Presentation on theme: "How Do Angiosperms Reproduce? Asexual & Sexual Methods"— Presentation transcript:
1 How Do Angiosperms Reproduce? Asexual & Sexual Methods
2 Vegetative Reproduction Form of asexual reproduction where new plants grow from parts of an existing plant (roots, stems, leaves)New plants are clones of the original plant because their genetics are the same
3 Stem ModificationsRhizomes: underground stems store food and can give rise to new plants along their lengthEx: ginger
4 Stem Modifications Stolons: stems that grow on top of the ground’s surface to establish new plants.Ex: strawberries, quack grass
5 Stem Modifications Bulbs: stem is only a small disk that is just above the rootsEx: green onions and garlic
6 Stem Modifications Tubers: fleshy, food-storing swellings at the tip of an underground stemEx: potatoes
7 Other ModificationsCuttings: A piece of root, stem or leaf is cut from a mature plant, and when in favorable conditions, forms its own roots and/or shoots. (ex: fruit trees)Fragmentation: broken pieces of some plants will regenerate when conditions are favorable (e.g. mosses)
8 Benefits to Asexual Methods Usually faster than reproducing with spores or seedsMore uniformity than with sexual methodsThe only way to reproduce fruits that do not produce seeds
9 Sexual ReproductionFlowers are the sexual reproductive structures of angiosperms.Sexual reproduction involves pollination and fertilization resulting in the formation of seed.Part of the flower grows into a fruit that contains seeds.
10 Flower PartsSepalsPetalsStamensmale organsPistilfemale organ
11 Stamens (Male Organs) Filament: the slender stalk Anther: the capsule at the top of the filament
12 Pistil (Female Organ)Stigma: the sticky enlargement at the top of the pistil; pollen sticks here.Style: the slender stalk of the pistil.Ovary: the swollen cavity at the base of the pistil. Female sex cells are located here.
13 Pollination the transfer of pollen grains to the pistil Pollen is produced in the anther and released when mature. Pollen contains the male gametes.A pollen grain attaches to the sticky stigma of a flower.
14 Types of PollinationSelf-pollination - pollen is transferred from the anther to stigma of the same flowerCross-pollination - pollen is transferred from the anther of one plant to the stigma of another
15 Fertilizationis the joining of male and female gametes to form a zygoteA pollen tube grows down to the ovary.
16 FertilizationTwo sperm travel down the pollen tube --- one fertilizes the egg and the other helps to form endosperm (stored food for seed). This is called double fertilization.3. The ovary enlarges and a seed forms.
18 Seedis a complete embryo with cotyledons surrounded by an endosperm and protected by a seed coat
19 Seed a) seed coat – protects the embryo b) endosperm – stored food for young plantc) cotyledons - store food for the young plant, until it has big enough leaves to make its own food through photosynthesis.d) embryo - looks like a miniature plant inside the seed.
20 SeedThe seed is a new generation that contains genetic information from both the egg and pollen.