1
Q
Impacts of Eutrophication and Pollution
What is eutrophication?
A
- When there is an abundance of nutrients running into water –> causes algae to thrive near the surface (for access to sunlight) and overgrow.
- The lower algae are outcompeted and die.
- The decomposers then break them down, however use up the oxegyn in the process, as they have so much matter to decompose.
- This results in insufficient oxegyn for the fish, thus they die.
2
Q
Impacts of Eutrophication and Pollution
What is meant by Biochemical Oxegyn Demand?
A
- For bacteria (primary decomposers in aquatic environments) to effectively recyle nutrients, they need oxegyen to complete their own ceulluar respiration.
- The amount of oxegyn required by the bacteria is called the Biochemical Oxegyn Demand.
- When there is an increase in DECAYING algae (from eutrophication), this increases the activity of the bacteria,
- –> increases the BOD and uses up the avilable oxegyn, netaively impacting the aquatic animals.
3
Q
Impacts of Eutrophication and Pollution
What is Biomagnification?
A
- When there are traces of toxins in the water –> the impact is worst for the higher trophic levels.
- The lower trophic levels will have a small amount –> the next trophic level eats several of them, so ends up with a higher level.
- The next trophic level eats more of those –> ends up with a higher amount (etc).
- By the highest trophic level, the amount becomes dangerous.
4
Q
Impacts of Eutrophication and Pollution
What is something referred to as ‘biodegradable?’
A
- Should be able to be broken down completely and dissolve into soil.
- Not leave any remaining chemicals or plastics.
- Something can be biodegradable if it largely dissolves but does leave behind some microplastics.
- The terms refers to something compostable and largely degradable.
5
Q
Impacts of Eutrophication and Pollution
What are classified as ‘macroplastics?’
A
- Plastics are classified based on their size.
- Any debris larger than 5mm is considered macroplastic.
- (this includes plastic bottles/ bags)
- these macroplastics can end up being mechanically broken into microplastics.
- They also create large landfills –> dangerous to aquatic life.
6
Q
Impacts of Eutrophication and Pollution
What are classified as ‘microplastics?’
A
- Plactic debris that is less than 5mm are called microplastics
- due to their small size, they can be ingested unknowingly by fish and other organisms.
- they may have previously been macroplastics but now mechanically decreased in size
- in other cases, they are actually ingredeitns in cosmetics and cleaning products.
- these microplastic ingredients are illegal most places now due to the concern over their connection to cancers/ diseases.
7
Q
Impacts of Eutrophication and Pollution
The importance of rewilding
A
- Definition: any acitivies that are conservation efforts aimed at restoring and protecting natural processes and wilderness areas.
- It is an in-situ strategy, and involves leaving the area to nature and avoids a lot of active human management.
8
Q
Impacts of Eutrophication and Pollution
The role of fertilisers in Eutrophication
A
- Is caused by an excess of nutrients in a body of water causing the algae surface overgrowth.
- One of the main causes of that surplus of nutrients is overuse of fertilisers (usually full of usable nitrogen), that then runs off in rainwater into other bodies of water.
- Despite fertilisers benefits, caution against the overuse is important to prevent eutrophicaiton.
9
Q
Impacts of Eutrophication and Pollution
The biomagnification of Mercury
A
- The burning of coal and the production of cement are two activities that are releasing Mercury into the environment.
- That mercury then runs off into bodies of water where it is converted by micro-organisms into a form called methyl mercury, which is then absorbed by small fish –> transferred up the food web.
- Larger fish who eat many smaller fish end up with higher levels.
10
Q
Impacts of Eutrophication and Pollution
The biomagnification of DDT
A
- DDT is a synthetic insecticide, that was cheap and effective against mosquitos and other vectors
(oragnsisms that functiona as a carrier of an infectious agent between organisms of a different species). - After usuage for a decade, (spraying from an aircraft), helpful insects vanished and resistance became common –> it was ending up in bodies of water.
