High School Biology Methods for Investigating Population Density

Different methods have different scope of application, for example, the sample method is suitable for plants and animals with a small range of activities, not at the microbial level. Sampling detection method: shake the culture medium in the test tube, take a part of it and dilute it, and then count the number of microorganisms under the microscope.

The marker recapture method is suitable for animals with a large range of activities. ......Microcounting is a counting method, not a method of investigating population density. It is recommended that the younger brother (sister?)

Make a list of how they relate to each other, remembering how it works and why it works for this creature.

As soon as I looked at this question, I thought that it might be the teacher or the student who was very good at thinking.

In my opinion, if the current sex ratio of a population is out of balance, and the short-term effect on the population is a decrease in the birth rate, which leads to a smaller proportion of juvenile individuals in the population, a larger proportion of older individuals, and a larger proportion of older individuals, then the mortality rate of that population will increase over a long period of time. (I feel like this explanation is a bit far-fetched, hahaha).

Population density was surveyed using the following methods: marker recapture method, sample method, removal sampling method, direct counting method.

1. Marker recapture method (survey sampling method, estimation method):

Within the activity range of the surveyed population, a part of the individuals are captured, marked and then released back to the original environment, and then recaptured after a period of time, and the population density is estimated according to the proportion of the number of marked individuals in the total number of individuals in the recaptured animals.

Population number First capture and number of flags Second catch Number of markers in the second capture.

2. Sample method:

In the distribution range of the surveyed population, several quadrats were randomly selected, and the population density of each quadrat was obtained by calculating the number of individuals in each quadrat, and the average population density of all quadrats was used as the estimation of the population density.

Commonly used sampling methods: five-point sampling method, equidistant sampling method.

3. Removal sampling method.

In a closed population, the population gradually decreases with continuous capture, the number of individuals obtained by the same capture force gradually decreases, and the cumulative number of successive captures gradually increases. When the number of catches per unit effort is equal to zero, the cumulative number of catches is an estimate of the population size.

4. Direct counting method.

A method of microscopy using a hemocytometer to perform a large single-cell microbial count, which is a commonly used method of bioenumeration, is simple, fast, and intuitive.

Sampling Method: It is used to investigate plants and insects or eggs with very low mobility. is one of the most commonly used methods for estimating population density.

Sampling methods include five-point sampling and equidistant sampling. For example, investigate the number of dandelions in a meadow.

Marker recapture method: used to investigate animals with strong mobility and large range of movement. For example, investigating the population density of rats in a certain area.

Sampler sampling method: used to investigate the richness of small animal groups in soil. Common small animals are spiders, centipedes, earthworms, etc.

The methods of taxonomic statistics of small animals in the samples are as follows: named calculation method and visual estimation method.

Sampling method: A method of counting microorganisms such as yeast in the culture medium. The obtained sample is now placed on a slide (chamber) and a microscope is required.

Dilution coating method: For bacteria, it can be counted and colonies can also be observed.

Advantages: It can be counted, and the characteristics of the colony can be observed.

Disadvantages: less absorption, more troublesome, the plate does not dry the effect is not good, easy to spread.

Plate scribing method:

Advantages: Colony characteristics can be observed and mixed bacteria can be separated.

Cons: Can't count.

It is generally used for purification from strains.

Sections 5 and 6 of them are taught in Elective 1 at the high school level and are used for the cultivation and enumeration of bacteria. It is rarely used to do general questions.

This depends on whether the target is an animal or a plant or a microorganism, as well as the size of the target area, as well as the population density.

There are only two types of exams, the sample method and the flag recapture method.

This method is mostly suitable for plants and some organisms with a small range of activities, such as earthworms. The marker recapture is suitable for organisms with strong activity ability and large range of activities, such as mammals, birds, fish, insects, etc.

Liquid sampling test.

Grass and the like.

Five-point sampling and equidistant sampling can be used for plants, marker recapture for animals (strong activity ability, large range of activity), and sampler sampling method (small range of activity, like small animals in the soil).

I don't remember the specifics of the sampling method.

Marker recapture and sample methods are methods for investigating population density.

The sampler sampling method is used to investigate the species of soil small animals, the visual estimation method and the named statistical method are the methods used to investigate the specific counting of soil small animals. One is accurate and one is blurry.

Microcounting is the method of observing and counting the number of a certain microorganism under a microscope.

The dilution coating plate method is a method of calculating the number of microorganisms such as bacteria by forming colonies on the medium after dilution;

Population density survey with: marker recapture method, sampling method, sampler sampling method to investigate soil microorganisms: sampler sampling method:

Visual estimation method, named statistical method to investigate the population of yeast (like other bacteria): microscopic counting method to culture microorganisms: dilution coating plate method, plate marking method.

Population density does not accurately reflect the trend of population population change, because population density only reflects the number of a certain period of time, but the change trend cannot be seen from population density. The trend of population changes should be analyzed for the birth rate and mortality rate of the population.

Population Density Profile:

The number of individuals in a population per unit area or unit volume is the population density, which is the most basic quantitative characteristic of a population. The density of different populations varies greatly, and the density of the same population also varies under different conditions.

As a unit space, in addition to physical space such as area and volume, for smaller populations, habitat units such as plants, branches, leaves, and fecal masses are also used. When it is difficult to estimate the true density of each unit of space, the number of catches can also be used to express its relative density by certain methods (such as timed acquisition, trapping, fishing, etc.). In addition, the density of the total area of an area is called coarse density, and the density of actual habitat is called economic density or ecological density. ‍

No, the population density reflects the number of a certain period, pay attention to a certain period. However, this characteristic alone does not reflect the trend of population growth. To know how a population grows or wanes, it is necessary to study other quantitative characteristics, such as birth and death rates.

Uh, I think the first sentence is fine.

On the fact that there are more females than males, and the population density is decreasing, and I think that some species, like ants, need a female to be an egg-laying machine to separate from the original population and become another population, resulting in a decrease in the original population density.

Analysis]: The average growth of individuals mentioned here is the growth of the number of individuals, due to the increase in the density of fish populations, resulting in the intensification of intraspecific struggles, the increase in mortality is high, the birth rate is declining, the growth will decline, the greater the density, the more obvious the disadvantage and destruction, when the population density reaches a certain level, the growth will be 0.

Answer: B

The sex ratio affects the birth rate, and the birth rate is a direct factor in determining population density, so the sex ratio is an indirect factor affecting population density.

(1) The crucian carp has strong activity ability and wide range of activities, and the marking refishing method is adopted; The formula for calculating the marker recapture method is: the number of individuals in the population (n) the total number of markers = the total number of recaptures The number of individuals marked in the recapture, i.e., n:200=160:10, n=3200

2) Plant population density survey is commonly used sampling methods, and attention should be paid to random sampling during the survey, ragweed and gray-green quinoa are both producers, and the relationship between them is competition

3) The vertical distribution of plants is related to light intensity, and the vertical distribution of animals is related to habitat space and food

4) The species of organisms increase, the more complex the structure of the community, the succession is carried out on the basis of the original, which belongs to secondary succession Therefore, the answer is:

Flag recapture method Animals with strong mobility and a large range of movement.

2) Sampling method random sampling competition.

3) Light intensity.

Food (4) complex; Secondary succession.