Biology Term 4

BIODIVERSITY

endemic

species only belonging or native to particular people or country

ecological organisation levels in ascending order

Organism→Population→Community→Ecosystem→Biosphere

population

• group of organisms of same species in particular geographical area at partiuclar time

• research focus on size and how it changes over time

species

• group of organimsms with similiar characterisits (similiar anatomical characteristics, common gene pool)

• can interbreed to produce fertile offspring - different species cant

• compete with each other for researches

community

• sum of all living organisms of different species,or biotic factors, in common geographical area

• different sepceis are interdependent , exhibit range of interactions

• reseach focuses on interactions between species (factors effecting and consequences if removed from community)

ecosystem

• interaction of living (biotic) factors (e.g. communities of organisms) and non livign (abiotic) factors (e.g. physical surroundings)

• research on analysing how nturiwnts and energy are stored and how they flow thru ecosystems

biosphere

• highest level of ecological organisation 

• global ecoystem or zone of life on earth 

• made up of all ecosystems on earth 

biotic and abiotic factos

biotic - living compounds of ecosystem

abiotic - non-living physical componenents

intraspecfic and interspecific interactions + 3 types of interactiosn

intraspecific - interactions between members of same species

interspecfic - between memebrs of different species


competition, predation, symbiosis

competition

• compete for same resources (e.g. light, oxygen, nutrients, prey, space, sexual partners)

• no 2 species have identical requirements - overlap is where there is competition

• outcome generally has negative effects on weaker competitors

• more intense amongst members of smae species 

• outcompeted species must adapt to remaining available resources or become extinct 

• significant drive of natural selection and evolution

predation

• one organism (predator kills and consumes another or parts of it (prey)

• generally occurs between different species, when same sepcies it is cannibalism

• cannibalism helps species survive times of limited resources

• affects no of organisms in population, biodiversity of community, evolution of organisms involved

Herbivory

• consumption of all or part of photosyntehtic organism, generally plant, by animal

• can result in death of photosyntehtic organisms but nto always

• photosynthetic organisms are producers in most food chains

• herbivores and plants drive adaptations in both species

• herbivores - digest and extract nutrients from plant matter plants - physical and chem defences

symbiosis

• distict relationships between organisms of two different species 

• three categories - mutualism, commensalism, parasitism 

mutualism

• both species benefit

• e.g. on image

commensalism

• one species benefits, other in unaffected

• e.g. on image

Parasitism

• one benefits, other is harmed

• invovles organisms called parasite harming organism called host

• e.g. on image 

decomposers

heterotrophs that extract energy from remains/waste products of organisms from all trophic levels - break down dead matter and recycle nutrients - wihtout, dead organisms and matter build up

trophic levels, consumers

trophic level - relative position of an organism in the food chains

1st - producer, synthesises own energy-rich compounds (e.g. plants)

remaining - heterotrophs, feed on producers and other animals consuming producers, consumers

first consumer in fodo chain - primary consumer - 2nd trophic level

seconadry consumer - eats primary consumer, 3rd trophic level

consumer at top of food chain - apex predator, no natural predators

food web - many linked fodo chains, more accurate

biodiversity

varity of living things on earth (genetic info, ecosystems). 

3 different levels - genetic, species, ecosystem

genetic diveristy and gene pool definitoin + effect

• diversity within species

• more individuals in the population, greater genetic diversity

• different populations generally have different genetic compositions (gene pools - sum of all genes of individuals in population)
  
  

• llarge gene pool → more likely to survive changing environmental conditions - increased chance some individuals have genotytpe surviving changing conditions

• better adapted to new environment conditions (selection pressures) are more liekly to pass suitable traits to offspring

• less gentic diversity can result in one environmental changes wiping out individuals - natural selection

genetic drift

• random changes in the gene pool of the population

• small populations are more susceptible to genetic drift

• bottleneck effect - random loss of genes due to environmental events (natural disasters, e.g. bushfire)

• large reduction in genetic diversity because population members are killed - survivors are necessarily better adapted to the environment

species diveristy

• variety of species within community

• essentail for perpetuation of the community - addng or removing species changes entire ecosystem as relationships and interactions between factors is removed

ecosystem diversity

• variety of ecosystems on earth

• hels regulate chilmati conditions, recycle nutrients, maintain soil quality, maintain balance in atmosphere

• essential for perpeutation of life

taxonomic levels/taxa (singular - taxon) in descending order + how they are based on

• based on shared characterisits as well as molecular similarities (domains highest, most general, species lowest, most specific)

