1. Introduction
Ecology (생태학): The study of the interrelationships between plants and animals that live in a particular physical environment
Ecosystems:
(1) short for Ecological system
System: consists of elements that interact with one another
(2) Communities of organisms and the physical environment (e.g., sunlight, rainfall, soil nutrients, etc.)
(3) can vary greatly in size (e.g., a couple meter diameter of a pond,
자하연 (자하골에 살던 紫霞 申緯, 1769-1847)
a tropical rainforest, or global biosphere, i.e, ultimate Earthbound ecosystem = Atmosphere (대기권) + Hydroshpere (수권) + Lithosphere (암석권)
(4) Materials flow in and out of the ecosystem. However, materials in and out of the ecosystem < materials that cycle within the ecosystem
(5) can change with time (extreme environmental condition change – flooding, drought, temperature change, volcanic activity, forest fire, etc.) – 1925년 을축대홍수로 인한 한강 변화 1970 년 공유수면 매립으로 석촌호수 탄 생
부리도(浮里島)
Forest fire (Yellow Stone National Park)
(6) Natural or artificial (e.g., constructed wet lands, agricultural lands, etc.)
Habitats (서식지): the place where a population of organisms lives
Bears (Yellow Stone National Park, U.S.) Bald Eagle (‘Bald’ 머리가 흰 동물)
Deer (Yellow Stone National Park, U.S.)
Bisons (Yellow Stone National Park, U.S.)
Wolf (Yellow Stone National Park, U.S.)
Tiger (Where?)
2. Human Influences on Ecosystems
Although ecosystems change naturally, human activities can speed up natural processes by several orders of magnitude in terms of time. (e.g., large-scale agricultural operations, stock-breedings, dams, etc.)
Human activities can change ecosystems through the destruction of species by loss of habitat (global extinction vs. local extinction).
Release of toxic chemicals (예, Pesticides (DDT, Dichlorodiphenyltrichloroethane), fertilizers, PCBs - a nonconducting material for transformer, 변압기 절연체, etc.) Nonnative (exotic) species (e.g., zebra mussel, American bull frog 황소개구리,
bluegill, bass, 솔잎혹파리, 재선충)
침묵의 봄 (Silent Spring by Rachel Carson in 1962) - 미국 느릅나무병 (elm)의 사례: 1930 년대 유럽에서 미국으로 수입된 느릅나무 목재로 인해 전염. 나무 의 수액을 통해 이동하는 균류 형태의 병원균이 독성물질을 분비하여 나무를 고사시킴. 느릅나무에 사는 딱정벌레(beetle)가 매개체(vector). 딱정벌레 방재
를 위한 살충제(DDT) 살포로 오염된 느릅나무 잎을 먹은 지렁이(earthworm)
가 오염되고, 이 지렁이를 먹는 울새(robin) 절멸 (exterminated) Episode of DDT:
1874. O. Zeidler synthesized
1939. P. H. Muller identified the killing ability and won the Nobel Prize (1948) 1940s widely used as insecticides (especially for lice-Typhus and mosquito-
Malaria) and pesticides
1955. WHO used DDT to prevent Malaria (mortality rate 192/100,000 → 7/100,000, In Sri Lanka, patients 2,500,000/yr → 31/yr)
1962. Silent Spring was published 1972 DDT was prohibited in US.
Malaria was raged again in some areas, e.g., Africa and West southern Asia.
2006. WHO recommended indoor limited application of DDT in those regions.
Malaria vs. DDT prohibition?
DDT was prohibited in only US not in Africa and Asia. Mosquito may develop resistance to DDT.
Excessive hunting – (e.g., Dodo bird, rhinoceros, etc.). Prey and Predator (특정 종의 멸종은 먹이 사슬 상의 아래 위 다른 종에게 직접적인 영향)
A stuffed Dodo bird
도도새는 인도양의 모리셔스(Mauritius) 섬에 서식했던 새이다. 이 새는 땅에 둥지
를 틀고 나무에서 떨어진 과일을 먹고 살았다. 섬에는 포유류가 없었고 아주 다양 한 종의 조류들이 울창한 숲에서 서식하고 있었다. 도도는 날지 못하는 새로, 날 개가 퇴화하여 날 수 없었다. 날개가 퇴화한 이유는 도도새가 살던 땅에는 도도새 를 위협할만한 맹수가 없었기 때문이다.
