D, ESS2. E; Engaging in Argument from Evidence. Video Synopsis Academy botanist Dr. Nathalie Nagalingum explains how, more than million years ago, early plants played a notable role in adjusting Earth's physical surface as well as our planet's climate. She meets with a peer to discuss the evidence that scientists currently have to support her story. Subtitles are available in Spanish, Chinese, and many other languages! Click the CC button and toggle the settings to select your language.
While this video doesn't necessarily cover the following standards in depth, it is a compelling resource you can use to supplement your curriculum that does.
Examples include how photosynthetic life altered the atmosphere through the production of oxygen, which in turn increased weathering rates and allowed for the evolution of animal life; and how microbial life on land increased the formation of soil, which in turn allowed for the evolution of land plants. In this active model, students will simulate sugar molecule production to store energy—using ping pong balls! Observations inspire scientific questions and drive discoveries.
Explore seasonal primary productivity on Earth! Our collection of educational videos will help your students visualize data and understand scientific concepts. Sign up for event updates and exciting announcements. Read the book aloud to the students. Refer back to their list of questions to see if the book answered any of their questions. Discuss the answers. Talk about other facts learned in the book. Have them name different types of trees and compare what they look like size and structure and how they change over time.
Ask them what time of year they like the apple tree best. Also, discuss the focus questions: What do plants need to grow? Why do we need plants? What can we do for plants? Have students name the basic needs of plants: sun, water, soil and food. Discuss how they will provide these needs in the community planting project planned in Lesson One: Garden for Life.
Make some specific plans for who will carry out these tasks. Conduct an experiment to explore the patterns of change in living plants. Some change is predictable, such as the changes to a tree as they grow and throughout the seasons.
Set up the experiment and ask the students to predict what changes will occur. Observe the set-up over time, and have students record their observations. See Handout One : Change Experiment for the steps of the experiment. Discuss changes to the leaves. Post experiment questions: Is the twig a living thing?
Whether it is windy, rainy, snowy, freezing to death or that a scorching heat wave overwhelms us… the plants are there! It is indeed one of their characteristics to adapt to highly fluctuating environmental conditions. Plants have to deal with very large differences in temperature , light and humidity depending on the time of day, the seasons and the places where they grow. The nature of the soil also determines particular conditions for plant growth and development, and significant deficiencies in mineral nutrients nitrogen, phosphorus, etc.
Some irrigation water, or land by the sea, causes saline stress Stress caused by soil salinity. This salinity can be natural or induced by agricultural activities such as irrigation with low quality water or the use of certain types of fertilizers. These fluctuations in the physical environment favour the geographical distribution of plants according to their ability to adapt to a biotope Location with relatively uniform determined physical and chemical characteristics.
This environment is home to a set of life forms that make up biocenosis: flora, fauna, micro-organisms. A biotope and the biocenosis it supports form a given ecosystem. This is the case for garrigue plants in the south of France. But plants do not only interact with their physical environment.
They also interact with other l iving organisms. They give plants better access to soil nutrients and help them better resist environmental stresses. Others are harmful to them by infecting them, such as viruses, bacteria, phytopathogenic fungi, or by eating them, as is the case with many insects and herbivores in general.
Just as plants have adapted to the physical variations of their environment, they have, over the course of evolution, developed responses to defend themselves against the aggression of pathogens. Figure 2. The life cycle of plants: in spring when temperature, humidity and light conditions are favourable, the seeds in the soil germinate and the roots and leaves of young seedlings allow the plants to develop.
At a given stage of their development they flower and produce new seeds that will be buried in the ground to germinate the following year. Vegetative organs roots, leaves die in autumn when conditions become unfavourable… but if the individual plant has disappeared, the species persists thanks to the seeds. There are annual plants that disappear in winter when conditions light, humidity, temperature are unfavourable to reappear the following spring from the germination of their seeds, or from underground storage organs such as bulbs and tubers.
Perennials , on the other hand, are still clearly visible in the bad season, during which they often enter dormancy, losing their leaves, such as deciduous trees , to resume growth in good weather, from their buds [2]. Unlike animals, plants do not flee to avoid adverse or aggressive conditions that jeopardize their integrity or survival. They do not have the central nervous system that allows animals to analyze the information their senses provide them, triggering actions to adapt to changing situations.
