Ch. 9 & 10 Plants

Plant Diversity Ch. 9 Lesson 1: What is a Plant?

Characteristics of Plants Made of Eukaryotic Cells Chloroplasts Cell Wall Vacuoles Multicellular Made of many tiny cells Cells have specialized functions Producers Use outside energy source, such as the Sun, to make their own food Make sugar called Glucose Characteristics of Plants

Present day plants and Green algae evolved from a common ancestor Plants and Green Algae share chemical similarities, the same pigments, as well as DNA similarities Protection Cuticle: Waxy Protective layer on leaves, stems and flowers Support Cell wall provides support Cell wall made of cellulose: Cellulose: Organic compound Plant Adaptations

Plant Adaptations Transporting Materials Reproduction Vascular Tissue: Composed of tubelike cells that transport water and nutrients Reproduction Seeds and Spores move throughout the environment Animals, wind, and water all help move seeds and spores Plant Adaptations

Plant Classification Seedless Plants Reproduce by spores Do not have flowers Some don’t have vascular tissue Seed Plants Most plants are seed plants Some have flowers that produce fruit with seeds Some produce seeds in cones Each seed has tissues to surround, nourish and protect the tiny plant embryo inside it

Ch. 10: Plant Processes Lesson 1: Energy Processing in Plants

Materials for Plant Processes: -Xylem and Phloem Xylem and phloem are the two vascular tissues that move or transport materials throughout the plant Water enters the plant through the roots The water then moves to the xylem to travel to the rest of the plant

Materials for Plant Processes: -Xylem and Phloem Like us, plants need food, water, and oxygen. Unlike us, plants make their own food-a liquid sugar. Liquid sugar moves out of food making cells into the phloem The liquid sugar then flows to all parts of the plant Cells break down the sugar to release energy

Leaves and Photosynthesis *Remember: Photosynthesis: a series of chemical reactions the convert light energy, water, and carbon dioxide into the food-energy molecule glucose and give off oxygen Leaves and Photosynthesis Since they cannot eat as people do, plants make their own food. Leaves are the major food-producing organs of plants Layers of the leaf: Top and Bottom: epidermal cells Bottom layer has openings called stomata CO2, water vapor and O2 pass through stomata Epidermal cells can produce a waxy covering called the cuticle

Leaves and Photosynthesis Layers of the leaf: Middle Layers: Contain chloroplasts, the organelle where photosynthesis occurs Top middle: Palisade mesophyll cells Packed tightly to expose cells to light Bottom middle: Spongy mesophyll cells Have open spaces to allow for gases to flow

Capturing Light Energy Chlorophyll absorbs the energy from sunlight in the 1st step of photosynthesis. Most plants look green because chlorophyll reflects green light but is better at absorbing the other wavelengths of light. The energy is then used to split the water molecules.

Making Sugars Sugars are made in the 2nd step of photosynthesis In the chloroplast, Carbon Dioxide from the air is converted into sugars by using the energy stored and trapped by chlorophyll CO2 combines with Hydrogen atoms (taken from splitting water molecules apart) This forms the sugar molecules Plants can either use the sugar as energy or they can store it.

Cellular Respiration *Remember* Cellular Respiration: a series of chemical reactions that convert the energy in food molecules into a usable form of energy called ATP. Cellular Respiration All organisms require energy to survive. Energy is in the chemical bonds of food molecules Cellular Respiration is a process that releases that energy Glucose molecule break down during Cellular Respiration: Energy released is used to make ATP This process requires Oxygen Produces water and Carbon Dioxide as waste products. Occurs in cytoplasm and mitochondria of cells

Cellular Respiration and Photosynthesis

Plant Responses Have you ever been in a dark room when someone suddenly turned on the light? Quickly shutting or covering your eyes is a reaction to a stimulus Stimuli are any changes in an organism’s environment that cause a response. (singular, stimulus) Plants often respond slowly to stimuli. Light is a stimulus. A plant responds to light by growing toward it. This might take several hours

Plant Reproduction Ch. 10 Lesson 3

Plants reproduce Asexually, Sexually or Both! Sexual Reproduction Asexual Reproduction Usually requires two parents Plants sperm cell combines with plants egg cell Result is a Zygote, grows into a plant New plant is combination of its parents When a portion of a plant develops into a separate new plant New plant is genetically identical to the original (parent) plant Stolons: Horizontal Stems Advantage: Only 1 parent is needed

Alternation of Generations Plants have life stages called generations: Diploid stage and Haploid stage Alternation of Generations: Occurs when the life cycle of an organism alternates between diploid and haploid generations Haploid cells: Individual chromosomes Diploid cells: Homologous Chromosomes

Reproduction in Seedless Plants Both Mosses and Ferns show an alternation of generations Plants grow from haploid spores produced by the diploid generation They then produce both sex cells, fertilization takes place Zygote results and grows by mitosis

Reproduction in Seed Plants Role of Pollen Grains Forms from tissue in a male reproductive structure of a seed plant Each grain contains nutrients and a hard outer covering Pollen grains produce sperm cells Large amounts of pollen are produced by male reproductive structures Wind, animals, gravity and water can carry pollen Pollination Occurs when pollen grains land on a female reproductive structure of a plant that is the same species as the pollen grains

Role of Ovules and Seeds The Ovule is the female reproductive structure of a seed plant where the haploid egg develops After Pollination, sperm enter the ovule and fertilization occurs A zygote forms and develops into an embryo An embryo is an immature diploid plant the develops from the zygote A seed is an embryo, its food supply, and a protective covering

Reproduction in Flowerless Seed Plants (Gymnosperms) Flowerless seed plants are known as Gymnosperms Common Gymnosperms: Pines, Firs, Redwoods and Yews Needle or Scalelike leaves Usually evergreens (leaves all year) Life cycle : Alternation of Generations Cones are male and female reproductive structures Cones contain haploid generation

Reproduction in Flowering Seed Plants (Angiosperms) Most flowers have both male and female reproductive structures The Stamen is the male reproductive organ of a flower Pollen grains form at the tip of the stamen in the anther. Filament supports the anther The Pistil is the female reproductive organ of a flower Pollen lands on the tip of the pistil, called the stigma Stigma is the tip of long tube called the style Ovary is at the base of the style. Ovary contains one or more ovules Ovules will eventually contain a haploid egg Female structures Male structures

Life Cycle of an Angiosperm Pollen grains travel from anther to stigma where pollination occurs Pollen tube grows from pollen grain into the stigma, down the style, to the ovary Sperm develop from cell in pollen tube When pollen tube enters an ovule, fertilization takes place Zygote that results develops into an embryo Each ovule and its embryo become a seed The ovary and sometimes other parts of flower develop into a fruit that contains seeds

Fruit and Seed Dispersal Fruits and seeds are important sources of food for people and animals Most seeds of flowering plants are inside of a fruit An ear of corn is made of many fruits or kernels. The kernel is mostly seed Strawberries have tiny seeds on the outside of the fruit Fruits help protect and disperse the seeds. Some fruit like the dry dandelion fruit are light and float on air currents When an animal eats a fruit, the seeds can pass through the digestive system with little or no damage to the seed. The animal then deposits the seeds with its wastes, usually a far distance from the original plant