BIODIVERSITY

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  • Created by: BUSHRA
  • Created on: 06-04-13 11:48

BIODIVERSITY

BIODIVERSITY

  • A species is a group of individual organisims very similar in appearance, anatomy, physiology, biochemistry, and genetics whose members are able to interbreed freely to produce furtile offspring
  • A habitat is the place where an organism lives
  • Biodiversity is the variety of life - the range of living organisms to be found

DIFFERENT LEVELS OF BIODIVERSITY

  • The range of habitats in which different species live. Even in your school grounds or in a local park there may be a variety of habitats. Carefully manicured lawns, ponds, dark corners between buildings or a small patch of trees are all different habitats. Each habitat will be ocupied by a range of organisms
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BIODIVERSITY

  • The difference between species. All species are different from each other. These could be obvious structural differences, such as the difference between a tree and an ant. They could be functional differences such as differences between bacteria that cause decay and those that help us digest food
  • Genetic variation between individuals belonging to the same species. This is the variation found within any species that ensures that we do not look alike
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SAMPLING

SAMPLING

  • Random sampling means studying a small part of the habitat and asuuming it contains a representaive set of species that can be applied to the whole habitat. The sample sites must be chosen at random
  • Choose an area to sample - a small area within the habitat being studied
  • Count teh number of individuals of each species. how we do this depends on what you're counting e.g :
  • For plants you'd use a quadrat ( a frame which you place on the ground) or a transect ( strech a rope or tape measure across a habitat and take samples along the line)
  • For flying insects you'd use a sweepnet ( a net on a pole) or a light trap ( uv light to attract inects than they fall into a vessel containnig alcohol)
  • For ground insects you'd use a pitfall trap ( a small pit that insects can't get out of)
  • For small animal use a tullgren funnel ( a light above the leaf litter dys out the leaf allowing the insect to get trapped into a jar)
  • For aquatic animals you'd use a net
  • Repeat the whole process- take as many samples as possible. This gives a better indication of the whole habitat
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SAMPLING

  • Use the results to estimate the total number of individuals or the total number of different species in the habitat being studied
  • When sampling different habitats and comparing them always you use the same sampling technique

THE SAMPLE HAS TO BE RANDOM

  • To avois bias your sample has to be random. There are three ways:
  • Take sample at regular distances across the habitat
  • Use random numbers, generated by a computer or a random number table to plot coordinates within the habitat
  • Select coordinates from a map of the area and use a portable global positing satellite system to find the exact position inside the habitat

WHY DO WE NEED TO STUDY A HABITAT?

  • Human activities affect the environment in an umber of ways
  • Environmental impact assessment (EIA0
  • EIA is used to estimate the effects of planned development on the environment
  • The importance of maintaing habitats and reducing damage we do to them

 

 

 

 

 

 

 

 

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MEASURING BIODIVERSITY

SPECIES RICHNESS  AND SPECIES EVENESS

  • The greater the species richness and species eveness ina narea the higher the biodiversity
  • Spcieces richness is the number of different species in an area. The higher the number of species the greater the species richness. It's measured by taking random samples of a habitat and counting the number of different species
  • Species eveness is a measure of releative abudance of each species in an area. The more similiar the population size of each species the greater the species eveness. It's measured by taking random smples of a habitat and counting the number of individuals of each  diiferent species

SIMPSONS INDEX OF DIVERSITY

  • Species present in a habitat in very small numbers shouldn't be treatedthe same as those with bigger population
  • Simpson's index of diversity takes into acccount of bothe species richness and species eveness 
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MEASURING BIODIVERSITY

  • Simpson's index of diversity can be calculated by

                        D = 1 - (  (n/N)2    

  • n =  Total number of individuals of one species
  • N = Total numer of organisms of all psecies
  • = Sum of
  • Simpsons index of diversity is always a valu between 0 and 1. The close it is to 1 the more diverse the habitat is. The greater the species richness and species eveness the higher the number
  • A high vale of diversity means a samll change in the environment will effect one species so the effect on the whole habitat is small. The habitat tens to be stable and able to withstand change
  • A low value of diversity suggests habitat dominated by a few sepcies so a small change in the environment can damge or destroy the whole habitat
  • E.G there are 3 differnt species of flower in a field - a red, white and blue species. There are 11 organisms altogether N=11. There are 3 reds, 5 whites and 3 blue specices. so the indix diversity is : D = 1 - ( (3/11)2 +(5/11)2 + (3/11)2 = 0.64 
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CLASSIFICATION

