Biology Semester 1 Exam Flashcards

Question

Collaboration

Answer 1

- Is when the same species work together for the benefit all - Intraspecific: relationship between the same species - Interspecific: the relationship between members of different species

Answer 2

- Energy is the capacity to cause change , particularly to do work and it can exist in many different forms such as heat , light and chemical - The sun provides the most of earths energy - Producer conduct photosynthesis so they are able to transfer energy to consumers to use for respiration and movement - The chemical energy stored in plants as organic matter can be measured and called biomass

Answer 3

- The process by which plants use sunlight water and carbon dioxide to create oxygen and energy in the form of sugar - Only producers can perform this task - 6CO2+6H2O→C6H12O6+6O2. - Sun is the source of all energy - Plants are the only ones with chlorophyll - plants take in carbon dioxide (CO2) and water (H2O) from the air and soil. -

Answer 4

- cellular respiration, the process by which organisms combine oxygen with food molecules , diverting the chemical energy in ATP ( stored from of energy ) and carbon dioxide and water. - C 6 H 12 O 6 + 6 O 2 --> 6 CO 2 + 6 H 2 O - ATP is formed and is stored energy form - Helps with synthesis , growth , repair , reproduction , maintaining temperature, mechanical work, and chemical work - Only in consumers

Answer 5

- Biogeochemical cycling: refers to the pathway of matter through living components ( organism ) and non-living organism components ( such as soil , rocks and water ) of an ecosystem - The model describes how chemical elements such as carbon and nitrogen are transformed and stored in both biological and geological components - Recycled through biological food webs and through geological processes such as weathering , erosion and volcanic activity - The water cycle is important especially as water provides a habitat for a diverse range of living things and it the medium for most biological reactions to take place

Answer 6

- Allow ecologist to monitor the sustainability of feeding relationships in a ecosystem - Producers: plants are autotrophs are they are able to make their own food by transforming light to energy from the Sun using photosynthesis. ( eg. Grass ) - Primary Consumer: they feed on producers and the energy is transfer up ( example: grasshopper) - Secondary Consumer: they feed on primary consumers and the energy is transfer up ( example: fox ) - Tertiary Consumer: they feed on secondary consumer and the energy is transferred out of the pyramid , they often die of old age or diseases ( eg bald eagle ) - Scavengers: are animals that feed on the dead remains of other animals - Detritivores feed on the detritus and help speed up the process of decay by breaking down into smaller pieces - Decomposers: continue the process by breaking down the complex organic material into simpler inorganic matter and returning it back to the soil

Answer 7

- The nitrogen cycle is a balance is maintained between processes that withdraw nitrogen from the atmosphere and those that add nitrogen to the atmosphere - Nitrogen is an essential nutrient for plant growth

Answer 8

- Is the conversion of atmospheric nitrogen in nitrates - 3 ways: Lightning , soil bacteria , root nodule bacteria in legumes - Lightning ( atmospheric nitrogen fixation ) : causes nitrogen to combine with oxygen present in air to form nitrogen oxides - Root Nodule ( biological nitrogen fixation ) – by rhizobium baterica they infect the roots of the leguminous plants, leading the formation of nodules -> batercia takes up atmospheric nitrogen and convert it nitrates, at the nodules

Answer 9

- Is the process by which inorganic nitrogen compounds are converted into organic compounds and absorbed by living organism - These amino acids combine to form protein which are found in the fruit of the plant. - Fruits are eaten by Herbivores, then eaten by carnivores therefore nitrogen is passed down

Answer 10

- Is the decomposition of organic nitrogen into ammonia - The decay process converts their remains which contain protein into ammonia and ammonium compounds.

Answer 11

- Is the conversion of ammonia into nitrates - Ammonia is apart of the soil - Bacteria converts ammonia into nitrate

Answer 12

- Is the conversion of nitrates into free nitrogen - Denitrifying bacteria are acted upon as nitrates are a part of the soil

Answer 13

- Is constantly moving between different forms throughout the biosphere - It is stored in reservoirs - Its through: photosynthesis, respiration a ocean repiration - Is when carbon is exchanged between the biosphere, geosphere and hydrosphere - Removed from the atmosphere: photosynthesis and dissolving carbon dioxide into oceans - Added: burning of fossil fuel and plant respiration

Answer 14

Combustion: - Our cars use energy released by burning fossil duel - Carbon and carbon dioxide is a pollutant - Combustion involves burning them to release energy but a by-product of combustion is that releases carbon dioxide back into the atmosphere - Too much carbon dioxide increases the greenhouse effect - We deplete our oil reserves by adding the carbon cycle with an imbalance of oxygen and carbon

