Biodiversity, Classification, and Ecology Notes PDF

NOTEBOOK  Biodiversity Variety of life on earth in all its forms from a genetic level to entire ecosystems Gene diversity Variety of genetic information found with in a species the differences in genetic information allow new characteristics to possibly develop it is ess...

NOTEBOOK  Biodiversity Variety of life on earth in all its forms from a genetic level to entire ecosystems Gene diversity Variety of genetic information found with in a species the differences in genetic information allow new characteristics to possibly develop it is essential for evolution Species diversity Variety of different species that exist. All species have different roles that contribute to sustaining ecological processes and add to the values of biodiversity Ecosystem diversity Variety of different ecosystems found on the planet a combination of biotic and abiotic factors and their interactions. All have different contributions yet ave all connected and depend on others to ensure balance Values: economic, ecological life-support, recreation, cultural, scientific  Biodiversity hotspots An area that has a high level of biodiversity that are endemic to that area. Must have at least 1500 vascular endemic plant species Only 30% of original natural vegetation remains This means that the area is biologically richer and under threat. Hotspots assist with conservation efforts and are areas given priority to in an attempt to maintain large scale diversity. Most hotspots exist in locations where human activity is high indicating certain actions are negatively impacting biodiversity. Measuring biodiversity Spatial: location changes. Refers to how biodiversity compares across different locations or regions Temporal: time changes. Refers to the differences that exist over time typically looking at the same location Species richness: measure of the number of species in a given area doesn't consider relative abundance of each species Species evenness: measure of the relative abundance of each species present in an ecosystem  Classification Used to organise and group organisms together assisting with communication and identifying patterns that exist among groups of organisms, past and present. The variety of life on earth is diverse and requires organisation where taxonomy plays an important role Levels are called taxa. Taxa levels start broad including many different species and get more specific as we move down ending on individual species Domain Dumb Kingdom Kids Phylum Playing Class Chess Order On Family Freeways Genus Get Species Squashed The more taxa that organisms shave, the move closely related they are and the more recent their common ancestor. From this hierarchy the binomial nomelature system (two name naming) was derived. All organisms ave called by their genus and species name/group. The genus always have A capital letter and written once the species is always lowercase Classification keys Tools used by biologists to assist in identifying what groups organisms belong The most common method is a dichotomous key. The key is a collection of paired statements that are based on observable traits. The paired questions often present contrasting options that lead to a different question or to the species being identified.  Vary from single called to Heterotrophic multicellular organisms Domain: eukaryote Kingdom: fungi Mostly saprotrophic: feeding Rigid cell wall made of chitin on decaying materials Eg. Mushrooms, yeasts, moles and lichens  Small and restricted to moist, Subdivided into two major divisions based on terrestrial environments Lacking transport tissue structure: bryophytes and tracheophytes tissue: no xylem or phloem Multicellular organisms Don't possess true roots, stems, or leaves e.g. Mosses,Liverworts, Cell walls made of cellulose; Species diversity: 18600 + and hornworts food is stored as starch Bryophytes: non vascular plants Kingdom: plantae Reproduce via spores not seeds Seeds in specialised reproductive Tracheophytes: vascular plants structures called flowers Female reproductive ovary develops into fruit Possess transport tissue Seed plants Angiosperms Pollination usually via Clearly defined alternation of sporophyte Possess true roots, mind or animals and gametophyte generations stems, and leaves as well as stomata Gymnosperms Lack enclosed chambers in which seeds develop Seedless plants: phylum filicinophyta:fern Produce seeds in cones exposed to the environment  Polyp: cylindrical, some are e.g. Jellyfish, sea sedentary, others glide, or anemones, hydras, and somersault, use tentacles corals Some species have a life cycle as legs that alternates between polyp Medusa: umbrella shaped and and medusa free swimming by pulsating bell All are aquatic: most are marine Diploblastic with two basic body forms Phylum: Cnidaria Species diversity: 11000+ Phylum: annelida Kingdom: Animalia Animal cells lack cell walls E.g. earthworms, leeches, polychates Multicellular, heterotrophic organisms Over 800 000 Cylindrical, segmented body species described with chaetae (bristles) In 33 existing phyla Move using hydrostatic skeleton and or parapodia (appendages) Further subdivided into major phyla on the basis of body symmetry, development