Influence of ecological factors of the earth on plants. Presentation of the impact of anthropogenic factors on the environment Human impact on flora and fauna

Environmental factors and their impact on plants

As you studied botany, you learned that rainforest and tundra plants, forests and grasslands are different, even if they belong to the same species. When caring for cultivated plants, you have noticed that some crops are especially demanding on moisture, while others need bright lighting. You know that weeds are difficult to control because they produce many seeds that ripen earlier than the seeds of cultivated plants. Many weeds have long rhizomes with which they multiply rapidly. Plants are adapted to certain conditions, environmental conditions.

Let's remember what ecology and environmental factors are.

Habitat and environmental factors. All nature surrounding a plant is its habitat . It has all the conditions necessary for growth and development this plant but in different quantities and ratios. Factors (conditions) of the external environment can directly affect the plant, they are necessary for the existence of the organism, but the plant is not required. Factors such as light, moisture in the air and in the soil, temperature, the presence and concentration of salts in the soil, wind and some others affect the plant.

environmental factors any element of the environment that can have a direct or indirect effect on the body is called.

Find out how environmental factors can affect plants. An environmental factor can limit plant growth. For example, if the soil contains a small amount of mineral salts, and a crop is cultivated on it from year to year, then the salt reserves are exhausted and plant growth stops. If the environmental factor is below the critical level or, conversely, exceeds the maximum possible level, it becomes a plant growth limiter, even if other factors are present in the required amount. This environmental factor is called limiting factor . In the aquatic environment, oxygen is most often the limiting factor. For plants that love the sun (sunflower) - light. Moreover, not only the intensity of lighting is important, but also the duration.

At different stages of development, the plant reacts differently to environmental factors. It is known that the most resistant to too high or too low temperatures are the kidneys. higher plants, seeds, spores.

All factors together determine the conditions for the existence of plants, orliving conditions . It is clear that the living conditions Far North and in the steppe zone, in the forest and in the meadow are different. But habitat conditions change seasonally and even during the day. Plants, like all living organisms, have an amazing ability to respond to changes and adapt to environmental conditions.

Adaptation of plants to dry and hot habitats. In arid and hot habitats, plants must be able to extract water, store it, avoid excessive evaporation, but also not “overheat” in the sun.

Plants with powerful root systems live in semi-deserts and deserts. Some root systems are very deep, which allows them to use ground water. So in the bushesclan Juzgun roots go as deep as 30 m. In other plants (cacti) the root system is shallow, but widely overgrown, so during rare rains they quickly absorb moisture from large areas.

The third group of plants (for example, Tatar rhubarb ) does not have a highly developed root system, but they are able to absorb morning dew with their large leaves, spread over the surface of the earth.

These plants tend to have thick skins and very few stomata. They slow down the process of metabolism and as a result - growth.

Shrubs with a deep root system do not accumulate water, but retain it. To reduce evaporation, they small leaves densely pubescent. Often there are no leaves at all, and photosynthesis occurs in shoots that look like twigs or thorns.(saxaul). With a lack of water, a few stomatal gaps close.

In addition to adaptations for the absorption and conservation of water, desert plants have the ability to tolerate even long-term drought. Among them - ephemera - plants completing their life cycle from seed to seed within a few days. Their seeds germinate, and the plants bloom and bear fruit immediately after the rain falls. At this time, the desert is transformed - it blooms.

These plants survive a long period of drought in the seed stage.

Perennial bulbous or rhizomatous plants survive drought in the form of underground storage organs.

In the most amazing way, lichens survive a long drought, many lower plants, some species of club mosses and ferns, even a few flowering plants: they lose all moisture and, being completely dehydrated, are dormant until rain falls.

Adaptation of plants to cold and wet conditions.The living conditions of plants in the tundra are very harsh. First of all, it is temperature. Average monthly summer temperatures rarely exceed +10 °C. Summer is very short - about two months, but even in summer frosts can occur.

There is little precipitation in the tundra, respectively, and the snow cover is small - up to 50 cm. Therefore, they are dangerous strong winds- they can blow away the snow that protects the plants. Why is there a lot of moisture in the tundra? First, it does not evaporate as intensely as in warmer zones. Secondly, water does not go deep into the soil, as it is retained by a layer of permafrost. Therefore, there are many small lakes and swamps.

Plants in this zone are usually stunted and covered with snow in winter, which protects them from cold and wind. Root systems are superficial. On the one hand, their development is hindered by permafrost, on the other hand, by increased soil moisture and, as a result, a lack of oxygen in the soil. It is interesting that the structural features of the shoots resemble plants of a hot climate, only they protect not from heat, but from cold. This is a thick skin, wax coating, cork on the stem. Plants should have time to bloom and produce seeds in a short summer.

