Plants

What is a Plant? Autotrophs Eukaryotes Multicellular Central vacuole Cell wall Cellulose – makes the cell wall rigid Chloroplasts – where food is made

Adaptations for Living on Land Ways to obtain water and nutrients Retain water Transport materials Support their bodies Reproduce Cuticle – waxy, waterproof layer that covers the leaves and helps plants retain water Vascular tissue – tubelike structures that transport materials within a plant

Nonvascular Plants Mosses Liverworts Hornworts   Vascular Plants Seedless Vascular Plants Ferns Club mosses Horsetails Seeded Vascular Plants Gymnosperms Cycads Conifers Ginkgoes Gentophytes Angiosperms Monocots Dicots

Origins and Life Cycles Oldest plant fossils are about 400 million years old. Biologists compared chemicals: Chlorophyll – green pigment found in the chloroplasts Sporophyte – plant produces spores (tiny cells) Gametophyte – plant produces sex cells (sperm and egg cells)

Photosynthesis

The Nature of Light Transmission- allows light to pass through Reflection – light bounces back Absorption – take in light (absorbs) When light strikes the green leaves, green is reflected back and other colors are absorbed. Pigment – chemical that produces color – in plants, chlorophyll is the common pigment Accessory pigments – other colors (not green)

Photosynthesis The process of plants capturing light energy to make food. Plants need: Light energy Carbon dioxide Water To produce: Sugar Oxygen

Photosynthesis Chemical Formula

Seed Plants

Seed Plants - Characteristics Vascular tissue Use pollen and seeds to reproduce Along with: autotrophic, eukaryotic, cell walls

Vascular Tissue Phloem – transports food Xylem – transports water and minerals

Pollen and Seeds Pollen – contains cells that later become sperm cells Seed – contains a young plant inside a protective covering

Seed Structure A seed has 3 main parts: Embryo – the young plant that develops from the zygote Endosperm, cotyledon (seed leaves), or stored food Seed coat – protects seed from drying out

Seed Dispersal Animals Water Wind Self – example, ejection Germination – embryo begins to grow and pushes out of the seed

Roots 3 Main Functions Anchor the plant Absorb water and minerals Store food 2 Types of Roots Fibrous – clumps, example – onions Taproot – single, example – dandelions Root cap – protects the root

Stems 2 Main Functions Transportation – carries substances throughout the plant Support 2 Types Herbaceous- no wood and soft Woody – hard and rigid

Woody Stems outer bark – protects the cells inside Inner bark – living phloem Cambium - produces new phloem and xylem Sapwood – active xylem Heartwood – old, inactive xylem, provides support Annual rings – a pair (light and dark) represent one year’s growth

Leaves Leaves capture energy and carry out photosynthesis Stomata – small openings that open and close to control when gases enter and leave the leaf Transpiration – water evaporates from a plant’s leaves

Gymnosperms

Characteristics Gymnosperm – seed plant that produces naked seeds (not enclosed by a fruit) Naked seeds Needle-like leaves Deep growing roots autotrophic, eukaryotic, cell walls

4 Types of Gymnosperms Cycads – palm trees with cones, grown in tropical regions Conifers – cone bearing and largest, most diverse group, keep their leaves all year Ginkgoes – can tolerate pollution, only one species exists today Gnetophytes – trees, shrubs, vines, hot deserts

Reproduction Cones – reproductive structures Male cones produce pollen (male gametophyte) Ovules – female gametophyte that holds the egg cell After fertilization occurs, the ovule develops into the seed. Pollination – transfer of pollen from a male to a female reproductive structure

Angiosperms

Characteristics Produce flowers Produce seeds enclosed in fruits Along with: autotrophic, eukaryotic, cell walls

Structure of Flowers Flower – reproductive structure of an angiosperm Sepals – leaflike structures that surround a bud petals – most colorful part of the flower Stamen – male reproductive part Pistil – female reproductive part Ovary – contains the ovule which holds the egg cell

Reproduction in Angiosperms Pollination – grain of pollen falls on the stigma Fertilization – if pollen lands on stigma of a similar plant, fertilization can occur Zygote develops into the seed’s embryo As the seed develops, the ovary changes into a fruit Fruit – a ripened ovary

2 Types of Angiosperms Cotyledon – seed leaf, stored food Monocot - one seed leaf , corn, grasses, tulips Dicot – two seed leaves, beans, maple trees, roses