of the coelom, and external and internal structures  Soft bodied and unsegmented Exoskeleton made of chitin Most have radula (rasping tounge) Heart found on dorsal Aquatic and terrestrial species side of body Grown in stages Body comprises head, after molting muscular foot, and Open circulation system Aquatic species posses gills visceral mass (organs) Phylum:mollusca Most have compound eyes Jointed appendages E.g. snails, mussels, squid Species diversity:110 000+ Kingdom: Animalia Phylum: Arthropoda Segmented bodies Class: Crustacea Class: insecta Class: arachnida Most are capable Exoskeleton impregnated of flight with mineral salts Almost all are Mostly terrestrial Three body parts: head, terrestrial thorax, abdomen Mainly marine Gills often present Species diversity: Species diversity: E.g. spiders, scorpions, mites, Species diversity: 800 000+ 35 000+ ticks, and horseshoe crabs 57 000+ Two body parts: cephalothorax and E.g. roaches, butterflies and dragon E.g. lobsters, crabs, barnacles, prawns, isopods abdomen (except horseshoe crab) flies, bees, ants, beetles, bugs, flies  Dorsal notochord (flexible supporting rod) Lungs in adults, juveniles present at one stage in life Three may have gills subclasses Glandular skin with hair or fur monotremes Mammary glands Post anal tail present at Heart positioned , marsupials, produce milk Species diversity: 4 500+ some stage in development on ventral side placentals External ear present Dorsal, tubular Species diversity: 48 000+ nerve cord Endotherms with hair or fur Circulation system Pharyngeal closed in most Class: mammalia Diaphragm between thorax slits present and abdomen Phylum: Chordata Kingdom: Animalia Class:reptilia Class: amphibia Ectotherms with Class: aves Gas exchange through skin no larval stages Strong, light skeleton Terrestrial endotherms Species diversity: Eggs with soft Eggs with hard, 3900+ leathery shell Mostly terrestrial calcareous shells High metabolic rate Aquatic and terrestrial (limited to damp environments) Teeth are all the same type E.g. frogs, toads, salamanders Gas exchange assisted by and newts air sacs E.g. snakes, lizards, crocodiles, turtles, and tortoises Species diversity: 8 600+  Classification and characteristics of organisms Characteristics are features that can be used to describe an organism Classification is based on the idea: members of the same group shave characteristics that aren't present in members outside the group Physical characteristics When creating classification method presented in systema naturae, Linnaeus used physical characteristics as the basis. Taxonomists today still use PC to classify organisms. Almost any aspect of an organism that can be described can be used this way Methods of reproduction Ability to reproduce is fundamental for life on earth. Methods of reproduction can be used to classify organisms Among mammals reproduction is used to seperate three groups Eutherian: mammals give birth to live young after a gestation period where the foetus develops Marsupials: give birth to live young at a very early developmental stage young develop in a pouch Monotremes: very small group that lay eggs Molecular sequence Recently, chemical sequence in DNA has been used to classify organisms. The order of bases within different genes affects the physical features of organisms Individuals within a species have some differences in the order of bases however they're much smaller that the differences between different species. Protein structure can also be used as order of amino acids can vary in different groups of organisms. Required assumptions for cladograms: More closely related organisms are, more characteristics they will share Some characteristics that are shared by a group will not be resent in distant groups When multiple possible ways an organism can be related, the simplest is the most likely to be correct  Ecology The study of the interactions of organisms with their physical environment and with other organisms To live in certain ecosystems organisms typically have adapted to the conditions and sit in the 'zone of tolerance' in relation to abiotic factors Biotic factors are interaction either between different species or iTunes the same species Key words Ecosystem Biotic Abiotic Biomes Community Habitat Population Terrestrial Aquatic Dominant species  Relationships and interactions Biotic factors are the interactions that exist in an ecosystem. The interactions depend on the organisms present and the convolution that has occurred Relationships include: predator prey, collaboration, competition: inter and intra, and symbiosis:mutualism, commensalism, parasitism Predator prey An organism: predator, consuming another: prey for energy needs Many predator prey interactions exist in an ecosystem, however the amount of energy passed on decreases as we 'move up' to the apex predator. The predator prey interaction is dynamic yet balanced  Symbiosis General term given to a long term interaction between two or more different species Symbiotic relationships are defined by the outcomes for the individual organism Mutualism Both species or organisms benefit from relationship, common relationship with communities In the absence of this relationship many