Plants

What is a Plant? Multicellular eukaryotes Cell wall made of cellulose Photosynthetic Non-motile

What is required for survival? Sunlight Water Minerals Gas exchange Movement of water and nutrients

Basics Parts Leaves Roots Stem – Gametophyte/ sporophyte Light collectors for photosynthesis Roots Absorb water and minerals Stem – Contains vascular tissues Xylem – tube used to move water Phloem – tube used to move food (nutrients) Gametophyte/ sporophyte reproduction

Plant Life Cycle Two alternating phases called the “alternation of generations” Diploid phase – aka sporophyte phase Plant produces spores Haploid phase – aka gametophyte phase Plant produces gametes through meiosis Gametes fuse during fertilization to create a new plant

Groups of Plants - Bryophytes Mosses, liverworts, hornworts Depend on water for reproduction Sperm has to swim to egg Lack vascular tissue – rely on osmosis for transport of water Typically only a few centimeters tall

Moss

Liverworts

Hornworts

Groups of Plants – Seedless Vascular Plants Ferns, club mosses, horsetails Contains vascular system – xylem and phloem – to move water and nutrients Can grow much taller and more upright Requires water for reproduction

Ferns

Club Moss

Horsetails

Groups of Plants – Seed Plants Two groups – Gymnosperms and Angiosperms Reproduction free of water Flowers, cones – seed-bearing structures Pollen Contains sperm and is carried by wind or animals Lands on female structure – called Pollination Seeds protect embryos and provide a food source

Gymnosperms - “Naked Seed” Cone-bearers: includes gnetophytes, cycads, ginkgoes, conifers Reproduction takes place within cones Pollen cones – produces pollen grains Seed cones – produce ovules (eggs) Pollen is typically carried by wind to a seed cone Seed cone contains a sticky secretion to “catch” the pollen to ensure pollination

Gymnosperms - “Naked Seed” Fertilization occurs when sperm and egg fuse creating a zygote Zygote develops into an embryo and develops within a seed Seed Cone Pollen Cone

Gymnosperms

Angiosperms – Flowering Plants All reproductive structures are contained in flowers Every flower contains male structures that create pollen and female structures that create ovules Rely on animals for pollination, rather than wind Create fruit to protect seed

Angiosperms

Angiosperms – Flowering Plants Monocots Dicots Seeds Single cotyledon Two cotyledons Leaves Parallel veins Branched veins Flowers Flower parts in 3s Flower parts in 4s or 5s Stems Vascular bundles scattered Vascular bundles in a ring Roots Fibrous roots taproot

Angiosperms - Flowers Flowers have 4 specialized parts Sepals – leaf-like structure of flower Enclose the bud before it opens and protect developing flower Petals – colorful part of flower Used to attract pollinators Stamen – male structure Anther – produces pollen Filament – supports anther

Angiosperms - Flowers Carpel (aka Pistil) – female structure Ovary – contains ovules (eggs) Stigma – sticky portion of carpel – catches pollen Style – supports stigma; contains a tube that allows sperm to travel from stigma to ovary

Angiosperms - Fruit As seeds mature, the ovary walls thicken to form fruit that encloses the seed A fruit applies to any seed that is enclosed within its embryo wall – so vegetables would also be considered fruit in this case Huge advantage in dispersal How?