Plant Notes Ms. Williams Biology

Characteristics of Plants Multicellular Eukaryotic Photosynthetic autotrophs Have thick cell walls made of cellulose The stems and leaves are covered by a waxy, waterproof coating called a cuticle

Non-Seed Plants Reproduce using spores A spore is a diploid (2n) reproductive cell, produced by meiosis, which can withstand harsh environmental conditions. Most non-seed plants are non-vascular (do not contain vascular tissue

Non-Seed Plants Examples of non-vascular, non-seed plants are mosses, liverworts and hornworts

Non-Seed Plants These plants grow close to the ground to get water by a process called osmosis. Other types of non-seed plants contain vascular tissue Examples of vascular, non-seed plants are ferns, horsetails and club mosses

Alternation of Generation Plants reproduce by a process called alternation of generation This has 2 stages: A haploid (n) stage called a gametophyte, which produces sex cells (eggs or sperm) A diploid (2n) stage called the sporophyte

Alternation of Generation This is the plant that you normally see. In some cases, the sporophyte produces spores

Seed Plants Have features that allow them to reproduce without water. These include pollen, cones, flowers and seeds.

Seeds Can survive long periods of unfavorable conditions Protects embryonic plant from drying out

Seeds There are 3 parts to a seed: Embryo - the tiny developing plant Cotyledon - food source for embryo Seed Coat - protects seed from damage and water loss

Seeds Seeds allow plants to disperse to new places Seeds can be dispersed by wind, water and animals Seeds may also have hooks, wings and feathery projections to help them move

Seeds Seed plants can be grouped according to whether their seeds are enclosed in a fruit

Gymnosperms

Gymnosperms Plants with seeds that do not develop within a fruit Most have seeds formed in cones, which have protective scales Male cones produce pollen, female cones produce eggs

Male vs. Female Cones

Gymnosperms Examples include pine, fir and spruce trees These are pollinated by the wind

Gymnosperms Conifers, or evergreens, have the following adaptations: Needles have a compact shape and a thick cuticle to prevent water loss Stems have a thick layer of xylem that insulates the tissues inside Leaves and branches are flexible to bend under the weight of snow & ice

Angiosperms

Angiosperms - “flowering plants” Plants with seeds protected by a fruit Largest and most diverse group of plants Provide most of the food eaten by humans

Angiosperms The fruit is the ripened ovary of the flower The flower is the reproductive structure of angiosperms Need insects, birds or other animals to pollinate the plant

Angiosperms These animals are attracted by the color and shape of the flower

Two classes of angiosperms based on their seeds Types Monocot Dicot Examples Corn, grass, lily Bean, tree, cactus # of Cotyledons 1 2 Vein structure in leaves Parallel Branched # of flowering parts 3’s or multiples of 3’s 4’s or 5’s or multiples of 4’s or 5’s Vascular tissue arrangement in stem Scattered Ring

Angiosperms 3 Types of lifespans in angiosperms Annuals - flowering plants that mature and complete their life cycle in one year

Angiosperms Life spans Biennials - flowering plants that take two years to complete their life cycles

Angiosperms Life Spans Perennials - flowering plants that live for more than two years; come back year after year