Unit 3 Flashcards
(129 cards)
1
Q
Why does species distribution occur?
A
The distribution of any given species is
the result of evolutionary forces having
shaped its ecological interactions.
2
Q
What are the two factors that species can interact with?
A
Abiotic factors (non-living), Biotic factors (Other living things)
3
Q
What is population distribution?
A
Where the animals are found
4
Q
What is population abundance?
A
How dense a population is
5
Q
What is demography?
A
Age structure of the population
6
Q
What is the definition of a population?
A
It is a group of individuals of a
single species living in the same
general area at the same time.
These individuals rely on the same
resources, are influenced by similar
environmental factors, and are likely
to interact and breed with one
another.
7
Q
What is the range of a population?
A
The range of a species is the area where it is found during its lifetime
and includes areas where individuals may migrate or hibernate.
8
Q
What determines the range of a said species?
A
abiotic factors and positive and negative interactions with biotic
factors define the range of a species.
9
Q
What are some examples of positive and negative biotic factors?
A
Predators, parasites, disease, and competitors act as negative interactors, while prey and food sources act positive interactors.
10
Q
What are some examples of abiotic factors?
A
Temperature, water availability, salinity,
sunlight, soil.
11
Q
How do we calculate population density?
A
Density is the number of individuals
within a population per unit area or
volume.
12
Q
How to we define dispersion in a population?
A
Dispersion is the pattern of spacing
among individuals within the
boundaries of the population.
13
Q
What are metapopulations?
A
Metapopulations consist of a group of spatially separated populations of the same species which interact at some level.
14
Q
Are ecosystems homogenous in space and time? Are they completely appropriate to all species? What does this cause?
A
No they are not. This causes fluctuation in densities and influences migration patterns.
15
Q
What three distributions we often see in populations?
A
A clumped distribution, a uniform distribution and a random distribution.
16
Q
What is a condition necessary for populations to uphold if subpopulation are part of a metapopulation.
A
There must be gene flow between subpopulations.
17
Q
What can reduced gene flow cause?
A
Allopatric speciation or sympatric speciation.
18
Q
What is a life table?
A
A life table includes age-specific data
of the survival and reproductive
patterns of a population.
19
Q
What is a survivorship curve?
A
A survivorship curve displays the proportion or numbers in a cohort still
alive at each age
20
Q
How is change in population size calculated?
A
Birth+immigrants-(death and emigrants)
When this number is positive, the population is growing
21
Q
When ressources are unlimited, what theoretically happens to growth?
A
Unlimited growth occurs
22
Q
Why does unlimited growth never occur for a long period of time?
A
Resource availability or access
decreases as a population grows, which makes it harder for a population to grow.
23
Q
How is growth rate calculated?
A
Difference in population over difference in time.
24
Q
What function does population growth look like when the population appears in a new environment or numbers have been greatly reduced?
A
Exponential curve
25
What factors appear to influence a population as its density grows?
Density dependant factors
26
What is intraspecific competition?
It is a type of interaction where individuals in a population compete for limited resources. (if variation exists within the population, the better competitors will outcompete the others and lead to the death of the poorer competitors.)
27
What is the influence of increased population density on immigration?
It causes reduced immigration, as there are less ressources available for new individuals.
28
What is threshold host density?
Threshold host density refers to the minimum concentration of individuals necessary to sustain a given disease.
29
Why does increased density mean for easier spread of disease.
Disease spread easier when individuals are close to each other. Therefore, in a dense population, disease will spread easier as the Individuals are closer to each other.
30
What is carrying capacity?
It is defined as the maximum
population size that a particular
environment can sustain. (number at which the population stops growing because of density dependant factors.
31
What are some examples of limiting ressources?
Energy, shelter/refuge, nutrients,
water, and nesting sites.
32
What is the logistical growth model?
It is a mathematical model that incorporates
the change in growth rate as the
population size nears the carrying
capacity
33
What happens to the growth of a population as the population increases?
It goes down
34
What is a community?
A community is an association of populations of different species that live and interact in the same place at the same time.
35
What is a metacommunity?
A metacommunity is defined as a set of local communities that are linked by dispersal.
36
What is interspecific competition? Is it a win win interaction, a lose win or a lose lose interaction?
It is species competing for a specific resource. It occurs when different species compete for a particular resource that is in short supply. It is lose lose.
37
What are some consequences of interspecific competition?
