Life on Earth Flashcards
1
Q
3 tiers that we can measure biodiversity
A
genetic
species (aka taxonomic)
ecosystem
2
Q
biological species concept
A
is a species when it can make a fertile offspring
3
Q
erwin (1998) experiment
A
using pesticide on a tree in the Panamanian rainforest
found over 400 species of beetle in the canopy
22 in the lower limbs and trunk
4
Q
example of hybridisation posing a challenge in describing plant species
A
false oxlip - hybrid between primrose and cowslip
5
Q
examples of plants that use uniparental reproduction
A
brambles, hawthorns, dandelions
6
Q
definition of Biodiversity - Gaston and Spicer (2004, pg.6)
A
The variety of life, in all its many manifestations. It encompasses all forms, levels and combinations of natural variation and thus serves as a broad unifying concept.
7
Q
how can we use fossils to identify species?….and an example
A
We study changes in fossils to see new species occurring through evolution. EG - There used to be a horse the size of a Labrador - 56-34 mya
8
Q
Estimated no. insect species
A
2-30mn
9
Q
what are chordates
A
vertebrates and closely related invertebrates
mammals, reptiles, amphibians, birds
10
Q
what are the two main drivers of species decline?
A
habitat degradation and exploitation
11
Q
what are the twin crises?
A
climate change and species extinction
12
Q
what was the Mediterranean climate like 20ka ago
A
much cooler and dryer
13
Q
where is resource over exploitation by humans the most damaging to species?
A
marine environments
14
Q
why is fossil record difficult to use to identify species
A
we can’t see the tissue and therefore can’t identify reproductive organs
15
Q
why is the no. species unknown?
A
they may be unknown to science (ie only known by indigenous people such as in tropical habitats)
many not discovered, especially soils and deep ocean benthos
16
Q
why was wegeners theory not accepted at first?
A
no evidence for the tectonic movements.
he wasn’t taken seriously by the geology community as he was an atmospheric scientist
17
Q
what is the current working estimate of the no. species?
A
3.5-111.5 million
18
Q
how does biogeography link to colonialism
A
Slaves were used to collect plant specimens, live and dead animals, shells and rocks such as for Sir Hans Sloane and Carl Linnaeus
In naming humans as Homo Sapiens, Linnaeus divided them into 4 categories based on physical appearance; Africa, America, Asia and Europe with a hierarchy favouring Europeans. This lead to race science which devastates groups of people.
Expeditions to understand life on Earth came along side imperial expansions - Joseph Banks (Kew Gardens) went along side James Cook
fossils are held far from where they were collected or excavated
current world distribution of flora and fauna are linked strongly to colonialism - British, Spanish French and Dutch restructured alien flora world wide.
19
Q
elements of ecological diversity
A
biomes, bioregions, landscapes, ecosystems, habitats, niches, populations
20
Q
elements of genetic diversity
A
populations, individuals, chromosomes, genes, nucleotides
20
Q
elements of organismal diversity
A
domains/kingdoms
phyla
genera
species
subspecies
populations
individuals
21
Q
what is genetic diversity
A
differneces in the genetic makeup between species
22
Q
what is organismal diversity and give example
A
diversity within and between taxa.
eg - marine environment has more animal phyla, but fewer species, than terrestrial realms
23
Q
genera
A
A Principle taxonomic category that ranks above species and below family; denoted by a capitalised Latin name
24
what are the five kingdoms in taxonomy
bacteria, protists, plants fungi and animals
25
what are organisms classed into
kingdom, phylum, class, order, family, genus and species
26
what is the 3 domain classification
bacteria and archaea (both prokaryotes) and eukarya
27
what are archaea
single celled microbes without a nucleus (prokaryotes). look like bacteria, but different genome and often live in extreme environments
28
what are bacteria
prokaryotic (no nucleus). unicellular with no organelles. include pathogens and probiotics.
29
what can we use the molecular clock for
shows when species diverged from each other
30
Noss (1990) onion diagram... 3 ways of measuring biodiversity
compositional, functional, structural
31
IUCN red list meaning
species is endangered
32
how was the iberian lynx species moved from critically endangered to endangered?
captive breeding
33
simple definition of biogeography
reasons why species are found where they are
34
2 key components of measuring diversity
no. entities
degree of difference between those entities.
35
how can genetic diversity be measured
directly - identifying and cataloguing variation in nucleotides, genes and chromosomes
indirectly - quantifying variation in phenotypic features shown to have a genetic basis.
36
definition of genotype
set of genes an organism carries
37
definition of phenotype
physical features of an organism. influenced by both genotype and environment
38
why does **Practical application** mean biodiv is measured mostly in terms of species richness (Gaston and Spicer, 2004)
**Practical application** measurable in practice - estimations are consistent of number of species of a given status in a given tason in a given area at a given time.
