UNIT 3. PLANTS
5 prima primary ry / Natur Natural al Scie Science nce Pedro Antonio López Hernández Colegio La Presentación de Granada
CHARACTERISTICS CHARACTERISTICS OF PLANTS A plant is a living thing with limited mobility. There are many different types of plants. All plants have one thing in common: they are living things that make their own food.
PARTS OF A PLANT 3. LEAVES They capture sunlight and carbon dioxide from the air. Then, they use the sunlight, carbon dioxide, water and minerals to make nutrients. 1. ROOTS They enable plants to take in water and minerals from the soil. Some plants store
They need four substances to make their own food: water, minerals, sunlight and carbon dioxide. They use three main organs to make it:
CLASIFFICATION OF PLANTS
Flowering plants
Non-flowering plants
2. STEMS They keep the plant upright and support it. The trunk of a tree is a very thick stem. It also carries water, minerals and nutrient to other parts of the plant through vessels.
They have organs like flowers, fruits and seeds that help them to reproduce.
Angiosperms
Angiosperms, like apple trees, are plants that grow fruit with seeds.
Gymnosperms
Gymnosperms, like pine trees, are plants that have seeds but don´t have fruit.
They don´t have seeds . They reproduce through spores. Spores are tiny cells that germinate and grow into a new plant.
Ferns
Mosses
They have root, leaves and stem. Fern spores are formed on the underside of the leaves
They don´t have root, leaves and stem. Moss spores are produced in capsules.
PLANT NUTRITION
Photosynthesis
Respiration
Plants make their own nutrients through photosynthesis. They absorb carbon dioxide and water with minerals and release oxygen into the air.
This process take place in green leaves during the day. Leaves absorb energy from sunlight through a green pigment called chlorophyll and use it to produce glucose and oxygen.
Water
Carbon dioxide
Glucose
Sunlight
Plants absorb oxygen from the air. Then, the oxygen ands nutrients are transformed into energy. Fi nally, the plant releases carbon dioxide and water vapour into the air. Respiration takes place during the day and night, because they need energy 24 hours a day.
Oxygen Oxygen
Sunlight Oxygen
Carbon dioxide
Water and minerals
It is related to how plants get energy.
Glucose
Carbon dioxide
HOW DO PLANTS MAKE NUTRIENTS? Day
1.
2.
3.
4.
Plants Plants absorb absorb water water and dissolv dissolved ed minerals through their roots. This mixture of water and minerals is called raw sap.
Elaborated sap: Nutrients
PHOTOSYNTHESIS Produces nutrients. Releases oxygen.
Xyle Xylem m vess vessel elss are tubes that carry the raw sap from the roots to the leaves.
Raw sap: Water and minerals
Leave Leavess absor absorb b carb carbon on diox dioxid ide e through pores called stomas.
Phot Photos osyn ynth thes esis is takes place inside the leaves. Sunlight transforms raw sap and carbon dioxide into nutrients inside the leaves.
5.
The nutrient nutrientss formed formed inside inside the leaves are called elaborated sap.
6.
Phl Phloem oem vess vessel elss are small tubes that transport elaborated sap all over the plant.
Night
ENERGY
RESPIRATION They produce energy. Releases carbon dioxide.
ENERGY
RESPIRATION They produce energy. Releases carbon dioxide.
Water and minerals
SEXUAL REPRODUCTION IN PLANTS 1. REPRODUCTION IN FLOWERING PLANTS
It takes place inside the flower when two reproductive cells from two different plants come together. This generates a new plant that is similar to them.
Classification of flowers
They have male and female reproductive organs
Male organs
Corolla
The stamen is the male reproductive organ:
Female organs The pistil is the female reproductive organ:
1. The stigma has a sticky top to trap pollen.
1. The anther produces and holds pollen. They usually look like fine yellow dust.
2. The style is a tube tat connects the stigma and ovary. 3. The ovary is the central part of the pistil and contains the ovules.
2. The filament gives support to the anther.
Calyx
4. Once an ovule is fertilised it becomes a seed.
Hermaphrodite flower
Male flower Female flower
The male flower produces pollen.
The female flower produces ovules.
In many flowers, the male and female parts are inside the same flower.
THE POLLINATION OF FLOWERS
Pollination occurs when pollen reaches the pistil and travels down it, where it fertilises the ovule. This is called fertilisation. Then, the ovary becomes a fruit and the ovul e becomes a seed.
Wind, insects and other agents can accidentally transport pollen from one flower to another.
When seeds fall to the grou nd and germinates, a new plant grows.
Self-pollination
Cross-pollination
Female flower Seed
Fruit
Male Flower Pollen
New plant
New plant
2. REPRODUCTION REPRODUCTION IN NON- FLOWERING PLANTS
They don´t have flowers or seeds. They T hey use spores to reproduce. Ferns reproduce this way.
1. Sori (singular, sours) are sacks that contain thousands of spores. They are located under the fern leaves. 2. Spores fall to the ground and form organs that produce reproductive cells.
3. After fertilisation, a new fern begins to grow.
ASEXUAL REPRODUCTION IN PLANTS
Many plants that grow flowers and seeds can also reproduce through fragmentation. In fragmentation, a new plant grows from a fragment of the parent plant.
1. First, a small small fragment fragment breaks breaks off the plant. plant. 2. Then, Then, the fragment fragment falls to the ground ground and germinates. germinates. 3. Finally, a new plant plant begins to grow. This This new plant is an identical replica of the parent plant.
Types of fragments:
Stolons are aboveground stems that grow horizontally. As they grow, they develop roots that produce a new plant. Strawberries
Cutting are stems that produce new roots when they are separated from the parent plant. Geraniums and grapevines grow from
Tubers are underground stems. Tubers store many nutrients that they get from the soil. Potatoes are tubers.
Bulbs are at the bottom of the stem. They grow underground. Bulbs store nutrients for the plant. When planted in the ground, each bulb gives rise to a new plant. Garlic and onions are bulbs.
Rhizomes are underground stems that grow horizontally. New plants grow from these stems. Asparagus and iris plants are rhizomes.
HOW DO PLANTS RESPOND TO THEIR ENVIRONMENT? Plants can move
Plants react to their environment by moving. There are two different ways plants move:
Nastic movements
The movement of the plant does not involve growth. For example: A carnivorous carnivorous plant suddenly closes it leaves when an insects touches it.
1. Phototropism is a tropic movement and occurs when plants grow towards sunlight.
Tropic movements
2. Hydrotropism is another tropic movement that occurs when the roots of plants sense water in the ground and always grow towards the source of water.
They occur when plants move towards or away from a stimulus and involve growth. For example: Some plants grow toward sunlight.
3. Gravitropism occurs when plants react to gravity. This
HOW DO PLANTS RESPOND TO THEIR ENVIRONMENT? Plants respond to the seasons
Plants also respond to environmental changes in light, temperature and humidity and this influences their life cycle. Observe how the Beech trees (deciduous) responds to weather changes in each season:
