Everyday Life: Our Life Cycle
A baby is growing in Manny’s aunt’s tummy. Manny also started his life in his mother’s tummy. When he was born, Manny was a baby. A year or so after that, he became a toddler like Lucia. Manny has grown taller as he gets older. In less than 10 years, he will be a teenager. He will finish growing tall, and he will develop stronger bones and muscles as he becomes an adult.
After many years, he will have wrinkles and gray hair, just like his grandfather. Eventually, he will die. These stages make up the life cycle of a human being. Although the changes Manny sees happen gradually over time, we notice the differences between the stages of his family members.
All living creatures—not only humans —have life cycles. Plants, animals, and even insects have life cycles. Plants start as seeds. When a seed is planted in good soil with water, it grows into a seedling. Over time, the seedling grows into a plant. Some plants produce flowers and fruits, which contain seeds. When the plant dies, the seeds can be planted to grow new plants.
https://www.pbslearningmedia.org/resource/tdc02.sci.life.colt.plantsgrow/from-seed-to-flower/
http://interactivesites.weebly.com/plants.html
A baby is growing in Manny’s aunt’s tummy. Manny also started his life in his mother’s tummy. When he was born, Manny was a baby. A year or so after that, he became a toddler like Lucia. Manny has grown taller as he gets older. In less than 10 years, he will be a teenager. He will finish growing tall, and he will develop stronger bones and muscles as he becomes an adult.
After many years, he will have wrinkles and gray hair, just like his grandfather. Eventually, he will die. These stages make up the life cycle of a human being. Although the changes Manny sees happen gradually over time, we notice the differences between the stages of his family members.
All living creatures—not only humans —have life cycles. Plants, animals, and even insects have life cycles. Plants start as seeds. When a seed is planted in good soil with water, it grows into a seedling. Over time, the seedling grows into a plant. Some plants produce flowers and fruits, which contain seeds. When the plant dies, the seeds can be planted to grow new plants.
https://www.pbslearningmedia.org/resource/tdc02.sci.life.colt.plantsgrow/from-seed-to-flower/
http://interactivesites.weebly.com/plants.html
What is a plant - Primary Connections
Roots
Roots act like straws absorbing water and minerals from the soil. Tiny root hairs stick out of the root, helping in the absorption. Roots help to anchor the plant in the soil so it does not fall over. Roots also store extra food for future use.
Stems
Stems do many things. They support the plant. They act like the plant's plumbing system, conducting water and nutrients from the roots and food in the form of glucose from the leaves to other plant parts. Stems can be herbaceous like the bendable stem of a daisy or woody like the trunk of an oak tree.
Leaves
Most plants' food is made in their leaves. Leaves are designed to capture sunlight which the plant uses to make food through a process called photosynthesis.
Flowers
Flowers are the reproductive part of most plants. Flowers contain pollen and tiny eggs called ovules. After pollination of the flower and fertilization of the ovule, the ovule develops into a fruit.
Fruit
Fruit provides a covering for seeds. Fruit can be fleshy like an apple or hard like a nut.
Seeds
Seeds contain new plants. Seeds form in fruit.
Roots
Roots act like straws absorbing water and minerals from the soil. Tiny root hairs stick out of the root, helping in the absorption. Roots help to anchor the plant in the soil so it does not fall over. Roots also store extra food for future use.
Stems
Stems do many things. They support the plant. They act like the plant's plumbing system, conducting water and nutrients from the roots and food in the form of glucose from the leaves to other plant parts. Stems can be herbaceous like the bendable stem of a daisy or woody like the trunk of an oak tree.
Leaves
Most plants' food is made in their leaves. Leaves are designed to capture sunlight which the plant uses to make food through a process called photosynthesis.
Flowers
Flowers are the reproductive part of most plants. Flowers contain pollen and tiny eggs called ovules. After pollination of the flower and fertilization of the ovule, the ovule develops into a fruit.
Fruit
Fruit provides a covering for seeds. Fruit can be fleshy like an apple or hard like a nut.
Seeds
Seeds contain new plants. Seeds form in fruit.