• as they are smaller, become more sepcific and contian less sepcies

• species closely related have greater no of same taxonimic levels

binomial system of nomenclature

• every species given scientific name with two parts

• first part - genus (generic name) - capitalised (e.g. Homo)

• second part - species (specific name) - lower case (e.g. sapiens)

• binomial names are latin - type in italics or underlined if handwritten

• things with same genus different species are closely related but not same 

modern hierachial strucutre of biological classification + characterisits used to identify kingdoms - MEMORISE TABLE

limitations of species definition (organisms of same species can interbreed to produce fertile offspring, diff cant)

• reproductive isolation doesnt occur instatnly - two populations may have different physical features but may e able to interpreed still

• species definition cant be applied to asexually reproducing species

• could be lack of data to apply this species definition to particular species - could be lack of funding, species are extincy, interbreeding behaviour not documented

basis of classification - physical features and reproductive strattegies

• physical features are expression of genotype and environment, tehrefore organisms with fimilar features are often closely related- can be used in classifying range of diff organsisms

• some species reproduce sexually, others asexual - used to classify range of diff organisms (e.g. mammals - 1 of 3 repdoductive strategies so the groups are diff)

basis of classification - molecular sequencing 

• helped increase accuracy of biological classification by examining DNA sequences and prtein sequences

• comparing DNA (made up of long sequence of bases) and known gene sequences, inferences can be draft regarding common acnestors and degree of relateness

• limitation - cannot be used on extinct species as dna and proteins are degraded and cant be sequenced reliably - species that dont aerobically respire cant be compared using aminco acid sequencing of cyochrome c protein 

dichotomous key

• uses series of choices to clearly identify given speices

• presents series of mutually exclusive choices ased on particular characteristics

• to identify species pair of statments need to be applied, one is applicable, continues until correct statement leads to identity of species 

reproductive isolation (maybe add more to this)

• attraction of mates - pheramone chemicals released by one of the sexes - only attract members of their own species

• reproductive barriers foring isolating boudnaries around closely reltaed speices can be divided into two groups - prezygotic and postzygotic isolating mechanisms 

pre-zygotic and post-zygotic mechanisms

PRE ZYGOTIC

• any mechanism occuring before gametes fuse to make zygote

• e.g. diff matinc calls and rituals, specific pheramones, difference in flower shape/genitalia, different seasons/times for reproduction, inability of sperm to survive female reproductive system

• pollen tubes unable to grow in ovules in a flower

Post Zygotic

• any mechanism after gametes fuse to form a zygote

• e.g. zygote fails to develop (miscarraige), young fails to reach sexual maturity, offspring live but are infertile

adaptation

• feauter of organims increasing fitness (probability of surviving and reproducing in its haitat) - inherent

• generally 3 types - strucutural/anatomica, physiologica/functional, behavioural 

• adaptation is feature produced by natural selection for current fucniton in specific habitat 

• reasons for adapting - find nutrients, adjust to temp of habitat, dehend from herbivores or predators, increase reproducive chance, escape dangers, adjust to change sin habitat

PENTADACTYL LIMB! EDIT AND ADD THIS!

structural/anatomical/morphological adaptations

• physical body feature sof organism helping them survive

• genetically inherited, shaped by natural selection which acts on traits passed onto offspring

• do not develop during one organisms life but over many generations, increase biological fitness of organisms 

E.G.

• large earts of bilby/desert animals increases surface area to emit more heat and cool animal

• artic fox has small ears to reduce heat loss and stay warm

• streamline shape of dolphins help move in water

• long giraffe neck lets it reach leaves high in treetops

physiological/functional adaptations 

• geerally based on features that arent visible

• generally associated w metabolic processes, usually based on body chemistry and other processes that enhance survival and reproductoin

E.G.

• desert animals excrete concnentratd urine to conserve water

• secretion of tozins by plants to assist defence

• sense of smell of wolves assist huntings

• oxycoin horomone in humans promote bonding, breastfeeding increases oxytocin release in both mum and baby

CYTOCHROME C PROTEIN

• cytochrome c is protein necessary for aerobic repiration in virutally all living organisms

• varies from one species to another, dregree of similarity in amino acid sequences between species indicate closeness of evolutionary relationsships

• e.g - humans and chimpanzee match at all 104 amino acid postionts, indicates very close evolutionary relationship

behavioural adaptations 

• associated w paters of activity or behaviour 

• something animal does in repsone to external stimulus, increases chance of survival, innate OR learnt

