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ECOL211 > Linn Hoffman (L1-8 (not 6) > Flashcards

Linn Hoffman (L1-8 (not 6) Flashcards

1
Q

What are the five different types of population interactions?

A

Mutualism (+,+), Commensalism (+,0), Predation (+,-), Amensalism (0,-), Competition (-,-)

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2
Q

What is species richness?

A

The number of species in a community
Reduced resource limitation, increased niche overlap, specialisation in resource use, community saturation

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3
Q

What are the main influences on species richness?

A

Higher productivity, predation intensity, spatial heterogeneity, harshness of the environment, Intermediate Disturbance Hypothesis, environmental age and evolutionary time, and habitat area and remoteness (island biogeography)

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4
Q

What is species diversity?

A

A combination of species richness and evenness (distribution)

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5
Q

How is species diversity quantified?

A

The Shannon Index of Diversity
Rank-Abundance Curves

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6
Q

What is phylogenetic diversity and why is it important?

A

A measure of diversity that incorporates phylogenetic differences
It identifies and protects sets of species that are taxonomically distinct and represent the greatest variety of biological features
It is important in conservation efforts to prioritise species

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7
Q

What are EDGE scores?

A

Species are scored according to the amount of unique evolutionary history it represents (Evolutionary Distinctiveness) and its conservation status (Global Endangerment)
They incorporate species value based on originality or irreplaceability, and by urgency of action

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8
Q

What is functional diversity and why is it important?

A

A measure of the functional traits of organisms that influences ecosystem function
Traits can tell us the presence of different trophic groups, feeding habits, and behaviours that tell us the “jobs” that different species do and their interactions

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9
Q

Why are invasive species a key feature in functional diversity?

A

They may be useful in filling roles that native New Zealand organisms cannot, to make sure the ecosystem is highly functioning

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10
Q

What are the phylogenetic and functional differences between kiwi and hedgehog?

A

They have a large phylogenetic difference, but low functional difference
They are very different organisms, of a similar size but one is a bird and one is a mammal
They occupy the same niche, and have similar diets and foraging behaviours

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11
Q

What are lognormal distributions used for?

A

Communities are often represented by a lognormal distribution, most species being moderately abundant, but a few being very abundant or very rare
It allows us to predict the distribution of abundance among species

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12
Q

What are the main trophic levels?

A

Quaternary consumers (carnivores, eagles and orca)
Tertiary consumers (carnivores, snakes and tuna)
Secondary consumers (carnivores, frogs and small fish)
Primary consumers (herbivores, crickets and zooplankton)
Primary producers (sunlight, plants and phytoplankton)

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13
Q

What are bottom up controls?

A

Controls of the populations of higher trophic levels due to a decrease in the populations of lower trophic levels

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14
Q

What are top down controls?

A

Controls of the populations of lower trophic levels due to an increase in the populations of higher trophic levels

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15
Q

What is trophic facilitation?

A

This occurs when a consumer is indirectly helped by a positive interaction between its prey and another species

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16
Q

Why is trophic facilitation be a problem in conservation?

A

Due to indirect interactions between species
The decrease or increase in species populations may unintentionally impact other species populations

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17
Q

What is trophic cascade?

A

This occurs when the rate of consumption at one trophic level results in a change in species abundance or composition at lower trophic levels

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18
Q

How did the Alaskan kelp population decline?

A

Overfishing of sea lions and otters meant that orca didn’t have their normal diet to eat and they turned to sea otters
They have a much larger grazing intensity and sea otters are much smaller, causing the otter populations to decline
This caused sea urchins to bloom as they no longer had enough of a predator population to keep their numbers stable
This caused the kelp population to decline due to the increase in their predatory population

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19
Q

What is the whale pump and why is it important?

A

Whales defecating and putting nutrients into the ecosystem
It sequesters carbon into the ocean, and brings nutrients to the surface for photosynthesis, especially Fe and N

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20
Q

What are keystone species?