Life and Living:Plants are alive, just like people and animals. How do we know this? Living things all do certain things:
Living things have certain characteristics that make them easy to classify as living.
All living things:-
M = move
R = reproduce
S = are sensitive to changes in the internal and external environment
G = grow
R = respire (see right)
E = eliminate waste products
N = nutrition is required to produce energy to maintain life
This is known as MRS GREN to biologists.
Respiration is the chemical process that takes place in all living cells to make energy. Carbohydrates react with oxygen to produce carbon dioxide and water. This process should not be confused with breathing, which is the physical process of taking in oxygen through lungs, gills or absorption through the skin.
Mrs Gren and plants
Sometimes people doubt whether plants show the characteristics of living things but they do. Movement, sensitivity and respiration are the characteristics that are the most difficult to justify.
Plants do move as demonstrated by geranium leaves that rotate to follow the Sun and pea plant tentacles that coil around a branch.
Plants do respond to changes in their environment as their shoots grow towards light and their roots grow downwards.
Plants carry out two main chemical processes, photosynthesis and respiration. Photosynthesis is the process by which plants make their own food which is then broken down by respiration to produce energy. People often do not realise that plant cells need to make energy to keep the plant working and hence staying alive.
- They grow and die.
- They need energy, nutrients, air, and water.
- They produce young.
- They are made up of cells.
- They react to what's around them.
Living things have certain characteristics that make them easy to classify as living.
All living things:-
M = move
R = reproduce
S = are sensitive to changes in the internal and external environment
G = grow
R = respire (see right)
E = eliminate waste products
N = nutrition is required to produce energy to maintain life
This is known as MRS GREN to biologists.
Respiration is the chemical process that takes place in all living cells to make energy. Carbohydrates react with oxygen to produce carbon dioxide and water. This process should not be confused with breathing, which is the physical process of taking in oxygen through lungs, gills or absorption through the skin.
Mrs Gren and plants
Sometimes people doubt whether plants show the characteristics of living things but they do. Movement, sensitivity and respiration are the characteristics that are the most difficult to justify.
Plants do move as demonstrated by geranium leaves that rotate to follow the Sun and pea plant tentacles that coil around a branch.
Plants do respond to changes in their environment as their shoots grow towards light and their roots grow downwards.
Plants carry out two main chemical processes, photosynthesis and respiration. Photosynthesis is the process by which plants make their own food which is then broken down by respiration to produce energy. People often do not realise that plant cells need to make energy to keep the plant working and hence staying alive.
What is a seed
1. Have students discuss "I think a seed is living/nonliving.
2. Watch ABC clip
Video - http://splash.abc.net.au/media/-/m/106388
3. Explore seeds dry versus soaked.
4. Plant seeds in plastic bags
1. Have students discuss "I think a seed is living/nonliving.
2. Watch ABC clip
Video - http://splash.abc.net.au/media/-/m/106388
3. Explore seeds dry versus soaked.
4. Plant seeds in plastic bags
As is the case for animals, flowering plants have systems to maximise efficiency of reproduction to ensure the species survives through time.
Seeds and germination
Seeds contain both a food source and a small embryonic plant in a dormant state. Given a supply of freshwater and sufficient warmth, the seed will germinate, with the plant root growing through the water-softened seed coat and down towards water and the pull of gravity. The shoot then grows upwards through the soil to light.
Seeds of some Australian native trees (e.g. wattles) only germinate after bushfires. This ensures they only germinate when there is less competition by other plants for space and light.
Seeds and germination
Seeds contain both a food source and a small embryonic plant in a dormant state. Given a supply of freshwater and sufficient warmth, the seed will germinate, with the plant root growing through the water-softened seed coat and down towards water and the pull of gravity. The shoot then grows upwards through the soil to light.
Seeds of some Australian native trees (e.g. wattles) only germinate after bushfires. This ensures they only germinate when there is less competition by other plants for space and light.
Photosynthesis
Photosynthesis is the process in which green plants make their own food.
Plants make their own food with the help of: Soil, Air (carbon dioxide) and the Sun.
This gives energy (glucose) plus oxygen.