E.G

• desert animals are more active at night as conditions are cooler

• courtship rituals by birds or mating calls of frogs increase chance of finding mate and reproducing

• migration of humpback whales to colder waters to feed on krill, warmer waters to mate and reproduce 

• opossume play dead when confronted by preadtor 

photosynthesis

• photosynthetic organisms can capture and transform sunlight into chemical energy (glucose)

• chemical bonds holding co2 and h2o molecules together are broken, atoms are rearranged to make glucose and some oxygen

primary producers

producers of chemical energy, all other species in food web rely on them for energy

use glucose for daily energy needs, can transport excess into storage sinks that animals can consume

trophic levels in food webs/chains (energy transfers stat)

• energy is transferred from one level to another by consumption

• first trophic level is always primary producer/autotroph, remianing are consumers (heterotrophs)

• approximately 90% of the obtained energy is lost as heat and waste at each trophic level

• only approx 10% of energy orginally obtained by trophic level is avaialbel for next trophic level through consumption

inherited adaptations vs learnt adaptations

Inherited adaptations are passed on from parents to their offspring in their genes and can be structural, physiological or behavioural. Some behavioural adaptations that increase the chance of survival can be learnt throughout life by some organisms. These adaptations are not coded for by genes

dead organisms and wastes broken down….

• by decomposers - extract energy from remianing organic mamter and respire releasing heat back to environemtn

biogeochemical cycles (why and what interactiosn, tissues made of, decomposers)

• chemical elements and simple nutrient molecules needed by organisms are cycled within ecosystems

• involves interactions between biotic and abiotic components of the ecosystem

• matter is neither created nor destroyed - matter must be cycled from abiotic environment through living organisms and back to the abiotic

• involved decomposers - feed on dead and decomposing, metabolic actions break down organic material (e.g. carbs, protein, nucleic acids, lipids) into inorganic substances

• return to soil, increases soil fertility (abiotic component) to be incorporated back into the new plant (biotic component)
  
  

• mail elements making tissue - carbon, oxygen, nitrogen, sulphur, phosphorus, potassium, calcium

water cycle

• water form oceans lakes etc evaporate and turn into water vopour, rise into atmosphere

• transpiratoin form terrestrial plants also release water vapour

• vaporu cooles and condenses into clouds (condensation)

• water falls back to earth as precipitaion 

• some of it flows over land as runofff and reutrn to bodies of water, some infiltrates ground and replenishs groundwater

• snow and ice can also melt and runoff or pelocate to groundwater

• plants and animals do their thing wtih water 

carbon cycle

• CO2 is absorbed from atmosphere by plants (photosynthesis) and becomes glucose

• glucose is used as energy source for cellular respiration, releases Co2 or converted into other organic matter

• animals consume plants, transferring carbon thru food chain

• decomposition of dead organisms and waste releases carbon back to soil and atmosphere

• can be stored for long periods in carbon pools, carbon fluxes is movement of it beteeen them 

• e.g. carbon sequestriatoin (admospthere to ocean), combustio of organic matter (carbon sequesration)

nitrogen cycle

• nitrogen fixation - bacteria in soil or root nodules of legules convert atmospheric N to ammonia, taken by plants

• can also be fixed thru lightning or inductrial processes

• once in soil, nitrification - other bacteria convert ammonia into nitrites and then to intrates, absorbed by plants

• plants consumed by animals, transferring it through food chain

• dead animals are decomposed by bacteria and funfi, break down organic nitrogen compounds, return ammonia to soil (ammonification)

• dentrification - specialised bacteria convert nitrates back to nitrogen, release itno atmosphere and complete cycle

phosphorus cycle

• phosphoirus mainly found in rocks and sediments

• wearthering and erosion of rocks, releases inorganic phosphate into soil and water

• plants absorb phosphate through rooots

• plants have evolved mycorrihazae - symbiotic reltaionship between fungi adn plant roots, fungi enhance plants ability to absorb water and nutrients, plan give sfungi carbs from photosyntehsis

• animals consume plants, obtaining phosphorus molecules into tissues, contineu down food chain

• dead animals decomposed by organic matter, return phosphorus to soil as inorganic phosphate

• leached into water, settels and forms sedimentary rock and restrats cycle through geological uplift

how is composition of community determined

• by environemnta conditions - e.g. water avaialability, soil nutrients, temp, fire frequency, salinity