There had been many birds in the Mauritius Island in the Indian Ocean.
The Dodo bird is one of the birds in the island, weighed 50 pounds of weight, and built nest on ground and ate fallen fruits.
Wings were degenerated because there was no natural enemy in the island.
1505 년 포르투갈 인들이 최초로 섬에 발을 들여 놓게 됨에 따라 이 섬은 향료
무역을 위한 어선들의 중간 경유지가 되었다. 50 파운드의 무게가 나가는 도도새 는 신선한 고기를 원하는 선원들에게 매우 좋은 사냥 감이었다. 이로 인해 많은 수의 도도새가 죽어갔다. 후에 네델란드 인들이 이 섬을 죄수들의 유형지로 사용 하게 되었고 죄수들과 함께 돼지와 원숭이들이 유입되었다. 섬에 들어오는 배들에 살던 쥐들의 일부가 섬으로 도망치기도 했다. 생쥐, 돼지 그리고 원숭이들은 바닥 에 둥지를 트는 도도새의 알을 쉽게 잡아 먹을 수 있어서 도도새의 알은 위험에 빠지게 되었다. 인간 남획과 외부에서 유입된 종들로 인해 도도새의 개체 수는 급 격히 줄어들었다. 모리셔스 섬에 인간이 발을 들여 놓은 지 100 년 만에 한때 많 은 수를 자랑하던 도도새가 희귀종이 되어버렸으며 1681 년에 마지막 새가 죽임 을 당했다. 도도새의 멸종에 관한 이야기는 잘 기록되어 있음에도 불구하고 이 새 의 완전한 표본은 보전되어 있지 않다. 단지 몇 부분의 몸체 일부와 스케치만이 있을 뿐이다. 도도새는 모리셔스 섬에서 사라진 조류의 일부일 뿐이다. 19세기 울 창한 숲이 차와 설탕 재배를 위한 플랜테이션으로 변함에 따라 많은 종들이 멸종 에 이르게 되었다. 모리셔스 섬에 고유한 45 개의 조류 중 21 개 만이 간신히 살 아남았다.
In 1505 Portuguese sailors arrived at the islands and they took the bird for fresh meat.
Later Dutch arrived and constructed a prison. They brought pigs, rats, and monkeys.
The exotic animals easily took egg of Dodo birds.
In 1681 the last Dodo bird was killed. It takes just 100 years for the Dodo birds to be exterminated.
Other many birds in the island were also exterminated. Only 21 species among 45 species were survived.
도도새는 1681 년에 멸종되었지만 이것으로 이야기가 끝난 게 아니다. 최근 한 과
학자가 모리셔스 섬에 특정한 종의 나무가 희귀종이 되어가고 있음을 알아차리게 되었다. 그는 이 종의 남아 있는 나무 13그루 전부가 300년 가량 되었으며 1600 년대 이래로 어떠한 발아도 이루어 지지 않았음을 알게 된 것이다. 이 종의 평균
수명이 300 년 정도임을 생각해 볼 때 남아 있는 나무들은 이미 너무 늙은 것들
이다. 그들은 곧 죽을 것이며 그 종도 멸종에 이르게 될 것이다. 그 나무가 300
년 전에 번식을 멈추고 또한 도도새가 300 년 전에 멸종에 이르게 된 것이 과연
우연의 일치일까? 아니다. 도도새는 이 나무의 열매를 먹고 살았으며 오로지 이 새의 소화기관을 통해서만 이 나무는 씨앗을 옮기고 성장시킬 수 있었던 것이다.
한 종의 생물이 사라진 지 300 년이 지난 지금 그것으로 인한 직접적 결과로 또 다른 종의 생물이 멸종에 이르게 된 것이다. 다행히도 칠면조를 이용해 그 나무의 새로운 세대를 성장시킬 수 있었고 이제 그 나무들은 도도나무 라고 불리게 되었 다.