In the leaf there is a substance called chlorophyll, it is what makes the leaves green.
Plants make their own food with the help of: Soil, Air (carbon dioxide) and the Sun.
This gives energy (glucose) plus oxygen.
In the leaf there is a substance called chlorophyll, it is what makes the leaves green.
Lesson 3. The flower
The germinated seedling continues to grow and uses up its stored food supply until it breaks through the soil surface, develops more roots and green leaves, and can photosynthesise (see Plant systems B: Photosynthesis, nutrition and respiration). It then grows, matures and develops reproductive systems called flowers.
Some species have separate male and female flowers, but most produce both pollen (male gametes or sex cells) as well as ovules (female gametes or egg cells) on the same flower.
The "male" organ is the stamen with a stalk (filament) and a large lobed tip (anther), where the pollen is produced.
The "female" organ (the pistil) includes the ovary where the ovules are formed, and the sticky stigma on top of a stalk-like style.
The germinated seedling continues to grow and uses up its stored food supply until it breaks through the soil surface, develops more roots and green leaves, and can photosynthesise (see Plant systems B: Photosynthesis, nutrition and respiration). It then grows, matures and develops reproductive systems called flowers.
Some species have separate male and female flowers, but most produce both pollen (male gametes or sex cells) as well as ovules (female gametes or egg cells) on the same flower.
The "male" organ is the stamen with a stalk (filament) and a large lobed tip (anther), where the pollen is produced.
The "female" organ (the pistil) includes the ovary where the ovules are formed, and the sticky stigma on top of a stalk-like style.
Next lesson:
The majority of plants on earth are flowering plants, including trees, grasses, cacti and other small plants, as well as the flowering plants we readily know.
Flowering plants all go through the same basic stages of a life cycle (birth, life, reproduction and death). Producing flowers and fruit are part of this life cycle. Flowers are the reproductive organs of a plant and usually contain both male and female parts. After fertilisation, the female parts of a flower develop into seed-containing fruits
Pollination and the formation and dispersal mechanisms of seeds are important components of the flowering plant's life cycle. Plants have developed relationships with animals to attract pollinators to visit them and animals to help spread their seeds.
When living things have relationships with one another it is called symbiosis (meaning ‘living together’ in Greek. There are a number of symbiotic relationships between living things. This unit explores the relationships known as ‘mutualism’ and ‘cooperation’.
The majority of plants on earth are flowering plants, including trees, grasses, cacti and other small plants, as well as the flowering plants we readily know.
Flowering plants all go through the same basic stages of a life cycle (birth, life, reproduction and death). Producing flowers and fruit are part of this life cycle. Flowers are the reproductive organs of a plant and usually contain both male and female parts. After fertilisation, the female parts of a flower develop into seed-containing fruits
Pollination and the formation and dispersal mechanisms of seeds are important components of the flowering plant's life cycle. Plants have developed relationships with animals to attract pollinators to visit them and animals to help spread their seeds.
When living things have relationships with one another it is called symbiosis (meaning ‘living together’ in Greek. There are a number of symbiotic relationships between living things. This unit explores the relationships known as ‘mutualism’ and ‘cooperation’.
Lesson 4.
Pollination - Pollination is the transfer of pollen from a stamen to a pistil. Pollination starts the production of seeds.
But how does pollination work? Well, it all begins in the flower. Flowering plants have several different parts that are important in pollination. Flowers have male parts called stamens that produce a sticky powder called pollen. Flowers also have a female part called the pistil. The top of the pistil is called the stigma, and is often sticky. Seeds are made at the base of the pistil, in the ovule.
To be pollinated, pollen must be moved from a stamen to the stigma. When pollen from a plant's stamen is transferred to that same plant's stigma, it is called self-pollination. When pollen from a plant's stamen is transferred to a different plant's stigma, it is called cross-pollination. Cross-pollination produces stronger plants. The plants must be of the same species. For example, only pollen from a daisy can pollinate another daisy. Pollen from a rose or an apple tree would not work.
Pollination occurs in several ways. People can transfer pollen from one flower to another, but most plants are pollinated without any help from people. Usually plants rely on animals or the wind to pollinate them.
