(1) Verification observation method. Based on the textbook, through observation, the theory of biological phenomena and essential characteristics in the textbook is observed and verified. For example, the textbook takes Chinese cabbage and radish as representative plants and summarizes the main characteristics of Cruciferae. Observe the flowers and fruits of other cruciferous plants mentioned in the textbook, verify and confirm the main characteristics of cruciferous plants, and then identify more cruciferous plants according to the verification results.
By means of verification and observation, the textbook theory is concrete and true. In the process of verification, it not only consolidates the theoretical knowledge learned, but also cultivates the idea of seeking truth from facts and pursuing truth.
(2) Comparative observation. Comparative observation is a method to grasp the characteristics of things and compare their similarities and differences. When observing two or more organisms or biological specimens, wall charts and models, the comparative observation method should be adopted. For example, when observing the external morphology of frogs and lizards, let students touch and observe the objects carefully first, then fill in their external morphology comparison table truthfully, and finally infer their respective living habits and living environment conditions according to their external morphological characteristics.
By contrast observation, all observation points are clear and easy to remember, which avoids the confusion of observation contents. In the process of comparative observation, we can initially gain the ability to compare and analyze different things.
(3) Sequential observation. Sequential observation refers to the method of observing biological morphology and structure in a certain order. For example, when observing the longitudinal section of the root tip under a microscope, from the top of the root tip upward: root cap → meristem → elongation → mature region. For another example, observing the structure of tomato pulp cells with a microscope, we can find the cell wall, cell membrane (not easy to see under the microscope), cytoplasm and nucleus in turn from outside to inside.
Sequential observation method can comprehensively observe the whole or local morphological structure of organisms, and the observation process is detailed and clear, avoiding the phenomenon of missing observation points.
(4) Dynamic observation method. This method is often used to observe the changes of life habits, physiological functions and biological phenomena. For example, when discussing the function of fins, cut off the pectoral fin and ventral fin of one crucian carp and the tail fin of the other crucian carp, and observe their swimming posture and speed. Through observation, the function of each fin will be found and summarized.
Dynamic observation is very interesting, forming the psychology of exploration and discovery.
In addition to the above observation methods, there are also key observation methods, regular observation methods, fixed-point observation methods, quantitative observation methods and so on. One or more suitable observation methods should be selected according to different observation objects, observation contents, observation purposes and observation conditions. No matter what observation method is adopted, it is required to combine point with surface in the observation process, that is, to fully understand and grasp the key observations.
According to specific requirements, truthfully draw records, analyze data and discuss observation results. For example, observe tomato pulp cells and onion epidermis cells with a microscope, guide students to draw their morphological structures with a microscope, and then make a comparative analysis. Why are the two kinds of cells similar in basic structure, but quite different in morphology and arrangement?
The observation method should be used properly, the observation process should be careful and meticulous, and the observation results should be recorded and drawn truthfully, which provides a basis for solving problems and contributes to the formation of observation ability.
3? Field practice of improving observation effect
In the wild, you can get in touch with biology and biological phenomena in many ways and angles. However, the site is vast, there are many kinds of creatures and the environmental conditions are complex and changeable. Only by having a clear observation object and purpose, and selecting representative contents as observation and analysis objects in a focused and timely manner can we get better observation results. For example, when observing the morphological structure of birds adapting to life habits, observe the beaks and feet of domestic chickens and ducks raised in the wild. Domestic chickens have sharp and hard beaks, which are suitable for pecking, toes separated, and hard and sharp claws, which are suitable for walking and planing; Domestic ducks have flat and wide beaks with serrated edges, which are suitable for filtering food in water, and webbed toes between their feet is suitable for swimming.