种群增长模型中的增长率和增长速率的比较

针对在一道高考题中出现的种群增长率与高中必修(人教版)教材中增长率的涵义不同,通过介绍种群增长模型的三种类型,旨在辨析增长率和增长速率.     

种群数量增长的“增长率”与“增长速率”辨析

在高中生物学教学中,关于种群数量增长的“S”形曲线的斜率称为“增长率”还是“增长速率”,一直存在争论。从种群数量增长的3种基本数学模型入手,结合中、英文对照,从这些争论的源头出发,通过总结对比,辨析2种表述方式的合理性。对相关的几个生态学参数进行对比归类,为高中生物学教学提供参考。     

具振动内禀增长率的单种群增长模型的振动性

研究离散的单种群增长模型x_(n+1)=x_nexp(rn (1-x_(n-k))/(1-cx_(n-k))),n=0,1,2,…,(*)的解的振动性,其中{r_n)_(n=1)~∞是任意实序列,k是正整数,0<相似文献   

一种自适应的种群增长模型及参数估计

通过对种群增长的非线性制约机制的数学形态分析,提出了一种新的种群增长数学模型ｄｘ／ｄｔ＝ｒｘ（１－（ｘ／ｘｍ）＾ｓ）其解析解为：ｘ（ｔ）＝ｘｍ／（１＋（ｘ＾ｓｍ／ｘ＾ｓ０－１）ｅ＾－ｒｓｔ）＾１／ｓ该模型当非线性密度制约指数ｓ〈１,ｓ＝１,ｓ〉１及ｓ→∞时分别对尖于ＳｍｉｔｈＬｏｇｉｓｔｉｃ,崔－Ｌａｗｓｏｎ及指数增长模型,具有自适应性,本文还提出了一种种群增长模型对数估计的搜索寻优方法,只要给出     

川西平原农田啮齿动物比较种群生态学Ⅰ.种群动态与繁殖

以1989至1995年在川西平原农田进行的啮齿动物标志重捕实验为基础,由种群密度、生物量以及出现频率的比较认为,大足鼠(Rattus nitidus)为此啮齿动物群落的优势种,褐家鼠(Rattus norvegicus)与社鼠(Rattus niviventer)为常见种,黄胸鼠(Rattus flavipectus)为稀有种.通过比较4种啮齿动物的种群动态、季节指数、变异系数发现,优势种密度变动的季节性最强,数量稳定性最大,无明显的年间变化;稀有种则相反,在种群动态上表现出最大的随机性和变动性,常见种的动态特征介于优势种与稀有种之间.优势种全年均有繁殖,稀有种的繁殖月份集中且有效性较低,常见种有较大的繁殖潜力.4种啮齿动物的种群动态及繁殖特征表明了优势种、常见种及稀有种的分化及多样性,以在同一生境的资源利用上达成共存.     

种群连续增长模型的学习过程

针对学生提出的问题“种群S型曲线为何在K／2时增长率最大”,通过多种渠道寻求答案,对“K／2”的实际应用提出了自己的见解。     

大丰麋鹿种群的增长与管理

大丰自然保护区于１９８６年引入麋鹿３９头,到１９９４年发展为１９１头,其成体平均产仔率为８３．５％,周岁内仔鹿成活率为９１％。周岁后年存活率平均为９７％。根据Ｌｅｓｌｉｅ矩阵模型,到１９９８年,麋鹿将发展到４００余头,接近其环境容纳量,到２０００年将发展到约１６００头。届时它将逐渐达到稳定年龄分布。雌性麋鹿４岁时繁殖价最高。约为新产仔鹿的１．８倍。将麋鹿种群调整到环境容纳量水平上的固定年龄分布后,每年从１～２龄麋鹿中调出约２８只（７０．９６％）。即可维持在种群规模为４００头的固定年龄分布。     

川西平原农田啮齿动物比较种群生态学I. 种群动态与繁殖

以 1 98 9至 1 995年在川西平原农田进行的啮齿动物标志重捕实验为基础 ,由种群密度、生物量以及出现频率的比较认为 ,大足鼠 (Rattusnitidus)为此啮齿动物群落的优势种 ,褐家鼠 (Rattusnorvegicus)与社鼠 (Rattusniviventer)为常见种 ,黄胸鼠 (Rattusflavipectus)为稀有种。通过比较4种啮齿动物的种群动态、季节指数、变异系数发现 ,优势种密度变动的季节性最强 ,数量稳定性最大 ,无明显的年间变化 ;稀有种则相反 ,在种群动态上表现出最大的随机性和变动性 ,常见种的动态特征介于优势种与稀有种之间。优势种全年均有繁殖 ,稀有种的繁殖月份集中且有效性较低 ,常见种有较大的繁殖潜力。 4种啮齿动物的种群动态及繁殖特征表明了优势种、常见种及稀有种的分化及多样性 ,以在同一生境的资源利用上达成共存。     

