D4 Flashcards
(127 cards)
1
Q
What is a selection pressure?
A
An environmental factor that can influence the success of a population
2
Q
What is fitness?
A
Ability to pass on genes
3
Q
What is sexual selection?
A
A process similar to natural selection in which some organisms that can attract a mate to reproduce with more successfully, leading to an increase in this allele frequency in the population overtime
4
Q
What is antibiotic resistance?
A
Ability of bacteria to resist impacts of antibiotics
5
Q
How did Darwin’s theory lead to a paradigm shift in understanding?
A
Revealed that evolution is driven only by heritable traits. Shift from Lamarck’s theory of Inheritance of desirable acquired traits
6
Q
What are causes of genetic variation (that drive natural selection)?
A
Mutation (new alleles)
Meiosis inc. independent assortment and crossing over (new allele combinations)
Sexual reproduction (new allele combinations)
7
Q
What role does carrying capacity play in natural selection?
A
Creates a limit and thus, competition for survival. This means only the best adapted can survive, which leads to natural selection
8
Q
How do abiotic factors impact natural selection?
A
Often act as a selection pressure
9
Q
Explain how sexual selection has played a role in the evolution of birds of paradise
A
There was variation in the brightness of feathers among individuals.
There is competition to find a mate, which is a selection pressure
Males with big bright feathers advertise their wellbeing, better attracting mates. This leads to this variation of more colourful males being reproducing more often, thus having more offspring. This causes this variation to increase in frequency ovetime
10
Q
What is the experimental work of John Endler with guppies in Trinidad and Tobago?
A
In the 1970s, there was an investigation into whether predators influenced the colouration of guppies. In the absence of predators, sexual selection lead to more brightly coloured guppies; whereas with predators, colourness increased
11
Q
What are the steps of natural selection?
A
There is genetic variation among individuals.
There is a selection pressure, so there is competition to survive in that environment.
Some variations are better suited + more likely to increase survival.
Due to increased survival, individuals with that variation have more offspring.
Because trait is genetic, variation increases in frequency overtime.
12
Q
What are the steps in sexual selection?
A
There is genetic variation among individuals.
There is a selection pressure to find a mate, thus there is competition to find mates in that population.
Some variations are better suited and more likely to increase attraction of mates. Due to increased attraction of mates, individuals with that variation have more offspring. Because the trait is genetic, variation increases in frequency overtime.
13
Q
How does antibiotic resistance occur, an example of natural selection?
A
Some bacteria have an allele that means antibiotic do not impact them. When the selection pressure of antibiotic are introduced, bacteria are now struggling to survive. Sensitive bacteria die. Resistant bacteria now have an advantage so they survive. Surviving resistant bacteria rapidly reproduce, due to no competition with other bacteria. Offspring are also resistant and thus, the colony quickly becomes resistant
14
Q
What is a gene pool?
A
All the genes and their different alleles present in a population.
15
Q
What is allele frequency?
A
Proportion of total alleles that each allele occupies
16
Q
How does geographic isolation impact allele frequencies?
A
Natural selection can favour different alleles in different locations
17
Q
What makes neo-Darwinism a specific subset of understanding?
A
Addition of DNA and alleles, and how it is specifically inherited
18
Q
How is artificial selection similiar to natural selection?
A
Both lead to a change allele frequencies due to selection pressure
19
Q
How is artificial selection different to natural selection?
A
Selective pressure is the active breeding of traits
20
Q
How does neo-Darwinism define evolution?
A
Change in allele frequencies by natural selection
21
Q
What is the most common distribution of a trait?
A
Normal distribution
22
Q
What is directional selection?
A
A mode of natural selection in which one extreme is favoured, causing the allele frequency to continuously shift in one direction
Don’t lose extremes, just shifted towards one extreme
23
Q
What is stabilising selection?
A
A mode of natural selection where the average of a trait is the best suited. Extremes pose risk.
24
Q
What is disruptive selection?
A
A mode of natural selection where both extremes are favoured/have an advantage, thus population shifts in either direction.
