1

 

Plant Characteristics:

1. They obtain and use resources for energy

• need food, oxygen, and water, which provide required energy to perform the basic processes of life, such as

growing and developing, or repairing injured parts

•  Autotrophs !for example plants" provide their own food for energy through the process of  photosynthesis

•  Heterotrophs !for example animals" must find an external source for food

• #nergy is released from food in most organisms through the process of respiration

2. They respond to stimuli 

• $ stimulus is any change in an organism%s surroundings that will cause the organism to react

• #xamples& changes in: light, temperature, sound, amount of water, space, amounts or types of food, or other

organisms present

• 'he reaction to the stimulus is called a response. (t can be an action or behavior performed by the organism

3. They reproduce

• )rganisms have the ability to reproduce, or produce offspring that have similar characteristics as the parents 'here

are two basic types of reproduction:

•  Asexual reproduction:  a reproductive process that involves only one parent and produces offspring that is identical to

the parent

•  Sexual reproduction:  a reproductive process that involves two parents 'he egg !female reproductive cell" and sperm

!male reproductive cell" from these two parents combine to ma*e an offspring that is different from both

 parents

4. They grow and develop

• Growth is the process whereby the organism becomes larger

•  Development is the process that occurs in the life of the organism that results in the organism becoming more

complex structurally

• )rganisms require energy to grow and develop

Naming and Classifying Organisms-

'he study of classifying organisms is *nown as taxonomy

• $n organism is placed into a broad group and is then placed into more specific groups based on its structures

• 'he levels of classification, from broadest to most specific, include: *ingdom, phylum, class, order, family, genus,

and species

• 'he more classification levels an organism shares with another, the more characteristics they have in common

 Kingdom

• +hile scientists currently disagree as to how many *ingdoms there are, most support five !Plants, $nimals,

ungi, Protists, -onerans"

• )rganisms are placed into *ingdoms based on their ability to ma*e food and the number of cells in their body

.

 

 Phylum (pl phyla!

• (n the Plant /ingdom, phyla are sometimes referred to as divisions

• Plants are normally divided into two groups: vascular and nonvascular

• (n the $nimal /ingdom, there are 0 different phyla 'hese phyla can be divided into two groups: vertebrates and

invertebrates

"lass# $rder# %amily

• levels more specific, include fewer organisms Genus (pl Genera!

• Contains closely related organisms

• 'he genus is used as the first word in an organism%s scientific name

 Species

• $ll the organisms of the same type which are able to breed and produce young of the same *ind

• 'he species is used as the second word in an organism%s scientific name

 Scientific name

2 'he scientific name of an organism is made up of its genus and species

2 (t is written in italics !Genus species" with the genus capitali3ed

2 or example, Canis lupus is the scientific name for the wolf and  Pinus taeda is the scientific name for a loblolly

 pine &example: felix catus

4roups of Plants

$ll plants are included in this *ingdom, which is then bro*en down into smaller divisions based on several

characteristics, for example:

• 5ow they absorb and circulate fluids 6 vascular or nonvascular 

• 5ow they reproduce 6 spores or seeds7

• -ethod of seed production 6 cones or flowers7

• 'ype of seed leaf 6 monocot or dicot

&ascular Plants'  largest group

• well&developed system for transporting water and food7 they have true roots, stems, and leaves

• help circulate water and food throughout the plant

•  ylem transport water and minerals from the roots up to the rest of the plant

•  Phloem transport food from the leaves down to the rest of the plant

2 Examples: woody stems& trees 8 bushes, heraceous stems& grasses

 )onvascular Plants

• 'hese plants do not have a well&developed system for transporting water and food7 do not have true roots, stems,

or leaves

• 'hey must obtain nutrients directly from the environment and distribute it from cell to cell throughout the plant

'his usually results in these plants being very small in si3e

• #xamples: mosses, liverworts, and hornworts

0

 

 Seed'producing 

• 9eeds contain the plant embryo !the beginnings of roots, stems, and leaves" and stored food ! cotyledons

 