pH值对萼花臂尾轮虫种群增长及繁殖的影响

采用种群积累培养法,实验观察了 ｐＨ在３．５～１１．５之间（间隔 １）萼花臂尾轮虫 （Ｂｒａｃｈｉｏｎｕｓ ｃａｌｙｃｉｆｌｏｒｕｓ）种群的增长及繁殖．结果表明,该轮虫种群在ＰＨ６．５～８．５之间增 长较快, ８． ５时增长最快,即瞬时增长率 ｒ和种群密度较大和最大; ｐＨ在 ３． ５～４． ５和 ９． ５ ～１０． ５之间,种群为负增长,即 ｒ为负值; ｐＨ在 ５． ５～９． ５之间种群为正增长,即正为正 值．该轮虫存活的ｐＨ上限为１１．５,下限为３．５．在种群增长最适ｐＨ（８．５）条件下,该轮虫 的繁殖最快,即绝对带卵量最高（１３２个·ｍｌ－１）;ｐＨ在９．５时,其相对带卵量最高．为其它 ｐＨ值条件下的２～４倍．本研究结果可为淡水轮虫的大批量培养提供可靠的ｐＨ值技术指 标．     

《昆虫种群生态学——基础与前沿》

该书由科学出版社2005年出版,徐汝梅、成新跃编。介绍了昆虫生态学的基础与前沿,包括昆虫种群数量的时、空动态规律、调节机制及有关的研究方法。同时,还特别强调了空间生态学在昆虫种群生态学研究中的应用;并介绍了当前昆虫种群生态学的研究热点,如种群变动的遗传机制、昆虫与植物的协同进化等;结合重大的生态学问题,对昆虫暴发的一般理论、昆虫濒危与生物多样性保育、种群扩散与生物入侵、全球变化与昆虫种群动态等进行了论述。     

Extrapolation from Individual-Level Responses to Population Growth Rate Using Population Modeling

Ecological risk assessments of chemicals are often based on simple measurements of toxicity in individuals. However, the protection goals are often set at the population and community levels. Population models may be a useful tool to extrapolate from individual-level measurements to population-level endpoints. In the present study, the population growth rate (λ) was calculated for three sets of full life-cycle data (Tetranychus urticae exposed to agrimek, and Daphnia pulex exposed to spinosad and diazinon). The results were compared to λ from population models, where survival and/or reproduction were adjusted according to 4 d of data from the same life-cycle data. This was done to determine whether truncated demographic data can give results similar to that obtained with full life-cycle data. The resulting correlations were strong when both effects on survival and reproduction were included in the model (p < .001, 0.93 < R₂ < 1.00). There were also strong correlations in several cases when only effects on survival or reproduction were considered, although the total risk to the population tended to be underestimated. The results of the present study show that population models can be useful to extrapolate truncated data on the individual level to more ecologically relevant population-level endpoints.     

Effects of Climate Change on Plant Population Growth Rate and Community Composition Change

The impacts of climate change on forest community composition are still not well known. Although directional trends in climate change and community composition change were reported in recent years, further quantitative analyses are urgently needed. Previous studies focused on measuring population growth rates in a single time period, neglecting the development of the populations. Here we aimed to compose a method for calculating the community composition change, and to testify the impacts of climate change on community composition change within a relatively short period (several decades) based on long-term monitoring data from two plots—Dinghushan Biosphere Reserve, China (DBR) and Barro Colorado Island, Panama (BCI)—that are located in tropical and subtropical regions. We proposed a relatively more concise index, Slnλ, which refers to an overall population growth rate based on the dominant species in a community. The results indicated that the population growth rate of a majority of populations has decreased over the past few decades. This decrease was mainly caused by population development. The increasing temperature had a positive effect on population growth rates and community change rates. Our results promote understanding and explaining variations in population growth rates and community composition rates, and are helpful to predict population dynamics and population responses to climate change.     

Periodic Matrix Population Models: Growth Rate,Basic Reproduction Number,and Entropy

This article considers three different aspects of periodic matrix population models. First, a formula for the sensitivity analysis of the growth rate λ is obtained that is simpler than the one obtained by Caswell and Trevisan. Secondly, the formula for the basic reproduction number ℛ₀ in a constant environment is generalized to the case of a periodic environment. Some inequalities between λ and ℛ₀ proved by Cushing and Zhou are also generalized to the periodic case. Finally, we add some remarks on Demetrius’ notion of evolutionary entropy H and its relationship to the growth rate λ in the periodic case.     

The Effect of Atrophic Rhinitis on Growth Rate

Growth rate in pigs with turbinate atrophy was compared to growth rate in pigs without turbinate atrophy in 9 herds with atrophic rhinitis (AR) in which toxigenic strains of Pasteurella multocida had been isolated. Average reduction in growth rate in pigs with severe turbinate atrophy was 4.7 % as compared to pigs without turbinate atrophy. The difference was statistically significant only in some herds. Pigs with moderate AR gained on average 1.1 % less than unaffected ones. Thus, the study supports the assumption that AR is of economic significance in modern pig farming.