biology yearly

8/11/2019 Biology Yearly

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Biology Module 1 A Local Ecosystem

1.The distribution, diversity and numbers of plants and animals found in

ecosystems are determined by biotic and abiotic factors

Identify the factors determining the distribution and abundance of aspecies in each environment

Distribution refers to the region where an organism is found.Abundance refers to the number of individuals in the area and is usually described asa density.

Aquatic - There are several abiotic factorsthat affect abundance and distribution oforganisms in aquatic environments including:

o Pressure Variations ranging from low pressures in surface waters to extremepressure in deep ocean trenches.

o

Light penetrationplants need adequate light for photosynthesis. This is truein both environments (aquatic and terrestrial). In water the light is only able topenetrate to a certain depth. Water doesnt absorb all light. About 30% is

reflected off the surface. At certain depths water absorbs different wavelengths(what we see as colours). Water absorbs the wavelengths that a majority ofplants use for photosynthesis extremely quickly. This means that as the depthincreases not only does the light penetration decrease, the quality of the light

decreases as well.

o The salt concentration of the water Marine organisms are suited to aspecific type of water (ranging from the extremely salty Dead Sea to freshwater

which has almost no salt) and if they were to be placed outside this they would

die (due to osmosis)

o Temperature The range of temperature is important as well becauseorganisms prefer to live in certain temperatures ranging from hot springs throughwarm tropical seas to freezing Antarctic oceans.

o Gas Availability This ranges from small amounts of gas available in warmerwaters to plentiful amounts of gas in turbulent waters of oceans and cold streams

Terrestrial There are several abiotic factorsthat affect abundance and distributionof organisms in aquatic environments including:

o

TemperatureMost organisms prefer to live between 0 45 degrees

o Soil compositionMany species only prefer specific soil types.

o Rainfall patterns Many organisms will only live in areas where the rainfall is

specific to their needs. If the organisms prefers high rainfall and humidity it willlive in areas where these conditions are prominent.

o Altitude increasing altitude results in colder temperatures, reduced rainfall anddecreased pressure which are specific factors that affect the abundance anddistribution of the organism.

o Availability of saltsin the soil there must be specific salts for the plants.Plants will only thrive if there are those specific salts available.


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There are also other factors that affect distribution and abundance of both aquatic andterrestrial organisms including:

o Availability of resources and Limiting factors A limiting factor is a singleresource that determines the maximum population of a specific species in thatarea. In aquatic environments this could be factors such as food resources. The

amount of food available will determine the abundance of the organism in thatenvironment.

o Competition Competition for resources from both the same species and otherspecies for specific resources can alter the abundance and distribution of that

aquatic organism in that particular environment.o Predation This is when one organism consumes another. If a species has

numerous predators in its environment, its abundance and distribution will

fluctuate.

o Ability to mate This refers to the organisms ability to reproduce efficiently. Ifthe organism reproduces extremely quickly its distribution and abundance arelikely to rise dramatically whereas if it was the opposite the distribution andabundance will remain steady.

o Chemical Factors such as pH of the soil

o Dynamic Factors such as wind speed and patterns, wave action. These arenatural factors that will affect the organism and its environment.

describe the roles of photosynthesis and respiration in ecosystems

Photosynthesisis the process by which plants take carbon dioxide and water and withthe use of sunlight convert it into glucose and oxygen.

6H2O + 6CO2 Light C6H12O6 + 6O2

Photosynthesis is significant in any ecosystem because it produces the chemical energyneeded for all ecosystems to survive. The ultimate source of all energy on Earth is thesun. Plants use chlorophyll to capture some of the suns energy in photosynthesis. This isvital because this energy is then able to flow through the ecosystem for survival. Thus

the ecosystem depends on plants conducting photosynthesis.

The overall role of photosynthesis is to provide energy for all other organisms in theecosystem. The plants conduct photosynthesis to store energy. The plant gets eaten byan animal and part of the stored energy (about 10%) is passed on to the animal and soon. In ecosystems there is no re-use of energy. It is either used by the living thing orlost as heat. Because of this, a continual input of energy is required to keep living

systems functioning and that is the ultimate role of photosynthesis.

Respirationtakes place in the mitochondria of all living cells and results in the releaseof energy for organisms to use. Glucose if broken down in the presence of oxygen to

produce carbon dioxide and water and in doing so energy is released. Energy in the formof ATP (adenosine tri-phosphate) is released as heat from this process and is used forcell functions such as growth, repair and maintenance.