species would become threatened or extinct because they cannot Irvine by themselves e.g. pollinators: the pollinator benefits from feeding on the nectar while the plant benefits by being pollinated e.g. the woylie is a seed disperser in WA, its ability to disperse sandlewood seeds could help with the regeneration of the WA sandalwood Commensalism Only one organism benefits from interaction, other is unharmed e.g. remora fish attach to shark and get left over food and a ride but the shark is unaffected Parasitism Interactive between a parasite and a host The parasite lives on or within the host deriving nutrients from the host causing them harm ectoparasites: such as lice and ticks, live and feed on external surface of host organism endoparasites: such as tapeworms, live and feed within their host organism e.g. native mistletoe is a parasitic plant that uses eucalypt trees as host e.g. fleas on dog Disease Interaction between disease causing organism and host, can affect biodiversity of an ecosystem e.g. myxomatosis causes disease in rabbits disease in this instance allows biodiversity of Australian ecosystems to increase, by reducing rabbit populations stopping them from outcompeting native animals for resources  Competition Refers to the struggle between organisms for limited resources such as food, water, space, light, or mates. Occurs when two or more individuals require the same resource, and that resource isn't abundant enough to support them all fully. Can significantly influence population dynamics, species distribution and ecosystem structure. Types of competition Intraspecific competition: occurs between two individuals of the same species, since they share identical resource needs, competition can be intense. e.g. two oak trees growing close together compete for light, water and soil nutrients Consequences: leads to natural selection, only the most adapted organism can survive and reproduce Interspecific competition: occurs between individuals of different species that require the same resources e.g. wolves and coyotes competing for prey in the same habitat consequences: can lead to competitive exclusion where one species outcompetes and eliminates the other from that niche or resource partitioning where species adapt to use different parts of the resource to coexist Competitive exclusion principle Also known as as Gauses law, states two species competing for the same limited resource cannot coexist indefinitely in the same ecological niche, eventually one species outcompetes the other  Niches An ecological niche covers a range of different traits, behaviours, and characteristics of organisms including feeding sources, timing and trophic levels, breeding behaviours, timings and location, interaction between and with biotic and abiotic factors Fundamental niche: idealistic spread and distribution of an organism when their are no limiting factors impacting it Realised niche: real niche that organisms fit into when their limiting factors prevent survivability in certain areas When organisms have overlapping niches they will experience competition, the greater the overlap the more competition. Two organisms can completely share a niche due to competitive exclusion principle. Generalist vs specialist species Generalist: thrive in a wide variety of environmental conditions and can make use of a variety of resources. This gives them increased opportunities of finding mates, shelter, and resources. However, they have to compete with more species, they also may not be as effective at exploiting food sources or habitats and overproduction may exhaust their resources. Competition forces them to adapt, shift habitats, or exploit alternative resources, shaping distribution. Specialist: thrive only in a narrow range of environmental conditions or has a limited diet they can exploit food sources more efficiently and have a higher reproductive rate due to stability. They also have evolved unique adaptations to help with survival. However they are vulnerable to environmental changes and are more susceptible to scarcity leading to increased risk of extinction. They thrive in environments where they can dominate a niche.  Tolerance limits Refers to the range of environmental conditions organisms can survive in. They are often linked to temperature, pH, and some solutes and their concentration. Organisms will have an optimal range where their population numbers will be at their highest, shouldering this zone is the zone of psychological distress. In this zone organisms numbers decline due to demands of surviving. The zone after this is the zone of intolerance where organisms are unable to survive and there will be no population here.  