A

Species that have an inordinate influence on the community structure due to their low biomass (abundance and size)

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21
Q

What are foundation and dominant species?

A

Species that have a substantial influence on community structure as a consequence of their high biomass (abundance and size)

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22
Q

What is competition?

A

The process by which individuals of one species suffer reductions in fecundity, survivorship, or growth as a results of the presence or activities of a second species
If resources are not limited, species can fight over it but there is no competition ecologically

23
Q

What are the two mechanisms of interspecific competition?

A

Exploitation competition - indirect competition through shared resources
Interference competition - direct competition involving one species actively preventing access to resources, or inhibiting growth or survival of another species (allelochemicals in plants, lions vs hyenas, kudzu vine smothering trees)

24
Q

What is the fundamental niche?

A

The ecological space (set of conditions) that can be potentially occupied by a species in the absence of all other competitors or predators

25
Q

What is the realised niche?

A

The actual ecological space (set of conditions) occupied (realised) by a species in the presence of other competitors and predators in different physical or chemical conditions
The realised niche can be larger than the fundamental niche, but not often

26
Q

What is the Competitive Exclusion Principle?

A

If two competing species coexist in a stable environment, then they do so as a result of niche differentiation
If niche differentiation is not possible, then one species will eliminate or exclude the other due to being better adapted

27
Q

How does competition occur between dissimilar animals (rodents vs ants)?

A

Rodents excluded - ant colonies increased by 71%
Ants excluded - rodents increased by 18% and 24% in biomass
Rodents and ants excluded - seed density increased by 450%

28
Q

What does resource partitioning rely on?

A

Ecological and evolutionary compromises, splits in space and time
Narrow resource spectrums - a high degree of specialisation (little overlap) in their resource use
Broad resource spectrums - more kinds of resources available to support more species

29
Q

What is the resource partitioning between warblers?

A

They all occupy the same tree, but sit and have their nests in different parts and heights of the tree, so they can all live in the same place without harming others’ populations

30
Q

Why don’t competitive dominant species take over?

A

Environments compromise of a patchy mosaic of variable conditions in space and time, unpredictable and non-uniform changes
Patch dynamic theory - every patch has a different history and no species can monopolise everywhere (competition-colonisation trade off)

31
Q

What is the Intermediate Disturbance Hypothesis?

A

Species can become dominant if there is
Infrequent disturbance
Small extents
Long time since impact

Species can become extinct if there is
Frequent disturbance
Large extents
Short time since impact

Sweet spot in the middle of these factors that mediates competitive interactions and natural events

32
Q

Why do abiotic factors lead to microclimates?

A

Abiotic conditions are often a lot more patchy than we assume, leading to microenvironments and more possibilities for species with different niches to coexist in what seems to be a homogenous environment

33
Q

What are the three types of predation?

A

True predators (usually carnivores), grazers (herbivores), and parasites

34
Q

What are the feeding habits of true predators?

A

They consume several or many prey during their lifetime and invariably kill them
Frogs, spiders, snakes, killer whales, baleen whales, seed-eating birds, lions

35
Q

What are the feeding habits of grazers?

A

They attack several or many prey and consume only part of each one and usually do not kill them
Sheep, locusts, leeches, mosquitoes, fleas
The parasite boundary is unknown around leeches, mosquitoes, and fleas

36
Q

What are the feeding habits of parasites?

A

They attack one or very few prey (hosts), form an intimate association and consume only part of each, and usually do not kill them
Tapeworm, mistletoe, aphids
Parasitoids attack one prey (host) and consume it all and invariably kill it, somewhere between predators and prey

37
Q

What are the different types of parasitism?

A

Sexual parasitism
Brood parasitism (cuckoo birds)
Kleptoparasitism (seabirds)

38
Q

Why do organisms have different diets?

A

Animals that hide from predators, such as mice, are more likely to stay hidden and eat seeds and leaves

39
Q

What do optimal foraging and dietary preferences depend on?