A scientist found that the number of specific trees was decreasing and the existing 13 trees were over 300 years. It means that there has been no germination since 1600s when the Dodo bird was exterminated. He found that Dodo birds eat the fruits of the tree and spread seeds. We can understand disappearance of a species affects directly or indirectly the presence of the other species. Finally the trees were multiplied by Turkeys and are called “Dodo Trees”.
Przewalski’s Horse in the Mongolia
3. Energy and Mass Flow in Ecosystem
Ecosytems would not be possible without the flow of energy into them. The sun is the primary source of this energy because all biological life depends on the green plants that use sunlight as s source of energy. Tropic levels can be classified phototrophic and chemotrophic depending on energy source and autotrophic(독립영양) and heterotrophic(종속영양) depending on carbon source.
Type of Respiration:
Electron acceptors: aerobic(호기성), anaerobic(혐기성), and anoxic(NO3-
, NO2-
, SO42-
, etc.)
Food web (or Food chain): Relationship between organisms in an ecosystem
Primary producer: sunlight-using organisms. Autotrophic(독립영양), e.g., photosynthesis
6CO2+ 6H2O + 2,800 kJ energy from sun chlorophyll
�⎯⎯⎯⎯⎯⎯⎯� C6H12O6+ 6O2
Primary consumers(초식동물, herbivores): eat plant material. Obtain energy from chemicals formed by other organisms. Chemoheterotrophs (종속영양)
Secondary consumers(육식동물, carnivores): eat the flesh of animals, Chemoheterotrophs (종속영양)
Decomposers: consume the materials excreted by living organisms or released during the decay of dead organisms.
c.f. Omnivores(잡식)?
Ecological pyramid: Quantitative relationships of energy flow by plotting the mass of biomass (all organisms) with trophical level
Efficiency of energy flow
As we move up the food chain the amount of biomass present decreases. (e.g., In a meadow as an ecosystem, the majority of the biomass would occur as plants.) Much of the food consumed by an organism higher on the tropic level is either lost as
undigested waste or burned up to produce heat. Very little is actually converted into body tissue that can be eaten by organisms higher up the food web.
It is often assumed that only 10% of the energy consumed by an organism in the form of plant matter is converted into animal tissue. For example, 1 MJ in Phytoplankton → 0.1 MJ in zooplankton → 0.01 MJ alewife(small fish) → 1,000 J in lake trout → 100 J can be used to produce tissue of humans
3.1 Bioaccumulation
Bioaccumulation(생물축적): The total uptake of chemicals by an organism from food items as well as via mass transport of dissolved chemicals through the gills and epithelium (상피)
Biomagnification(생물농축): The process that results in the accumulation of a chemical in an organism at higher levels than are found in its own food.
Chemicals may become more and more concentrated as it moves up through a food chain. For example, DDT 10 ppm in soil, 141 ppm in earthworms, 444 ppm in robins
Bioconcentration: The uptake of chemicals from the dissolved phase. Usually refers to chemicals foreign to the organisms not the natural chemicals
Concentration fish = (concentration in water) x (bioconcentration factor)
Japan’s Lessons on the Economy and the Environment
Part 1:
Part 2:
Par 3:
http://www.youtube.com/watch?feature=iv&v=VXoDtPuB3Qo&src_vid=wrjkG YLkfvQ&annotation_id=annotation_262502
Par 4:
http://www.youtube.com/watch?feature=iv&v=gabNPbo6rGk&src_vid=VXoDt PuB3Qo&annotation_id=annotation_19909
4. Nutrient Cycles
4.1 Carbon cycle
- Photosynthesis is the major driving force for carbon cycle.
- Ocean serves as the greatest reservoir of carbon (e.g., dissolved carbon dioxide gas, and carbonate and bicarbonate ions,). The concentrations of CO2 in shallow waters are higher than those in deeper waters due to high productivity.