- It was absorbed by phytoplankton and then absorbed up through the food web resulting in high levels in top predators.
- In predatory birds the high levels caused weak eggs that cracked during incubation.
11
Q
Impacts of Eutrophication and Pollution
Methods for Rewilding
A
- The most classic example of rewilding is the reintroduction of keystone species (often apex predators, but not limited to) to restore balance.
- Other examples however include creating pathways between isolated habitats to increase gene flow and stop harmful human activities such as logging or hunting.
- Once these measures are initiated, the habitat is left alone to reestablish itself naturally within management.
12
Q
Impacts of Eutrophication and Pollution
What is happening at Hinewai Reserve in NZ?
A
- Is a rewilded area that began 30 years ago.
- Started at 109 hectares but now is 1,250 hectares.
- It has been a place to regeneratie native vegetation and wildlife by removal of invasive species.
- Has also been left to slowly rebuild free of human interventions.
13
Q
Ecological Succession
Ecological Succession
A
- Defnition: a predictable series of change over time in the species that live in an area.
- It is triggered by a change in the abiotic/ biotic factors in an ecosystem leading to groups of species replacing the previous groups over time.
14
Q
Ecological Succession
What is Primary Succession?
A
- Occurs when new land is created and organisms arrive to prepare the land for other living organsisms.
- For it to be primary succession there must be no pre-existing soil.
- The land is usually rock or sand that lacks nutrients.
- The initial stages of primary succession involve mosses and lichens realeasing enzymes and chemicals that create cracks in rocks and start to form soil.
15
Q
Ecological Succession
What is secondary succession?
A
- There was a previously fully formed ecosystem in the area.
- Then there is a disturbance to the established ecosystem (like a forest fire) that dramatically reduces the living community.
- It will then have to rebuild over time.
- The key is that the event does NOT remove the soil, so regrowth occurs more quickly than with primary succession.
16
Q
Ecological Succession
What is the importance of Pioneer Species?
A
- These are the first species to live in a newly establishing ecosystem.
- When there is a bare rock during primary succession, the pioneer species are lichens and moss which are photosynthetic and do not sue roots, so can grow in harsh environments.
- They are responsible for breaking down the rock into soil.
- For secondary succesion, the pinoeer species to return first would be small grasses and flowers.
17
Q
Ecological Succession
What is a Climax Community?
A
- During the stages of succession, larger plant life arrives and outcompetes some of the initial pioneer species.
- But over time the area will increase not just in the number of organisms but in the biodiversity of organisms.
- The pinnacle of succession is the most diverse and populated ecosystem, called the Climax Community.
- The climax community is STABLE –> will remain until a dramatic change in biotic and abiotic factors or naturaul disaster.
18
Q
Ecological Succession
What is Cyclical Succession?
A
- Whilst in a forest ecosystem, succession does build to one stable climax community, that is not true for all ecosystems.
- Some are marked by a changing cycle of communities.
- Definition: A pattern of vegetation change in which a small number of species tend to replace each other over time in the absence of large-scale disturbance
19
Q
Ecological Succession
Arrest of Succession
A
- If left undisturbed, succession should continue in the predictable steps towards a climax community.
- Human activities though can prevent an ecosystem from reaching its potential and cause it to arrest (stop) in an earlier stage of succession or even more backwards.
- E.g, this occurs due to grazing by large livestock populations that keep habitats as grasslands instead of developing into forests.
20
Q
Causes of Climate Change
What is meant by the Greenhouse Effect?
A
- Short-wave radiation from sunlight such as UV radiation —> penetrates atmosphere –> is re-emitted back as high-wave raditaion.
- Greenhouse gasses trap some of that re-emitted radition and it is transmitted back and heats up earth.
- Occurs naturally, and is essential for maintaing a warm enough climate for living organisms.
- However, the addition of extra greenhouse gases through human activities has enchanced the effect and causes excess warming.