Answer 15

Photosynthesis: - Plants pull carbon dioxide out of the air through photosynthesis - With carbon and water , photosynthesis produces sugars like glucose to make their own food - It fuels all living things as source of energy

Answer 16

- Humans consume plants therefore there is transfer of carbon dioxide which our cells break down as we consume called cellular respiration - Once consumed the carbon dioxide is released into the air through cell respiration and can be used for photosynthesis again

Answer 17

Carbon Dioxide dissolves in the ocean: organism like phytoplankton use the Carbon dioxide for photosynthesis and produce oxygen. This oxygen can be used for respiration by other marine organism. This take place in the upper ocean. In the deeper oceans, dissolved carbon dioxide can also be used to form carbonic acid which turn is used to form the calcium carbonate which is used by the marine organisms to create hard shells. The calcium carbonate can precipitate and form sediment, which over time can become limestone rock

Answer 18

Ecological niche: the way is which species function within their environments – for example what they feed on , what time they feed , where they live and when they reproduce ( spatial habitat )

Answer 19

- Food sources and feeding activities - Habitats - Reproductive site and reproductive behaviour - Relationship with other species in the community - Abiotic factor

Answer 20

- Is the ideal niche a species would occupy if there were no competition , predators and parasites

Answer 21

- Is must narrower - It results from an organism’s inability to exploit the resources of its habitat because its restriction causes by other organism - Restriction such as species not distributed evenly

Answer 22

The division in the use of resources to reduce competition

Answer 23

: postulates that no two species can occupy the same niche in the same environment for an extended period of time - Russian ecologist: G.F Gause in 1934 - He concluded that two species , competing for the same resource cannot coexist in the same community - Note that two ecologically similar species can coexist in the same community if they have one or more differences in their niche

Answer 24

- Birth rate - Death rate - Migration

Answer 25

Keystone species: not necessarily abundant in number in food web but can exert a larger effect on population numbers of other species in the community

Answer 26

- Role: nutrient recycling , seed dispersal , predation - Developed by Robert Paine based on his removal experiments - Essential in the re-establishment of ecological structure - It has often considerably low abundance and biomass compared to dominant species

Answer 27

- Kill mature trees - Robs eocsystems of their vegetation diversity - Reduce food resources for wildlife - Loss of healthy mature woodlands - Grasslands implicated in decline of goannas, snakes , seed-eating birds such as Gouldian finch and some mammals - Reduction in soil fertility , habitat displacement and vegetation diversity

Answer 28

- Deforestation is when humans remove or thin forest for lumber or to use the land where tree stood for crops , grazing or development as the population increases and people migrate - Pushing some of WA vulnerable wildlife to extinction , habitat displacement - The fertility of the soil will decrease creating more chances for soil erosion

Answer 29

- Invasive species are animals or plants from another region of the world that don’t belong in their environment - Affect: loss of alteration of native habitat - Immense damage to our soils - Also increases the competition for food

Answer 30

- Are resources that will eventually run out ( eg like fossil fuels ) - Leads to habitat loss - Agricultural conversion and urbanization - Changes in diversity of species

Answer 31

- Is the practice of collecting , processing and saving native seeds for conservation - Seeds can be stored long term to preserve threatened species and to restore biodiversity - This increases genetic diversity to build a more stable ecosystem

Answer 32

Reduce invasive species - Conventional techniques include fencing , trapping , position, and shooting - Species such as cane toad that non-native who is introduced into the Australian ecosystem - Disrupt the native ecological balance with high levels of reproduction , increased competition and lack of resources

Answer 33

Revegetation - Is process of replanting vegetation and rebuilding the soil of disturbed land for rehabilite or protect degraded land - Prevent further soil erosion and Reducing wind erosion

Answer 34

- Bee are important to preserve biodiversity and they are always under attack and by planting nectar-producing wildflowers in your backyard can protect these pollinators - Remove harmful pesticides from the backyard - Or even bee box for local bees to call home -

Answer 35

Wildlife Conservation - Implementing programs to protect endangered and threatened species can help to maintain biodiversity. - This can include captive breeding programs, habitat restoration, and monitoring of populations to prevent over-harvesting or poaching. Examples including FHPA - which is Fish Habitat Protection Area which protection range of organism from the WA Fisheries, examples like this will help the future generation of the species of fishes as they will be able thrive