Energy in ecosystems Energy enters ecosystems in two ways, photosynthesis and chemosynthesis. Organisms that complete these reactions are called producers or autotrophs. They take inorganic molecules and different forms of energy and convert it into an organic molecule that contains chemical energy. The formation of this energy by producers is vital for sustaining life in an ecosystem. All organisms in an ecosystem depend on the energy made by producers for a variety of reasons including: growth, repair, homeostasis, reproduction, and metabolism. Energy moves through ecosystems through consumption or predation, food chains and food webs. Not all organisms are autotrophs and must consume biomass to gain their energy. Organisms that consume others are called heterotrophs or consumers Energy moving in ecosystems Energy enters an ecosystem as sunlight, autotrophs convert the light energy into chemical energy via photosynthesis. Once here the plants convert the glucose into other chemicals. Organisms consume the plant and convert molecules into energy using cellular reproduction. The organisms that consume plants re commonly herbivores, but are always called primary consumers. These organisms are consumed by secondary consumers, typically carnivores. The pattern continues to tertiary consumers that consume secondary consumers and quartenary consumers, often the apex predator. This single path of energy is know as a food chain Food chains only represent a single path and not a real representation of energy flows in ecosystems. Given more than one organisms exist at each trophic level a more accurate representation is a food web. They are collections of food chains, having multiple organisms in each level and some occupying multiple trophic levels  Productivity and energy flow Ecosystem productivity The rate at which chemical energy is produced in an ecosystem. Represents the foundation of all ecosystem functions and directly correlates with the rate of photosynthesis Photosynthetic efficiency: measures how effectively producers convert light energy into carbohydrates. Varies based on light availability, temperature, and access to essential resources like water and carbon dioxide Biomass stored as energy: represents total mass of biological matter in a given area that can be used as an energy source serving as a erasure if stored chemical energy Measuring ecosystem productivity Photosynthetic efficiency. Plants absorb light but don't use all of it. Gross primary production: total amount of energy plants capture from sunlight and convert into chemical energy Net primary productivity: energy left over after plants use some for their own respiration. Cellular respiration: harvests biochemical energy from organic substances like glucose. This metabolic process Converts sugar into carbon dioxide, water, and ATP. Every organism depends on this for survival Types of consumers Herbivores: plant eaters, occupy second tropic level, convert plant biomass to animal tissue. Primary consumers e.g. deer, rabbit, grasshopper Carnivores:meat eaters, obtain energy by consuming other animals. Regulate prey population, secondary or tertiary consumers e.g. wolves, eagles, sharks Omnivores: eat both plants and animals, occupy multiple trophies levels, flexible feeding strategies e.g. bears, humans, crow Scavenger: feed on dead organisms. Recycle nutrients back into ecosystems. Critical for waste removal e.g. crabs, vultures, hyenas Ecological impacts of tropic cascades Top down effect: removing top predators triggers chain reactions throughout food webs. Prey populations explode without natural control mechanisms Bottom up disruptions: removing primary producers affects all higher tropic levels, entire food webs collapse Intermediate effects: removing middle level consumers creates unexpected changes. Predators loose food sources, plants face reduced herbivory  Decomposers Organisms that recycle energy and matter in ecosystems. They are often left off food chains and webs, yet are always present in ecosystems. Decomposers have access to all trophic levels as all organisms die have waste products recycled. Organisms that consume dead and waste material are called detrivores, these organisms increase the surface area of the dead matter to enable decomposers to have a faster rate of converting the molecules from organic to inorganic to enable recycling  Ecological pyramids Quantitative representations of ecological system. Three forms of ecological pyramids. Numbers, biomass, energy All pyramids are draw to scale, as a result the pyramids have three shapes Upright, inverted, partially upright Each trophic level has its own section in the pyramid. Each pyramid is a snapshot at a point in time. Ecosystems are dynamic and constantly changing. Numbers: these represent the numbers or abundance of organisms in each trophic level Biomass: biological matter in an organism, the matter that is organic, contains energy. This pyramid follows a similar pattern to energy pyramids as it represents the amount of living tissue in a trophic level Energy: shows the amount of energy available at each level. Energy amount declines as we move up each trophic level. Due to energy being converted into waste or heat, this energy is not available for energy transfer. Rough measure is that ten percent of energy is passed on with ninety recent being lost  Biogeochemical cycle This is the general term used to explain the movement if matter in ecosystems. All matter then moves between the living and non living parts in a constant and dynamic matter. We have three key cycles water, carbon, nitrogen  Carbon cycle Carbon is an important element in ecology to form organic molecules. It is the key element in all organic molecules. Carbons reservoir is in the