatures (narrower temp. range in the oceans)
Problems which needed to be overcome
1. keeping membranes moist for gas exchange (e.g., roots in the soil)
2. supporting locomotion without buoyancy of water (e.g., woody stem)
3. transporting water in the body (e.g., vascular system)
4. conserving water in the body (e.g., leathery tissues)
5. reproduction in a dry environment (e.g., pollination)
6. development of the early embryo (e.g., in a protective seed)
7. surviving rapid environmental changes (e.g., dormant)
• Sexual life cycle -- haploid (gametophyte) and diploid (sporophyte) phases alternate. • Evolutionary trend:
fr. gametophyte (haploid) dominance ‹ to sporophyte (diploid) dominance def. Alternation of generations: A sexual life cycle in which haploid (gametophyte) and diploid (sporophyte) phases alternate.
def. Gametophyte: haploid form of a life cycle of a plant, characterized by "alternation of generations", (produce gametes).
def. Sporophyte: diploid form of a life cycle of a plant, characterized by "alternation of generations" (produce spore-bearing structures).
Vascular bundles (Phloem and Xylem, in vascular plants)
def. Phloem: Vascular tissue in plants transporting food materials (glucose and other organic molecules) from the leaves to other parts of the plant. (Two kinds: sieve-tube cells, and companion cells.)
def. Root: Specialized structure for the absorption of water and minerals in higher plants.
def. Vascular bundles (vascular tissue): Transport tissue in plants consisting of xylem and phloem.
def. Xylem: Vascular tissue in plants transporting water from the roots to other parts of the plant. (Two kinds: vessel elements, and tracheids.)
Reproductive structures (Flower, in flowering plants)
• The flower def. Anther: Sex organ in plants with pollen sacs that produces the male gametophyte (pollen).
def. Cone: Reproductive structure in gymnosperms, consisting of modified leaves or scales, that produces pollen in males or eggs in females. (Two kinds: male -- pollen cone, female -- seed cone.)
def. Embryo: Stage in a multicellular organism that develops from a zygote before it becomes free living (in seed plants the embryo is part of the seed).
def. Filament: The stalk of a stamen.
def. Flower: Reproductive structure of angiosperms, a complex structure made from modified stems and leaves, producing pollen in the males, and eggs in the females.
def. Fruit: The structure in angiosperms that contains seeds.
def. Ovary: The female sex organ in both plants and animals that produces haploid sex cells -- eggs (ova), in plants the lower region of the pistil.
def. Ovule: In seed plants the structure contained in the ovary and develops into the seed.
def. Petal: The usually conspicuously colored part of a flower (modified leaves) located above the sepals.
def. Pistil (carpel): Sex organ in plants with the ovule that produces the female gametophyte (the egg or ova).
def. Receptacle: The part of the flower stalk that that bears the flower.
def. Seed: Specialized structure (mature ovule) in gymnosperms and angiosperms that contains the embryo (embryonic sporophyte).
def. Sepal: The usually inconspicuously colored (green) part of a flower (modified leaves) located below the petals.
def. Sporangium (pl. sporangia): In fungi and plants, a structure within which cells undergoes meiosis to produce haploid spores. (A structure in which spores are formed.)
def. Spore: 1. Single celled reproductive structure, usually an asexual haploid cell produced by a sporophyte that divides by mitosis to produce new haploid individuals (could also be a sexual haploid cell that first must unite with another sexual spore to produce a new life stage); 2. A resistant, resting body adapted to survive adverse environmental conditions.
def. Stamen: The male reproductive structure of a flower (consisting of the anther and the filament).
def. Stigma: The upper region of the pistil that serves as a receptive surface for pollen grains.
def. Style: The middle region of the pistil, often a slender column that arises from the top of the ovary and through which the pollen tube grows.
Gas flow in plant leaves
• Stoma
def. Stoma (pl. stomata): In a plant leaf, a tiny mouth-like pore that opens and closes to regulate the flow of carbon dioxide and other gases.
Classification
• The evolutionary tree of the plant kingdom consists of 4 major branches (nonvascular plants, seedless vascular plants, seed vascular plants, and flowering plants).
Evolutionary step 1: Living on land
Note: plants originated in the oceans
Nonvascular Plants
1. swimming flagellated sperm
2. non-vascular tissues (no internal transport system -- plant must remain small)
3. spores (reproduction)
4. simple reproductive structures
i. Phylum Hepatophyta Liverworts ii. Phylum Bryophyta Mosses
Evolutionary step 2: Vascular tissues (Water and nutrient transporting vessels)
Note: mosses have no vessels (no xylem or phloems)
Seedless Vascular Plants
1. swimming flagellated sperm
2. vascular tissues (internal transport system -- plant can be large)
3. spores
4. simple reproductive structures
i. Phylum Equisetophyta Horsetails ii. Phylum Pteridophyta Ferns iii. Phylum Psilotophyta Whisk Ferns iv. Phylum Lycopodophyta Club Mosses
Evolutionary step 3: Reproduce by means of SEEDS
Note: previous phylum reproduced by means of spores
i. Phylum Coniferophyta Conifers (Pinophyta) ii. Phylum Cycadophyta Cycads iii. Phylum Ginkgophyta Ginkgos iv. Phylum Gnetophyta Ephedras (Gnetophytes)
Evolutionary step 4: Produce seeds in structures called FLOWERS
Note: previous phylum produced seeds in cone-like structures
-- largest group of plants (also Magnoliophyta, Angiospermophyta)
a. Class Liliopsida (Monocotyledons -- Monocots)
(Lilies, Orchids, Grasses, and Palms) – germinate w. one leaf
– leaf venation parallel
– flower petals 3 or 6 (or multiples)
- vascular bundles in the root: ring in the center
- vascular bundles in the stem: scattered
b. Class Magnoliopsida (Eudicotyledons -- Eudicots)
(most flowering plants)
-- largest group of angiosperms (old name Dicots) – germinate w. two leaves
– leaf venation "fishbone"
– flower petals 4 or 5 (or multiples)
- vascular bundles roots: in a "plus" or "x"
- vascular bundles stem: in a ring along the edge
- - - Photosynthesis (Khan Academy You Tube) - - -
COMMENT ON THE YOUTUBE: Yet another awesome video!! I'm so grateful for these videos; honestly, you make the sciences so easy to understand and even INTERESTING!
I also love how you said at 2:28, "we? eat the cow, if we're not vegetarians" -- thank you, as I am a vegetarian myself :)
(Source: Dr. Nilsson's old lecture notes. Permission given in 2001 by McGraw-Hills then sales representative, Don Grainger, to use the picture online on lecture notes.)
Plants (an other photosyntesizing organisms -- autotrophs), produce the oxygen in the atmosphere through the process of photosynthesis. It can be simply written as the reaction formula below, but it is a much more complex process consisting of two reactions -- the light-dependent reaction (or just light reaction) and the ligh-independent reaction (or the "dark reaction" or the Calvin cycle).
Age of algae (unicellular algae)
- - - Photosynthesis (Khan Academy You Tube) - - -