Answer 36

- Title - Scale - Key - Independent variable: - Dependent variable: - Equal distribution of number - Labelled subtitles

Answer 37

Food Chain: arrows in straight line Food web: messy and arrows

Answer 38

an ecosystem consists of a community and it environment ( the biotic and abiotic factors in a given area ) and the interactions between them

Answer 39

Can be sustained over long periods of time

Answer 40

stress in the form of extreme conditions: - flood - droughts - invasive species - disease - overexploitation > overall shows resilience

Answer 41

human impact on biodiversity and ecosystem increase

Answer 42

increase in human population increase food consumption increase in human impact

Answer 43

increase in human population increase in fuel usage ( wood then coal ) increase human impact

Answer 44

increase in human population increase in knowledge and life expectancy increase in human impact

Answer 45

it has a minimum of 1500 vascular plants that are not found in any other region on earth it has suffered at least a 70% reduction in its original natural vegetation

Answer 46

harmful fire regime habitat destruction cat and fox introduction predation spread of disease ( phytophthora< dieback )

Answer 47

habitat are environments in which species normally live

Answer 48

urbanisation manufacturing agriculture forestry mining fishing

Answer 49

is a human activity that greatly impacts ecosystems

Answer 50

is a human activity and is the greatest threat to biodiversity

Answer 51

Urbanisation is the extreme modification of an ecosystem by humans to support a human population of gradually increasing density; often, this happens as more people migrate to towns and cities from rural areas.

Answer 52

Urban ecosystems have reduced biodiversity and are dominated by people

Answer 53

There is little recycling of matter between the community (the living things present) and the non-living surroundings. Additional inputs of energy and matter are needed from other ecosystems to maintain modern standards of living

Answer 54

Agriculture is the practice of farming; cultivating soil, growing crops, raising animals, preparation of plant and animal products for market

Answer 55

Many animals and plants have lost their habitat due to land clearing

Answer 56

Habitat fragmentation – some parts of the habitat of an ecosystem are separated into isolated section

Answer 57

Create: Habitat Fragmentation - isolation of animal groups - habitat in fragments No interbreeding between sub-populations: - no sharing of genetic diversity - loss of resilience

Answer 58

The Gondwana Link program has been working to reconnect fragmented habitats across the south-west of Australia. If the Gondwana team reach their goal, 1000 km of continuous habitat will reconnect habitats from the dry woodlands of the inner region to the tall wet forests of the far south-west corner. Traditional land managers, organisations, farmers and conservation scientists have worked together to strategically revegetate gaps of cleared land to restore the fragmented habitat.

Answer 59

Overgrazing and the hard hooves of farm animals are factors that lead to land and soil degradation. Shallow rooted plants have more of an opportunity to grow on degraded land. With significantly reduced tree cover and an increase in shallow-rooted grasses, the topsoil becomes more exposed to the effects of abiotic factors such as wind and rain. Past land clearance practices, the move to shallow-rooted pastoral grasses and the overuse of fertilisers that have affected soil organisms have placed enormous pressures on the structure of the soil and the ability of the land to hold its topsoil.

Answer 60

Salinity’ refers to the concentration of salt in the soil. If the concentration of salt in soil becomes too high, plants such as crops will no longer grow and the soil is infertile.

Answer 61

Salinity is a significant problem that can happen when natural vegetation is replaced with crops that require irrigation In many agricultural areas of WA, the underlying reason behind the rising water table is the removal of deep-rooted, perennial (long lived), usually native, vegetation.

Answer 62

Step 1: human population increases, leading to increased food consumption and need Step 2: farming increases, with further clearing of deep-rooted trees Step 3: removal of deep-rooted native perennial species and planting shallow-rooted annual crops. Deep-rooted native plants remove water from underground aquifers and use in transpiration: this balances the input and output of aquifers. The root of shallow-rooted crops do not grow down far enough to reach the watertable to access water for transpiration or evaporation Step 4: watertable rises.As it rises , salt from surrounding soil dissolves into the water Step 5: water evaporates at the soil surface, leaving behind soil that is too salty for most plants to survive.

Answer 63

Introduced species are species that humans have intentionally or unintentionally moved from their native location to a new ecological region.

Answer 64

in their new location, they are without their natural predators, parasites and pathogens, which would usually limit their growth. The rate at which they have been introduced has increased with the increase in human travel by ship and air. Many introduced animals and plants become invasive species if they manage to establish populations in new areas; out-competing natives.