- Similar to how heat gets trapped in greenhouses.
21
Q
Causes of Climate Change
What is Infared Radiation?
A
- When sunlight (shorter wavelengths including ultraviolet rays and visable light) hits an object, some of it is absorbed and then readmitted in the form of infared radiation which is a longer wavelength form.
- This is the form of heat that gets trapped by greenhouse gases and sent back down to earth, warming it.
22
Q
Causes of Climate Change
What do we mean by climate?
A
- Refers to the long-term patterns of both temperature and precipitation.
- Unlike weather which frequently changes, climate of a region should be a consistant frature.
- Includes rainfall patterns and not just temperature .
23
Q
Causes of Climate Change
What is Albedo?
A
- The ability of a surface to reflect light is referred to as its albedo.
- Darker objects have lower albedo, meaning they absorb rather than reflect light.
- Ice and snow have a high albedo, which leads to them not warming up.
- If they start to melt due to climate change the surface has a decrease in albedo leading to more absorbed heat. and further melting.
24
Q
Causes of Climate Change
What is Permafrost?
A
- A term for the soil that ecists in very cold climate that is frozen solid.
- Permafrost is often below the surgace which does contain thawed soil.
- The permafrost means that most plants cannot survive bevause of the inability to form roots in the permafrost.
25
# Causes of Climate Change
What is a Montane Species?
- Rerfs to specoes that live on mountains.
- Most montane species have an altitude preference.
- One impact of climate change is that many montaine species have changed their preferred altitude.
26
# Causes of Climate Change
What is meant by Upslope Migration?
- Range migration refers to the tendacy for the preferred range of a species to change over time.
- Abiotic factors impact the range of tolerance -- so if abiotic facotrs change to to climate change -- it will impact the range.
- The most common impact is for the shift to be towards cooler climates (either a mirgation towards the north/ south poles --> poleward migration OR up in the altitude of montaine speices --> upslope migration)
27
# Causes of Climate Change
What are the important Green house gasses?
- The two most significant gasses that contribute to the greenhouse effect are carbon dioxide and methane.
- Both are released during fossil fuel extraction and is also emitted from marshes and during the melting of permafrost.
28
# Causes of Climate Change
Positive and Negative Correlations
- When there is a pattern between two variables it is called a correlation.
- If one variable increases, the other also increases, it is called a POSITIVE correlation.
- If as one variable increases, the other decreases, we call it a NEGATIVE correlation.
29
# Causes of Climate Change
The positive feedback loop of Climate Change
- Many impacts then cause further change.
- Warmer temperatures melt snow and ice which decrease the albedo of the surface causing more heat absoprtion which melts more snow and ice again lowering the albedo.
30
# Causes of Climate Change
Tipping Points in Climate Change
- When an ecosystem reaches a point where it shifts from being a carbon sink (like a forest --> due to the many trees and high photosynthesis rate aborbs more CO2) to a carbon source (ecosystems with more animal life that release more CO2 than they absorb), this point of change from a SINK to a SOURCE is called a TIPPING POINT.
31
# Causes of Climate Change
Climate Change in Boreal Forests
- The boreal forest/ taiga is just below the tundra and home to very cold avaerage temperatures.
- Snowfall is essential for this biome for producing water in spring and summer when it melts.
- Climate change is causing less snow and creating drought ---> less photosynthesis --> browning trees and risking fires.
- Caused it to reach a tipping point where it is actaully now a source --> emits and respires CO2.
32
# Causes of Climate Change
Impact of Climate Change on migratory birds
- A very large number of birds moved to a higher latitude over a period of 50 years, referred to as upslope range migration --> due to warming from climate change, birds are having to move opwards to find a climate that is optimal for them
33
# Causes of Climate Change
Shifts in latitude range by species
- Species have shifted to a cooler latitude in response to warming temps --> the abiotic changes have pushed them outside their optimal range of tolerance.