CLASSIFICATION

  • Biological classification is the process of sorting living things into groups. Natural classification does this by grouping things according to how closely related they are. Natural classification reflects evolutionary relationships
  • Taxonomy is the study of the priciples of classification. there are eight levels of groups used in classification. The eight levels are: (1) Domain, (2) Kingdom, (3) Phylum, (4) Class, (5) Order, (6) Family, (7) Genus and (8) Species. As you go down there are more groups at each level but fewer organisms in each group
  • Phylogency is the study of the evolutionary releationships between organisms. The more closely species are releated, the closer the evolutionary tree and the more recently in the past they shared a common ancestor
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CLASSIFICATION

THE FIVE KINGDOMS

  • PROKARYOTES - Have no nucleus, have a loop of naked DNA that is not arranged in linear chromosomes, have no membrane bound arganeele , smaller ribosomes compared to ther groups, carry out respiration not in mitochondria but on a special membrane system ( mesosome), have cells smaller than those of eukaryotes, may be free living or parasitic; cause disease, unicellular (single celled) and less than 5 um
  • PROTOCITISTS - Include all the organisms that do not fit into the other four kingdoms. Many are single celled but some are multicellular, are eukaryotes, show a wide variety of forms, show various plant like or animal like features, are mostly free living and have autorophic or heterotrophic nutritions
  • FUNGI- Are organisms that are mostly free living and sprophytic (cause decay). They consist of a mycelium with walls made from chitin, are eukaryotes, have cytoplasm that is multinucleate
  • PLANTS- Are multicellular organisms that gain nutrition from photosynthesis. They are eukaryotes, have cells surrounded by a cellulose cell wall, produce multicellular embryos from fertilised egges and have autotrophic nutrition ( poduce own food) 
  • ANIMALS- Are heterotrophic ( consume plants and animals) multicellular eukaryotes. They have fertilised eggs that develop into a ball of cells called a blastula and are usually able to move.
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CLASSIFICATION

WHY WE CLASSIFY LIVING THINGS

  • For our convenience
  • To make the study of living things more manageable
  • To make it easier to identify organisms
  • To help us see the relationships between species

BINOMIAL NAMING SYSTEM

  • The nomenclature ( naming system) used for classification is called the binomial sysytem- all organisms are given one internationally scientific name in latin that has two parts
  • The first part of the name is the genus name and has a capital letter. The second part is the species name and begins with a lower case. Names are always written in italics and if they're handrwritten they're underlined
  • The binomial system helps to avoid the confusion of using common names

 

 

 

 

 

 

 

 

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CLASSIFICATION

DICHOTOMOUS KEYS

  • Dichotomous keys provide a way to identify organisms based on abservable features
  • They consist of a series of questions each with only two possible answers. Each answer leads to the name of the organism or another question, and so on until the organism is identified

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CLASSIFICATION

CLASSIFICATION SYSTEMS

  • Early classification systems only used observable features to place organisms into groups, e.g whether they lay eggs, can fly or cook
  • But this method has problems. Scientists don't always agree on the relative importance of different features and groups based solely on physical features may not show how related organisms are
  • Classification systems are now based on observable features along with other evidence
  • The more similiar organisms are, the more related they are. we now use a wide range of evidence to see how similiar, and therefore how releated organisms are.
  • MOLECULAR EVIDENCE - The similarities in protiens and DNA. More closely related organisms will have more similar molecules. You can compare things like how DNA is tored, the sequence of DNA bases and the sequence of amino acids in protiens from different organisms. e.g. the base sequence for humans and chimpanzee DNA is about 94% the same
  • EMBRYOLOGICAL EVIDENCE - The similarities in the early stages of an organisms development
  • ANATOMICAL EVIDENCE- The similiarities in structure and function of diffrent body parts
  • BEHAVIOURAL EVIDENCE- The similarities in behaviour and social organisation of organisms
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CLASSIFICATION