Tundra trees only once a century produce seeds that can germinate. Seeds fully ripen only when the summer is warm for the tundra for two years in a row. As a rule, tree seeds fall into conditions unsuitable for germination. Many tundra plants reproduce vegetatively, such as mosses and lichens.

Light as an environmental factor. The amount of light that a plant receives affects both its external appearance and internal structure. Trees grown in the forest have taller trunks and a less spreading crown. If they grew under the canopy of other trees, then they are oppressed and much worse developed than their peers in the open space.

Shade and light plants can also differ in the arrangement of leaf blades in space. In the shade, the leaves are arranged horizontally to capture as much as possible. sun rays. In the light, where there is enough light - vertically to avoid overheating.

Shade-grown plants have larger leaves and longer internodes than sun-grown plants of the same or similar species.

Leaves are not the same internal structure: in the light leaves, the columnar tissue is better developed than in the shadow ones. In the stems of light plants, more powerful mechanical tissue and wood.

Interactive lesson simulator. (Complete all the tasks of the lesson)

Audio fragment "Environmental factors" (4:33)

ABOUTnature circling the body -this is his habitat. science, studythe relationship of organismswith each other and with the environment,called ecology. influence the plantyat environmental environmental factors:light, temperature, humidity, wind,soil composition, etc. All factors necessaryplants that are used for lifeliving conditions. Excess orlack of one or morelogical factors affectthe structure of the body. Plants fitsuccumb to living conditions incertain boundaries.

The environmental factoris below the critical levelor, conversely, exceeds the maxihardly possible for a plantvein, called limitingfactor .

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Slides captions:

Combined lesson:

Check of knowledge: Independent work on the topic studied: "Families of plants of the monocotyledonous class." We prepare and sign the leaflets!

And their effects on plants Environmental environmental factors Study of a new topic:

The purpose of the lesson: 1. Get acquainted with the Factors of the environment. 2. Find out their influence on living organisms (plants). 3. Get to know how plants are classified into groups with respect to abiotic environmental factors.

ECOLOGY The science that studies the patterns of life of living organisms (in any of its manifestations at all levels of organization) in their natural habitat, taking into account changes introduced into the environment by human activity. And the mutual influence of the environment and organisms on each other.

Learning new material

Environmental factors are called: Conditions of organic and inorganic nature, directly or indirectly affecting the state and properties of an organism, population, natural community.

Environmental environmental factors Abiotic Biotic Anthropogenic Factors of non-living nature Factors of living nature Factors of human activity

1. Light 2. Pressure 3. Humidity 4. Radiation: a) Ultra-violet b) infrared c) radioactive d) Electro-magnetic, etc. 5. Minerals. 6. Chemical substances. 7. t *(temperature) Abiotic Factors of non-living nature Biotic Factors of living nature Anthropogenic Factors of human activity 1. Animals 2. Plants 3. Fungi 4. Bacteria 5. Viruses a) Direct b) Indirect (indirect)

In relation to light: plants are subdivided…. Light-loving Shade-loving Shade-tolerant

Heat-loving In relation to temperature: plants are ... .. Cold-resistant

Plants in Excessively Moistened Habitats Effects of Moisture on Plants: Plants in Dry Habitats Plants Living in Average (Sufficient) Moisture Conditions

Moisture-loving In relation to moisture: Drought-resistant

Animals Biotic environmental factors Fungi Bacteria

Direct impact Anthropogenic environmental factors Not direct impact

Think! List the abiotic environmental factors known to you and their significance. What groups are plants divided into regarding: A) Light B) Moisture C) Temperature Fixing the material:

A/C $ 54-55 questions Give examples of each type of environmental factor and its effects on plants

We do not live in a vacuum. We have to interact with the environment every time. We interact with the atmosphere, temperature, humidity, other people, animals. And all this cannot but affect us. When it's too hot, you can get heatstroke, if a person standing next to you has the flu, then we are also very likely to get infected. Also, life appearance plants are directly dependent on the environment. We will learn exactly how in this lesson.

Ecology is the science of the relationship of living organisms and their communities with each other and with the environment.

Environmental factor - a phenomenon or object that affects the body.

Environmental factors:

An ecological niche is a set of conditions necessary for the existence of a certain species. Any living organism is able to exist only under certain values ​​of environmental factors.

sunlight serves as a source of energy for plants, as it is necessary for photosynthesis (see Fig. 1). Light also has a regulatory effect on plant growth, flowering, fruiting.

Rice. 1. Photosynthesis

For timothy and strawberries, light is necessary for seed germination.

Plants in relation to light:

1. Light-loving (heliophytes). Able to grow only on brightly lit surfaces (feather grass, wheat, pine, Robinia).
2. Shade-loving (sciophytes). They can only grow in shady places. In the bright sun, burns (crow's eye, anemone) may appear.

