Environmental Biology Flashcards
What is environment
The environment is the complex of physical, chemical, and biotic factors that act upon an organism or an ecological community and ultimately determine its form and survival
Environmental biology
Is the study of biological components of the environment and its relationship with each other and with abiotic components.
Organisational levels of the environment and definitions
Individual(organism) - Any organism or living thing which has its own characters in physiology, evolution and behaviour in relation to environmental factors
Population - Group of individuals of the same species, living in the same area and producing fertile offsprings through interbreeding.
Community - collection of populations of different species living in the same area
interacting with each other.
Ecosystem - collection of communities as well as the abiotic factors with
which they interact.
Biosphere - entire portion of Earth that is inhabited by life.
Components of the environment
Abiotic components - non-living components. e.g: water, air, light, temperature, nutrients, sunlight, soil. usually resources are obtained from lithosphere, atmosphere and hydrosphere.
Biotic components - primary producers, consumers and decomposers
Niche and habitat
Niche is the role that a particular organism plays in the ecosystem
Habitat is the physical area where a species lives
Interactions between abiotic and biotic components of the environment
Biotic-biotic interactions- e.g. competition, feeding relationships, symbiotic relationships
between individuals and species.
Biotic-abiotic interactions- e.g. water uptake of plants from soil
Abiotic-abiotic interactions-e.g. chemical reactions occurring in the soil.
What are trophic levels
The producers and consumers in ecosystem can be arranged into several feeding groups, each known as trophic level (feeding level).
producers represent the first trophic level, herbivores represent the second trophic level, primary carnivores represent the third trophic level and top carnivores represent other levels.
Food chain
A food chain is a linear sequence of organisms through which nutrients and energy pass from one trophic level to another trophic level of an ecosystem beginning with a primary producer.
Primary production
is the amount of organic matter produced by autotrophs in a given area during a given period of time. (Unit: gm-2day -1or kg ha-1year -1)
ha = hectare
3 types of food chains
Grazing food chains - starts with a primary producer
Detritus food chain - Starts with detritus (dead remains of an organism)
Parasitic food chains - Starts with a host organism
In a forest ecosystem, most of the energy is transmitted in detritus food chains whereas the most amount of energy is transmitted in ocean ecosystems through grazing food chains
Food web
In a natural ecosystem isolated food chains does not exist
The food web is an interconnected feeding relationships in an ecosystem.
Energy loss along food chains
The flow of energy along a food chain is always unidirectional.
At each trophic level in the food chain, a considerable fraction (about 90 %) of the potential energy is lost as heat and respiration. As a result, organisms in each trophic level pass on lesser energy (about 10 %) to the next trophic level than they actually receive.
This limits the number of trophic levels in any food chain to four or five.
The most ecologically efficient food chain is the shortest one.
Ecological pyramids
The pyramids are a graphical representation which depicts the number of organisms, biomass and productivity at each trophic level.
The higher the steps in the ecological pyramid the lower will be the number of individuals and the larger their size.
The concept of ecological pyramid was developed by Charles Elton; these pyramids are also known as Eltonian pyramids.
Types of ecological pyramids
Pyramid of energy - represents the amount of energy at different trophic levels. As there is considerable loss of energy during the flow of energy from organism to other, the energy pyramid
always upright and vertical.
Pyramid of numbers - The pyramid of numbers depicts the relationship in terms of the number of producers, herbivores and the carnivores at their successive trophic levels. 2 types as upright (producer, herbivore, carnivore) and inverted (host, parasites)
Pyramid of biomass - n this pyramid there is a gradual decrease in the biomass from the producers to the higher trophic levels. 2 types as upright and inverted.
Biome
A biome is a large geographical area which is classified based on the predominant vegetation adapted to that particular environment.
Tropical forests
This biome is distributed close to the equator and extends to the sub equatorial areas
The average annual rainfall in tropical rain forests is about 2000 -4000 mm and in tropical dry forests it is about 1500- 2000 mm. Seasonal rainfall with a dry season of 6-7 months is prominent in the dry forests and a fairly constant rainy season is prominent in the rainforests.
average temperature of 25 -29 °C, whereas in the tropical dry forests it may reach up to 33 °C.
In tropical rainforests an emergent layer, canopy and sub canopy layers are visible. Evergreens are prominent in tropical rain forests whereas in dry forests leaves of deciduous species fall in the dry season. Epiphytes are common in this biome.
Highest diversity of plants and animals out of all terrestrial biomes
Tropical forests
Savana
Savanna is spread close to the equator and subequatorial areas.