Answer 65

Fox Feral Camels Cane Toad ## Rabbit

Answer 66

The use of chemical pesticides (chemical control) is a quick and effective method of getting rid of pests, but there is a downside: pesticides can be ecologically damaging as well as costly. A chemical control is a chemical such as a pesticide or poison, such as a bait, used to control the population of a pest/invasive species.

Answer 67

Biological control is another method of management, in which a species is used to control the population of a pest species. Biological control agents exploit relationships between organisms. Sometimes an integrated approach (using two or more measures) when rapid response is needed in the early stages of a pest reaching a new area. It combines the use of biological measures with the use of chemicals limited to narrow-spectrum agents that target specific species.

Answer 68

general predators specialised predators parasites microbial diseases eg caused by a viru

Answer 69

Field trials must be conducted in an isolated area to discover any unexpected effects before wide release, especially to check the risk of the biological control species becoming a pest itself. To be released more widely, the biological control species must: only target the pest species and not impact on other populations decrease in number as the pest species decreases in number not compete with native species for a resource (e.g. food or habitat).

Answer 70

Ladybirds have been introduced to Australia to battle aphids on citrus trees. This reduces the use of expensive chemical pesticides and limits the impact of these chemicals on other species.

Answer 71

Under strict regulations, invasive organisms are culled (killed) eg Australian red and grey kangaroos out-compete other species for resources in some ecosystems. Each year, more than 2 million kangaroos are culled. A small proportion of the meat is processed for human consumption, most of it for export

Answer 72

Some species are released from breeding programs back into their original or a disease/pest free environment for the purpose of building up their population. For example, Galaxias is a genus of native freshwater fish whose numbers have suffered since the introduction of the mosquitofish. Introducing Galaxias back into the wild is through finding uninfested waterways or artificially created ponds that have no linkswith infested water bodies.

Answer 73

Unsustainable use of natural resources – using resources more quickly than they can naturally be restored – has a huge effect on biodiversity.

Answer 74

Overharvesting means harvesting a species at a rate that exceeds the replenishing rate of the population

Answer 75

Organisms that have low reproductive rates, such as the African elephants (often poached for their ivory tusks), are especially vulnerable to overharvesting. This is because the sum of new individuals from births and immigration does not exceed the total individuals lost to death plus emigration.

Answer 76

There is competition for their use: for food, recreation, transport, commercial livelihood and as a repository for our wastes. Particularly by over-harvesting, commercial fishing has reduced the populations of many species, some almost to extinction. Shark numbers, for example, are at an all-time low. The reduction in populations of these and other fish affects other species through disruptions to food chains. Penguins and seals, for example, now compete with the fishing industry for food.

Answer 77

PROBLEM: by-catch The by-catch (undersized and over-sized fish caught and discarded) poses problems for species that are fished commercially. As populations of fish (such as the valuable snapper) decrease, there are fewer fish reaching reproductive age to sustain population growth PROBLEM: bottom trawling Destructive to ocean ecosystems; involves dragging a large net across the seafloor. Deep-sea fish species are targeted globally, but bottom trawling is known to also remove vast amounts of non-target species, including habitat forming deep-sea corals and sponges.

Answer 78

In WA, recreational fishing licences and fishing seasons are compulsory and are used to control fishing levels

Answer 79

Eutrophication is a process that occurs when excess nutrients, particularly nitrogen and phosphorus, enter a body of water and become highly concentrated, leading to excess growth of organisms such as algae

Answer 80

2. The fertilisers are usually enriched in nitrogen and phosphorous 3. Excess nitrogen and phosphorous not absorbed by roots are often leached from the soil by run-off (rain water or irrigation). 4. The run-off can reach local water bodies such as lakes and cause algal blooms 5. An algal bloom is a rapid increase in the population of algae or other microorganisms at the surface of a water body that blocks sunlight from entering. When this happens, autotrophs that live under the surface die. 6. Algae die and are decomposed by bacteria. 7. As bacteria consume the dead algae, they use large amounts of oxygen from the water, which depletes oxygen levels. The water can become hypoxic (low in oxygen) and possibly anoxic (completely devoid of oxygen). 8. The low oxygen levels do not meet the respiration needs of aquatic organisms, so fish and other populations die

Answer 81

Biomagnification is the sequence of processes in an ecosystem by which higher concentrations of a particular non-biodegradable chemical are reached in the tissues of organisms higher up the trophic levels

Answer 82

Biomagnification occurs because the biomass at any given trophic level is produced from a much larger biomass ingested from the trophic level below. The concentration of the chemical increases in the tissue at each trophic level. A classic example of biomagnification is DDT, a pesticide

Answer 83

Large amounts of the world’s plastic rubbish enter waterways. Many aquatic animals mistake plastic for food. Turtles frequently ingest plastic bags, confusing them with their prey, jellyfish. Plastic can be consumed by wildlife, causing disease and death

Answer 84

the average long-term, predictable atmospheric weather conditions at a site over a period ranging from months to many thousands of years). Climate is made up of such variables such as rainfall (precipitation), temperature, intensity of sunlight and wind.