• organisms adapt to their niches

SCLEROPHYLL FOREST ADDD

rainforests

• dense, biodiverse

• primarily in tropical regions

• high rainfall, rich vegetation

• major carbon sink, regulate atmosphere and climate 

e.g. tropical, temperate, decidous, mangrove, montane, mixed, boreal

tundra

• cold, treeless, high mountains and arctic

• permafrost, minimal vegetation

• specialised plants and animals well adapted to extremely cold conditions

• store frozen methane, crucial role in carbon cycle
  

e.g. arctic, antarctic, alpine

desert

• arid, sparse rainfall, extreme temp fluctuation and limited vegetaton

• plants are well adapted to store and retin water, animals are noctornal or burrowers

e.g. hot and dry deserts, demi-arid ceserts, coastal deserts, cold deserts

freshwater

• marine, not salty

• diverse range of equatic life

• regualre water cycles, provide essentail resources to populations

e.g. rivers, streams, lakes, ponds, wetlands, estuaries 

ocean

• cover most of earths sources, variety of habitats

• coral reefs are one of most biodeiverse ecosystems

• vital role in regulating climate, supporting marine biodiveristy, corviding resources such as ozygen water and food

e.g. open ocean, coral reefs, deep sea, kelp forets 

grasslands

• open, explansive, dominated by grasses and few treest

• vital role in carbon storage, soil health, agricutlruer

• found in tropical and temperate zones

e.g. temperate, savannas, steppes, pampas

alpine

• high altitude, cold temp, strong winds, short frowing season

• support specialised animal species adapted to extreme cold

• plants are hardy grasses, shrubgs, mosses

e.g. apls, andes, himalayas, rocky mountains

compare tropical rainforest, clerophyll woodland, australian hot and dry desert, and freshwater pond

adaptations for abiotic components: low oxygen levels, low solute concentrations, high viscosity of water, low light intensity

ecosystem stability

persist if can capture, transform, and trasnfer energy, cycle essential nutrients and elements. rich diversity = resist change and remian intact

stable ecosystem - maintained over long periods of time

unstable ecosystems - now species diveristiy, more vulnerable to change

ecological niche

• specific role/function organims plays within ecosystem - defined by living and nonliving factors

• how a spceies fits into its habitat and ineracts with it 

• act as selection pressures, ensure most suitable individuals in species survive to reproduce 

niche overlap

• similar niche results in overlap

• niche overlap graph shows it - small zone, less competition, big zone/identical/similar niche, high competition

• high overlap → one population goes extinct

fundemental and realised niche + chtlamus and balanus things example

fundemental niche - full range of environmental conditions and resources an organism can theoretically use

realised niche - portion of that range the organism actually occupies due to competition, predation, or other limiting factors

zonation

• spatial distributon of a species/communities across distinct envrironmental gradeitsn 

• influenced by variying abiotic factures - create diff habitats across zones

• within the zoens speciesi inhabit (based on ability to survive and thrive), organisms fill their niches

• illustrates how both habitat preferences and niche roles drive distribuition and strcutre of ecosystems 

stratification and layers of rainforest

• vertical layering of habitats within an ecosystem

• creates disticny layers - each with own set of abiotic conditions, influencing types of species that can inhabit each layer

• each layer provides diff habitats that support specialised organisms adapted to those specific conditions

• within each layer, organisms occupy ecological niches

forest floor, understory, canopy, emergent layer

keystone species

• play a crtiical role in maintaining strucutre, balance, and health of ecosystems )greater affect of stability of ecosystem than others)

• presence or absence has a disproportionately large impact on the environment and variety of species in it

• infleuncce factors (e.g. population control, resource availability, habitat structure) to help regulate ecosystem dynamics

• without, ecosystems become destabilised

loss of keystone species (sea otters)

• changes ecosystems as certain other species will also be affected

• sea otters ear urchins, which eat kelp

• klps neach provides marine organisms with food and shekter and oxygen for aerobic respiration

• larger sea otters, less urchins, more kelp resulting in large well develped foresets

• decrease in ppulatino size of otters (increased predation by whales) causes other populations to decline, more urchin, less kelp

daily change impact on ecological change

• day and night affect the abioitc components of an ecocysstem - change during it

• changes in light intesnisty, temp, humidity

• nocturnal animals are also a change

seasonal change impact on ecological change

• cyclic changing of seasons results in changing weather patterns in ecosystems

• caused by revolution of earth around the Sun, resutls in 4 distinct seasns

• affects abitioc factors like temp, rainfall, soil moisture, evaporation rates, flwoing rivers, snow cover

• changes in abiotic factors impact biotic factors and affect type and amount of food available

• winter _> days are shorter, temp decreases

• polar regions need alternative food sources, move to warmer places, or hibernate

• abiotic in spring supports the reproduciton of plants and animals

• size of populations of species can change so much that community visibly changes 

long term ecological change + ecological succession

• occur if abioitic and biotic components oc ecosystem are significantly altered, such as colonisation of new species or natural disaster or humans

• may change abitioc and biotic components sm that conditions are more suitable for other speicies

• slowly and permamenyyl changes mix of species in ecosystem

• unidiractional type of change is ecological succession

primary succession

• Primary succession starts in lifeless areas without soil (e.g. bare rock, retreating glaciers, volcanic islands).