Interspecific competition can lead to lead to competitive exclusion; the local
elimination (extirpation) of one of the two competing species if it is too strong. It can also cause the organism's niche to change over time.
38
What is the competitive exclusion principle (Gause’s law)?
It states that two species cannot coexist in a community if their niches are identical.
39
What is an ecological niche?
An ecological niche is the total of an organism’s use of the biotic and
abiotic resources in its environment. (what they need to survive)
40
What is a fundamental niche?
A fundamental niche is the range of conditions that allows a species to
survive and reproduce. (occurs in the absence of competition) (So it is the theoretical span where a species can thrive)
41
What is a realized niche?
A realized niche is the range of conditions under which a species actually occurs in natural communities. (Real span over which a species can thrive)
42
What is ressource partitioning?
It is the differentiation of niches, via
natural selection, that enables similar
species to coexist in a community.
43
How can competition influence evolution?
It can cause animals that share the same niche to evolve towards a different niche than competitors to be better suited for the environment.
44
What usually causes more character change: allopatric conditions or sympatric conditions?
Sympatric conditions (in allopatric conditions, competition is absent, so character displacement isn’t necessary)
45
What is predation? What is a consequence of this interaction?
Refers to a carnivorous interaction
where one species, the predator, kills
and eats the other, the prey.
Predator-prey interactions help shape evolution via natural selection.
46
What are the adaptations predation brings about?
Feeding adaptations of predators
(include claws, teeth, fangs, stingers, and poison)
Defensive adaptations of prey (include hiding, running, camouflage, and
poison.)
47
What are some predator strategies?
Chasing prey, camouflage or mimicry to
avoid notice by their prey, and
structures that attract prey.
48
What are some prey strategies?
Prey strategies against predation
include fleeing, hiding, living in groups, mechanical defences, special coloration, mimicry.
49
What is mimicry?
It is the close external resemblance of an animal or plant (or part of one) to another animal, plant, or inanimate object. (Serves to mislead other organisms).
50
What are the two types of colouration and what purpose do they serve?
1. Aposematic coloration. It provides a
warning to predators, who will
tend to avoid prey with bright
coloration because it signifies
chemical defences.
2. Cryptic coloration. It provides
camouflage, making a prey
harder to see.
51
What is batesian mimicry?
batesian mimicry occurs as a palatable or harmless species evolves to
mimic an unpalatable or harmful species.
52
What is mullerian mimicry?
Mullerian mimicry occurs as two or more venemous or dangerous species evolve to resemble each other; not a result of common ancestry (i.e. convergent evolution).
53
What is the difference between camouflage and mimicry?
camouflage occurs when organisms
resemble the environment, while
mimicry occurs when organisms resemble other organisms.
54
What is deimatic behaviour?
deimatic behavior occurs as prey make themselves appear more dangerous via coloration, sound, making itself larger, or even mimicry.
55
What is herbivory?
Herbivory is the process whereby a
herbivore eats photosynthetic
organisms, like plants or algae.
56
What has herbivore led to?
It has led to the evolution of
mechanical (spines, tough leaves)
and chemical defenses in the plant
and consequent adaptations by
herbivores.
57
What is symbiosis?
Symbioses occur when 2 or
more species live in direct and
intimate contact with one
another
58
What is parasitism?
Parasitism is a process by which an organism derives its nourishment from its another one (host), which is harmed in the process.
59
What is mutualism?
It is interspecific interactions that benefit both species.
60
What is commensalism?
Process by which one species benefits and the other is not affected.
61
What is species composition?
Species composition describes all
organisms in a given community
62
What are feeding relationships?
Feeding relationships describe how energy is transferred in a
community
63
What is biodiversity?
Biodiversity describes the number of species and their relative abundances.
64
What is a trophic structures?
A trophic structure identifies the dynamics of a community based on the feeding relationships between organisms.
65
What is a food chain?
A food chain identifies the transfer of food energy up a community’s trophic levels.
66
What are food webs?
Food webs are the combination of multiple food chains to give scientists a better grasp of the actual way in which species interact.
67
What are decomposers?
Decomposers, including bacteria and fungi consume dead (or dying)
organisms and transform the components of the animal into usable material for autotrophic organisms.
68
What is the bottom-up model for food webs?
This model postulates that increased productivity at the lower trophic levels will increase productivity at the
higher trophic levels, as there will be more ressources available for the environment as a whole.
69
What is the top-bottom model for food webs.