A

Optimal foraging and dietary preferences depend on encounter rate and handling time

40
Q

What is handling time?

A

The time it takes the predator to find the prey to the time the prey is eaten

41
Q

What is prey switching?

A

Where some predators that focus on the most abundant prey, tend to switch from one prey species to another which is more plentiful

42
Q

How do Acacia species respond to grazing?

A

Plants have evolved mechanisms that reduce their likelihood of being grazed or promote their regrowth after grazing (evolutionary arms race), such as producing toxins, can be bitter and have thorns
Some species of Acacia can increase the levels of cyanide in their leaves in response to grazing, and release ethylene to warn other plant species as well as their own

43
Q

What is masting and why is it important?

A

They “starve” predators during non-masting years, then overwhelm them with large amounts of food, allowing for more seeds to survive
Masting allows plants to hide (in time) from seed-eating herbivores, then overwhelm them by sheer numbers

44
Q

What are the predator-prey population cycles?

A

An increase in the prey population is followed by an increase in the predator population
The resulting increase in predation is followed by a decline in the prey population
With fewer prey available, the predator population declines
The decline in the predator population is followed by an increase in the prey population
Modelled by the Lotka-Volterra Predator-Prey Model

45
Q

What are the assumptions of the predator-prey population cycles?

A

Prey population finds ample food at all times
Food supply of the predator population depends entirely on the size of the prey population
The rate of change of population is proportional to its size
During the process, the environment does not change in favour of one species and genetic adaptation is inconsequential
Predators have limitless appetite

46
Q

What are factors that influence interaction strength?

A

Consumption rate per individual predators declines with increasing predator density
Age/size selective predation
Prey switching and decoupling of predator-prey population dynamics
Each mechanism can weaken or intensify interactions

47
Q

What are the consequences of annual variation in seed availability (masting)?

A

More seeds are produced following mild winters and hot summers
Kakapo breeding occurs in the same years as rimu masting years
Beech masting produces a lagged population response in mice, high populations persists for a year after the mast which causes differences in interactions for other predators and their prey, such as stoat populations increasing that decrease kiwi populations

48
Q

What can happen to a community if it is disturbed?

A

It may return to its original states or settle into an Alternative Stable State

49
Q

What are Alternative Stable States?

A

Stability occurs when the community resides within a state
A change in some factor may cause the community to move to another state
Reversal of the change may not result in a return to the original conditions if the initial shift was sufficiently large

50
Q

What is community resistance and resilience?

A

A measure of the change after the disturbance
The time taken to return to the original state after the disturbance
Diverse communities have better resilience and resistance

51
Q

What are the indirect effects of predation?

A

When two or more species interact in a way that involves one or more intermediate species
Fish indirectly facilitate terrestrial plant reproduction
Fish eating larval dragonfly leads to lesser dragonfly population which eat pollinators which cannot pollinate terrestrial plants, and they cannot reproduce

52
Q

What are mutualistic interactions?

A

When both species gain a net benefit from the other
Obligate mutualists - when two species provide fitness benefits to each other and require each other to persist
Facultative mutualists - when two species provide fitness benefits to each other, but the interaction is not critical to the persistence of either species

53
Q

Bats and pitcher plants relationship

A

Pitcher plants feature an ultrasound reflector attractive for mutualistic bats
The reflector enables the bats to easily identify the plant’s pitchers
The bats provide the pitchers with feces in exchange for roosts

54
Q

How do mutualistic interactions affect community structure?

A

Mutualistic interactions allow for more species to tolerate different ecosystems, due to the effects other species have
Removing the cleaner fish from coral reefs caused the abundance of client fish to decline by 75% and the number of species by 50%
Ants and acacia trees, higher number of trees attacked by long horned beetles when ants (specifically C. mimosae) are excluded as they fight off herbivores and outcompete other ant species

ECOL211 (3 decks)

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