Plants

Chapter 8

Course of Study Objectives7.) Describe biotic and abiotic factors in the

environment.Examples:- biotic-plants, animals;- abiotic-climate, water, soil• Classifying organisms as autotrophs or heterotrophs

5.) Identify major differences between plants and animals, including internal structures, external structures, methods of locomotion, methods of reproduction, and stages of development.• Describing the processes of photosynthesis and cellular respiration

What is a Plant?Characteristics of plants:

Autotrophs-they make their on foodEukaryotes- they have a true nucleusTheir cells have a cell wall

Plant Adaptations Adaptations plants have made to survive on

land include…Plants obtain water and nutrients from the soil.Plants retain water by using a waxy, waterproof

layer that covers the plant’s leaves called a cuticle.

Large plants transport water, minerals, and food through vascular tissues . Small plants transport water, food, and minerals between cells.

Vascular tissues and cell walls help plants support themselves.

Many plants have adapted to make fertilization occur in a dry environment.

Vascular and Nonvascular PlantsPlants are divided into 2 groups

Nonvascular plants- lack vascular tissuesVascular plants- contain vascular tissues

Complex Life CyclesPlants have 2 different stages in their life

cycle.(p.255)Sporophyte stage- the plant produces spores

(cells that grow into new organisms)Gametophyte stage- the plant produces sex

cells

Plant Life Cycle p. 255

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Nonvascular PlantsThe three groups of nonvascular plants

include:MossesLiverwortsHornworts

These low growing plants live in moist areas so they can absorb water and nutrients from their environment.

Nonvascular Plants

Liverworts Moss

Hornworts

Seedless Vascular TissueSeedless vascular plants have true vascular

tissue and reproduce by spores.There are three types of seedless vascular

plants: FernsClub MossesHorsetails

Seedless Vascular Tissue

Fern Club Moss Horsetail

Seed PlantsAll seed plants share two characteristics

They contain vascular tissueThey use pollen and seeds to reproduce

Vascular TissueThere are 2 types of vascular tissue

Phloem-moves food down the plantXylem- moves water and minerals up the

plant

Seed PlantsSeed plants reproduce using 2 unique

adaptations…Pollen- a tiny structure that contains the cells

that will become sperm.Seed-the structure that incases and protects

the young fertilized embryo.

Seed StructuresThere are three main parts of a seed

Embryo-the fertilized eggStored food –used during development Cotyledon- embryonic leaf/leaves

Seed DispersalSeeds are dispersed by 3 different ways

By animalBy waterBy wind

GerminationsSeeds may lay dormant for a period of time

before they start to grow/germinate.Germination- occurs when the embryo

begins to grow again and pushes out of the seed.

RootsRoots anchor a plant in the ground, absorbs

water and minerals from the soil, and sometimes stores food.

There are two different types of root systemsFibrous root systems-dense, tangled mass of

fibrous rootsTaproot systems- one long, thick main root

Fibrous roots

Taproot

StemsStems carry substances between the

plant’s roots and its leaves.Stems provide support for the plant.There are two types of stems

Herbaceous-soft stems with phloem and xylem.

Woody-hard stems with several different layers of tissues.

Annual RingsCambium- layer of cells which divide to

produce new phloem and xylem.When new xylem is made, the old xylem

becomes heart wood. Each layer of old xylem makes up a pattern called an annual ring.

LeavesLeaves capture the sun’s energy and carry

out the food-making process of photosynthesis.

Stomata-a small hole that popes open and close to control when gases enter and leave the leaf.

Transpiration-the process by which water evaporates from a plants leaves.

Stomata

Gymnosperms and AngiospermsThere are two types of seed plants

Gymnosperms- produce naked seedsAngiosperms- flowering plants that produce

seed with fruits.

GymnospermsFour types of gymnosperms exist

CycadsConifersGinkgoesGnekophytes

Reproduction of a GymnospermThe egg develops in a structure called an

ovuleFirst, pollen falls from a male cone onto a

female cone. In time, a sperm cell and an egg cell join together in an ovule on the female cone.

Reproduction of an AngiospermsAll angiosperms use flowers for

reproduction.Parts of a flower

Sepals-small leaflike part of the plantPetals-colorful leaflike structuresStamen- male reproductive partsPistil- female reproductive parts

PollinationPollinators-small organisms that ensure

that pollination occurs.First, pollen falls on a flower’s stigma. In

time, the sperm cell and egg cell join together in the flower’s ovule. The zygote develops into the embryo part of the seed.

Monocots and DicotsAngiosperms are divided into two major

groupsMonocots-one embryonic leaf (cotyledon)Dicots-two embryonic leaves

TropismTropism-a plants growth response toward

or away from a stimulus.Three important stimuli to which plants

show tropism areTouch-ex. Vines growing around a wire Light- ex. Plants growing toward lightGravity- ex. A plan’st root’s growing down

and stems growing up.

HormonesPlants respond to touch, light, and gravity

because they produce hormones.Auxin is a major plant hormone that makes

the plant grow in the presents of light.

Seasonal ChangesWhat triggers a plant to flower? The amount

of darkness a plant receivesShort-day plants-flower when nights are longer

than a critical length (bloom in fall or winter)Long-day plants- flower when nights are

shorter than a critical length (bloom in spring or summer)

Day-neutral plant- not sensitive to dark or light Dormancy-a period when a plant’s growth or

activity stops.

Life Spans of AngiospermsAngiosperms are classified into annuals,

biennials or perennials.Annuals- complete a life cycle within one

growing year.Biennials- complete a life cycle within two

yearsPerennials- complete a life cycle in more than

two years