The scientific study of plants. (a.k.a, plant biology) Botany The scientific study of plants. (a.k.a, plant biology)

Areas of Botany Plant Anatomy Plant Physiology Plant Taxonomy Plant Geography Plant Ecology Plant Pylogeny Plant Genetics Plant Cell Biology Economic Botany Ethnobotany

Plant Importance Oxygen production Food & Beverages 95% from only 20 species Use of plant extracts (e.g., medicines, perfumes, dyes, flavoring, etc…) Aesthetics & Home gardening 33 million Americans have home gardens

Plant Basics 262,000 species of plants 90% of them are flowering plants Plants are either woody (trees/shrubs) or herbaceous. Plants are either annuals, biennials, or perennials.

What exactly is a plant?

Characteristics of Plants Multi-cellular Eukaryotic (have nucleus and other membrane-bound organelles) Sexually & Asexually-reproducing Have cellulose-rich cell walls Have chlorophyll & are photosynthetic* Immobile *If not photosynthetic, then descended from photosynthetic organisms! (see next slide →)

Devilish Dodder—Not Your Typical Plant Also known as devil’s gut and strangleweed. Dodder lacks chlorophyll, so it can’t produce it’s own food. Parasitic plant Dodder is not rooted in soil.

Although plants are unique, they share characteristics with all living organisms …

Plants Are Highly Organized Cells Tissues Organs (leaves, roots, etc…) Organism Population Community Ecosystem

Plants Take In & Use Energy Photosynthesis—conversion of radiant energy into chemical energy stored in sugar (glucose) Respiration—the release of stored chemical energy for use by the cell

Plants Grow & Develop Growth—an increase in the size/weight of an organism. Some plants continue to grow throughout life. Development—includes all changes in an organism from the start of life to death. Fertilized egg → Embryo (within seed) → seedling → Adult plant

Plants Reproduce Reproduction—the formation of a new individual by sexual or asexual means

Plants Respond to Stimuli Stimuli to which plants respond include: Direction, Color & Intensity of Light Temperature Orientation toward gravity Etc… Some plants respond in a dramatic way—Venus fly trap

Plant Populations Evolve Over Time Adaptations—characteristics that enable an organism to better survive in a certain environment. Physical features (e.g., thick, succulent leaves of cacti) Behaviors (e.g., dormancy)

General Plant Anatomy The plant body is organized into a root system and a shoot system: Root system is generally below ground. Shoot system consists of vertical stems, leaves, flowers, & fruit that contain seeds.

Roots Anchor plant Absorb water & nutrients Transport to stem Some store food Root hairs increase surface area

Shoots a.k.a. stems Support plant Storage of water and food Turgor pressure against cell wall holds plant up Storage of water and food Transport materials Photosynthesis

Leaves Transpiration: evaporation of water through pores in the leaves Draws water through plant’s vascular system Absorption of sunlight for photosynthesis

Kingdom Plantae A brief introduction …

How do we classify plants?* There are a variety of ways to classify plants, but one of the most general ways is to group them according to their reproductive strategy: Spore: simple reproductive cell with hard, outer wall Seed: embryo, food supply & protective coat *We will cover this in depth at a later time!

Seedless nonvascular plants Water and nutrients move from high concentration to low (absorbed) Require a moist environment Mosses & liverworts

Seedless vascular plants Ferns Horsetails Reproduce by spores

Seed plants All have vascular tissue Seed structure: Embryo Cotyledon(s): store food for embryo

Gymnosperms Seeds produced in cones Ginkgo Conifers (pine, fir, spruce) Most conifers are evergreen

Angiosperms Flowering plants Monocots: 1 cotyledon Dicots: 2 cotyledons Fruit: ripened ovary of a flower Flower structure will be covered in lab! Includes trees, grasses, houseplants

Monocots vs. dicots Number of cotyledons Veins in leaves Flower parts 1 Usually parallel Multiples of 3 Dicots 2 Usually netlike/ branched Multiples of 4 or 5