The average annual rainfall in this biome is around 300-500 mm. A prolonged dry season of approximately 8-9 months is prominent. The average temperature range is 24- 29 °C. However in subequatorial areas seasonal variations may occur. Many insects (termites), lions and zebras are the common animals which are adapted with long range vision and long distance migration. Tall grass cover with scattered trees.
Desert
Desert is a temperate or tropical biome
annual average rainfall is less than 3000 mm per year.The temperature varies seasonally and daily and exceeds 50 °C in hot deserts while in cold deserts it drops below -30° C. Water conservation is a prominent feature and contains many nocturnal animal species
Adaptations of desert plants
Succulent plant body
Most plants have C4 pathway of photosynthesis
Deep roots in shrubs
Presence of spines and thorns
Presence of toxins in leaves
Chaparral
Chaparral occurs in mid latitude coastal regions
Chaparrals receive an average annual rainfall of 300-500 mm. They experience rainy winters and dry summer. The average temperature is between 10 to 12 °C but can reach up to 40 °C.
Chaparral is vulnerable to fire caused by human activities.
Adaptations of plants found in chaparral
Seed germination occurring only after a hot fire.
fire resistant roots.
Uses of food stored in the fire resistant roots for resprouting after a fire.
Quick re -sprouting enables usage of nutrients released by the fire.
Tough evergreen leaves in woody plants to survive in droughts.
Temperate grasslands
These grasslands occur under temperate climatic regimes that are intermediate to those that support forest and desert.
The average rainfall is 300 to 1000 mm per year.
During winter seasons the average temperature falls below -10 °C and in summer it is about 30 °C.
The prairie is often divided into three types according to height of the dominant vegetation—tall-grass, mixed-grass, and short-grass.
The tall-grass prairie is now an endangered natural ecosystem
Temperate broadleaf forests
Distribution of temperate broadleaf forests are at mid latitudes in the northern hemisphere. The average annual precipitation is between 700 to 2000 mm.
Average temperature during winter is zero while in summer it is up to 35 °C
The dominant trees are mostly deciduous. A vertical layering (stratification) can be seen in temperate broadleaf forests. They are closed canopy layer, one or two strata of understory trees, shrub layer and herb layer. There are only few epiphytes can be found.
Northern coniferous forests
Precipitation: Annual average precipitation is around 300- 700 mm and a periodic drought is also common. The temperature is -50 C in winter and 20 C0 in summer.
The northern forest is dominated by coniferous trees. They have needle like leaves that prevent high transpiration.
Largest biome on earth
Northern coniferous forest
Tundra
Amounting 20% of earths land surface. Alpine tundra occurs at high altitudes on mountains, while arctic tundra occurs at low latitudes.
average precipitation around 200 to 600 mm and the alpine tundra receives > 1000 mm precipitation respectively. During the winter time temperature falls below -30 C and during the summer temperature it is always less than 10 C.
A layer of permafrost which is a permanently frozen layer of soil can be seen. This permafrost layer restrict the growth of the roots of plants.
Sri Lanka is situated in which zone
North-equatorial tropical zone
Groups of ecosystems of Sri Lanka
Terrestrial ecosystem
Inland wetland ecosystem
Ecosystems with coastal regions
Tropical wet low land rainforests
Found below 900m elevation
Annual temperature is 28 C
Annual rainfall is 2000mm-5000mm
Vegetation is filled with woody lianas .
Sinharaja, Kanneliya, Nakiyadeniya.
Animal species are Purple faces langur, Sri Lankan slender loris, Golden wet zone palm civet.
Plant species are Hora, Naa and Hal.
Tropical montane forests
Elevation 1500m above sea level
Temperature is 16 C and rainfall is 2000mm.
Characterised by the short canopy of 13m. Trees with umbrella shaped rounded crowns, twisted branches and small leathery leaves which accommodates strong winds prevailing in the region.
Plant species are Keena, Walkurudu, Gal weralu.
Animal species are Sri Lankan yellow eared bulbul, Sri Lankan highland shrew, Sambar
Knuckles range, Piduruthalagala and Hakgala
Tropical dry mixed evergreen forests / Dry monsoon forests
Distributed in areas below 300m altitude. Annual temperature is 29 C while rainfall is 1000mm - 1500mm. Plant species are Weera, Palu, Kaluwara. Animal species are leopard, bear and deer.