- Their natural selection in slower than cliamte change, thus they are unable to adapt to their previous environment and instead migrate to a cooler environment. --> this is a movement to a higher latitude in Northern Hemisphere species (POLEWARD MIGRATION)
34
# Polar and Ocean Changes
What is Land-fast ice?
- A frozen layer of sea water attatched to the land --> emperor penuins use this to breed on.
35
# Polar and Ocean Changes
What is Ocean Stratification?
Stratification --> 'layers'
- Warmer less salty water is less dense, therefore floats of top of dense, cold, saltier water.
- The layers will mix with CURRENTS, wind and tides, but the more stratified the ocean is, the greater the difference in layers, the less mixing there is.
- Climate change is increasing the stratification which will reduce the trasnport of heat and gases to lower water. (lower water has nutrients, top layer has oxegyn.)
36
# Polar and Ocean Changes
What is Calcification?
- The chemical reaction that leads to the formation of calcium carbonate needed by coral reeds.
- Requires calcium carbonate ions (CO3).
- If there is a lot of CO2 in the ocean, the carbonate ions are used up in chemical reactions that mix CO2 and H2) and CO3 to form hydrocarbonate ions.
37
# Polar and Ocean Changes
What is Carbon sequestration?
- The capture and storage of carbon.
- Occurs naturally in photosynthesis, growth of biomass and formation of shells.
- To increase carbon sequestration would address climate change, could be through forest regeneration/ restoring wetlands.
38
# Polar and Ocean Changes
Impact of Climate change on the Emperor Penguin.
- They breed on landfast ice --> by the time it breaks off in summer, egs have hatched, chicks are prepared to find food.
- Climate change causes the ice to break off from the land too early in the breeding season for the young to survive.
39
# Polar and Ocean Changes
Impact of Climate Change on Walruses
- Walruses breed on sea ice chelves so the mother can swim from the ice to bring back food to the young.
- Reduction of these spaces means walruses have less space to care for new young.
- Many are moving further up towards the North Pole.
- Others are staying but moving onto land --> casuing mother to leave their young longer and predation of the young has increased.
40
# Polar and Ocean Changes
How are ocean currents impacted by temperatures?
- Ocean currents --> move warmed water near the equator to the poles.
- Moved by winds, and the roation of Earth.
- Cold water has more nutrients --> the moving current brings those nutrients to the surface and towards the coasts, supporting food webs.
- El Nino events impact the currents --> cause warmer surface waters (increase the stratification), both of which are reducing nutrient movement due to currents.
41
# Polar and Ocean Changes
Impact of El Nino events on Aquatic Environments
- During El Nino events, trade winds weaken and warm water is pushed back and stays still, rather than the currents that move colder water and its nutrients.
- Can be annual or sporadic --> when they occur, water stays warmer and the nutrients from colder water do not arrive.
- Impacts the ability of producers to photosynthesise, lowering productivity.
- Means less food available throughout the food chain and fewer fish as a result.
42
# Polar and Ocean Changes
How does CO2 impact the pH of oceans?
- When CO2 dissolves in water, it forms H2CO3 which is carbonic acid.
- From the carbon acid, H ion break off forming bicarb/ carbonate and H ions are acidic and will lower the pH of the water (INCREASE ACIDITY)
43
# Polar and Ocean Changes
Impact of Ocean Acidification on Coral Reef Ecosystems
- More CO2 dissolving into the ocean --> more carbonate formed, which is then sued to form bicarbonate to stabilise the free hydrogen.
- When in bicarbonate form, it is unable to bond with the calicum and form the calcium carbonate needed by the coral.
44
# Polar and Ocean Changes
Reforestation vs Afforestation
To increase carbon sequestration is to increase plant life --> to thus increase photosynthesises rates. Methods to do this:
AFFORESTATION:
- planting trees in areas where they currently do not exist.
REFORESTATION:
- restocking of forests that have been depleted but in an existing forest ecosystem.