The role of respiration is to remove oxygen from the air, return carbon dioxide to the airand provide energy for the organism. Thus, organisms respire in order to carry out dailyactivities. The role of respiration is to used the stored energy within an organism to carryout its daily functions. Without respiration, an ecosystem wouldnt function as none ofthe organisms would be able to use the energy they had stored which means they would

die.


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Identify the general equation for aerobic cellular respiration and outlinethis as a summary of chain of biochemical reactions

Aerobic cellular respiration is respiration that occurs under the presence of oxygen.Respiration involves a series of chemical reactions. It is a controlled process, occurringas a sequence of about 50 different chemical reactions, each one catalyzed by a different

enzyme. Energy is released slowly in small amounts. The chemical energy is stored inthe bonds of complex organic molecules and is released when these bonds are broken.The energy is transferred to the energy carrier molecule ATP.

ATP is the energy store of the cell. When the energy is available , ADP (adenosine) di-phosphate) collects it. When the energy is needed, ATP supplies it. In fact, respirationcan be thought of as the process by which ATP molecules are made in a cell.

ADP + P + glucose + oxygen many reactions carbon dioxide + water + ATP

38ADP + 38P + C6H12O6 + 6O2 Many reactions 6H2O + 6CO2+ 38ATP

2. Each local aquatic or terrestrial ecosystem is unique

Examine trends in population estimates for some plant and animal species

within an ecosystem

Transects can be used to determine the distribution of an organism.

Transects - A transect is a narrow strip that crosses the entire area being studied, fromone side to the other. Transects provide an accurate and easy method of representing anarea. Plants are usually the subjects of transects, but the distribution of extremely slow

or non-moving animals can still be calculated. There are two types of transects - plan

sketch and profile sketch. A plan sketch is an aerial or surface view of a representativearea within an ecosystem. A profile sketch is a side-on view of an area showing to scalethe distribution of organisms along a line.

There are numerous ways of estimating populations through the use of samplingtechniques. These techniques are used if it is too difficult to count the exact number ofspecies or if only a round estimate is sufficient.

Quadrats - It is much easier to calculate the abundance or population of plant speciesbecause they the stay in the one place. Quadrats are squares (the size of which depends

on the organism - the larger the organism the larger the quadrat) which are randomlyplaced in the area that is being studied. The number of organisms within the quadrat is

counted and this can be used to determine the percentage cover of the organism withinthat area. For example, if the abundance of grass was calculated to 54% of the total

area. And it was known that approximately 1000 blades of grass covered 1 square metreand the total area was 10 meters squared, the population of the grass could beestimated to be approximately 5400.

Capture-Mark-Recapture This is a method which involves catching a certain numberof individuals of a particular species, marking or tagging them in some way. They arethen released into the wild and then at a later time a group of the same species is

caught and the number that were already tagged is recorded. This is then repeatednumerous times. This method is appropriate for mobile organism where it is virtuallyimpossible to count all individuals at one time.


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The formula used to estimate the population goes as follows:

Number Captured X Number Recaptured

Number Marked in the recapture

SamplingTechnique

Advantages Disadvantages

Transects - Provides a quick, easy and inexpensivemethod for measuring species occurrence.- Minimal Disturbance to the environment

- Only suitable for plants or slow moving animals- Species occurring in low numbers may bemissed.

Quadrat - Easy and inexpensive- Minimal disturbance to the environment- Can also be used to determine distribution

- Only suitable for plants or slow moving animals.

Capture-Mark-

Recapture

- Simple method that provides an estimateof abundance for animals in largepopulations that are difficult to count.

- Only suitable for mobile animals- Time consuming- Can be disturbing to the environment

identify examples of allelopathy, parasitism, mutualism and commensalism inan ecosystem and the role of organisms in each type of relationship

Allelopathy This is the process by which plants are able to produce allelochemicals(also called biomolecules) which they release into the environment. Theseallelochemicals inhibit the growth of other plants in the area surrounding the plant, thusreducing competition for the plant, which increases the chances for the plants survival.

Not all plants have allelopathic tendencies. Since space is crucial to the survival ofplants, those that are able to produce effective allelochemicals are extremelyadvantaged. Since the fewer the plants around, the more water the plant can absorbfrom the soil, and more soil for stability and more sunlight to absorb.