Wilpattu, Yala, Wasgamuwa, Maduru-oya, Ritigala Strict Nature reserve
Tropical thorn shrubs
Found in arid lowlands. Annual temperature is 31 C while rainfall is 1000mm. Plant species are Gini, Ranawara and Heeressa. Animal species are leopard, elephant and deer. Hambantota, Mannar, Puttalam
Savanna (Sri Lanka)
Periodic fires are common in this ecosystem. Plant species are Nelli, aralu, mana, iluk. Bibile, Monaragala, Mahiyanganaya, Wellawaya.
Extensive wet patana are only found in
Hortan plains
What are tussock grasses
Grasses found within wet patana which does not reach uptown 1m in height. e.g: Arundinella villosa, Chrysopogan nodulibarbis
Patana
Wet patana are found 1500m from sea level. Rainfall is 2000mm and temperature ranges from 5-18 C. Grasses do not reach more than 1m in height and are known as tussock grasses.
Dry patana are found 500m - 1600m. Average rainfall is 1400mm - 2000mm. Temperature is 18-24 C. Grasses grow unto 1-2m in height such as Pangiri mana. Hantana, Gampola, Welimada and Haputale.
Definition of wetlands
According to Ramsar Convention, wetlands are defined as areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide not exceed six metres.
Sri Lanka has how many river basins
103 natural river basins
Marshes and swamp forests
Marshes are lying low lands filled with water of surface run-off, seepage of ground water and flood of rivers. Plant species are habarala, Colocasia, Kekatiya and Pan
Swamp forest are forest vegetation inundated with water for a short amount of time. Wathurana swamp at Bulathsinhala located in the Kalu ganga basin.
Villus
Flood plains of reservoirs. Vegetation contains grasses and sedges. Mahawelli flood plain, Wilpaththu national park
Lagoons and estuaries
Lagoons are coastal wetlands generally separated from the sea by a sand barrier. Negambo and Bundala lagoons
Estuaries are formed in places where rivers enter the sea and does not contain a sand barrier. Maduganga, Benthota.
Mangroves
Characteristics are saline/brackish water, loose soil and anoxic (low O2) conditions. Plant species are Kadol and Mas athu gas, Karan Koku and Katy-ikili
They have a thick cuticle to reflect Sunrays, Some have salt glands to secrete excess salt, They have special roots to intake atmospheric O2, They germinate while attached to the mother plant (viviparous)
Salt marshes
Marshlands of arid coastal areas where soil dries up forming crystals of salts during the dry period. characterised by high wind, high temperature, low rainfall and sand blowing with salts. Plant species are Saliconia sp. Manner, Puttalum, Hambantota
Sea grass beds
In large lagoons where wave action is low, shallow sea bed is accompanied by sea grasses. These are not actually glasses but called as grasses due to their shape of the leaves (Halophyla Sp, Halodule Sp). Provides breeding sites for many fish species.
Coral reefs
Known as rainforests of the sea which contains calcareous structures secreted by a group of marine invertebrates. High productivity and high biodiversity of organisms which inhabit these areas. Sea turtles and dolphins often accommodate these areas. Gulf of manner, Southern cost from akurala to tangalle.
Reservoirs
There are no natural lakes in Sri Lanka.
Plant species are nelum, manel and kekatiya. In addition invasive species such as japan jabara and salvinia are found as well.
Sea shore
Long sea shore of Sri Lanka varies in nature. Most common is the sandy sea shore which includes high temperature throughout the year, salt spray and high winds are characteristics features. Plant species are maha rawana rewula and muhudu binthmburu
Sand dunes
Characterized by the stunted and sparse vegetation found in large masses of sand. Shapes of sand dunes are determined by wind speed and direction. They are raised beaches of sand. Mullativu
Definitions of climate change and global warming
Climate changes are significant long-term changes of the climate attributed directly or indirectly to human activities in addition to natural climatic variability observed over comparable time periods.
Global warming is the increase in the average temperature of the earth’s surface due to enhanced green house effect of green house gases
Contributing factors on global warming and climate change
- Increase of the emission of CO2 and other greenhouse gasses (GHG) due to human activities
2.Deforestation and decrease of the vegetation cover of the world
3.Destroying the large quantity of phytoplankton by UV radiation due to the deple tion of the ozone layer.
Green house gases and method of emission
CO2 is the most common GHG emitted due to the burning of organic matter such as fossil fuels, burning of forests and solid waste.
CH4 is a GHG with a higher GWP. Emitted by anaerobic decomposition, enteric fermentation, cattle farming and paddy cultivation. Less abundant than CO2
N2O is a GHG with a high GWP. Emitted as a by product in fertiliser use and production, in internal combustion engines, nitric acid production and other industrial processes. Can remain in the atmosphere for a longer time period.