Answer 85

the atmospheric conditions in an area over a short time, usually 2–3 days. Weather forecasts or predictions can be very unreliable. Weather is not a gauge for climate change, because it is too short term.

Answer 86

a significant change in the global climate that can be identified by changes in the average and variability of such features as temperature and precipitation, and that lasts for a long time, typically decades or longer.

Answer 87

Scientists are able to analyse samples from ancient ice cores extracted from polar ice. The layers of ice in the ice core contain bubbles of gas trapped long ago and other factors that reveal data about past carbon dioxide levels and temperature data. Scientists have been able to collect and analyse data from Antarctic ice cores to calculate estimates of average global temperatures and carbon dioxide levels spanning 400 000 years.

Answer 88

Atmospheric concentration of carbon dioxide has also risen and fallen in cycles. The cycles in carbon dioxide concentration and temperature appear to coincide. There is evidence to support a relationship between the sudden rise in concentration of carbon dioxide in the atmosphere in the last few hundred years and the rise in average global temperature.

Answer 89

greenhouse gasses

Answer 90

Greenhouse gases (gases that trap heat) are probably the most significant drivers of our climate. The human activities of burning fossil fuels and deforestation are increasing the concentrations of carbon dioxide and other greenhouse gases in the atmosphere.

Answer 91

The greenhouse effect is the insulating effect of these gases in the atmosphere, which prevent some of the solar radiation from escaping Earth’s atmosphere. The gases trap and absorb some of the heat originating from the Sun, which keeps Earth warm. The natural greenhouse effect is an essential process for maintaining Earth’s average global temperature within a range that is warm enough for humans to survive. Concentrations of greenhouse gases have increased and too much heat is being retained – the enhanced greenhouse effect.

Answer 92

essential process for maintaining Earth’s average global temperature at a warm enough range for human to survive

Answer 93

concentration of greenhouse gases are increased and too much heat is retained resulting in an increase in aver

Answer 94

diagram on the chapter 6 ppt

Answer 95

Climate change is causing increased melting of glaciers and polar ice sheets, resulting in a gradual increase in sea level. Plants and animals are also affected by global climate change when the timing of seasonal events, such as flowering or pollination, is affected by global warming. As the abiotic and then biotic factors change in an ecosystem, some species experience different selective pressures affecting their survival. These could include habitats becoming unsuitable, not enough food or conditions that require fast migration. As we lose individuals and species, biodiversity declines and the result is a decline in the resilience of ecosystems.

Answer 96

increase in death rates in elderly and poor increase heat stress in livestock changes in tourist destination

Answer 97

increase in property and infrastructure loss increase in infections disease epidemics increase in risk to human life

Answer 98

the united nations educational, scientific and cultural organisation, globally supports the idenification, protection and preservation of cultural and natural heritage that is of outstanding value to humanity. eg. Ningaloo cost or the great barrier reef

Answer 99

the program targets regions that are rich in unique biodiversity ( inclusion of those rules ). There are 36 hotspots around the worlds in need of conservation eg. South-west WA

Answer 100

projects are undertaken to protect migrating species such as whales and bird. Several whale species migrate north from the Southern Ocean into the warm tropical waters off northern Australia to breed during the winter months. eg. the conservation management plan for blue whales

Answer 101

Numbats are now restricted to two small wild populations in south-west WA at Dryandra Woodland and the Tone-Perup Nature Reserve. The species is listed as endangered and there may be as few as 1000 numbats left in the wild. The numbat captive-breed-for-release program is designed to provide additional animals for release into the wild to establish new populations or to augment existing ones. Perth Zoo has been involved in the captive breeding for release of numbats since 1992. During that time, 268 captive-bred numbats have been released into the wild at nine locations in two states, resulting in the establishment of four new self-sustaining populations; three in Western Australia and one in New South Wales.

Answer 102

They were joined to form a super continent called Pangaea. Pangaea split into Laurasia (north) and Gondwana (south). Gondwana split to form the southern land masses, South America, Africa, India, Australia and New Zealand.