• Example: Galapagos Islands off the coast of Ecuador. (volcano underdasea)

• Wind-blown spores of lichens and mosses settle in rock crevices and begin colonisation.

• Dead lichens and mosses mix with eroded rock fragments to form simple soil.

• Soil becomes stable and nutrient-rich, allowing grasses and small herbaceous plants to grow.

• Plant roots stabilise soil and break down rock further, deepening the soil.

• Death and decay of plants add nutrients and organic matter.

• Small shrubs and animals colonise the developing ecosystem.

• Mature soil forms, enabling the growth of trees dispersed by animals.

• After hundreds of years, a rich, stable climax community develops from bare rock.

secondary seccession

• Secondary succession occurs in already mature ecosystems after a disturbance (natural disaster or human activity).

• Example: wildfires causing large, random loss of life.

• Surviving species result from chance, not better adaptation (genetic drift event).

• Begins with germination of wind-blown and surviving underground seeds.

• Warm, nutrient-rich soil with ash promotes rapid plant growth.

• New plant populations establish quickly, forming varied communities.

• Escaped animals and new species return or migrate to the area.

• Competition among species shapes population sizes and ecosystem structure.

• Occurs faster than primary succession.

• Duration depends on disturbance size and original ecosystem stability.

compare primary and secondary succession

primary no soil, secondary yes soil

human impact COME BACK AND EDIT - UNFINISHED

• exponential growth of human population resutls in strain put on natural resources

• resources are finite are being used at faster rate than being replaced 

land clearance

• destruction of native vegetation and habitats to repurpose land

• froest size decreases as human poplation increases

• inclusdes deforestation (permanent clearance of trees from forests)

• results in habitat destruction - main contributing factor for endangerment or extinction

• can also cause habitat fragmentation - occurs when natural forests are broken into smaller patches that cant sustain communities and rich biodiversity

reasons to maintain natural vegetation

• provide range of habitats maintaining species diversity

• provide vegetation with deep roots which maintian water table levels and prevent soil salinity

• help maintain and protect soil from erosion

• absorb CO2 (greenhouse gas) and produce O2

• help maintain regional rainfall patterns

• help reduce no. of weeds and feral animals

habitat fragmentation (australia specific)

• temeprate woodlands most threatened type of ecosystems in aus - 80% cleared

• high no of theread native animals and plants

• environmental impact of clearing - no old trees mean birds dont have nesting sides, individual species beingg threatened/destroyed means chain reaction affect to biological processes (and food webs)

• domestic animals grazing means less food

• loss of native grasses means no food - ideal conditions for other species - breaking down remianing woodland habitat

• gragmenred patches/islands of native vegetation created - if small, cant sustain important exological processes as effectively

• causes decline in species diversity

• leads to rise in water table and soil salinity problems when deeprooted plants are gone

introduced species

• invasive or extoic

• compete with native species for habitat and resoruces or directly feed on them

• two species with identical niches cant live togehte rin a community, one will have competitive advantage and survive other extinct

• competitive advantages - larger fundemental niche, lack of predators, haster rproduction rates

• e.g. feral cats, dogs, foxes, rabbits, pigs, goats, cane toads, camels, rats

cane toads (ugly mfkers)

• native to central and south american countries

• introduced in hawaii and bought to QLD to be bilogicla control agents for cane beetles

• uncsuccessful biological control - introduced species ate more than just cane beetles

• has virtually no natural predators, spread over huge areas of Aus

• signigicant impact on biodiversity

• predators die after ingesting cane toad because they have poisonous glands on back

feral cats

• same species as domestic cats but live and reproduce in wild, survive by hunting or scavenging

• introduced by european settlers as pets

• produce 3 litters of kittens a year (rapid population increase)

• 5-23 mil in aus, inhabit 99.8% of australian aldn

• kill more than 2.6 billion animals every year

• main threat to australian biodiveristy - credible threat to over 200 native species, contribtued to extinctino of more than 20 mammal species already

• need to reduce number of them (culling)