E.g. colour
25
What is genetic equilibrium?
A state in which allele frequencies remain the same (in reference to one trait/gene)
26
What are the five conditions for genetic equilibrium?
Large population size
No immigration or emigration
No selective pressures/favoured phenotype
Random mating
No generation of new alleles by mutation
27
What is the purpose of the Hardy Weinberg equation?
To assess whether observed genotype frequencies are different to what they would be if genetic equilibrium occurred
28
What are the two equations used in Hardy Weinberg calculations?
p + q = 1
p2 + 2pq + q2 = 1
29
What are the steps involving Hardy Weinberg calculations?
- Calculate q2 (aa) = # recessive phenotype / ppln size
- Calculate q (a)
- Calculate p (A)
- Calculate p2 (AA) and 2pq (Aa)
30
What does q represent in Hardy Weinberg calculations?
Recessive allele
31
What is sustainability?
When an ecosystem can fully support itself without outside influences?
32
What are tipping points?
The point where so much damage has occurred that the ecosystem cannot sustain itself and collapses
33
What is required for long-term ecosystem sustainability?
Sufficient energy supply
Nutrient recycling
Genetic diversity in individual species
Response to climate change / abiotic factors remain in zone of tolerance
34
How can an ecosystem has a sufficient supply of energy?
Enough producers, balance between trophic levels
35
How can a sufficient supply of energy to the ecosystem be disrupted?
Loss of producers (deforestation)
Invasive species (trophic imbalances)
Extinction of keystone species (trophic imbalances i.e. eutrophication)
36
How can nutrient recycling be disrupted?
Poaching and logging i.e. organisms do not stay in ecosytem until death
Erosion that washes away topsoil
37
How can a high level of genetic diversity be disrupted?"
Competition from invasive species can lead to a decrease in population size, an increase in inbreeding and (ultimately) decreased genetic diversityy
38
How can abiotic factors remaining in zone of tolerance be disrupted?
Climate change happens further than species can adjust
39
How has deforestation affected the Amazon Rainforest?
Before deforestation, the Amazon Rainforest regulates its own water cycle (due to large amounts of plant life that transpire, cause clouds and then precipitation). When deforestation removes plants, the reduction in transpiration disrupts the water cycle. This causes temperatures to rise and rainfall to decrease, leading to droughts and fires, which causes this positive feedback loop
40
What is the tipping point for the Amazon?
When it can no longer be a forest//is a grassland
41
What is a mesocosm?
Small experimental area set up as an ecological experiment. (Usually sealed containers with necessities to function as a self-contained sustainable mini ecosystem)?
42
Why is a sealed glass mesocosm better than an open tank?
Better representation of a sustainable ecosystem, allows matter to be recycled and thus, show self-sufficiency
43
Why are aquatic mesocosms more successful than terrestrial ones?
Requires less components to build, recycling of amtter
44
What is a Winogradsky column?
A microbial mesocosm, with different layers with differing abiotic conditions
45
What is included in a mesocosm?
Pebbles at bottom (for drainge, to prevent overmoist soil)
Activated charcoal (prevent bacterial overgrowth, extra H20 drainage)
Soil (room for growth of roots)
At least one plant (for photosynthesis to create energy)
Spray of water
46
What is a keystone species?
Any type of organism that has a disproportionate impact on the structural of its ecological community
47
What is a trophic cascade?
When the removal of a top predator destabilises the trophic levels below it, and disrupts the balance of the ecosystem
47
What is soil erosion?
Loss of the topsoil (that is the most nutrient rich and has impacts on the rest of the ecosystem)
47
What is leaching?
When rain/irrigation water dissolves chemicals and carries them away from the roots of plants
47
What are agrochemicals?
Chemicals used in agriculture
48
What is carbon footprint?
Total amount of greenhouse gases that is generated by an activity
49
What is tillage?
The process of preparing soil for a crop by loosening it, by mechanical means (uses fossil fuels)
50
What did ecologist Robert Paine discover about the removal of a sea star from intertidal zones?