Examples of allelopathy:

1) Eucalyptus leaf litter Eucalyptus trees foliage are able to produceeffective allelochemicals. When the leaves of the eucalyptus tree fall onto the ground,they decompose. During the decomposition of the leaves, the allelochemicals (in the

form of acid) are released into the soil and these inhibit the growth of other plants inthat area.

2)Sorghum species (cereal grass) release a chemical in the root exudatesthat disrupts mitochondrial functions and inhibits photosynthesis.

Symbiosis: Term used for interactions in which two organisms live together in a closerelationship that is beneficial to at least one of them.

There are three types of symbiotic relationships:

1)ParasitismThis is where one species benefits where as the other is harmed. A

parasite obtains food and shelter from the host organism. They feed on the tissues orfluid of the host but do not usually kill it, as this would destroy the parasites food supply.Ectoparasites are those that live outside the body of the host, whereas endoparasiteslive internally.

Examples of Parasitism:

Tapeworms live attached to the lining of the digestive system of their hostanimal and absorb digested food without causing any serious harm,however, the animal does become weaker and slightly sick.


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Ticks and fleas feed off the blood of dogs. They are benefiting whereas thedog is being harmed and it tries to scratch them to get rid of them.Fleas/ticks may result in the dog becoming extremely ill and even death.

2) Mutualism this is where both the organisms in the relationship benefit.

Examples of Mutualism

The relationship between the anemone and the clown fish (also known asthe anemone fish). The clown fish attracts prey to the anemone and as the

prey approaches they are stung by the tentacles of the anemone. This thusprovided food for the anemone. The clown fish feeds on the remains of theprey and it receives protection from predators and also food. The anemone

is able to obtain its feed this way as well as be cleaned by the clown fish.Thus it is mutualistic. Note:the clown fish becomes immune to anemonessting by brushing itself on the tentacles.

The ant plant has a mutualistic relationship with a species of ant. The plant

has a swollen bas in which the ants are able to build their colony. The antscarry corpses and excreta to parts of the chambers within the plant. This

allows the plant to absorb the waste nutrients.

3) Commensalism This is where one species benefits and the other is unaffected.

Examples of Commensalism

The relationship between the remora fish and the shark. The remora fishattaches itself to the shark and thus is able to get a free ride and feed from

scraps from the sharks food but appears not to benefit the shark.

Barnacles and whales. Barnacles attach themselves to the surface of thewhale. They are able to be transported to diverse areas rich in food. Thewhale however is unaffected.

describe the role of decomposers in ecosystems

Decomposers, or SAPROPHYTES, are organisms that obtain energy by breaking down the

dead bodies of other organisms or their wastes (eg. faeces). Decomposers return

nutrients into the soil so that they can be re-used.

define the term adaptation and discuss the problems associated with

inferring characteristics of organisms as adaptations for living in aparticular habitat

Adaptationare inherited characteristics of organisms that increase the chance ofsurvival of the species. Adaptations are also often described as characteristics oforganisms that are suited to the organisms habitats.

Adaptations can either be structural, behavioral or physiological. Structuraladaptations are the physical characteristics (anatomy) of the organism to help it survive(eg. For a spider, its eight legs is an adaptation because it allows for agile, nimble

movement). Behavioral adaptation is the way an organism will act that increases itschance of survival. (e.g. When you wear a jumper because it is cold outside). A

physiological adaptation is one that is related to the internal functioning of the organism(eg. A kangaroo will be able to produce two types of milk for its joeys which are ofdifferent ages).


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It is sometimes difficult to infer that the characteristic of an organism is an adaptation toits particular habitat because:

- The organism may be observed outside the habitat in which it evolved, forexample, in a suburban garden.

-The characteristic may provide no particular advantage in a particularhabitat but has been inherited from ancestral organisms that inhabiteddifferent habitats.

- It may simply be difficult to be certain how a particular characteristic helps

a species to survive.

describe and explain the short-term and long-term consequences on theecosystem of species competing for resources

When in competition two organisms use one or more resources in common, such asfood, shelter and mates. The competition is so the organism can acquire a limited factor

in the environment. Organisms may compete with members of their own species ormembers of other species. Competition between members of the same species is knownas intraspecific competition. Competition between members of different species iscalled interspecific competition. Usually interspecific competition is less intense than

intraspecific.

There are two types of competition:

Resource competition where the organisms utilize a resource that is inshort supply

- Interference competition where the organisms harm each other while

obtaining a resource, even if that is not in limited supply.