When animals such as bees, butterflies, moths, flies, and hummingbirds pollinate plants, it's accidental. They are not trying to pollinate the plant. Usually they are at the plant to get food, the sticky pollen or a sweet nectar made at the base of the petals. When feeding, the animals accidentally rub against the stamens and get pollen stuck all over themselves. When they move to another flower to feed, some of the pollen can rub off onto this new plant's stigma.Plants that are pollinated by animals often are brightly colored and have a strong smell to attract the animal pollinators.
Another way plants are pollinated is by the wind. The wind picks up pollen from one plant and blows it onto another.As plants cannot move about to mate, they rely on other organisms, wind, or water to transport the pollen to other flowers. Cross-pollination increases biodiversity in the offspring by mixing two parental types, but some plants do self-pollinate.
Pollination
Plants that are pollinated by wind often have long stamens and pistils. Since they do not need to attract animal pollinators, they can be dully colored, unscented, and with small or no petals since no insect needs to land on them.
http://www.mbgnet.net/bioplants/pollination.html (slow motion video)
QUIZ
1. Wind-pollinated flowers have:
a)Abundant pollen on long dangling stamens.
b)An absence of bright colours or exotic flower shapes.
c)Large feathery stigmas.
d)All of the above.
2. Pollination is the transfer of pollen from the:
a)Anther to the ovary.
b)Filament to the style.
c)Anther to the stigma.
d)Stigma to the anther.
3. Which is the correct order of occurrence in seed formation?
a)Flower formation, pollination, fertilisation, seed formation.
b)Flower formation, fertilisation, pollination, seed formation.
c)Flower formation, pollination, seed formation, fertilisation.
d)Pollination, flower formation, fertilisation, seed formation.
To be pollinated, pollen must be moved from a stamen to the stigma. When pollen from a plant's stamen is transferred to that same plant's stigma, it is called self-pollination. When pollen from a plant's stamen is transferred to a different plant's stigma, it is called cross-pollination. Cross-pollination produces stronger plants. The plants must be of the same species. For example, only pollen from a daisy can pollinate another daisy. Pollen from a rose or an apple tree would not work.
Pollination occurs in several ways. People can transfer pollen from one flower to another, but most plants are pollinated without any help from people. Usually plants rely on animals or the wind to pollinate them.
When animals such as bees, butterflies, moths, flies, and hummingbirds pollinate plants, it's accidental. They are not trying to pollinate the plant. Usually they are at the plant to get food, the sticky pollen or a sweet nectar made at the base of the petals. When feeding, the animals accidentally rub against the stamens and get pollen stuck all over themselves. When they move to another flower to feed, some of the pollen can rub off onto this new plant's stigma.Plants that are pollinated by animals often are brightly colored and have a strong smell to attract the animal pollinators.
Another way plants are pollinated is by the wind. The wind picks up pollen from one plant and blows it onto another.As plants cannot move about to mate, they rely on other organisms, wind, or water to transport the pollen to other flowers. Cross-pollination increases biodiversity in the offspring by mixing two parental types, but some plants do self-pollinate.
Pollination
- Vector-pollinated flowers are bright coloured, curious shapes, scented, and contain nectar and plenty of pollen to attract insects and birds. These pollen carriers (vectors) inadvertently get excess pollen on them which wipes off onto the broad, grooved, sticky stigmas of other flowers they visit. Many flowers have the arrangement of floral parts to prevent self-fertilisation.
- Wind-pollinated flowers lack large, bright petals and scent, and produce abundant pollen on long dangling stamens, from flowers well above leaves (e.g. grasses) or flowers which emerge before the leaves (e.g. many deciduous trees). The stigmas are long and feathery to catch the wind-blown pollen thus increasing the chance of pollination.
Plants that are pollinated by wind often have long stamens and pistils. Since they do not need to attract animal pollinators, they can be dully colored, unscented, and with small or no petals since no insect needs to land on them.
http://www.mbgnet.net/bioplants/pollination.html (slow motion video)
QUIZ
1. Wind-pollinated flowers have:
a)Abundant pollen on long dangling stamens.
b)An absence of bright colours or exotic flower shapes.
c)Large feathery stigmas.
d)All of the above.