1963-193. Manually removed seastar from intertidal zone. This lead to mussels taking over (because of lack of predator) and reducing space for other invertebrates, as well as overgrazing. Found that it was a keystone species
51
What is required for harvesting of resources to be sustainable?
Rate of removal has to be under/equal to rate of replacement
52
What is the case study of Black cherry trees in relation to sustainable harvesting of resources?
Colour made it sought out for furniture, but it is very slow growing. Clear cutting nearly caused extinction. Have since implemented regulations, leading to the selective removal of large older trees
53
What is the case study of the Chilean Sea Bass in relation to the sustainable harvesting of resources?
In 1970s was discovered by tourists.
Widespreaad overfishing through longlinging
Since 200s, regulations have been implement in terms of technique and amount
54
What are some factors limiting agricultural sustainability? How cna they be changed?
Tillage preparation that erodes topsoil (plant cover grops)
Mechanical tillage (non-mechanical/solar alternatives)
Nutrient leaching moves valuable nutrients away from soil (mindful irrigation)
Monocultures spread pesticide resistance (don't do)
55
What is eutrophication?
Excessive nutrient enrichment of water, leading to algal blooms and ecological imbalance
56
What is biochemical oxygen demand (BOD)?
Amount of oxygen required by bacteria to complete cellular respiration
57
What is biomagnification?
Accumulation and increase in the concentration of a substance in the tissues of an organism in successively higher trophic levels
58
What is biodegradable?
Able to be broken down completely and dissolve in soil, without leaving any remaining chemicals
59
What is rewilding?
ANy activities or conservation efforts aimed at restoring and protecting still present ecosystems
60
How does excess fertiliser use lead to eutrophication?
Excess fertiliser use can lead to fertilisers running off in rainwater, into bodies of water. The fixed nutrients within them start the process of eutrophication
61
What are some rewilding methods?
Reintroducing keystone species, creating corridors between isolated populations to allow gene flow, stopping harmful human activities, removing invasive species, distribute seeds
62
What is happenin in the Hinewai Reserve in New Zealand?
Rewilded area that began 30 years ago. 109 hectares to 1250 hectares. Place to regenerate natural vegetation and remove invasive species
63
What is the process of eutrophication?
Excess fertiliser use on farms runs off (made worse by leaching)
Excess nitrogen in water bodies causes an algal bloom at the surface of the water. This blocks light and causes overcompetition for lower algae. Lower algae start to die, and as the surface algae hits carrying capacity, this algae starts to die as well. This leads to an increased need for decomposition by bacteria, which requires cellular respiration. This increases the biochemical oxygen demand, leading to lower oxygen supplies in water. This leads to animals dying due to lack of oxygen
64
What is the process of biomagnification?
Small amounts of toxins dissolve in water/soil.
Lower trophic levels ingest small amount of tissue. It is harmless to them, but stays in their tissue.
The next trophic level eats a larger amount of it (due to increased need for biomass), and thus has a larger amount of the toxin. Levels increase at each trophic level thus, at higher trophic levels, the amount can be damaging
65
What are some examples of biomagnification?
Mercury: released by industry plants and making cement
DDT: synthetic insecticide
Microplastics
66
What is a microplastic?
Plastics under 5mm
67
How are microplastics formed?
From macroplastics that have had mechanical wear and tear
OR
in cosmetic/cleaning products
68
What are macroplastics?
Plastics >5mm
69
How are macroplastics formed?
Usually through human littering esp. plastic bags
70
How do macroplastics harm aquatic life?
Mistaken for food OR get intertwined in them
71
How do microplastics harm aquatic life?
Ingested with water and thus, can accumulate and block intestines
72
What is ecological succession?
Predictable series of change over time in the species that live in an area. Triggered by a change in abiotic/biotic factors
73
What is ecological succession?
Ecological succession where there is no pre-existing soil. Initially, mosses and lichen must release enzymes that start to form soil
74
What is secondary succession?
