Download 6-2.4 notes Plants - Thomas C. Cario Middle School

Flowering plants have special structures that function for
1. defense
2. survival
3. reproduction.
DEFENSE

Plants have structures for defense that protect them from threats.

Without these defenses the plants would die.

Examples of natural defenses that plants have developed over time are
thorns or poisons.
1. Thorns are sharp outgrowths from the stems of plants that function
in defending the plant from being eaten by some animals.
2. Poisons:
 Plants have important chemical substances specifically designed to
discourage animals from eating them.
 Some of these substances simply discourage a plant’s predator by
making the plant foul-tasting.
 Others can sicken or even kill the predator.
 In some cases the substances keep away predators only until the plant
has matured.
 Then the poison level decreases so that the fruit can be eaten, and
the seeds dispersed.
769881759
SURVIVAL
Plants have structures for survival. Parts of the flowering plant that
function for survival include:
Leaves
 Function as the site of food production for plants.
 Photosynthesis, respiration, and transpiration take place here.
Stems
 Support the plant.
 Hold the leaves up to the light.
 Transport water from the roots to the leaves and other plant parts
 Transport food made in the leaves to growing parts of the plant.
 Function as food storage sites.
Roots





Help anchor the plant in the ground.
Absorb water and nutrients from the soil.
Store extra food for the plants.
The more root space that is available, the more water and nutrients it
can absorb.
There are two types of root systems: fibrous roots and taproots.
1. Fibrous roots consist of several main roots that branch off to
form a mass of roots. Examples are grass, corn, and some trees.
2. Taproots consist of one large, main root with smaller roots
branching off. Examples are carrots, dandelions, or cacti.
769881759
REPRODUCTION
Parts of the flowering plant that function in reproduction include:
Flowers
 Produce seeds.
 Many contain both male and female parts needed to produce new
flowers.
 Flower petals are often colorful or have a scent so as to attract
insects and other animals.
Stamem
 The male part of a flower that has an anther on a stalk (filament).
 The anther produces the pollen.
Pistil
 The female part of the flower that holds the flower’s:
 ovary – contains the ovules or egg cells,
 stigma – the sticky top where pollen grains land, and
 style – a stalk down which the pollen tube grows after
pollination has taken place.
Seeds
 Fertilized ovules from which new plants are formed.
 A fruit that is formed from the ovary often protects them.
769881759