 ! and are

surrounded by a seed coat rom those seeds, new plants grow

• 'here are two major groups of seed&producing plants: cone&bearing plants and flowering plants

 Spore'producing 

• 9pores are much smaller than seeds

• $lmost all flowerless plants produce spores

• #xamples& mosses and ferns

%lowering Plants

• lowering plants differ from conifers because they grow their seeds inside an ovary, which is embedded in a

flower

• 'he flower then becomes a fruit containing the seeds

• #xamples include most trees, shrubs, vines, flowers, fruits, vegetables, and legumes

"one'bearing Plants

• -ost cone&bearing plants are evergreen with needle&li*e leaves

• Conifers never have flowers but produce seeds in cones

• #xamples& pine, spruce, juniper, redwood, and cedar trees

 *onocot 

• $ seed with one food storage area is called a monocotyledon, or monocot 

• lowers of monocots have either three petals or multiples of three

• 'he leaves of monocots are long and slender with veins that are parallel to each other

• 'he vascular tube structures are usually scattered randomly throughout the stem

• #xamples&include grass, corn, rice, lilies, and tulips

 Dicot 

• $ seed with two food storage areas is called a dicotyledon, or dicot 

• lowers of dicots have either four or five petals or multiples of these numbers

• 'he leaves are usually wide with branching veins

• 'he vascular tube structures are arranged in circular bundles

• #xamples& roses, dandelions, maple, and oa* trees

Defense, Survival, and Reproduction

 Structures for Defense

Plants have structures for defense that protect them from threats and without these defenses the plant might die

#xamples of natural defenses that plants have developed over time may be

2 thorns that can defend the plant from being eaten by some animals

2 fruits and leaves with poisons so that they are not eaten by animals

2 the ability to close its leaves when touched ! thigmotropism "

 

 Structures for Survival 

Parts of flowering plants that function for survival may be:

2 ;eaves function as the site of photosynthesis, respiration, and transpiration in plants

2 9tems support the plant and hold the leaves up to the light 9tems also function as food storage sites

o 'he xylem in the stems transports water from the roots to the leaves and other plant parts

o 'he phloem in the stems transport food made in the leaves to growing parts of the plant

Roots

• anchor the plant

• absorb water and nutrients from the soil

• store extra food for the plants

• 'he more surface area on the root, the more water and nutrients it can absorb

•  +oot hairs help to increase this surface area

• 'here are two types of roots:

1. %ibrous roots consist of several main roots that branch off to form a mass of roots

#xamples& grass, corn, and some trees

. Taproots consist of one large, main root with smaller roots branching off #xamples&carrots, dandelions, or cacti

 Structure for +eproduction

Parts of the flowering plant that function in reproduction include:

%lowers

• lowers produce seeds

• -any flowers contain both male and female parts needed to produce new flowers

• lower petals are often colorful or have a scent to attract insects and other animals

 Stamen

• male part of a flower,has an anther  on a stal* ! filament "

• 'he anther produces pollen that contains the sperm cells

 Pistil 

• female part of the flower, contains:

• $vary& contains ovules where the egg cells are produced,

•  Stigma" the stic*y top where pollen grains land

•  Style" stal* down which the pollen tube grows after pollination has ta*en place

 Seed 

• 'he ovule that contains the fertili3ed egg !embryo" from which new plants are formed

• $ fruit that is formed from the ovary often protects them

• 9eeds have special structures that allow them to be dispersed by wind, water, or animals

• 'he seeds coat helps protect the embryo from injury and also from drying out

 

ife Cycle of !lants

Germination

• +hen seeds are dispersed from the parent plant, they can either lay dormant or they can begin to grow

immediately given the right conditions

• 'his early stage of seed growth is called  germination

• 'he roots begin to grow down, while the stem and leaves grow up

 Plant development 

2 )ver time the seed grows into a mature plant with the structures necessary to produce more plants

%ertili,ation

2 +hen pollen, which is produced in the stamen of a flower, transfers from stamen to pistil ! pollination" and then

enters the ovule, which is located in the ovary of a flower,  f ertili,ation occurs