atmosphere as carbon dioxide. The atmospheric carbon is fixed to a location in plants via photosynthesis. Plants create carbohydrates from atmospheric carbon dioxide this is known as assimilation. From the plants it moves to heterotrophs via consumption. These organisms metabolise the glucose and create CO that releases into the atmosphere All organisms then produce waste products and die passing on the remaining carbon to Decomposers that also complete cellular respiration and produce carbon dioxide released into the atmosphere. If conditions are appropriate, organisms may become fossil fuels over time. This reservoir would remain unused however human activities burn the fossil fuels and release carbon back into the atmosphere, combustion. Carbon also interacts with the ocean and is required for ocean ecosystems. Carbon dioxide dissolves into the water and can be used by photosynthesis organisms in the water. From here simulator patterns of carbon movement exist that occur on land. When some organisms die in water not only can they form fossil fuels but they can form limestone, a large reservoir of carbon.  Nitrogen cycle Key element in routines and nuclei acids. Depends on different organisms to convert unusable nitrogen compounds into useable ones. These organisms include bacteria that live in the soil and others that live in legumes. Plants can absorb nitrogen and assimilate it from their surroundings. However animals need to consume nitrogen from food sources to assimilate it. Nitrogen fixation Can occur through biotic means with nitrogen fixing bacteria that are present in the soil or in root producers or through abiotic such as lightning or artificial production of fertilisers. The process of fixation takes the atmospheres nitrogen puts it in the soil in a different form. Nitrification Once in the soil nitrifying bacteria interact with the nitrogen compounds and convert into nitrite or nitrate. Nitrates are the most commonly used molecules by plants and once absorbed they are assimilated. Assimilation The plants are consumed passing the nitrogen on to the consumer who will also assimilate the molecules. Once waste products are produced, decomposers convert any available nitrogen into ammonia through the process of ammonification. Ammonification Nitrifies convert unusable ammonium into nitrates or nitrites and continue the cycle Denitrification Denitrifying bacteria also exists that remove the nitrogen from the soil converting the nitrates into nitrogen gas and releasing it to the atmosphere  Fieldwork techniques Quadrats Small randomly placed squares of a known area where we can do multiple types of measures. Capture recapture Used to estimate populate size Key assumptions No death, emigration or immigration Same sampling/capture technique Tags do not impact survival All organisms mix freely and randomly  Population growth rates Rate is referring to amount of change a population is having over a period of time. Can increase, decrease, or remain constant. If birth + immigration > death + emigration = population increasing, positive growth rate If birth + immigration = death + emigration = population and growth rate is constant If birth + immigration < death + emigration = population is decreasing, negative growth rate Distribution Random: organisms spaced irregularly; locations of on organism doesn't affect that of another. Eg specific trees in forests Uniform: organisms are evenly spaced; presence if one affects closeness of another. Eg penguin colonies Clumped: number of individuals grouped together and groups make up population as a whole. Eg schools of fish Keystone species A species that has a large effect on community structure relative to its biomass or abundance. Highly influential relationships with a number of other species. Can have a large effect on population numbers of other species in a community even though it may not be abundant. It can prevent organisms from lower trophic levels from monopolising food resources and space. E.g. dingoes They help regulate herbivore populations and invasive species. Without dingoes these species can overpopulate leading to habitat destruction and overgrazing.  Population growth graphs A population is a collection of the same species in a given area. Each population growth rates vary depending on the organism and the conditions in the area. J curve. Boom and bust a: lag phase. Slow growth due to low numbers b: exponential or rapid growth. Due to limited mortality and no negative impacts, undergoes rapid expansion c: carrying capacity. Population reaches maximum numbers it can support d: bust. Immediate and rapid decline S curve. Logistical growth a: lag phase b: exponential or rapid growth c: reduced growth: as the population approaches carrying capacity there is an increase in environmental resistance which will negatively impact the growth or the population and reduce growth rate. d: plateau. When population is at cc it will fluctuate above and below cc. As population is above, environmental resistance increases and reduces population size. When below, er is lower therefore population will increase. Carrying capacity A habitat has limited resources and therefore can only support a certain number of individuals