Plants Chapters22-25

What is a Plant? Eukaryotic organism Eukaryotic organism Multicellular Multicellular Autotrophic Autotrophic

Chloroplast Plants have chloroplast that carry out Photosynthesis Plants have chloroplast that carry out Photosynthesis Photosynthesis (uses sunlight as energy sourche): CO2 + H20 -> Glucose (C6H12O6) and O2 Photosynthesis (uses sunlight as energy sourche): CO2 + H20 -> Glucose (C6H12O6) and O2 Chloroplast are green pigment that reflects green light Chloroplast are green pigment that reflects green light Has internal membrane that increases surface area Has internal membrane that increases surface area What is the advantage to Photosynthesis/Autotroph: What is the advantage to Photosynthesis/Autotroph: Can make own food don’t need to hunt of find Can make own food don’t need to hunt of find

Plant cells have cell walls to add rigidity and protect the cell Plant cells have cell walls to add rigidity and protect the cell The cell walls are made of cellulose which we cannot digest The cell walls are made of cellulose which we cannot digest Cellulose is a Carbohydrate Cellulose is a Carbohydrate

Plant types Plant types Mosses Mosses They lack a vascular system and true rootsThey lack a vascular system and true roots Low growing plants that like to live near a water supplyLow growing plants that like to live near a water supply These evolved fists- why they are most primitiveThese evolved fists- why they are most primitive

Ferns Ferns Have roots and a vascular systemHave roots and a vascular system Do not have seedsDo not have seeds

Roots The usually underground portion of a plant that lacks leaves The usually underground portion of a plant that lacks leaves serves as support serves as support draws minerals and water from the surrounding soil draws minerals and water from the surrounding soil sometimes stores food sometimes stores food Root hairs- provide increase surface area Root hairs- provide increase surface area Roots are specialized for Mitosis why? Roots are specialized for Mitosis why?

What is vascular tissue? Tissue in the plant that transports water and nutrients Tissue in the plant that transports water and nutrients Xylem – transports waterXylem – transports waterXylem Phloem – transports nutrientsPhloem – transports nutrients Transpiration – water flows through the plant from root to leafTranspiration – water flows through the plant from root to leafTranspiration Released onto leaf undersurface through stomata and evaporates Released onto leaf undersurface through stomata and evaporates

How are roots and vascular tissue an adaptation: allow plant to live in more arid conditions How are roots and vascular tissue an adaptation: allow plant to live in more arid conditions Grow to taller heights because can move water and nutrient by means other then diffusion Grow to taller heights because can move water and nutrient by means other then diffusion

Gymnosperms Cone bearers Cone bearers Seeds are exposedSeeds are exposed Called evergreens or conifersCalled evergreens or conifers Remain green all year- why is this an advantage?Remain green all year- why is this an advantage? Can perform photosynthesis all year Can perform photosynthesis all year

Seeds A fertilized plant ovule containing an embryo. A fertilized plant ovule containing an embryo. Why is this an adaptation: sexual reproduction -> increased genetic variation Why is this an adaptation: sexual reproduction -> increased genetic variation

Germination Process by which plants emerge from seeds and begin growth Can lay dormant for long periods and wait on proper conditions Temperature Water Why is this advantageous? Best chance for survival

Pine Needles The long, slender shape reduces leaf area, which, in turn, reduces the amount of water vapor escaping the leaf. (one time less surface are is an adaptation) The long, slender shape reduces leaf area, which, in turn, reduces the amount of water vapor escaping the leaf. (one time less surface are is an adaptation) Pine needles are shed year round – just not all at one time. Pine needles are shed year round – just not all at one time.

Angiosperms Flowering plants Flowering plants Seeds protected by a layer of tissueSeeds protected by a layer of tissue Flowers are the reproductive organsFlowers are the reproductive organs Ovaries surround and protect seed inside the flowerOvaries surround and protect seed inside the flower Many times the ovaries will develop into fruitMany times the ovaries will develop into fruit

Flowers known as a bloom or blossom known as a bloom or blossomblossom is the reproductive structure found in flowering plants is the reproductive structure found in flowering plantsreproductiveflowering plantsreproductiveflowering plants The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs. The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs. Increased by pollinatorsIncreased by pollinators

Pollinators are attracted to flowers because of bright colors and they smell nice (same reason we like them) Spreads pollen (sperm) to other flowers increasing genetic variation