2. Pollination is the transfer of pollen from the:
a)Anther to the ovary.
b)Filament to the style.
c)Anther to the stigma.
d)Stigma to the anther.
3. Which is the correct order of occurrence in seed formation?
a)Flower formation, pollination, fertilisation, seed formation.
b)Flower formation, fertilisation, pollination, seed formation.
c)Flower formation, pollination, seed formation, fertilisation.
d)Pollination, flower formation, fertilisation, seed formation.
Fruits taste good for a reason. When a fruit fully matures it is taken by birds, animals or humans for consumption. Once the fruit passes through the digestive tract of whatever consumed it, the seeds are secreted back into the soil, potentially giving way to a new generation of plants. This gives way to a new flower-to-fruit cycle. Uneaten fruits fall from the tree and decompose into the soil, also potentially leading to new plants.
Seed dispersal
Fertilisation
When the pollen grain lands on the stigma of another flower of the same species, a pollen tube grows down to fertilise the ovule, forming the embryonic seed plant. The ovary area develops into a fruit enclosing the seeds. Thus an apple with six seeds is formed from one flower which was successfully pollinated by at least six pollen grains fertilising six ovules.
Vegetative reproduction
Some plants can grow from cuttings, and runners. As this involves only one parental type, it is a form of asexual reproduction. It allows fast spreading of a successful "parent" but does not increase biodiversity.
Seed dipsersal
Seed dispersal is when seeds are carried away from the parent plant either deliberately or accidentally.
People plant some seeds, but most plants don't rely on people. Plants rely on animals and wind and water to help scatter their seeds.
Seeds must be carried to other areas to reduce competition between new seedlings for resources (light, space and water). This may be on animal feet or fur (e.g. sticky burrs), by water or wind, or via animals eating the fruits and dropping the indigestible seeds elsewhere (e.g. plum or apple) or in faeces (e.g. tomato, blackberry).
http://www.mbgnet.net/bioplants/seed.html (shows clips of different types of seed dispersal)
People plant some seeds, but most plants don't rely on people. Plants rely on animals and wind and water to help scatter their seeds.
- Animal dispersal: Often, animals are involved in dispersal, as when ants, squirrels and mice, collect and store seeds (including nuts). If the store is forgotten, or the animal dies, the seeds might germinate. Animals disperse seeds in several ways. First, some plants, like the burr at left, have barbs or other structures that get tangled in animal fur or feathers, and are then carried to new sites. Other plants produce their seeds inside fleshy fruits that then get eaten be an animal. The fruit is digested by the animal, but the seeds pass through the digestive tract, and are dropped in other locations. Some animals bury seeds, like squirrels with acorns, to save for later, but may not return to get the seed. It can grow into a new plant.
- Other animals may eat a plant's fruit and scatter the undigested seeds in their dung.
- Finally, some seeds are sticky or have hooks that catch on to fur and feathers, so the seed can hitch-hike to a new location.
- Wind: The seeds of some plants are carried by other vectors such as wind. The kind of seeds which are often wind dispersed are smaller seeds that have wings or other hair-like or feather-like structures. Plants that produce wind blown seeds, like the dandelion shown in the video clip below, often produce lots of seeds to ensure that some of the seeds are blown to areas where the seeds can germinate.
- Water: Many aquatic plants and plants that live near water have seeds that can float, and are carried by water. Plants living along streams and rivers have seeds that float downstream, and therefore become germinate at new sites. The size of the seed is not a factor in determining whether or not a seed can float. Some very large seeds, like coconuts, can float. Some small seeds also float.
Seeds must be carried to other areas to reduce competition between new seedlings for resources (light, space and water). This may be on animal feet or fur (e.g. sticky burrs), by water or wind, or via animals eating the fruits and dropping the indigestible seeds elsewhere (e.g. plum or apple) or in faeces (e.g. tomato, blackberry).
http://www.mbgnet.net/bioplants/seed.html (shows clips of different types of seed dispersal)