Concepts of biology Community

CHAPTER BIOLOGICAL COMMUNITY Concepts Community structure Species diversity Spatial structure Nutrition structure Species interactions Definition the group of different species, occupy a given area interacting either directly or indirectly Definition Community has specific attributes that population doesn’t have: food chains, food webs, ecological pyramids changing of physical environmental factors materials and energy are accumulated and modified environmental improvement by advantageous ways Community’s names Distribution place Dominant species Life forms Categories Community’s boundary Many communities have obvious boundaries However, many communities not have obvious boundaries which overlap on each others, set up ecotones or buffer zones between main communities Ecotone community Community structure The number of species and their relative abundance define diversity Spatial structure and nutrition structure Interactions between populations in community Species component and number of individuals in each species Based on the Based on function the role Autotrophs Group of dominant species Group of minor species Group of random species Heterotrophs Consumers Decomposers Types of consumers Consumers Herbivores Carnivores Omnivores Relation between species component and number of individuals in species The more diverse of the number of species in community – the less number of individuals in species and in reverse From pole zone to equatorial zone, from open sea to coast, number of species is increasing, number of individuals in each species is decreasing In the development process of community, the number of species is increasing From low altitude to high altitude, from sea surface to oceanbed, number of species as well as number of individuals in species is decreasing Relation between species component and number of individuals in species To count Species diversity the number of species Diversity of community determines Ecosystem diversity Genetic diversity Interactions between populations in community Interactions between populations in community Amensalism Negative Positive interactions interactions Competition Predation Interaction between Commensalism Plants and Animals Protocooperation Mutualism Amensalism A inhibited – B unaffected (- & 0) www.rfviet.com thugian.com.vn www.tin247.com agriviet.com rimf.org.vn Competition (populations inhibit one another) Species compete with each others when their ecological niches coincide with each others Principle “cạnh tranh loại trừ”: There can not have two species which have coincided ecolodical niches Competition is one of motives of evolution Competition Occurs when limitation of living resources The closer of species to each other (in category) the more cutthroat competition If two species (different taxonomy) compete with each other – the one which has higher evolution level will be the winner If two species (same taxonomy) compete with each other – the one which has higher biological potential will be the winner The two species will live peacefully together if both of them have ability to separate ecological niches The two species (different taxonomy) also can live together Mô hình toán cạnh tranh quần thể N1: số lượng cá thể loài 1, với dung lượng K1 tốc độ tăng trưởng r1 Tương tự loài N2, K2 r2 dN KN  rN dt K dN dt dN dt = r1 N ( ) (4.1) = r2 N ( ) (4.2) K - N -α1N K1 K2 - N - α2N1 K2 1 2 hệ số cạnh tranh quần thể N1 N2 ngược lại Mô hình toán cạnh tranh quần thể theo (4.1) r1N1 [(K1 - N1 - N212) / K1] = dN1/dt = Biểu thức khi: r1 = 0; N1 = 0; K1 - N1 - N2 12 = N1 = K1 - N2 12 (4.3) N1=0 N2=K1/12 (điểm A, hình 4.1a) N2=0 N1=K1 (điểm B, hình 4.1a) theo (4.2) r2N2 [(K2 - N2 - N121) / K2] = dN2/dt = Biểu thức khi: r2 = 0; N2 = 0; K2 - N2 - N1 21 = N2 = K2 - N121 (4.4) Mô hình toán cạnh tranh quần thể Hình 3.2 Các đường đẳng khuynh dN/dt = (Theo Begon Mortimer, 1988) (a) : quần thể (b): quần thể Mô hình toán cạnh tranh quần thể Đồ thị cạnh tranh hai quần thể N1 N2 (Theo Begon Mortimer, 1988) Predation • predator (A) kills & consumes prey (B) (+ & -) • sets up food chains • It is most stressfull where it has just been established and reduced lightly over time • In order to meet predator’s demands, the preys usually have small body size, large number, high rmax and the development of prey number is always before the development of predator number • Parasitism is also one kind of predation Mô hình toán mối quan hệ vật ăn thịt mồi  dH / dt  H  V( H ) P  dP / dt  P[ f V( H )  m] (5.1) dH / dt  H  HP  H (  P)  dP / dt  P( fH  m)  (5.2) V: sinh khối vật mồi bị vật ăn thịt tính đơn vị thời gian f: phần lượng từ sinh khối sử dụng cho sinh sản vật ăn thịt [e H / H*/ (H / H*)] m  [e P/ P*/ (P / P*)]  = C (5.3) Trong đó: H*= m/f. P*= / Nếu H0 P0 số lượng tương ứng ban đầu vật mồi vật ăn thịt, thì: C = [eHo/H*/(H0/H*)]m  [ePo/P*/(Po/P*)] > Đây mô hình vật ăn thịt mồi Volterra Mô hình toán mối quan hệ vật ăn thịt mồi Toạ độ P [H*=m/f.; P*=/] C3 nghiệm hệ phương C1 trình (5.2) P* dH/dt= dP/dt=0, nên điểm cân C1 < C2 < C3 H* H Họ đường cong biễu diễn dao động số lượng hai quần thể vật ăn thịt - mồi hệ Relation between plants and animals Plants are diverse in species components, occur on all landscapes, grow quickly and ensure redundant biomass to animal Plants have adaptive morphologies Plant population size will restore when predator’s pressure decreases Many plant species can protect themselves by creating special substance or organ for re-development animalreiki.me.uk Apart from the role of preys, some plant species could “use” animal as the tools of scattering seeds, or pollinating www.conservationtreaty.org Sống nhờ and commensalism commensal (A) benefits; host (B) not affected (+ & 0) If only one of two species has benefit by living together, but does not harm to the partner – it is called sống nhờ If sống nhờ plus nutrition of one species depending to another, but does not harm to www.nearctica.com the partner – it is called commensalism dulichvietnam.asia www.cbu.edu Protocooperation Is an interaction between two species, both of them have benefit, but not obligatory (+ & +) Examples: cá Gadus Trachiurus nấp xúc tu Physostoma; Sự chung sống san hô Pocillopora elegans với tôm Alpheus cua Tropezzia, Tôm cua dùng san hô làm nơi trú ngụ đánh đuổi biển khỏi vật chủ chúng muốn gặm san hô; www.starfish.ch Mutualism Obligatory, both populations benefit (+ www.geology.iupui.edu & +) Examples: amplifiedwisdom.wordpress.com Algae and Protozoa Balanus, coral, jellyfish, worm Lichen on Mangrove members.optusnet.com.au vietsciences1.free.fr ... Decomposers Types of consumers Consumers Herbivores Carnivores Omnivores Relation between species component and number of individuals in species The more diverse of the number of species in community. .. development process of community, the number of species is increasing From low altitude to high altitude, from sea surface to oceanbed, number of species as well as number of individuals in species... Spatial structure of community Clumped HORIZONTAL STRUCTURE Uniform Random Spatial structure Horizontal distribution of community in estuary Assemblage (Guild): R Root, 1967: a group of species used