Kingdom Plantae

Green algae are believed to be the ancestors of plants. Invasion of plants – occurred about 430 million years ago

Characteristics of Plants: cell walls – composed of cellulose eukaryotes autotroph multicellular Survival NEEDS: sunlight gas exchange water & minerals movement of water and nutrients

Evolutionary trends in plants involved moving from water to land. Land Adaptations – to move from water to land, plants had to adapt…… systems that would support their weight – lignin strengthens cell walls to support growth underground absorptive structure – roots above ground shoot system – stem, leaves development of vascular tissue to transport water & nutrients prevent water loss with the cuticle and stomata male gametes (pollen grains) could be dispersed without water and the evolution of the seed

Classification is based on – Nonvascular or Vascular Tissue (xylem or phloem) Reproduction – produce seeds (embryo) or spores (reproductive cell) Compare DNA sequences

Plant ORGANS - STEMS to produce leaves, branches & flowers to transport water & nutrients to store nutrients ROOTS anchor plant in ground absorb water & nutrients LEAVES site of photosynthesis site of gas exchange site of transpiration

TROPISMS: Plants adjust the direction and rate of growth in response to environmental stimuli Gravitropism – a growth response to gravitational forces Phototropism— when stems/leaves adjust the rate and direction of growth in response to light Thigmotropism— plants shift a direction of growth as they contact objects

How do plants control their growth in response to environmental stimuli? Most plants do this by way of chemical messengers known as hormones. A hormone is a chemical that is produced in one part of an organism and transferred to another part to affect the activities of that part of the plant.

Types of Hormones AUXINS – responsible for regulating growth by stimulating the elongation of cells. ABSCISIC ACID – Inhibits plant growth during times of stress, such as cold temperatures or drought. GIBBERELLINS - growth hormones that cause plants to grow taller.

Can plants DEFEND themselves? Mechanical defense -incorporated into the physical structure of the organism. -- thorns, spines and stiff hairs that repel a predator Chemical defense - occurs when the plant produces stinging sensations, paralysis, poisoning, or just a bad taste. Camouflage - the organism blends into its environment or appear to be something they are not

Which one is poisonous and which one is harmless? Queen Anne’s Lace Water Hemlock

Two classes of angiosperms …. Monocots and Dicots