Answer 103

65 million years ago a catastrophic event destroyed most of life on earth. Dinosaur extinction led to the occupation of the vacant niches by vertebrates. 40 million years ago Australia parted from Antarctica and was isolated. Isolation and harsh Australian conditions led to development of unique species.

Answer 104

Changes in past ecosystems can be understood by studying regions with abundant fossils Studies on geological features can help uncover clues to the past environmental conditions Ice or sediment cores provide an excellent record of changes that have occurred over thousands, perhaps millions, of years Scientists can analyse changes in trapped gas composition to understand temperature change Organic matter – abundance of foods

Answer 105

Communities change progressively over time, one community being replaced by the next in the process of succession.

Answer 106

Catastrophic events such as volcanic eruptions, cyclones, earthquakes and tsunamis can cause the development of bare sites with no organisms inhabiting the affected area. This process, called nudation, starts a long-term process of change, involving three stages in general.

Answer 107

Changes in abiotic factors means the environment becomes more suitable for survival of new species During succession there are changes in population Biomass increases at each stage of ecological succession When a stable community is established it is know as climax community

Answer 108

when succession begin in a virtually lifeless area where soil has not formed

Answer 109

Pioneer plants arrive to colonise the area. For example: - lichens colonise rocks -mosses inhabit soils - bacteria and fungi form simple communities. These r-selected species are characterised by: - effective seed dispersal - rapid growth - rapid reproduction - producers. Small herbivores move in and new communities form

Answer 110

Through fire and flood, or human intervention by logging and land clearing for agriculture, dramatic changes to ecosystems occur. The cycling of matter and the flow of energy are interrupted as the components of the ecosystems are affected. Organisms can recolonise recently disturbed communities via secondary succession, regaining equilibrium although the number and kinds of organisms present may be different from the original ecosystem.

Answer 111

Begins with: a new area with no life: barren Soil: no soil to begin with Plants: pioneer plants Primary Productivity: lower productivity due to fewer plants ( biomass or energy ) Biodiversity: low biodiverisity for a long time

Answer 112

Begins with: begins with disturbance of an already established ecosystem/begins after primary succession Soil: soil is present at the beginning Plants: seeds and roots of established vegetation already present Primary Productivity: higher productivity due to ther being more plants and faster regrowth Biodiversity: faster development of wider biodiversity

Answer 113

Slow-growing, long-lived K-selected species: live in more stable environments than r-selected species outcompete other species are often tall established trees

Answer 114

A fire or tsunami can cause: a loss of vegetation a reduction of leaf litter a decrease in animal numbers an impact on abiotic interactions in a community.

Answer 115

Fire impacts the abiotic interactions in a community. It opens up spaces and creates a nutrient-rich seedbed resulting in secondary succession. The fire causes species such as bottlebrushes, hakeas, some acacias and eucalypts to regenerate from seed. Fire damage stimulates regrowth in other species smoke particles signal growth in others. The proliferation of new growth in a post-fire community attracts many mobile species such as wallabies, birds, small mammals and insects. The new growth sustains animals such as wombats and echidnas that may have survived the fire in underground burrows.

Answer 116

Fire regimes are determined by: - the season - the intensity of fires - how frequently fires occur

Answer 117

Fire-stick farming was used by the First Australians to clear areas of land as an aid for hunting.

Answer 118

Humans have inhabited Australia for the past20 000 years. Human impacts have included: species extinction through hunting and loss of habitat changes to the landscape through farming practices.

Answer 119

Urbanisation Habitat destruction Land and soil degradation Salinity Monoculture practices

Answer 120

Disruption of water flow Eutrophication Marine ecosystems Introduced species can become pests

Answer 121

Ecosystem models are useful representations of elements within the ecosystem, the relationship between the elements and the relationship with surrounding ecosystems. Ecosystem models are very useful for simulating and analysing the long-term dynamics and properties of complex ecosystems. They allow the use of information from different disciplines as well as analysing, interpreting and understanding field observations. This provides a basis for predictions of the impacts of changes in real ecosystems, the development of tools for management support and policy advice.

Answer 122

A population is a group of individuals belonging to the same species living in a particular area at the same time.

Answer 123

r-selected species are early colonisers in disturbed environments. As they fill the previously open spaces, they change the abiotic and biotic conditions of the environment and are soon overtaken by competitors.