This model postulates that predation controls community organization, as it limits prey populations, which limit production and so forth.
70
What is a trophic cascade?
a trophic cascade describes an event where a species occupying a trophic level is decimated, and the biomass at all other levels is impacted. (The effect will vary depending if the environment is top-bottom or bottom-up)
71
What will determine the impact of a trophic cascade?
The results of a density-mediated trophic cascade depend on the level of suppression. (how much it affects density)
72
What is a trait-mediated trophic cascade?
It is an event that occurs when
a predator induces a phenotypic change in the behaviour, development, morphology or physiology of a prey.
73
What is the dominant species in a community?
A dominant species is the most
abundant or collectively has
the most biomass.
74
What is the keystone species in a community?
a keystone species is the species that exerts the strongest control on community structure.
75
What is species richness?
Species richness provides the number of species present in a community.
76
What is relative abundance?
Relative abundance provides the proportion that each species represents of all individuals in the community.
77
What is the Shannon Diversity Index.
A method to quantify biodiversity. The formula is the following :
H = – (pA ln pA + pB ln pB + pC ln pC)
p=abundance of species
A,B,C= species
(Higher number=higher diversity)
78
What happens to productivity as biodiversity increases?
It also increases
79
What does productivity refer to?
Productivity refers to the rate of generation of biomass (primary
production and primary consumption) in an ecosystem.
80
What is a theory proposed to explain the increase of productivity when there is increase in biodiversity?
When there are more species, there is niche partitioning. Therefore, because more niches are used, more ressources are used, which means that more production is possible.
81
What is species stability?
Stability refers to the temporal constancy of a community, resistance to environmental change or resilience after a disturbance.
82
What happens to stability as biodiversity increases?
It also increases
83
What is the insurance hypothesis?
The insurance hypothesis states that a diverse group of species may be
more resilient to environmental or biological perturbations because different species exhibit different tolerances and responses to
changes in environmental and biological factors. So if there are more species, there is a greater change that some of them will be less affected by perturbation.
84
What is a disturbance in the environment?
Its is an event, such as a storm, fire, flood, drought, overgrazing, or human activity, that changes a community by removing organisms from it or altering
resource availability
85
What is the nonequilibrium model?
The non-equilibrium model describes communities as constantly changing after being affected by disturbances.
86
What are the two types of disturbances and how are they different?
high disturbance level results from high intensity and high frequency, while a low disturbance level can result from either low intensity or low
frequency.
87
What is the intermediate disturbance hypothesis?
It states that moderate disturbances
foster greater species diversity than
low or high levels of disturbances as high intensity disturbances cause too much stress for new species to establish themselves and low disturbance intensity never disrupt the dominant species, so new species are outcompeted.
88
What is ecological succession?
It is the transition in species composition in disturbed areas over ecological time.
89
What is primary succession and how does it occur?
primary is the first colonisation of plants in a lifeless area, such as volcanic ground. It begins with the apparition of lichen, lichen and other pioneering species. Other species than follow and the land becomes habitable.
90
What is the essential step to primary succession?
Soil formation must occur first to allow autotrophes to colonise the area.
91
What is secondary succession?
secondary succession occurs when an existing community has been removed by a disturbance such as a clear-cut or fire, while the soil is left intact. The territory will first be colonized by grass, than by woody shrubs and finally by trees until it it completely regenerated.
92
What is climate change?
It is the pattern in variation of temperature, atmospheric pressure, humidity, precipitation, wind and atmospheric particulates.
93
What is the difference between climate and weather?
Climate is the long-term pattern of weather in a particular area, while weather only describes the short-term conditions of these variables in a given region
94
What is paloeclimatology?
Paleoclimatology is the study of ancient
climates. This is inferred by observing abiotic evidence, such as sediments found in lake beds and ice cores, and biotic evidence, such as tree rings and coral.
95
What is anthropogenic climate change?
it refers to the change in climate associated with the production of
greenhouse gases emitted by human activity.
96
What are suggested hypotheses for climate change that have been rebuked?
Change in solar output (no change in solar output), Change in Milankovitch cycles (angle of rotation of the earth around the sun) (too slow) and volcanic eruptions (not enough gases released).
97
Why is there a seasonal change in C02 in the atmosphere>
As plants open in spring in the north and absorb a lot of carbon dioxide. When they die/hibernate in the winter there is a significant amount of pants that do not absorb C02. Therefore C02 levels go up during the winter and go down during the summer.
