Bài giảng sinh vật học quần thể Population

LOGO “ Add your company slogan ” Chapter Populations Chapter Populations Definition and concepts Properties of populations • Population size and density • Spatial structure • Age structure • Sex ratios and reproductive structure Interactions of individuals within a population • Negative interactions • Positive interactions DEFINITION is a group of individuals of the same species that inhabit a given area POPULATION CONCEPS Monomorphic species:  Narrow distribution area,  Relatively homogeneous environmental living condition  Only one population  Usually endemic species, easily be exterminated  Be preserved Cá cóc Tam Đảo (Paramesotriton deloustali) POPULATION CONCEPS Polymorphic species:  Wide distribution area,  Unhomogeneous living condition environmental  All populations adapt to each local living condition  Set up new ecological physiological characteristics  May have different originate new species Shellfish: Cepaea nemoralis and genetics, POPULATION SIZE (usually denoted N) is the number of individual organisms in a population REVERSE RELATION Individual size Individual size is small Individual size is big Number of individuals Many in number of individuals and low biomass Few number of individuals and high biomass Cá diếc bạc Tảo xoắn Spirulina Vi khuẩn gây bệnh tả Chim Se Sẻ Tàu ROLE OF POPULATION SIZE  Large size high ability to maintain the life  Population size of the same species in temperate zone is usually bigger than it’s in low latitude region ROLE OF POPULATION SIZE Minimum number of individuals  Typical characteristic of species  Maintains population’s functions  If the number of individuals of one population is lower than minimum number this Maximum number of individuals  Is affected by environmental factors  The maximum number (K) is equal to environmental capacity population will be perished Cá Cháy Cá Mòi EQUATION OF POPULATION SIZE Nt +1 = Nt + B – D + I – E Number of birth and immigration Births nhập cư Population size Number of death and emigration chết AGE STRUCTURE The number or proportion of individuals in different age classes Physiological age Ecological age AGE STRUCTURE Populations can be divided into three ecologically important age classes or stage: Prereproductive Reproductive Postreproductive AGE PYRAMIDS Young population (developing) Stable population Degraded population (chấm: sau ss; trắng: ss; gạch: trước ss) Cross section of tree trunk showing annual growth rings By measuring the width of each ring, a pattern of radial growth through time can be established AGE CHARACTERISTICS OF THE POPULATION  The more complex of age structure – the higher survival and stability of the population  The simplicity or complexity of age structure is depend on high or low life expectancy of species and depend on geographic latitude  The differences of age ratio within a population show the adaptation to environmental conditions  Age structure of population is changed according to reproductive cycle  In the advantageous environment, age structure is changed by increasing group of prereproductive age and in reverse SEX RATIOS INPOPULATIONS  The proportion of males to females  Depends on:  reproductive property of species  life cycle www.aquabird.com.vn  influence of environmetal factors REPRODUCTIVE STRUCTURE  The proportion of males to females in the periods of: prereproductive, reproductive and postreproductive  Depends on:  Environmental factors  Reproductive style NEGATIVE INTERACTIONS One to one struggle – Intraspecific competition Parasite – host interaction Prey – peradator interaction ONE TO ONE STRUGGLE – INTRASPECIFIC COMPETITION  Limitation resources of living  Depends on density and Allee effect Gadus morhua •The individuals used to separate ecological niche to decrease intraspecific competition PARASITE – HOST INTERACTION  Uncommon, only occurs in very difficult conditions of nutrition Ceratias Cryptopsaras http://images.google.com.vn/imgres?imgurl=http://tolweb.org/tree/ToLimages/ceratiid_males.jpg&imgrefurl=http://tolweb.org/Ceratiida e&usg= cBWQEc_X4A5klYqcIpZ0SpERO58=&h=324&w=299&sz=68&hl=vi&start=1&tbnid=etGgK4n80w2BCM:&tbnh=118&tbnw=109&prev =/images%3Fq%3DCeratias%2Bsp%26gbv%3D2%26hl%3Dvi%26sa%3DG PREY – PERADATOR INTERACTION  Eating each other innerspecies, occurs in very special conditions Perca fluviatilis http://images.google.com.vn/images?gbv=2&hl=vi&q=Perca+fluviatilis&btnG=T%C3 %ACm+ki%E1%BA%BFm+H%C3%ACnh+%E1%BA%A3nh Cá Mối http://images.google.com.vn/images?gbv=2&hl=vi&q=c%C3%A1+M%E1%BB%91i POSITIVE INTERACTIONS Assemblage or herd instinct Social behavior Long –term cooperation by the herd instinct Common in nature, supports each others They can recognize each others by pheromone or colours Temporary cooperation Assemblage or herd instinct Social behavior bees http://images.google.com.vn/images?gbv=2&hl=vi&q=ong ants termites http://images.google.com.vn/images?gbv=2&hl=vi&q=ki%E1%BA%BFn http://images.google.com.vn/images?gbv=2&hl=vi&q=m%E1%BB%91i ... TV  Phytobenthos and  Movement population (determined population size)  Hard to see population (dangerous animals) zoobenthos ĐV đáy Hổ SPATIAL STRUCTURE OF POPULATION  Patterns of the spatial... ROLE OF POPULATION SIZE  Large size high ability to maintain the life  Population size of the same species in temperate zone is usually bigger than it’s in low latitude region ROLE OF POPULATION. .. environmental capacity population will be perished Cá Cháy Cá Mòi EQUATION OF POPULATION SIZE Nt +1 = Nt + B – D + I – E Number of birth and immigration Births nhập cư Population size Number