  • New technologies ( e.g DNA techniques, better microscopes) can result in new discoveries
  • Scientists can share their new discoveries in meetings and scientific journals. How organisms are classified in continually revised to take account of any new findings that scientists discover e.g. skulls were classified in the family Mustelidae until molecular evidence revealed their DNA sequence was significantly different to other members of that family. So they were reclassified into the family Mephitidae
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CLASSIFICATION

FIVE KINGDOMS VS THREE DOMAINS

  • In the older system the largest groups were the five kingdoms - all organisms were placed into one of these groups
  • In 1990, the tree domain system was proposed. This new system has three domains- Bacteria, Archaea and Eukarya
  • In the three domain system, organisms with cells that contain a nucleus are placed in the domain Eukarya( this contains four of the five kingdoms). Organisims that were in the kingdom of prokaryotae ( which contains unicellular organisms without a nucleus) are eperated into two domains the Archaea and Bacteria
  • The lower hierarchy stays the same - Kingdom, Phylum, Class, Order, Family, Genus and Species
  • The three domain system was proposed because of new evidence, mainly molecular. e.g. the Prokaryotae were reclassified into two domains because new evidence showed large differnce between the Archaea and Bacteria
  • Molecular evidence- the enzyme RNA polymerase is different in Bacteria and Archaea. Archaea but not bacteria have similar histones to Eukarya
  • Cell memebrane evidence- the bonds of the lipids in the cell membrane of Bacteria and Archaea are different. The development and composition of flagella are also different
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VARIATION

VARIATION

  • Variation is the presence of variety of differnces between individuals
  • Genetic variation is caused by differences between the genes and the combinations of genes or alleles
  • Continuous variation iss variation in which there is a full range of intermediate phenotypes between two extremes e.g height in humans, length of leaves an an oak tree
  • Discontinuous variation is variation in which there are discrete groups of phenotypes with no or very few individuals between e.g sex- males or females, blood groups- A,B,AB,OR O
  • Variation is the differences that exist between individuals. Every individual organism is unique- even clones show variation it can occur:

(1) Within species- Variation within a species is called INTRASPECIFIC variation. e.g individual eurapean robins weigh between 16g and 22g and show some variation in many other characteristics including length, wingspan, colour and beak size

(2) Between species- The variation between different species is called INTERSPECIFIC variation. e.g. the lightest species of bird is the bee hummingbird, which weighs around 1.6g on average. The heaviest species of bird is the ostrich which can wiegh up to 160 kg (100000 times as much)  

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VARIATION

GENETIC FACTORS

  • Different species have different genes
  • Individuals of the same species have same genes but different versions of them ( called alleles)
  • The genes and alleles an organism has make up it's genotype
  • The differences in genotype result in variation in phenotype- the characteristics displayed by an organism
  • Examples of variation caused only by genetic factors include blood group in humans (O,A,B or AB) and antibiotic resistance in bacteria
  • You inherit your genes from your parents. This means variation caused by genetic factors is inherited

ENVIRONMENTAL FACTORS

  • Variation can also be caused by differences in the environment e.g climate, food, lifesyle
  • Characteristics controlled by environmental factors can change over an organisms life
  • E.g. of variation caused only by environmental factors include accents and whether people have pierced ears
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VARIATION

BOTH

  • Genetic factors determine the characteristics an organism's born with, but environmental factors can influence how some characteristics develop. e.g
  • Height- genes determine how tall an organism can grow. But diet or nutrient availablity affect how tall an organism actually grows
  • Flagellum- genes determine if a microrganism can grow a flagellum but some will only start to grow them in certain environmentse.g if matal ions are present
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ADAPTATION