Manmade industrial gases, namely, Perfluorocarbons (PFCs), Hydrofluorocarbons (HFCs) and Sulfur Hexafluoride (SF6) are also considered as greenhouse gases with a very high global warming potential.
Black carbon or the carbon particles which are suspended in lower atmosphere emitted due to incomplete combustion of fossil fuels, and other organic matters. These particles are extremely small, ranging from 10 μm 2.5 μm. These Black Carbon have an enormous ability to absorb heart and it cause to increase the air temperature
Enteric fermentation
natural part of the digestive process in ruminant animals such as cattle, sheep, goats, and buffalo
Carbon sequestration
Forests remove carbon dioxide from the atmosphere and fix through photosynthesis (carbon sequestration). Deforestation reduce the carbon sequestration capacity, carbon capture on the planet (i.e soil carbon) and increase the atmospheric CO2 concentration.
Due to the conversion of forests lands into agricultural or farming lands such as palm oil.
Phytoplanktons and how they contribute to prevent global warming
Normally the carbon absorption capacity of phytoplankton are higher than terrestrial plants. Though the phytoplankton are unicellular microscopic organism they have been distributed in large area and they were responsible for the 60%-70% of absorption of atmospheric carbon
Effects of global warming and climate change
Sea level rising
Extreme weather events
Less production of foods (threat to food security)
Degradation of coral reefs
Increase in the insect population
Loos of biodiversity
Ozone layer depletion
Most ozone particles are concentrated in the region of stratosphere in between 10-50 km of the atmosphere,
Naturally, the total concentration of ozone in the stratosphere remains relatively constant with the concentration of 300 to 350 Dobson Units (D.U). Ozone depletion is described when levels fall below 200 D.U
This thinning of the ozone layer refers as Ozone hole due to CFCs, MeBr, Helene and HCFC.
Effects of the Ozone Layer depletion include eye diseases, skin cancer and infectious diseases.
It is a known fact that the physiological and developmental processes of plants are affected by UV-B radiation, It directly destroyed phytoplankton which form the foundation of aquatic food webs in the sea and it cause to reduce the composition of food web in the sea ecosystem. UV-B can also cause damage to early development stages of fish, shrimp, crab, amphibians and other animals.
Desertification
process of land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors, including climatic variations and human activities
The main driving forces of desertification can be separated into climate variations and human activities,
Deforestation is another main factor to decertification because of it is directly influencing to reduce the rainfall, precipitation, soil humidity and water recharge of underground reservoirs
Over-exploitation of water and soil, uncontrolled mining and excessive use of agro-chemical products and as well as poor land management practices also caused to desertification.
Effects of desertification
water scarcity, destroys habitats of animal and plant species and reduces agricultural activities mainly the growth of crop species., food security of the people as well as for the animals and carbon storage capacity of plants and soils will also be reduced in the long run.
The Convention on International Trade in Endangered Species of Wild Fauna and Flora
CITES
The aim of CITES is to ensure that international trade of specimens such as horns and skins of wild animals and whole plant or parts of plants does not threaten their survival. e.g: skin of Sri Lankan Leopard and cycas plants
Convention on biological diversity
CBD
goals include the conservation of biological diversity, sustainable use of components of biological diversity, fair and equitable sharing of benefits arising from genetic resources
Convention on wetlands
Ramsar convention
Wetlands of Sri Lanka declared as ramsar sites
Anawilundawa, Bundala, Kumana, Maduganga, Vankalai and Wilpattu
International convention for the prevention of pollution from ships
MARPOL
International convention for the protection of the ozone layer
Montreal protocol
Convention on climatic change
Kyoto protocol
Basel convention
The Basel Convention on the Control of trans boundary movements of hazardous wastes and their Disposal intends to protect human health and the environment against the adverse effects of hazardous wastes.
two types of wastes defined as “other wastes” such as waste containing heavy metals such as Lead (Pb) and Mercury (Hg) and wastes from hospitals which contains contaminants.