45
# Phenology and Insect Life cycles
What is phenology?
- The study of the timing of periodic events in living organisms, such as breeding seasons, migration and hibernation.
- Occur is cycles and the specific of the timing of those evens in phenology.
- Often caused by abiotic factors.
46
# Phenology and Insect Life cycles
What is a photoperiod?
- Refers to the number of hours a day when the sun in shining.
- In most habitats the photoperiod changes throughout the year.
- For plants, the photoperiod length often determines the phenological changes. --> some plants flower when the days become longer, other when the day becomes shorter.
47
# Phenology and Insect Life cycles
What is meant by the term Trophic Mismatch?
- The annual cycles of one species often relates to another, EG: birds might return from migration during peak plant productivity.
- If an abiotic change disrupts the annual cycle of one species, the other could fall out of sync --> TROPHIC MISMATCH.
- Can reduce the survival/reproduction of one species when their cyclical events are out of sync with their food source.
48
# Phenology and Insect Life cycles
Time Specific Events in Plants
Most significant plant activity --> linked to timing of flowering.
- The hours of daylight directly cause the blooming of flowers in spring/ autumn.
Another example --< bud set and bud burst in deciduous trees.
- The forming of a bud set as winter approaches stores energy and prevents growth --> then as the days get longer, bud burst causes the growth of new leaves and flowers.
49
# Phenology and Insect Life cycles
Time Specific Events in Animals
Time specific event in animals:
1) MIGRATION.
- Bird species migrate during winter and then return to breed.
- They use the length of the day as their primary cue for when to return to the original habitat.
- To do this successfully --> needs to be food and nesting sites available in the new habitat.
2) HIBERNATION
- Insects use pollen as a food source, hiberante in winter and leave hibernation when flowering is set to occur.
50
# Phenology and Insect Life cycles
Climate Change and Insect Life Cycles
BEETLES LIFE CYCLES.
MONOVOLTINE CYCLE: one generation is produced a year.
BIVOLTINE CYCLE: two generations are produced each year.
- Warmer temperatures are correlated with more beetles underoing the biovoltine cycle and completing TWO life cycles per year.
- Beetles burrow in spruce bark to lay eggs and the larvae feed on the wood, thus each life cycle does structural damage to the trees.
- More insects increase their life cycle with climate change --> more tree are dying.
51
# Evolution and Climate Change
What is Microevolution?
- Tracking the changes over time to a single phenotypic trait (often therefore to its associated gene and allele frequencies)
- EG: The Hardy Weinberg equation to track how allele frequencies are changing over time --> studies microevolution.
52
# Evolution and Climate Change
What is meant by a 'polymorphism?'
- Two or more common phenotypes for a trait.
- 'Many forms'
- For a polymorphic trait, at least two variations are common and successful --> for both/ many to remain present, neither would have an advantage.
53
# Evolution and Climate Change
Climate Change in relation to Evolution
- Climate change alters abiotc factors. --> could impact the fitness of different phenotypes.
- Often causes natural selection to slowly alter the predominant phenotype of a population.
EG: Warmer temperatures have contributed to the increase in freq of the brown tawny owl compared to the grey owl (used to be better camouflaged by snow but now there is less.)
Biology
flashcards
Decks in class (41)
# Cards
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B4.141
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B4. 23
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C4.138
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C4.230
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A4. 137
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A4. 225
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D4.134
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D4.224
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D4.353
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A1.1.254
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B1.121
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B1.18
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B.1.223
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A2.123
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A2.229
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A2.313
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B3.142
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B3.252
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B3.329
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C3.162
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C3.239
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D3.178
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D3.252
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D3.336
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A3.131
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A3.223
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C2.131
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C2.239
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B2.132
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B2.219
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B2.331
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D2.134
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D2.244
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D2.320
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C1.132
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C1.229
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C1.333
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D1.131
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D1.230
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D1.328
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(Continued) D1.322
