Chapter 2.1-2.3 What are Plants? PDF

Chapter 2. What are Plants? Prepared by: AMLlorando What are Plants?  2.1 Origin of Plants Life on Earth began about 3.5 billion years ago with prokaryotes (bacteria and archaeans). − Photosynthesis arose 2.8 billion years ago in a cyanobacterium. Organel...

Chapter 2. What are Plants? Prepared by: AMLlorando What are Plants?  2.1 Origin of Plants Life on Earth began about 3.5 billion years ago with prokaryotes (bacteria and archaeans). − Photosynthesis arose 2.8 billion years ago in a cyanobacterium. Organelles evolved followed by division of labor and specialization. − DNA became located in its own organelle, the cell nucleus. − Development of organelles was followed by division of labor and specialization. − Eukaryotes have nuclei (plants, fungi, animals, algae).  2.1 Origin of Plants Eukaryotes diversified, some gaining mitochondria and some gaining chloroplasts (via endosymbiosis). ✓ Those with mitochondria evolved into protozoans, fungi, and animals. ✓ Those with mitochondria and chloroplasts evolved into plants and algae. All organisms fit into three large groups called domains: Bacteria, Archaea, and Eukarya.  2.1 Origin of Plants Over 297,000 plant species exist today; wide diversity of adaptation is important. For any aspect of the environment, many types of adaptation are possible. – There is no single, perfect adaptation. – There are alternative adaptations. – There are ways of coping with different environments and the multitude of factors within them.  2.2 Characteristics of Life Cells Homeostasis Reproduction Metabolism DNA/ Heredity Growth & Development  2.3 Characteristics of Life Cells Basic unit of life Living things have one or more Microscopic  2.2 Characteristics of Life Homeostasis maintenance of a relatively stable internal environment. Examples: Body temp., oxygen level, blood sugar level, pH, water level.  2.2 Characteristics of Life Reproduction process by which living things give rise to offspring. May be simple or complex  2.2 Characteristics of Life Metabolism ability to obtain and use energy for growth and movement. Examples: Cellular Respiration, Photosynthesis  2.2 Characteristics of Life DNA/ Heredity Genetic material that is passed on during reproduction. DNA & RNA tell each cell what and how to make proteins.  2.2 Characteristics of Life Growth & Development ▪ permanent or irreversible or morphogenesis refers to increase in size the ordered change or process in plants ▪ Accompanied with cell differentiation and Series of discrete events; development degree of response such as percentage germination ▪ Measured in terms of increase in length, height, width, volume or number  2.3 Overview of Plant Structures Vegetative Organs Stems, roots, and leaves − Leaves harvest energy from the sun and package it into the sugar called glucose. − Roots obtain minerals and other nutrients. − Stems bear leaves. Vegetative organs do not carry out sexual reproduction.  2.3 Overview of Plant Structures STEMS Almost all stems bear leaves that are attached at regions called nodes. Axillary buds, just above the nodes, can become branches or flowers.  2.3 Overview of Plant Structures ROOTS Almost always confined to one end of the stem. Can emerge along a stem, as in ivy that climbs on trees and fences. English ivy (Hedera helix)  Golden Pothos (Epipremnum aureum)  2.3 Overview of Plant Structures LEAVES flattened green outgrowth from the stem of a vascular plant. Primary site of photosynthesis Varies in size  Largest leaf 6-10 ft high, 14 ft wide Gunnera manicata  Longest leaf (~52 ft) Raphia regalis  Largest waterlily (4 to 6 ft) Victoria amazonica  2.3 Overview of Plant Structures Reproductive Organs In ferns, these are barely distinguishable from vegetative organs. Conifers make seed cones and pollen cones. Angiosperms make flowers.  2.3 Overview of Plant Structures Ferns The reproductive organs of ferns are basically just foliage leaves that produce sporangia on their underside.  2.3 Overview of Plant Conifers Structures Conifers make seed cones and pollen cones. When the seeds are mature, the cone will expand enough to cause the scales to separate and allow the seeds to fall out. Seed cones: Female Pollen cones: Male (Both grow on the same tree)  2.3 Overview of Plant Structures Angiosperms Flower-bearing plants. have their seeds enclosed in a fruit vascular seed plants in which the ovule (egg) is fertilized and develops into a seed in an enclosed hollow ovary. ovary itself is usually enclosed in a flower  References Mauseth, James D. An Introduction to Plant Biology. Sixth Edition Shipunov, Alexey. Introduction to Botany. June 7, 2021 version. 192 pp. URL: BioExplorer.net. (2023). Types of Plants: The Four Major Classifications of Plants. Bio Explorer. https://www.bioexplorer.net/plants/.  Up next.. Continuation: 2.4 Plant Classification Chapter 3: The Plant Cell  Botany lab Bring the following per group: Unpeeled Red onion (Allium cepa) Hydrilla verticillata sprig Macerated Potato (Solanum tuberosum) Macerated Corn (Zea mays) Macerated Gabi (Colocasia esculenta) San Francisco leaf Mayana leaf Ripe tomato Sharp Blade Tissue Alcohol Dropper Glass slide Cover slip