ADAPTATION

  • An adaptation is a feature that enhances survival and long term reproductive success
  • Adaptations develop because of evolution by natural selection
  • Adaptations can be behavioural, physiological and anatomical
  • A behavioural adaptaion is an aspect of the behaviour of an organism that helps it to survive the conditions it lives in. e.g. possum sometimes play dead - if they're threatened by a predator they play dead to escape attack. This increases thier chance of survival
  • A physiological adaptation is one than ensures the correct functioning of cell processes. e.g some bacteria produce antibiotics- these kill other species of bacteria in the area. This means there's less competition, so they're more likely to survive
  • Anatomical means structural. Any structure that enhances the survival of the organism is an adaption. e.g. may bacteria have flagella that enable them to move independently. The flagellum is a structural feature that increases their chance of survival
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ADAPTATION

XEROPHYTIC PLANTS

  • Xerophytic plants are adapted to living in very dry conditions
  • Behavioural adaptation - Xerophytes respond to shortage of water in a number of ways such as closing the stomata when little water is available, at night it is cooler and air is humid so some open the stomata at night so less water is lost, some plants fold or roll their leaves so moist air is trapped in leaves and water potential is lowered and some plants open stomata when thay are short of water as it causes leaves to wilt and less surface area exposed to the sun
  • Physiological adaptations are the mechanisms by which plant can open or close it's stomata, fold leaves or store water.e.g cactus has a stem with an accordion-fold structure, during dry periods the folds tighten into ridges and become more pronounced. When water becomes avilable, the catus absorbs it from the ground. The water fills the cells of the stem so it can be stored for years. The cells expand and cause the stem to expand and become more rounded. The accordion folding becomes less obvious
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ADAPTATION

  • The plants have many stuctural adaptations such as the roots may be shallow, but spread out over a wide area, this allows them to absorb a lot of water. The roots may be very long. This enables the plant to reach water that is deep underground. The stem or leaves may be fleshy- an adaptaion to store water and the leaves may be reduced in size- this reduces the surface area for evaporation. The leaves may be very waxy, so moisture can leave the leaf only through the stomata. The leaves may be curled, folded, hairy or have their stomata sunk in pits. These adaptaions trap a layer of moist air next to the stomata, reducing the water potential gradient for water vapour to diffuse into the atmosphere. All these adaptations reduce water loss by transpiration
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CONSERVATION OF SPECIES

CONSERVATION OF SPECIES

  • Extinction occurs when the last living member of a species ceases to exist
  • The extinction of even one species leads to loss of biodiversity. If we lose half the species in the world this will cause a huge loss of biodiversity. Natural vegatation is very diverse and leads to loss of habitats. As more habitats are removed the chances of extinction of certain species becomes greater.
  • Human activities that reduce biodiversity and cause extinction include hunting for food (over harvesting), killing for protection, killing to remove competitors for our food, pollution and habitat destruction such as deforestation
  • Many species of animals and plants are important to the global economy. Products derived from plant and animal species are traded on a local and global scale. They include things like food and drink, clothing, drugs, fuels and other industrial materials. It's important to ocnserve all the organisms we currently use to make products as wellas those we don't currently use they may provide us with new products in the future e.g new drugs. The ecological reasons for maintaining biodiversity are all down to the complex relationships betwen organisms and their environment. The loss of just one species can have pretty drastic effects e.g distruption of food chains, distruption of nutrient cycles, loss of habitats and habitat destruction.
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CONSERVATION OF SPECIES

  • The ethical reasons are that organisms have the right to exist-they should'nt become extinct due to our activities, some people believe we have moral responsiblity to conserve biodiversity for future human generations and there are also religious and spritual reasons for conservation- harmony with the natural world is important to many beliefs and philosophies. The anesthetic reasons are areas rich in biodiversity provide pleasant attractive environments that people can enjoy and the more biodiversity in an area the more vistors the place is likely to attract- this also has economic advantages. 
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CONSERVATION OF SPECIES

CONSERVATION IN SITU

  • Conservation in situ means attempting to minimise human impact on the natural environment and protecting the natural environment
  • Legistation is possible to stop such activities aas hunting, logging and clearing land for development and agriculture.
  • Conservation areas have been developed to stop unacceptable activities such as natural parks and natural reserves.