Biology Preliminary Evolution of Australian Biota

Evidence for the rearrangement of crustal plates and continental drift indicates that Australia was once partof an ancient super continent

identify and describe evidence that supports the assertion that Australia was once part of a landmasscalled Gondwana, including:

matching continental margins position of mid-ocean ridges spreading zones between continental plates fossils in common on Gondwanan continents, including Glossopteris and Gangamopteris

flora, and marsupials similarities between present-day organisms on Gondwanan continents

Matching Continental Margins

The continental margin is the zone between the ocean basin and the mass of the continent. The continental shelf is

the area underwater from the shore to the continental margin. If the continental margins of the continents in thesouthern hemisphere are aligned like a jigsaw, you can reconstruct the great southern landmass Gondwana, whichformed when Pangaea split around 150 mya.Gondwana consisted of the present day continents South America,Australia, Africa, India and Antarctica. When the continental margins are aligned, it is important that rock types androck structures also align.


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Sec 3: Continuation of species has resulted in part, from the reproductive adaptations that have evolved inAustralian plants and animals.

Distinguish between the processes if meiosis and mitosis in terms of the daughter cells

produced.

Spindle forms on the equator the cell which is

able to pull the chromosomes away

Chromosomes are attached via a centromere.

Spindle retracts after the

chromosomes are in their desired

location.


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Meiosis is a type of cell division that produces gametes. Gametes are sex cells and have half the normal number ofchromosomes. Mitosisis the process in which the cell nucleus divides into two.

There are some similarities between meisos and mitosis. However meisois involeces two cell divisions and produces4 haploid daughter cells (called tetrads) while mitosis involves one cell divison and produces two identical daughtercells. Mitosis occurs in all living things while meisosis occurs only in organisms that sexually reproduce.


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Internal fertilisation

In an aquatic environment

Internal fertilisation is not a necessary adaptation for most aquatic species; however, it is a successful method offertilisation in this environment. Fewer gametes are required because of the higher chance of the gametes uniting.

In a terrestrial environment

Internal fertilisation has only been possible on land because of overcoming the need for water for fertilisation. Thismethod of fertilisation is very successful as the mechanism for direct transfer of gametes avoids dehydration and loss by

dispersal, so fewer female gametes are required. The success of this form of fertilisation is very high as the environmentis enclosed in a confined space protecting from predation and disease. Even the driest environments can be colonisedsuccessfully by using this method.

describe some mechanisms found in Australian flora for:

pollination seed dispersal asexual reproduction

with reference to local examples

Pollination

Pollintion is the transfer of pollen from an anther to a stigma in flowering plants ( angiosperms) and from make tofemale cones in conifers (gymnosperms).

Parts of a Flower:

There are two types of pollination:- Self pollination- Cross pollination

Self Pollination:

In some Australian plants the pollen matures and the anthers split open releasing the pollen which is usually deposititedon its own stigma. This is self-pollination. In many species the stigma and anthers of a flower mature at different stagesto prevent self pollination as it is underisable for evolution.

Example: Daisy and Sun orchids self pollinate

Cross Pollination:

When pollen from a flowers anther pollinates a flowers sitgma from a different plant, the process is called cross-pollination.

Gymnosperms have only one method of cross pollination and that is wind. Wind pollination occurs in these plants whenthe anther which is usually long released the very light pollen. They usually lack nectar and scent and the large stigmas

are well exposed inorder to catch the airborne pollen. Example: Native pines and grasses use wind pollination.


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Some angosperms use wind pollination but many have evolved to use differing methods ofcross-pollination

1) Insect Pollination

Most flowering plants are pollinated by insects especially bees. In many cases, the insect and the plant are dependanton each other the plant needs a pollinator and the insect needs food. To attract the insects the flowers have a scent,colour and specific arrangement of petals. The petals often have marks called honey guides to guide the insect tothe stigma where they depost pollen from the last flower they visited and then to the stamen to collect new pollen andthen to the nectar for the reward. The filaments holding the anther are short and stiff so that pollen can be transferredwhen the insect brushes past.

Example of an insect pollination plant is the bottle brush or the eucalyptus.

2) Bird Pollination

Birds usually pollinate red flowers. Many flowers are long and thin and only the beaks of honeyeaters can reach thenectar. The pollen can be sticky or powdery and large amounts of nectar are produced.

Examlpe of a bird pollination plant is the Waratah. Waratah flowers are red, long, tubular and slightly curved; their rate

of nectar production is relatively high and they are commonly visited by nectar-feeding honeyeaters.