Shade-tolerant. They grow well in lighted places, but they can also tolerate slight shading (linden, oak, ash).

Both overheating and too low temperatures are detrimental to any plants. Too high temperatures lead to loss of moisture, burns, destruction of chlorophyll.

action high temperatures heliophytes are susceptible, in connection with this they have a number of adaptations: they can turn the leaves, shed the leaf blade, leaving only the petiole, the leaves are turned into spines (cacti). Reducing the area of ​​the leaf blade helps heliophytes avoid excessive evaporation of water. Dense white pubescence or silver color of the leaves help the plant reflect most of the rays falling on it.

When water freezes, ice crystals form in the cells, which damage them. When the temperature drops to minus values, the chemical processes in the cell slow down, an imbalance occurs that can lead to death.

The appearance of plants in cold habitats: evergreen, with small hard foliage, low (do not exceed the height of the snow cover) (dwarf birch, willow).

Many plants for dry and cold periods can fall into a dormant state when all life processes are slowed down. In woody plants, the shoots of this year become woody and the thickness of the cork layer increases. herbaceous plants lose all above-ground organs. Shrubs and trees shed their leaves. Aquatic plants sink to the bottom (duckweed), retain only bottom leaves (water lily).

Sclerophytes - plants of arid habitats (cornflower false-spotted (see Fig. 2)). They have tough leaves.

Rice. 2. Cornflower false-spotted

Succulents are plants of arid habitats that are able to store moisture in the fleshy formations of the body - stems, leaves (aloe (see Fig. 3), cacti).

Rice. 3. Aloe

Plants in relation to humidity

1. Aquatic plants and plants that live in conditions of excess moisture
2. Plants of dry habitats
3. Habitat plants with normal moisture

The chemical composition of the soil

Plants get minerals from the soil. Most of all they need compounds of phosphorus, nitrogen, potassium. They also need compounds of boron, manganese and iron.

Animals feed on plants, so plants have protective devices: needles, thorns (acacia), hard foliage ( steppe plants), poisons (nightshade plants).

Other animals enter into mutualistic relations with plants: bees, butterflies, pollinate plants. Birds spread their seeds by eating delicious berries.

Mutualism is a mutually beneficial relationship between 2 organisms.

Large plants shade smaller ones, so there is a division into tiers. Epiphytic plants (orchids) can use others as support.

Plants are involved in maintaining the constancy of the composition of the air (they release oxygen and absorb carbon dioxide).

They take part in the formation of soils (root systems absorb some substances and release others). After the plant dies, most of the substances return to the soil.

The roots of plants fix the slopes of hills, ravines, protect the soil from erosion (destruction).

Forest plantations (see Fig. 4) are used to protect fields from dry winds and fires.

Rice. 4. Forest plantations

Large woody plants that evaporate a large amount of moisture. Can be used to drain wetlands (eucalyptus).

People cut down forests, drain swamps, irrigate arid lands. This destroys natural habitats and creates conditions for agricultural crops. New varieties of plants are being developed.

Deforestation can lead to the loss of fertile soil and the formation of deserts. In case of illiterate irrigation, waterlogging of the soil can occur.

In 3 identical pots with the same soil, plant 3 coleus. Grow them for a month different conditions: one in bright light and with additional illumination, the second - in normal daylight, the third - in partial shade - 3 meters from the window. Watch the growth and development of plants. Try to draw conclusions.

Schematically sketch the shape of the crowns of trees (birch, linden, pine) grown in different lighting conditions. Draw your own conclusions.

An extreme form of plant adaptation to extreme conditions environment (cold, dryness, heat) - this is suspended animation.

Anabiosis is a state of the body in which traces of vital activity are so small that there are no visible signs of life.

So, mosses endure winter freezing or complete drying in a state of suspended animation, from which they return to normal life after thawing or rain.

Bibliography

1. Biology. Bacteria, fungi, plants. Grade 6: textbook. for general education institutions / V.V. Beekeeper. - 14th ed., stereotype. - M.: Bustard, 2011. - 304 p.: ill.
2. Tikhonova E.T., Romanova N.I. Biology, 6. - M.: Russian word.
3. Isaeva T.A., Romanova N.I. Biology, 6. - M.: Russian word.

1. Biolicey2vrn.ucoz.ru ().
2. Rae.ru().
3. Travinushka.ru ().

Homework

1. Biology. Bacteria, fungi, plants. Grade 6: textbook. for general education institutions / V.V. Beekeeper. - 14th ed., stereotype. - M.: Bustard, 2011. - 304 p.: ill. - With. 263, tasks and question 5, 6, 7 (.
2. What are the groups of plants in relation to light. Describe them.
3. What are the environmental factors? Describe them.
4. * Choose 2 plants different types and take them to environmental groups in relation to light, humidity, temperature.