Answer 124

K-selected species Larger, longer-lived species dominate Fewer offspring Outcompete r-selected species Close to carrying capacity of environment

Answer 125

Open ecosystem: migration occurs freely in response to environmental changes

Answer 126

Closed ecosystem: migration does not occur, but births and deaths still impact population size

Answer 127

Pop growth rate = (birth rate + immigration rate) - (death rate + emigration rate) = (br + ir) - (dr + er)

Answer 128

A useful method of representing collected data is the construction of population pyramids. Figure 5.3 shows population pyramids for two different human populations. You can see that the pyramid for population A is wider at the bottom indicating a healthy future reproduction rate, with the number of children quite high. Population A has a greater proportion of children than does population B. What is the significance of this? Scientific data about age distribution and sex ratios can assist in the management of populations. Each year federal, state and local governments collect and collate information on the state of wild fish stocks. It is this information that is used to determine the level of both recreational and commercial sustainable fishing. Sustainability ensures that over-fishing does not drain the stocks, and that young (smaller) fish are able to contribute to the populations in the future. This information can be used to plan how to ensure sufficient numbers of young live to reach reproductive age, how to develop strategies for protecting endangered species and maintaining ecosystems, and how to restore degraded ones.

Answer 129

Clumped (grouped) distribution: a number of individuals is grouped together and the groups make up the population as a whole. This is sometimes to do with social behaviour as in schools of fish, or clumping of vegetation in mini-habitats where biotic and/or abiotic factors are favourable.

Answer 130

Uniform (continuous) distribution: organisms are evenly spaced; the presence of one organism determines how close or distant another will be. It is common in relatively high-density populations of some animals that set up breeding territories

Answer 131

Random distribution: organisms are spaced irregularly; the location of an organism does not affect the location of another (more common for plants than for animals).

Answer 132

Direct observation Direct observation involves: Sighting, or Counting, or sampling a population

Answer 133

For each quadrat: the number of individuals of each species is counted and recorded, or * the relative numbers of each species is estimated using a scale from abundant (3) to absent (0), or * percentage cover is estimated, and * the totals of the quadrats are averaged.

Answer 134

The density can also be calculated. Estimating total population size of area under study Average density of members of species (estimated) = total number of individuals counted / area of each quadrat x number of quadrats

Answer 135

A transect is a line drawn through a community and the information gathered is used to determine the distribution of species within that community Data gathered using transects offers fairly accurate information regarding distribution of individuals and/or species; whereas quadrats offer a comprehensive picture of species abundance, but not distribution.

Answer 136

Capture–mark–recapture is used to sample mobile species. A random sample of individuals of a species is taken and an overall estimation of the abundance of the species is made.

Answer 137

Step 1 Capture: animals are caught randomly and in such a way that they are unhurt. Small animals are trapped in cages or pitfalls in the ground, birds are trapped in fine nets and some animals are caught easily when they ‘freeze’ in spotlights. Flying insects are attracted to light traps. Step 2 Mark: each captured animal is marked so that the mark is not obvious to predators or harmful to the organism. Insects are usually marked with a blob of paint, whereas birds are tagged on the leg or wing. The animals are returned to their habitat and left to mix with the unmarked individuals. Step 3 Recapture: later, a random sample is taken and the number of marked individuals counted. The timing of recapture needs to be appropriate to again capture a random mixture of individuals, but without leaving it so long that many of the original marked individuals have died. From this information the total population can be estimated. The procedure has to be planned carefully so that the chances of each individual being caught are equal. Sometimes ‘trap happy’ individuals will be sampled over and over.

Answer 138

Species distribution modelling is used to predict future needs and resource management and is a more recent technology used for conservation and management. Little Penguins on Phillip Island fitted with GPS transmitters could be used to plot their movements as they search for food. This data helps monitor their season movements in time and space. GPS tracking is also used to track the movements of migrating animals such as birds and caribou, and is most efficient when tracking water animals such as whales, sharks, sea turtles and many sea birds. The signal is received by a satellite which ensures the animals are tracked when not in sight. Radio tracking is older technology than the GPS tracking systems. In this instance, the signal is transmitted from the unit attached to the animal to a receiver, much like a home transistor radio. The animals are physically followed by the scientists who will have the receiver in a car, truck or aeroplane. The data collected determines the movements of the animals and their destination. The information is then used to determine the best management strategy to ensure the safe movement of the animals involved.

