2 PlantsWhat are plants?Eukaryotic, multicellular organisms that have chlorophyll and carry out photosynthesisFor the most part, they are terrestrialLive in almost all types of environmentCan be big, or can be smallRemember, they are autotrophic!
3 Plants are Invading the Land! About 500 million years ago, a group of green algae developed adaptations that enabled them to invade the land.Over 85% of land plants are flowering plants, the Angiosperms.14% are mosses and ferns.1% are conebearing plants (Gymnosperms).The challenges to invading the land include:preventing water lossabsorbing and transporting waterfertilization and protection of the embryoStructural support
5 Alternation of Generations Plants have a life cycle that involves two distinctly different generationsSporophyte generation is diplod (2N) and has plant parts in which meiosis can take place to be haploidGametophyte generation is haploid (N) and develops structures that produce gametesThe gametes will be produced through mitosisWhen two haploid gametes unite a diploid zygote is formed
6 Nonvascular PlantsNonvascular plants include mosses, hornworts, and liverworts, and are commonly known as bryophytesThey all have these following characteristicsThey lack vascular tissueThey do not have true roots or leavesThe gametophyte generation is the most prominent part of the life cycleSperm swim to the egg
7 Moss Life CycleThe moss plant you generally see is the gametophyte generationTwo structures that produce gametesAntheridium is made up of a jacket of cells surrounding the developing spermArchegonium is a flask shaped structure that produces the eggWhen sperm mature, antheridian opens and sperm will swim through a film of dew or rainwater to archegoniumSperm and egg nuclei fuse, diploid zygote is produced and is in the sporophyte generation
8 Vascular TissuePlants, excluding the bryophytes have a vascular system to transport water and nutrients throughout the plantRoots are underground structures that anchor the plant and absorb water and mineralsLeaves are structures specialized for carrying out photosynthesisStems are structures which connect the roots with the leaves and position the leaves so they receive sunlight
9 Vascular Tissue Two kinds of vascular tissue: xylem and phloem Xylem consists of a series of dead, hollow cells arranged end to end to to form a tubeCarries water and minerals up from the roots through the stem to the leavesPhloem carries organic molecules (sugars, aa) produced in the leaves to other parts of the plant where growth takes place
10 RootsRoots never stop growing by their tips to try and get new territory for available nutrients and waterMost roots are storage places for the food produced by the plant to store during harsher seasonsSome roots are a source of food for us, such as carrot, turnips, and radishes
11 Stems Two basic functions of stems: Support the leaves Transport raw materials from root to leaves and food from leaves to rootsInside the bark here are seven layers of xylem tissue. Each layer of xylem constitutes 1 years tree growth
12 Leaves Leaves carry out photosynthesis Have a large surface area to try to collect as much sunlight as possibleStomates open and close to control the rate at which water is lost and gases are exchangedDuring times of drought, the stomates are closed to reduce the rate at which the plant loses water
13 Seedless Vascular Plants Seedless vascular plants include whisk ferns, horsetails, club mosses and fernsThey have vascular tissue, but do not produce seedsNot as limited to wet areas as nonvascular plants, because they have roots and vascular tissue.Still need water to move sperm
14 Ferns Most abundant of the seedless vascular plants Found in greater number in the tropics, but can be found throughout the worldSome are very small, while some can grow to be very large.Some have trunks which are 79 feet high, and leaves that grow up to 16 feet longThe stage you see when looking at ferns are mostly sporophytesThe vertical leaves on ferns are known as frondsOn the underside of the fronds, the spore producing parts are located, known as sori (sorus)
16 Seed-Producing Vascular Plants Seed is a specialized structure that contain an embryo, along with stored foot, enclosed in a protective coat, known as a seed coatTwo major groups of plants that produce seeds:Gymnosperms (conifers)Angiosperms (flowering plants)
17 GymnospermsGymnosperms (naked seed plants) are plants that have cones (woody structures) where their seeds are produced.Pollen grains are the male gametophytes, and the transfer of pollen is known as pollination.
19 Types of GymnospermsCyads – are stout, woody gymnosperms that have a ring of fernlike leaves on the top that live in tropical regions.Ginkgo trees- have fan-shaped leaves. There is only one species left, Ginkgo biloba. Reproductive strucutres of ginkgos are on separate trees.
20 Types of GymnospermsConifers are the common trees and shrubs that bear seeds in cones and many have needle- shaped leaves.
21 AngiospermsAngiosperms are plants that produce flowers and have their seeds enclosed in fruit.Fruit is a modification of the ovary wall into a special structure that contains the seeds.Flower is the structure, composed of highly modified leaves, that is responsible for sexual reproduction.
22 Flower StructurePistil is at the center of a flower, which is composed of the stigma, style and ovary.Stigma is the terminal portion of the pistil and is meant to receive pollen.Style is where the male gamete travels down into the ovaryOvary is the female reproductive structureStamen is male organ of a flowerFilament is the stalk of the antherAnther contains pollen sacs. The sacs release pollen on to the outside of the anthers that brush against insects on entering the flowers.