Ecological succession where there was a pre-existing fully formed ecosystem but a disturbance occurred. Don't have to rebuild soilg
75
What is a pioneer species?
First species to live on a newly established ecosystem
76
What is a climax community?
An ecological community that is at peak biodiversity and stability
77
What is cyclical succession?
Type of succession that entails a repetitive vegetation pattern with a changing cycle of communties
i.e no one stable climax community
78
What does it mean for succession to arrest?
For it to stop at an earlier stage than the climax community / move backwards
79
Examples of humans causing succession to arrest?
Grassland should become a forest. Overgrazing by livestock lead to the ecosystem being stuck as greenland
Wetlands should become peat bog, but they are drained of water to maintain being a wetland
80
How does the ground of an ecosytem in primary succession begin?
no soil, usually rock or sand, no nutrients
81
What causes primary succession?
Volcanic eruptions
Erosion exposing new areas
Human behaviours (i.e. cement pouring)
82
What are the pioneer species in primary ecological succession?
Moss and lichen break down rock, creating soil. They don't need root systems
83
What is the biomass progression of ecosystems in primary succession?
None -> low -> increasing
84
What is the productivity of an ecosystem in primary succession?
Begins low (caused by lack of plant life), will increase with time
85
What causes secondary succession?
Forest fire, human interference (i.e. deforestation)
86
What are the pioneer species of secondary succession?
Pre-existing seeds that go straight into grass/flowers
87
What is the biomass journey for secondary succession?
Starts relatively high and increases with time to become climax community
88
What is the role of abiotic and biotic factors in succession?
Producers requrie abiotic factors to move into the area, including access to water and nutrients. If no soil, lichen and moss break down rock (by releasing enzymes), which creates soil. This allows plants to thrive, due to the creation of biotic conditions for survival. This increase in primary productivity allows consumers to live, which creates room for higher trophical level consumers. This continues until peak biodiversity is reached
89
What is the greenhouse effect?
When additional greenhouse gases from human activities trap the Sun's energy, leading to excess warming
90
What is infrared radiation?
The form of heat that is trapped by greenhouse gases and sent back to earth
91
What is climate?
Long term patterns of temperature and precipitation
92
What is permafrost?
Soil that is frozen solid in very cold climates.
93
What is albedo?
Ability of a surface to reflect light
94
What is upslope migration?
Tendency for the preferred range of a species to change overtime towards a greater altitude
95
What does a tipping point mean, in relation to cliamte change?
Point of change from an ecosystem being a carbon sink to being a carbon source.
96
How has cliamte change impacted migratory birds?
Due to warming, birds have had to move up in altitude in order to find an optimal climate i.e. upslope migration
97
What is poleward migration?
shifting towards a cooler latitude in response to warming temperatures.
98
How does the greenhouse effect lead to the warming of the Earth?
The sun emits shortwave solar radiation. UV is absorbed and re-emitted as long-wave radiation. Greenhouse gases create a layer around the Earth, which trap this infrared radiation, warming the Earth.
Increased emissions mean there is too much trapping of infared radiation
99
How is the artic environment an example of a positive feedback loop, in relation to climate change?
Warmer environments
Ice melts.
More exposed land
Decreased surface albedo
Absorption of more heat
More warmth
Continues
100
What is happening in the Boreal Forest, in relation to climate change?
Should be having cold snowy winters, so that there is enough water for all when the ice melts. This prevents drought and meets the ecosystem's needs. This allows plants to survive and photosynthesise, making it a carbon sink.
However, less snow (due to warmer weather) leads to insufficient water in summer/spring (Drought). This means that trees die, which causes a forest fire. This reduces plant life, and reduces photosynthesis, which increases carbon dioxide. This leads to warmer temperatures, and also being a carbon source.
101
What is landfast ice?
Frozen layer of seawater attached to the land
102
What is ocean stratification?
Idea that warmer, less salty water is less dense and on top of dense/cold/saltier water
103
What are El Nino events? How do they impact aquatic ecosystems?