The principle for choosing a reserve or park must include:

  • Comprehensiveness- How many species are represented in teh area and what are the prevailing environmental conditions?
  • Adequancy-Is the area large enough to provide for the long term survival of all species, populations and communities represented?
  • Representativeness-Is there a full range of diversity within each species and set of environmental conditions?
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CONSERVATION OF SPECIES

ADVANTAGES

  • Plants and animals are conserved in their natural environment
  • It permanently protects biodiversity and representative examples of ecosystems
  • It permanently protects significant elements of natural and cultural heritage
  • It allows management of these areas to ensure that ecological integrity is maintained
  • It facilitates scientific research

DISADVANTAGES

  • Protected animals coming out of the reserve to raid crops- primates often raid farms for maize, mangoes and sugar cane
  • People continuing to hunt protected animals for food
  • Illegal harvesting of timber and other plant products
  • Tourists feeding protected animals or leaving litter

REPOPULATION

  • Where biodiversity is lost it is possible to rebuild it.e.g conifier crops are being cleared for wildlife habitat recovery 
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CONSERVATION OF SPECIES

CONSERVATION EX SITU

  • Conservation ex situ means conserving an endagered species by activities that take place outside its normal environment
  • Relocating an organism to a safer place e.g five white rhinos were recently relocated from the congo to kenya because they were in danger from poachers who kill them for their ivory
  • Breeding organisms is captive then reinforcing them to the wild when they are strong enough
  • Botanic gardens are controlled environments used to grow a variet of rare plants for the purpose of conservation, research, display and education. Endagered plant species as well as species that are extinct in the wild can be grown and reinforced into suitable habitats
  • Seed banks- seeds can be frozen nd stroed in seed banks for over a century without losing their fertility. Seed banks provide a useful source of seeds if natural reserves are destroyed e.g by disease or other natural disasters
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CONSERVATION OF SPECIES

ADVANTAGES

  • Protect individual animals in a controllled environment
  • Predatation and hunting can be manged easily
  • Used to reintroduce animals that have left the area

DISADVANTAGES

  • Only a small number of individuals can be cared for
  • It can be difficult and expensive to create and sustain the right environment
  • Less usccessful in in situ methods- many species cannot breed successfully in captivity, or don't adapt to their new environment when moved to a new location
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CONSERVATION OF SPECIES

INTERNATIONAL COOPERATION

RIO CONVENTION ON BIODIVERSITY 

  • It aims to develop international strategies on the conservation of biodiversity and how to use animal and plant resources in a sustainable way
  • The convention made it part of international law that conserving biodiversity is evryone's responsibllty
  • It also provides guidance to governments on how to conserve biodiversity

CITES AGREEMENT

  • CITES (convention on international trade in endagered species) is an agreement designed to increase international cooperation in regulating trade in wild animal and plant specimens
  • The member countries all agreed to make it illegal to kill endagered species
  • The agreement helps to conserve species by limiting trade through licensing, and making it illegal to trade in products made from endagered animals (rhino ivory and leopard skin)
  • It's also designed to raise awareness of threats to biodiversity through education 
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CONSERVATION OF SPECIES

ENVIRONMENT IMPACT ASSESSMENTS (EIA)

EIA ia an assessment of the impact a developing project such as building a new shopping centre or power station might ahve on the environment. it involves:

  • Estimating biodiversity on the project site and evaluating how the development might effect biodiversity
  • Identifiying ways that biodiversity could be conserved
  • Identifying threatened or endagered species on the project site and the laws relating to their conservation
  • Deciding on planning stipulations- measures that will have to be implemented if the project proceeds e.g relocating or protecting endagered species
  • Local authorites are often under pressure from conservationists who argue developments damage the environment and disturb wildlife- they feel that habitats should be left alone
  • EIA ensure that decision makers consider the environmental impact of developing projects- they're used to by local authorities to decide if and how projects will proceed  
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