Answer 139

Density: the number of individuals in a given area

Answer 140

Carrying capacity: the maximum population size of a species that can be supported in a given environment Knowing the density of populations can help assess an ecosystem’s ability to provide sufficient resources to support its populations

Answer 141

Factors in the environment, collectively referred to as environmental resistance, act on a population. If the population rises above the equilibrium or set point, competition for resources such as food and space begins to take effect. The increased ability of disease-causing organisms and parasites to spread also increases deaths and possibly reduces breeding. This could be to such an extent that the population falls. If it falls below the set point, there is less competition and the population begins to rise again. This kind of negative feedback process, or homeostatic control, keeps the population more or less constant (Figure 5.13). Is this scenario an example of K-selection or r-selection?

Answer 142

Equilibrium Population: Increase in Population -> raised environment resistance -> negative feedback -> falls in population -> population returns to norm near to the carrying capacity of the environment Fall in population -> lowered environmental resistance -> negative feedback -> increase in population -> population return to norm near to the carrying capacity of the environment

Answer 143

Density-dependent factors include competition, disease, parasites, predation and food supply. The greater the density of a population, the more individuals die or fail to reproduce.

Answer 144

Density-independent factors, such as severe weather conditions, volcanic activity or habitat destruction by clearing or fire, are those that affect all individuals in a population regardless of age or stage. These factors are seen vividly following a catastrophic event such as a bushfire or flooding. Populations of all living things usually decrease quite drastically due to either death or emigration to a habitat that is better able to meet their needs. In some cases, populations of species are not able to recover from such extreme environmental resistance and disappear from that ecosystem, which may eventually result in widespread extinction.

Answer 145

Population survival. A combination of factors, working together, determines the survival of populations. There are patterns in survivorship of various species. Species can be classified according to their probability of survival. This can be represented in a graph.

Answer 146

The rate of species lost is alarming, but there are examples of species being restored through: natural cycles of population change careful management legal protection of species

Answer 147

There are four kinds of biological control agents. 1. General predators: organisms that consume a great variety of pest species; e.g. ladybugs, target aphids, caterpillars, mites and small beetles Specialised predators: organisms that target one pest species, e.g. dragonflies target all life stages of mosquitoes Parasites: e.g. wasps lay their eggs in the bodies of hosts, leading to the host’s death. Microbial diseases: caused by bacteria, fungi and viruses that target species and cause death.

Answer 148

Culling ensures the: sustainability of ecosystems viability of native species.

Answer 149

Invasion of pest species devastates native populations. Native populations decline due to: -a lack of resources - a loss of habitat - predation. Eradication of pest species; e.g. through quarantine from protected stock. Reintroduce native species; i.e. restocking in captivity.

Answer 150

Fire can have varied effects on ecosystems. Fire intensities depend upon weather and fuel load. The rate of spread of a fire is affected by a variety of issues including wind speed, moisture content of the fuel, fuel particle size, vegetation height, fuel bulk density, percentage of dead fuels and topography. The immediate negative effects of fire on the biota of a community include loss of vegetation, reduction of leaf litter and an increase in animal suffering and decrease in numbers. The degree to which this changes the populations of species present in a habitat depends on the kind of fire (canopy, understorey or both), and its intensity and scope.

Answer 151

- Removes the slow-growing but dominant trees and shrubs, thereby opening up space for other living things (e.g. herbaceous, grass-like species) to come - Returns nutrients to the soil that were previously locked up in plant biomass - The heat of the fire can lead to biotic changes, because some species of bottlebrushes, hakeas, some acacias and eucalypts regenerate from fire-released seeds

Answer 152

-Germination of species which are difficult to germinate by other means - More uniform and earlier germination - Seedlings which are more robust

Answer 153

Long-term changes in an ecosystem can result from sequences of fires known as fire regimes. Fire regimes are determined by: the season in which fires occur the intensity of the fires most importantly, how frequently the fires occur. Eucalypts, acacias and shrubs that make up the unique Australian landscape thrive in the natural fires of lower intensity and frequency.

Answer 154

WA's mining boom has resulted in huge economic benefit to all Australians. However, mining blasting and digging has enormously changed the landscape, devastating many habitats. Eventually government enforced restrictions on mining development and when mining sites are allowed to be established, a restoration plan is required for the surrounding ecosystems. Koolanooka Mine Site, 400 km NE of Perth is one area that is in the process of being restored. The use of research provided effective ecological restoration of vegetation communities at Koolanooka, Blue Hills and Weld Range, which have been or will be impacted by iron-ore mining. The mine aims to restore 70 per cent of the known original species diversity.

Biology Semester 1 Exam Flashcards

(178 cards)