98
What is the trend for C02 in the atmosphere in recent year.
Linear trend of C02 increasing because of human activity.
99
What is a greenhouse gas?
A greenhouse gas is an atmospheric
gas that absorbs and emits radiation
within the thermal infrared range.
100
What are the main greenhouse gases?
Water vapour, Carbon dioxide, Methane, Nitrous oxide, ozone Chlorofluorocarbons and hydrochlorofluorocarbons
101
What is radiative forcing?
It describes the difference of insolation (sunlight) absorbed by the Earth and
energy radiated back to space.
102
What is the difference between positive forcing and negative forcing.
Negative forcing=more energy out than in from the sun
Positive forcing=less energy out than in from the sun
103
What are some changes associated to climate change?
Increased ambient temperature, changes in annual and seasonal precipitation, increased frequency of extreme weather events, ocean acidification., sea-level rises
104
What consequence does climate change have on species range?
It shifts/increases their range.
105
How does heat tolerance affect range of species that are cold intolerant when there is climate change?
If the species is heat tolerant and cold intolerant , its range will increase when temperature increases.
If the species is heat intolerant and cold intolerant , its range will shift towards the poles when temperature increases
106
What is phenology?
It is the study of recurring life cycle traits (in animals and plants) that are
influenced by abiotic factors, i.e. environmental conditions but an
emphasis on seasonal changes
(it has been mostly concerned with the dates of first occurrence of
biological events)
107
Why is a phenology shift a grave event?
It offsets ecosystems as organisms usually go through common phases at important times. So if one species goes through a change earlier, all other species are affected.
108
What is the difference between a community and an ecosystem?
A community is made up of populations of different species or organisms. These are biotic factors such as plants, animals, and bacteria. While an ecosystem is made up of a community, it also includes the abiotic factors in the environment such as the temperature, water, and the landscape of the area.
109
What is energy flow?
It describes how radiant energy enters an ecosystem and is transferred in chemical energy. (Never 100% efficient)
110
What is nutrient cycling?
It describes how certain atoms important for biological processes cycle from the abiotic environment to the biotic environment.
111
What is the cycle in which energy passes in the trophic levels?
Primary producers -> primary consumers -> secondary consumers ->all of these to decomposers.
112
What is the difference between détritivores and decomposers?
Decomposers recycle dead or decaying matter by secreting digestive enzymes and absorbing the necessary nutrients.
Détritivores consume dead or decaying material by ingesting it and digesting it. They than produce feces which are decomposed by decomposers.
113
What does primary production refer to?
It refers to the amount of solar energy converted in usable chemical energy, and thus biomass.
114
What does secondary production refer to?
It refers to the amount of energy in a consumer’s food that is converted into their own biomass.
115
How it production efficiency calculated?
Net secondary production/assimilation of primary production *100
116
Which organisms consume the vast majority of an ecosystems production?
Decomposers and detritivores
117
What is net secondary production?
It is the energy stored in the biomass of an organism.
118
What is assimilation?
It is the total energy taken by the organism when excluding the energy list as feces.
119
What is the average production efficiency of insects, of microorganisms, of ectotherms and of endotherms?
Inserts and microorganisms: forty percent
Ectotherms: ten percent
Endotherms: one to three percent
120
What is trophic efficiency?
It is the percentage of production transferred from one trophic level to the next. (Always less than production efficiencies)
121
What is the difference between energy and matter in an ecosystem?
Matter is recycled through a cycle between the abiotic and biotic parts of an ecosystem whereas energy comes as sunlight and is transformed in heat (second law of thermodynamics)
122
What is a carbon sink?
A process that absorbs carbon and stores atmospheric carbon in CO2.
123
What are some important carbon sinks?
Primary production, the ocean.
124
What is a carbon source?
Anything that releases carbon in the atmosphere.
125
What are some important carbon sources?
Respiration, deforestation, use of fossil fuels.
126
What are some ecosystem stressors resulting from human activity?
Habitat loss and degradation, ozone depletion, chemical pollution, nutrient enrichment and climate change.
127
What is biological magnification?
It’s the process by which toxins become more and more concentrated in the tissues of organisms that are higher in the trophic levels.
128
What is eutrophication?
It’s the process by whereby excessive nutrient richness of waterways can cause algal blooms.
129
What does eutrophication do?
Kills all life in a water as it forms a film that blocks all sunlight at the top of the water. This kills all other algae which kills all fish and marine life.