3) Mammal Pollination

Mammals such as bats and tiny honey possums pollinate flowers. The possums move over the flowers.

For example: Banksias allow for the honey possum use their long thin snout to reach the nectar. The pollen sticks totheir fur, which is then transferred to another plant.

4) Pollination by deceit

There are some orchids whose flower mimic the shape and colouring of female insects. The mimics are so realistic thatthe male insects will attempt to mate with the flowers, thereby pollinating them.

For example: The hammer orchids of Western Australia have a flower that resembles a wingless female wasp with shinyeyes, hairy thorax and a fat body. The flower is held outwards by a hinged arm. When the male wasp attempts to

copulate with the flower. The hinged arm flings the wasp to the other end of the flower (the stigma), where the pollen isdeposited. Pollen is located on the flower.

Seed Dispersal

After successful pollination and fertilisation of the flower, the seed develops. It is an advantage for a plant to spread or

disperse its seeds over a wide distance. This prevents overcrowding from occurring within the same plant species andincreases the chances of survival in situations of environmental change such as fire.

Seeds are dispersed by wind, Animal, fire, water or explosion.

1) Wind Dispersal

Some seeds are aerdynamically designed to be blown long distances by the wind. Very small seeds can be carried bythe wind. If the seed has food reserves it can be heavier but still dispersed by the wind if it has wings or a parachute orsome other form of buoyancy mechanism.

For example: Dandelions have feathery parachutes to catch the wind and float away and Hakea has a seed with wings.

2) Animal Dispersal

There are several mechanisms that are used in seed dispersal.

- Some seeds are hooks or burrs with bristles and spines to attach to fur and feathers. Eg. Bindii


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- Other seeds are in fuits and berries which are eaten by the animal. The seed is protected by an indistestiblelayer which passes through the digestive system unharmed to be dropped onto the ground at some other point.

For example: Mistletoe berries are eaten by the mistletoe bird and farily quickly the sticky seed is expelled by the bird

onto a tree branch, where the plant begins to grow. The deposit with feaces adds nutrients for the plant to grow.

3) Fire Dispersal

Several Native plants such as Eucalyptus only release their seeds after the occurance of a fire. After a fire, theeucalyptus is destroyed, exposing the capsules which release the seeds for dispersal usually by the wind. This providesa significant advantage as the seeds grow in a uncompetitive environment, allowing for them to flourish.

4) Water Dispersal

Some seeds rely of water dispesal, such as the water gum and mangrove. Seeds may float small or large distances fromthe parent plant along rivers and even across sees. The seeds are usually equipped with some sort of flotation devicethat allows for their protection.

5) Explosion

Some seeds are voilently propelled from the base of the fruit in an explosive dischanrge. Seeds are ejected from thepod at high speeds, caused by the drying and contraction of the pod. Some seeds such as the pea plant seeds can behurled almost two metres in the air. This allows for greater dispersal of the seeds.

Asexual Reproduction

Asexual Reproduction is the making of a new individual without the use of sex cells or gametes. Only one parent isrequired for the mitotic cell divisions to occur.

Some types of asexual reproduction are:

- Binary Fission - Bacteria

-

Budding Coral and Yeast- Spore formation Fungi and moss- Vegetative propagation roses (plant cuttings regenerate)- Fragmentation and Regeneration Starfish- Parthenogenesis Honeybees and Gecko

Vegatative Propagation

In vegetative propagation parts of the parent detach and will grow into new individuals.

The advantage of VP is that less time and energy is needed to produce new individuals the need for pollinators,pollination, fertilisation and the production of seeds + dispersal is removed.

The disadcabtage is the lack of genetic diversity. This is not a problem when the environment is stable but the lack of

variation reduces survival chances for the evolution if the environment changes.

The new plant is simply regenerated out of one of four parts stolons, tubers, rhizomes, and suckers.

Stolonsor runners are stems that grow along the sruface producing new roots and leaves at nodes. Spinefex grass or

strawberry plants are an example of this

Tubersare swollen underground stems that store food and new plants can grow from the tuber. For example, a potatois a tuber and they eye of a potato are the buds which can each grow a new plant

Rhizomes are underground stems that give rise to new shoots at the nodes. Ginger and grasses employ this techniquein order to reproduce.

Suckers are new shoots that arise from undergrouynd stems, often after fires. Certain types of pea plants or fanflowers are able to reproduce in this manner.


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