They are fixed to the soil by their roots , which provide the aerial parts with water and essential mineral elements: nitrogen, phosphorus, potassium, sulphur, iron, zinc, magnesium, manganese… [3]. Leaves are able to transform the light energy provided by the sun into carbonaceous organic molecules sugars, lipids, proteins through the reaction of photosynthesis Bioenergetic process that allows plants, algae and certain bacteria to synthesize organic matter from the CO 2 in the atmosphere using sunlight.
Solar energy is used to oxidize water and reduce carbon dioxide in order to synthesize organic substances carbohydrates. The oxidation of water leads to the formation of O 2 oxygen found in the atmosphere.
Photosynthesis is at the base of autotrophy, it is the result of the integrated functioning of the chloroplast within the cell. Briefly, let us recall that photosynthesis occurs in leaf specific cellular organelles Specialized structures with a specific function within the cell.
For example, the nucleus, mitochondria and chloroplasts , the chloroplasts Organites of the cytoplasm of photosynthetic eukaryotic cells plants, algae. As a site of photosynthesis, chloroplasts produce O 2 oxygen and play an essential role in the carbon cycle: they use light energy to fix CO 2 and synthesize organic matter.
They are thus responsible for the autotrophy of plants. Chloroplasts are the result of the endosymbiosis of a photosynthetic prokaryote cyanobacterium type within a eukaryotic cell, about 1. Their chlorophyll captures solar photons leading to the cleavage of water molecules and the release of oxygen , the assimilation of carbon from carbon dioxide CO 2 into organic molecules, and the production of chemical energy Adenosine Triphosphate or ATP Abbreviation of adenosine triphosphate.
A triphosphate nucleoside composed of adenine nitrogen base , ribose sugar with 5 carbon atoms and three phosphate groups forming a triphosphate group. A compound that both donates and stores energy present in all living organisms. Also used as building materials for nucleic acid synthesis.
Figure 3. The stomata of the leaves. B, Their bean shape defines an empty space in the middle, the ostiola, through which gas and water exchanges can occur between the leaf and the outer environment. The more or less important turgidity of the guard cells means that the ostiola can be opened or closed. Closing the stomata during the day when it is hot prevents the plant from losing its water.
The closure of stomata is controlled by flows of ions potassium, chloride, etc. From an anatomical point of view, these exchanges occur in very specific leaf structures: stomata Figure 3; [5] ,[ 6] which are composed of two cells of the epidermis, called guard cells.
Depending on the state of turgescence A cellular state associated with the elongation of the plant or animal cell whose vacuoles or vesicles are expanding due to water entry into the same cell. Stomatal function and photosynthesis are therefore two important parameters that contribute to the adaptation of plants to their environment, especially for drought adaptation or for plants living in arid environments such as deserts , as we will discuss later in this article.
Plants, because of their fixed life and their lack of sensory organs for perceiving the outside world on the one hand, and of a central nervous system on the other, have therefore evolved to adapt to contrasting environmental conditions in space and fluctuating over time. These two aspects of plant adaptation do not use the same concepts and mechanisms. In the first case, it is the spatial adaptation of different plant species to the different climates of the planet. Not all plant species grow everywhere, and this climato-geographical adaptation has been based on the principles of natural selection of beneficial traits, traits that have become established over time in the genetic heritage of the species see The adaptation of organisms to their environment.
Biologists are sure that once a species becomes extinct it never appears again. In the modern world, biologists can identify species by seeing whether the organisms can breed with one another. Paleontologists have much more trouble with fossil species, because the organisms are no longer around to breed!
All that can be done is to match up shells or imprints that look almost identical and then assume that they represent a species.
Paleontologists are sure that the fossil record is biased. That means that some kinds of organisms are much scarcer as fossils than they were when they were alive.
Other kinds of organisms are much better represented by fossils. Animals with hard shells and skeletons are represented well in the fossil record. On the other hand, soft-bodied animals are probably represented very poorly. It's likely that most soft-bodied species that ever existed are gone forever without a trace. Land animals are probably very poorly represented as well.
0コメント