in a population. The maximum size of a population an ecosystem can support with its limited resources is described as the carrying capacity of that ecosystem. Biotic and abiotic limiting factors Resource availability: food, after light, shelter. Percent of oxygen in water, predation , disease, natural disaster, weather. Limiting factors Density dependent Often biotic and include predation, competition, disease. Only come into play when population reaches a certain level, larger population stronger impact Density independent Factors that affect all individuals in a population regardless of how dense. Severe weather conditions, volcanic activity, habitat destruction, often seen following catastrophic event e.g. fire, flood. Chance of survival is not dependent on density  K and R selected In general, organisms are grouped into two groups based on key attributes that exist in their life cycle, methods and types of reproduction. K Selected: These are organisms that are longer lived and exist in stable ecosystems/environments. They give a lot of energy into developing very few offspring. Offer extensive parental care. They have longer life cycles and take an extended period to reach sexual maturity. Due to living in stable ecosystems, they will often live at or near carrying capacity. This means deviation in population size is uncommon. R Selected: These organisms are shorter lived and exist in unstable environments. Due to being shorter lived, they reach sexual maturity quickly. These organisms produce many offspring, offering little to no parental care.Given the opportunistic existence, they often live in unstable environments where they take advantage of favourable conditions and breed quickly. This means they often have a J curve growth graph with predictable cycles.  Ecological succession Change in ecosystems is a natural feature and can occur in varying levels. This can lead to a progressive change in communities over time. This is known as succession. There is a progressive shift in community structure and composition leading to a stable ecosystem. During succession there are changes in biotic and abiotic factors. Two types of Succession: Primary Succession: The commencement of succession from no pre-existing community. The formation from barren land/sites. Step one: Pioneer plants - particular species that depend on the environmental factors in the habitat. Usually, the first ones are autotrophs, such as lichens. Step two: Soil formation as pioneer plants die and decompose. A thin layer of soil is formed. Shallow soil makes moss possible. Over time bacteria, fungi and invertebrates are established and assist with simple community formation. Step three: Early colonising plants are successful due to characteristics: seed dispersal, rapid growth and reproduction. Generally fast-growing and typical of r-selected species. Often first to occupy unused resources and living space. They increase rapidly but often decline rapidly with competition. Step four: New community forms with producer organisms. Small herbivores such as insects have food and shelter. They become next link in food chain. Gradually a whole new community is formed. Step five: As succession continues, biodiversity increases. It is a slow process and is dependent on abiotic conditions. May take hundreds to thousands of years. Eventually, if there is no further disruption, a climax community is established. Secondary Succession: This is the progressive shift in community composition after primary succession. ↳ any change Step one: a such as fast growing pioneer plants colonise the area. Invertebrates enter the ecosystem Step three: slower growing trees begin to grow and stabilise the community. New herbivores then carnivores and omnivores arrive and become apart of the food web Step four: A new community forms and eventually becomes a climax community. Note that secondary succession always follows primary succession and a disturbance  Climax community The stable community present at final stage of succession.it is stable as long as environmental factors remain unchanged. Tend to be slowly growing long lived K selected species. Not all successions reach a climax community. Factors such as five and selective grazing by herbivores helps to create conditions allowing for example grassland to persist Primary and secondary succession compare similarities and differences Similarities: both involve ecological communities changing over time, both can lead to climax community, pioneer plants begin both successions Differences: PRIMARY SECONDARY Occurs in lifeless area occurs where ecosystem previously existed Lichens, mosses, and microorganisms initiate Fast growing plans like weed and grass utilise soil transformation existing soil nutrients Takes long to reach climax community, Progresses quicker potentially reaching climax often hundreds to thousands of years community in decades  Fire Five can have varied impacts on ecosystems and biodiversity. Australian ecology has evolved to survive and take advantage of fives. Fire has an immediate impact on the ecosystem which can be broken up into positive and negative outcomes. Immediate.. Decrease in biomass, number of organisms present declines. Loss of