Plant Reproduction Plant Reproduction Mostly sexual reproduction Mostly sexual reproduction Some plants have a way of carrying out asexual reproductionSome plants have a way of carrying out asexual reproduction

Pollen is the male gametes of plants Pollen is the male gametes of plants Can be compared to sperm cells in animalsCan be compared to sperm cells in animals Plants have ovules with eggs cells that can be fertilized by pollen Plants have ovules with eggs cells that can be fertilized by pollen The seed is an early embryo that can, in some cases remain dormant for long periods of time The seed is an early embryo that can, in some cases remain dormant for long periods of time

Covered seeds The seed coat protects the seed The seed coat protects the seed The endosperm (food supply) nourishes the embryo The endosperm (food supply) nourishes the embryo

Seed protection Less likely to be eaten Less likely to be eaten Protected from environment Protected from environment Nourishment for seed Nourishment for seed - better chance for survival

Seed dispersal Seed dispersal Seeds have different shapes or protective coverings to aid in their dispersalSeeds have different shapes or protective coverings to aid in their dispersal Adaptation: move away from parent plant or other seedlings – less competitionAdaptation: move away from parent plant or other seedlings – less competition

Leaves Wide broad leaves provide additional surface area to absorb sunlight Wide broad leaves provide additional surface area to absorb sunlight Increase photosynthesisIncrease photosynthesis However increase rate of water loss which could be bad- so how do plants over come thisHowever increase rate of water loss which could be bad- so how do plants over come this

Adaptation to avoid water loss Cuticle: waxy covering on leaves (lipids – hydrophobic) – keep water from entering or leaving Cuticle: waxy covering on leaves (lipids – hydrophobic) – keep water from entering or leaving Stomata: openings in the bottom of the leaf that allow water to exit Stomata: openings in the bottom of the leaf that allow water to exit Has guard cells on both sides of stomata to open and closeHas guard cells on both sides of stomata to open and close

Specialized leaves for habitat Water lilies: thick cuticle to keep water out Water lilies: thick cuticle to keep water out Cacti Needles: same as pine needles- reduce surface area (water loss) – also provide protection Cacti Needles: same as pine needles- reduce surface area (water loss) – also provide protection Broad leaves- for areas of limited sunlight (rainforest floor) Broad leaves- for areas of limited sunlight (rainforest floor)

Can Plants Move? Plants cannot get up and walk like us, but they can move stems and leaves toward certain stimuli Plants cannot get up and walk like us, but they can move stems and leaves toward certain stimuli These movements are called tropisms These movements are called tropisms

Gravitropism Plant grows upward against the pull of gravity Plant grows upward against the pull of gravity Allows seed to grow up out of soilAllows seed to grow up out of soil Adaptation: to get sunlightAdaptation: to get sunlight

Phototropism Plant grows toward light source Plant grows toward light source To get sunlight for photosynthesis To get sunlight for photosynthesis

Thigmotropism A plant’s response to touch A plant’s response to touch A plant’s response to touch A plant’s response to touch Can be used as protectionCan be used as protection Can be used for stabilityCan be used for stability Venus fly trap uses to obtain food(nutrients)Venus fly trap uses to obtain food(nutrients)

Plant Hormones Plant Hormones Important for growth and maturation Important for growth and maturation Are chemical substances that control a plant’s patterns of growth and developmentAre chemical substances that control a plant’s patterns of growth and development Example: Auxin’s role in phototropismExample: Auxin’s role in phototropism

Auxin stimulates the elongation of cells Auxin stimulates the elongation of cells When light hits the tip of a plant, more auxin is produced in the shaded area When light hits the tip of a plant, more auxin is produced in the shaded area The dark side of the stem elongates causing the stem to bend toward the light The dark side of the stem elongates causing the stem to bend toward the light

Uses of plants Plants are a major food source for heterotrophs Plants are a major food source for heterotrophs Where do plants get their energy?Where do plants get their energy? They are autotrophic and photosynthetic They are autotrophic and photosyntheticphotosynthetic Photosynthesis produces Oxygen Photosynthesis produces Oxygen

Other uses Oils Oils Medicine Medicine Lumber Lumber Aesthetics Aesthetics Shelter for animals Shelter for animals Commercial products Commercial products