Environmental Legislation and Policies in Sri Lanka
Fauna and Flora Protection Ordinance and National Environmental Act
Biodiversity
Includes all forms of life on earth. Biodiversity is the variability seen among individual of all sources including terrestrial, marine and other aquatic ecosystems and its relationship with the environment. Explained under 3 levels genetic, species and ecosystems
Basic component of biological diversity and largest scale of biodiversity
Genetic and ecosystems
Values of biodiversity
Environmental service value - CO2 fixation through photosynthesis, nutritional cycles, water cycle, purification of water, erosion prevention and flood control
Recreational value - source of revenue (national parks, zoological gardens and botanical gardens), develops of creativity
Ethical value - right of all species live on this planet
Educational value - through the study of nematodes, rats and primates, functions of the human body has been understood and certain medicines has been devoloped. Disaster management
Socio, cultural and economic value - wetlands are sacred for aborigines of Australia, 28 species if trees are sacred for buddhists and bulls are sacred for hindus
Threats of loss of biodiversity
Scientists have predicted that we are in the midst of the 6th mass extension ( most recent 1 been occurred 65 million years ago) . Extinction rate is 1000 times faster at present. Many mangroves and coral reefs has been lost and upto 50% species of cycads, conifers, mammals, birds and amphibians are facing extinction according to the IUCN red list.
Threats to biodiversity
Habitat loss/ fragmentation. e.g: mass scale destruction of mangroves in lagoons of Negambo and Puttalam
Overexploitation - Kotalahimbutu, sea cucumber and fish species such as tuna and cod
Pollution - Eutrophication and acid rains
Introduction of invasive alien species - Gandapana does not allow germination and seedling growth of other plants as it produces toxins which are added to the soil through leaf litter, Gini-thana in dry pathana causes wild fires due to its dry biomass.
Climate change
Invasive alien species
Invasive alien species are alien (exotic) plants and/or animals whose introduction and spread outside their natural geographic range threaten native biodiversity. Alien invasive species compete against or prey on native species which can make them extinct
Biodiversity hot spots
Areas with a high concentration of endemic species facing exceptional levels of threats have been described by Myers as biodiversity hotspots. Sri Lanka together with western Ghats of India have been identified ad biodiversity hotspots of South Asian region.
Extinction rate within the next 30 years
5-10%
Extinct
A taxon is Extinct when there is no reasonable doubt that the last individual has died. E.g. Dodo ( Lived in Mauritius), Wooly Mammoth (Lived in North America), Legume (Crudia zeylanica)
Extinct in the wild
A taxon is extinct in the wild when it is known only to survive in cultivation, in captivity or as a naturalized population (populations) well outside its natural habitat. E.g; Giant tortoise of Seychelles
Critically endangered
A taxon is critically endangered when the best available evidence indicates that it is facing an extremely high risk of extinction in the wild. Marbled rock frog and maha madu
Endangered
A taxon is endangered when the best available evidence indicates that it is facing a very high risk of extinction in the wild. Eg: Etha, wesak orchid
Vulnerable
A taxon is vulnerable when the best available evidence indicates that it is facing a high risk of extinction in the wild. Punchi Leena and buttercup
Endemic species
An endemic species is a species that is confined to a particular area or country, and not found growing naturally anywhere else in the world.
Plant species are hora and goraka
Animal species are the black ruby barb and the slender loris
Indigenous species
A plant or animal species that occurs in its historically known natural
range and that forms part of the natural biological diversity of a particular geographic area.
Snake head and kithul
Exotic (alien) species
A species that has been introduced from another geographic region to an area outside its natural range due to human activities. Tilapia and rubber
Migratory species
Migration refers to the act of moving from one place to another in a manner that is seasonally determined and predictable.
Indian fly Cather and Indian pitta
Relict species
The remnants of a once widespread species, which are now found in very restricted or isolated areas, due to fact that areas in which these species are found is lost in many parts of the world.
The Tuatara living only on a few small islands of New Zealand, Ichthyophis and Lingula found in Thambalagamuwa bay in Trincomalee
Flagship species
Flagship species is a species chosen as a symbol or icon to represent an ecosystem in need for conservation. These species are chosen for their vulnerability, attractiveness or distinctiveness in order to bring about support and acknowledgement from the public at large.
Bengal tiger of India, Giant panda of china and the blue magpie of Sri Lanka
Keystone species
These are species that play a very important role in the stability and functioning of a system. If that species is removed the system tends to collapse. e.g. Planktons of a pond
Basis of conservation
A principal goal of conservation is to ensure the long term survival of as many species as possible. Species that are in danger of extinction have to be specially protected and steps should be taken to ensure their continued reproduction and survival. Conservation can be done in two ways.
In-situ and Ex-situ
In-situ conservation
The species is protected and its reproduction facilitated in its natural habitat. Basically a large enough population and adequate, appropriate, habitat space has to be ensured. E.g. National parks such as Yala and Minneriya national parks, Forest reserves such as Kanneliya, Piduruthalagala
Ex-situ conservation
The species is taken out of its natural habitats, and looked after in places where its survival and reproduction are ensured.
Zoological gardens and Botanical gardens of a country play a key role in ex-situ conservation.