- Carbon mass: Oceanic (86%) >> Geologic (9%) > Terrestrial (5%)
- Solubility pump: The net driving force for dissolution of CO2 into waters. Polar waters are colder and denser at the surface than in the deeper regions. Surface waters have high CO2 dissolution due to low temperature, tend to sink, transport CO2 to deep water, keep surface waters lower in CO2, and drive dissolution from the atmosphere.
- Human effects: Combustion of fossil fuels (NOx),, large-scale production of livestock, burning of forests, etc. “Global warming”
- Carbon Capture & Storage (CCS)
4.2 Nitrogen cycle
- Nitrification (질산화)
- +
4 2 2 2
4NH (ammonium) + 6O = 4NO (nitrite) + 8H + 4H O+ (nitrosomonas)
- -
2 2 3
4NO (nitrite) + 2O = 4NO (nitrate) (nitrobacter) - Denitrification (탈질)
-
3 2 2 2
2NO (nitrate) + organic carbon = N + CO + H O
- Nitrogen fixation (Acaci 아카시나무, Alder오리나무, Beans including Peanut땅 콩을 포함한 콩류, Clover클로버 등)
- +
2 3 2 I
N + 8e + 8H + ATP → 2NH + H + ADP + P (inorganic phosphate) 수소생산!
- Human effect: industrial fertilizers, fossil fuel combustion(NOx), large-scale production of nitrogen-fixing crops.
4.3 Phosphorus cycle
- Natural sources of P: weathering of rock.
- Artificial sources: detergents, fertilizers, excretion, etc.
- Especially, important in a lake water quality.
4.4 Sulfur cycle
- Natural sources: volcano
- Artificial sources: fertilizers, combustion of fossil fuels (SOx), mining, etc.
- Sulfur-reducing bacteria (황환원미생물) reduce sulfate (SO42-
) to hydrogen sulfide (H2S) under anaerobic conditions.
- Most of the odor producing compounds are organics and they can be decomposed by microorganisms. However, H2S is inorganic. It can be oxidized by Sulfur-oxidizing bacteria to SO42-
and odor can be treated.
5. Population Dynamics
5.1 Bacterial population dynamics
Bacterial growth requirements
(1) A terminal electron acceptor (e.g., oxygen)
(2) Macronutrients (e.g., carbon, nitrogen, phosphorus, etc.) (3) Micronutrients (e.g., trace metals, vitamins, etc.)
(4) Appropriate environment (moisture, temperature, pH, etc.)
e.g., psychrophiles (< 20oC), mesophiles (25-40oC), thermophiles (45-60oC), stenothermophiles (> 60oC)
Growth in pure culture
- Lag phase: Initially nothing happens because bacteria must adjust to their new environment.
- Accelerated growth phase: Due to binary fission (each cell divides two new cells), log growth (or exponential growth)
Pt = P0⋅2n
log Pt = log P0 + n⋅log2
- Stationary phase: due to cession of fission (분열 중지) or balance in death and reproduction
- Death phase: bacteria die faster than they produce
- Carrying capacity: the point at which decline of population occurs
Growth in mixed culture
- Food competition
- Predator - Prey relationship
5.2 Animal population dynamics
- Exponential model: unlimited resources dN = r N
dt ⋅
where r = specific rate of change (if r = 0, no change) N = number of animals
t 0
N = N ⋅exp(r t)⋅
- Geometric (logistic) model: unlimited resources, however, growth occurs in discrete intervals, λ (불연속 성장)
N(t+1) r
= λ = e N(t)
where N(t+1) = population after (t+1) numbers in years N(t) = population after t years
r = specific rate of change (if r = 0, no change)
- Sigmoidal (or S-shape) curve
dN K-N
= r N
dt K
⋅ ⋅
where K = carrying capacity
0 -r t
0 0
N(t) = K N
N + (K - N ) e ⋅
⋅
⋅
limt→∞N(t) = 600 (= K)
5.3 Human population dynamics
Population pyramids: the age by gender data of a community at one point in time
P(t) = P exp(r t)0⋅ ⋅
where P(t) = population at time, t P0 = population at time, 0 r = rate of growth
= (birth rate) – (death rate) + (immigration rate) – (emigration rate)
Pt
P0 = 2 = er∙t