habitats, resources, and death decline population sites. Unstable environmental conditions for a period of time with fluctuations in temperature changes in light exposure and heat movement nutrient level in soil will increase. Positives Removal of invasive species Increases nutrients cycling by releasing stoved molecules to make accessible to organisms. Stimulates germination of certain native species Can increase consumable biomass for primary consumers Negatives Shift in conditions provide opportunities fir weed and invasive to grow with more space available If fires are regular native species are not able to germinate due to not being able to mature leading to a reduction in population Intensity of fire can change the ecosystem canopy and alter the growth and recovery of other species Fire can increase soil erosion. The removal of plants increase the chances for soil to be moved by the wind Fire stick farming Increases the frequency of fires Gave rise to pattern of vegetation that became dependent on regular burning Disrupted regular succession patterns to maintain a grassland state Plants that have fire become more common in fire dominated areas In many areas once fire tolerant landscapes are being burried alive by a spreading invasion of African grasses Introduced grasses build up huge fuel loads, supporting fires of an intensity and timing that native species cannot withstand  Australian plant adaptations Through co evolution Australian flora has developed many adaptations to fire Epicomic bud: dormant buds that exist in branches that immediately grow new foliage to ensure photosynthesis can occur Heat induced seed release: some plant species have seeds that are sealed closed that require heat to open the seal and release the seed Thick bark: an insulation layer that protects the inner stem, vascular tissue, of the plant Lignotubers: underground stems that have stored molecules to enable rapid regrowth Fire endured flowering: when nutrient levels in soil increase, plants take advantage and grow a flowering body.  Habitat destruction and fragmentation Habitat destruction The removal of ecosystems for the purpose of urbanisation, agriculture, and mining Results in a loss of habitat for organisms, resulting in the loss of species and impacting natural balance of ecological processes Impacts all levels of biodiversity Habitat fragmentation When a habitat or ecosystem is divided into smaller areas Impacts organisms that remain potentially reducing their genetic diversity as it reduces gene flow Genetic inbreeding results in a reduction of genetic diversity increases expression of deleterious characteristics and reduces survivability As genetic diversity decreases species level is impacted. Organisms leave, decrease in number, or go extinct leading to changes to energy flow and impacting other organisms Edge effects: conditions at the edges of fragmented habitats are often less suitable for many species leading to further decline in biodiversity Mitigation or conservation: Wildlife corridors: creating corridors to connect isolated patches of habitat allowing for wildlife movement and genetic exchange Seed banks: used for storage of seeds, for insurance again extinction and to conserve the gene pool in crop and other species  Invasive species Organisms that are no endemic or native to an area are introduced to a new ecosystem. Species are introduced for agriculture, person or leisure, biological control Invasive have many impacts on natural ecosystems. They have an impact on all impacts of biodiversity. Genetic: invasive species can interbreed with native organisms and reduce the genetic variability in a gene pool Bottleneck effects: an invasive species can reduce a population size and reduce gene pool Species: predation, competition, disease. The invasive species organisms reduce the overall number of species in an ecosystem through either predation: consumption, occupy similar niches and outcompete the natives or introduce new diseases to an ecosystem Ecosystem: the trophic levels and food webs can be disrupted and impact the overall function of an ecosystem. The natural or ecological processes can be disrupted due to the shifts in organisms and changes to abiotic can result, Invasive species are often generalist organisms that have wide tolerance ranges enabling them the capacity to survive in a variety of ecosystems  Land degradation Solid salinity The result of deep rooted plants being removed and replaced by short routed plants This results in the water table rising via rain and irrigation and leads to water making its way to the surface Once at the surface the water evaporates and leaves behind the salts that were previously dissolved This results in the soil salt concentration increasing to high and intolerable ranges. It is an irreversible event and leads to Barron, infertile, land. The salt may leech into nearby bodies of water that can impact the concentration of the water and negatively impact the organisms with a shift in salt concentration. Conservation Environmental: plant rows of short rooted crops alternating with deep rooted crops the keep water table deep Management: siphoning, draining, air pumping of a rising water table to lower it back down