 Seed production

2 )nce the ovule is fertili3ed it develops into a seed

2 $ fruit !fleshy, pod, or shell" then develops to protect the seed

2 9eeds are structures that contain the young plant surrounded by a protective covering

Reproduction

 Sexual reproduction

2 $ process of reproduction that requires a sperm cell !in pollen" and an egg cell !in the ovule" to combine to produce

a new organism

2 $ll flowering plants undergo sexual reproduction

 Asexual reproduction

• $ process of reproduction that involves only one parent plant or plant part and produces offspring identical to the

 parent plant

• -any plants can grow new plants asexually from their plant parts

• (f a plant is cut or damaged, it can sprout new growth from the stems, roots, or leaves

!lants use a variety of parts to produce ne" plants:

Tubers# bulbs

• underground stems

• 'he <eyes= or buds of tubers, for example potatoes, grow into roots and shoots to produce a new plant

• >ulbs, for example onions, are big buds made of a stem and special types of leaves

 +unners

• stems that run along the ground

• ?ew strawberries or some ivy grow from the tips of runners

• -any lawn grasses grow from runners

@

 

 Stem "uttings

• +hen a piece of cut stem is planted, roots may form from the cutting, and then a full plant develops

• 9ugar cane and pineapple are examples of plants grown from stem cuttings

 +oots

• 9ome fruit trees and bushes send up <suc*ers= or new shoots from the roots

• 9ome plants have roots that can produce new plants from root pieces, such as a sweet potato

 -eaves

2 9ome houseplants produce little plants right on their leaves

2 or example, $frican violets can produce plants from leaves placed on top of soil

 Photosynthesis' process to ma*e sugar 

"hloroplasts' found in the cells of the leaf, contain chlorophyll , a green pigment that absorbs light energy

2 Auring this process, plants use carbon dioxide gas from the air !ta*en in through openings in the leaf called stomata

 

"

and water !ta*en in through the roots" to ma*e sugar !food" in the leaves

2 Auring the process of photosynthesis, oxygen is also produced 'he oxygen is released into the air through the

stomata

 +espiration

• 'o obtain the energy from the food it produces, plants must brea* down the sugar in the cells throughout the plant

in a process called respiration

• (n this process, oxygen from the air !ta*en in through the stomata" combines with the sugar, which is then bro*en

down into carbon dioxide and water

• Auring this process, energy is released 'his energy can now be used by the plant to perform life functions

• 'he carbon dioxide and water that are formed are then given off through the stomata in the leaves

Transpiration

2 9ome of the water ta*en in through the roots of plants is used in the process of photosynthesis

2 5owever, plants lose most of the water through the leaves 'his process is called transpiration

2 +ithout a way to control transpiration, plants would wither up and die ortunately, plants are able to slow down

transpiration

2 Guard cells, mostly on the underside of the leaf, open and close the stomata

2 +hen the stomata are closed, water cannot escape from the leaf

Response to Environment

•  Dormancy' time when the growth or activity of a plant or seed stops due to changes in temperature or amount of

water

• allows various species to survive in environments

• ensures that seeds will germinate when conditions are favorable for survival of the small seedlings

• or example, leaves fall from trees prior to the conditions of winter and the leaf buds do not open again until

conditions are favorable in the spring

B

 

Tropism" growing or moving their stems, roots, or leaves toward or away from the stimulus

 Phototropism' plant grows or moves in response to light

Gravitropism' plant grows or moves in response to gravity7 also called  #eotropism

 .ydrotropism' plant grows or moves in response to water 

Thigmotropism'  plant grows or moves in response to touch

#ungi- *ingdom of organisms that do not ma*e their own food

2 must grow in or on other organisms, such as plants

2 example& grain mold, corn smut, and wheat rust, cause diseases in those plants that result in crop losses

2 Aiseases caused by fungi may also affect other important crops, such as rice, cotton, rye, and soybeans

2 (f a fungus infects a tree, fruit, or grass, it can eventually *ill the plant