Trade winds weaken, causing warm water to be pushed back and be stagnant. This stops the movement of cold water (with nutrients) arriving, leading to less photosynthesis, food and fish in the areas where the nutrients are meant to arrive
104
What is reforestation?
Restocking of forests that have been depleted
105
What is afforestation?
Planting trees where they currently don't exist
106
How does climate change impact emperor penguins?
Melting of landfast ice (due to global warming) too early.
It is not safe for breeding, as chicks are not mature enough when it splits to swim back to land
107
How does climate change impact walruses?
Melting ice means they don't have a habitat. They have to move to land to compensate for this; however, it is too far to travel -> being exhausted and falling off. There is also not enough space. Young are being left alone for too long
108
How should the stratification of ocean layers be?
Small amounts of warm, salty water with access to oxygen but not nutrients.
Below this, small amounts of cooler water that is nutrient rich but oxygen poor.
Currents move the layers, allowing for nutrient upwelling and movement of oxygen
109
What is happening to ocean stratification, due to climate change?
Increased warm layer. More divided and more stratified. This means currents are slower/less dramatic so less nutrients and oxygen being spread. This is particularly affecting the lower layer of the oxygen that need oxygen.
110
What is the process of ocean acidification?
There is excess atmospheric carbon dioxide, so it is dissolving in the ocean. The carbon dioxide combines with water to form carbonic acid (H2CO3), which dissociates to become carbonate and hydrogen ions. The H+ ions lower the pH of the ocean.
When there are excess H+ ions, HCO3- (bicarbonate) is formed, at the expense of the formation of CaCO3 (calcium carbonate). This leads to a lower supply of calcium carbonate for corals who use it as an exoskeleton, leading to damage for coral species
111
What is carbon sequestration?
The capture and removal of carbon
112
What are methods of carbon sequestration?
Planting of trees, which will increase photosynthesis.
Increase peat bogs (pull carbon down and form fossil fuels), by stopping drainage of these areas
113
What is phenology?
Study of the timing of periodic events in living organisms' lifecycles
114
What is a photoperiod?
The number of hours a day the sun is shining.
115
What is a trophic mismatch?
When the annual cycles of one species is disrupted (due to a change in abiotic factors), which impacts another species that relies on this cycle.
116
What are some time specific plant activities?
Flowering, bud set + burst in deciduous trees
117
What are some examples of time spcies animal activities?
Migration
Hibernation
118
What is the trophic mismatch that is occurring between Artic Mouse-Ear Chickweed and Reindeer?
The plant uses temperature as its phenological cue for leaf bud burst.
The reindeer uses hours of daylight, as its phenological cue to migrate home and breed.
Usually, temperature and photoperiod are synchronised so there is maximum plant productivity during reindeer breeding season.
However, temperature is impacted by climate change; but photoperiod is not. This means peak productivity is happening too early for reindeer breeding season, so there is less food available for new reindeer
119
What is the trophic mismatch between the Great Tit and Caterpillar?
Caterpillar reaches peak biomass in relation to temperature.
The Great Tit's breeding co-incides with caterpillar's peak biomass, so its babies are born when caterpillars are the plumpest.
However, warmer temperatures and milder winters are causing an earlier peak in biomass for caterpillars. As natural selection is slower than climate change, the birds are born with less food access.
120
How has climate change impacted the life cycle of the bark beetle, and how is this affecting trees?
Bark beetles burrow during their life cycle and lay eggs within trees, which damages the trees. Their life cycle requires warmth, thus happens during summer. One life cycle per summer is sustainable for trees. However, climate change is leading to longer summers, so beetles can complete two life cycles per summer. This double egg burrowing is leading to the death of trees
121
What is microevolution?
Changes overtime to a single phenotypic trait
122
What is polymorphism?
Two or more common and successful phenotypes for a trait
123
How does climate change impact evolution?
Climate change is altering abiotic factors and impacting the fitness of different phenotypes, which leads to slowly altered predominant dominant phenotypes within a population
124