39
why does **existing information** mean biodiv is measured mostly in terms of species richness (Gaston and Spicer, 2004)
a substantial amount of info already exists on patterns in species richness, this has been made available in scientific literature. futher info can be extracted from museum collections and computerised data bases
40
41
why does **surrogacy** mean biodiv is measured mostly in terms of species richness (Gaston and Spicer, 2004)
species richness acts as a surrogate measure for many other types of variation in biodiversity.
generally if numbers are moderate; greater no. species will embody more genetic diversity, more organismal diversity and greater ecological diversity.
42
# h
how does **wide application** mean biodiv is measured mostly in terms of species richness (Gaston and Spicer, 2004)
the species unit is commonly seen as the unit of practical management, of legislation, of political discourse and of tradtion. variation in biodiv is often pictured as variation in species richness
43
**Key points** Why biodiv is measured mostly in terms of species richness (Gaston and Spicer, 2004)
* practical application
* existing information
* surrogacy
* wide application
44
2 KEY POINTS with explaination- **limitations** of measuring biodiversity in terms of species richness (Gaston and Spicer, 2004)
* definition of species - lack of agreement on *what a species is*. species can be regarded as hypotheses, opinions of concepts, as much as real robust entities. More than 7 major species concepts from either theoretical/practical perspectives.
* different types of diversity. example - 2 different species of mouse would be equally as *diverse* as a mouse and a squid. - but is this likely....normally 10s if not 100s thousands of species? Plus species richness correlates to other types of diversity
45
7 main species concepts provided in (Gaston and Spicer, 2004)
* biological
* cohesion
* ecological
* evolutionary
* morphological
* phyologenetic
* recognition
46
Definition of biological species concept
states that a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring; they do not breed successfully with other population
47
Definition of cohesion species concept
The smallest group of cohesive individuals that share intrinsic cohesive mechanisms (eg interbreeding ability, niche)
48
ecological Niche meaning
* The specific area where an organism inhabits
* The role or function of an organism or species in an ecosystem
* The interrelationship of a species with all the biotic and abiotic factors affecting it
49
morphological species concept
Classifies organisms based on observable phenotypic traits;It can be applied to asexual organisms, fossils, and in cases when we don't know about possible interbreeding ; There is some subjectivity in deciding which traits to use
50
limitations of morphological species concept
* species boundaries are unclear
* sometimes different species look alike
* only uses phenotypic data
51
limitations of biological species concept
* excludes asexual taxa
* complicated by natural hybridisation
* polyploidy (where offspring recieve more than 1 pair of chromosomes)
52
(Gaston and Spicer, 2004) Provides **3 reasons** why working with the fossil record is a constraing to understand history of life on Earth...
* **fossil record is far from perfect or even.** The record is far better for some periods than others.
No. species leaving fossil record range from <1 to at most a few % of those that ever lived.
* **only a tiny fraction of the fossil record has been recovered**
* **the record, and the portion recovered, is biased** towards the more abundant, widespread and lionger lived species. Also biased towards some types of organisms than others. ie soft bodied organisms like jellyfish are rarely fossilised while there are *bilions* of brachiopods (hard bodied).
53
examples of major groupings of soft bodied organisms that have left no fossil remains
the Platyhelminthes - flatworms, flukes and tape worms
54
what % of fossil species are marine animals
95%
55
what estimated % of primate species that have existed are known from fossils (and cite)
at most only 7% (Tavare et al, 2002)
56
while the fossil record continues to provide the bulk of insigns into the history of biodiversity...**what else? is playing a significant role**
molecular evidence
57
how can molecular evidence show history of biodiversity?
* we study the molecular data to see patterns of phylogenetic relatedness
* more different sequences will have diverged earlier in the evoulationary process
* assuming rates of molecular sequences diverging.. - we can create a molecular clock and estimate times of evolutionary events
58
examples of molecular and fossil evidence differing - and (cite)!
* molecular evidence suggests atleast 6 animal phyla originated deep in the Precambrian (400 myr+), much earlier than their first appearance in fossil record
*(Wang et al, 1999)
59
limitation of molecular evidence in understanding history of LoE
we assume rates of molecular divergance and the nature and dynamics of molecular clock.
60
4 geological eons
Hadean, Archean, Proterozoic, Phanerozoic
61
last 3 geoloic eras
Palaeozoic, Mesozoic, Cenozoic
62
periods within Cenozoic
Tertiary, Quaternary
63
Epochs within the Quaternary
Pleistocene, Holocene
64
Major events in Precambrian re life on earth
Origin of life - First multicellular organisms
65
Major event in Cambrian re life on earth
All of the major phyla arose that are present in fossil record including the first vertebrates
66
Major event in Permian re life on earth
mass extinction of marine invertebrates, origins of mammal-like reptiles and modern insects
67
Major event in Triassic re life on earth
Origin and diversification of ruling reptiles, origin of mammals, gymnosperms dominant
68
what are gymnosperms
Seed producing plants (spermatophytes) that do not flower - for example conifers
69
what are angiosperms
flowering plants. produce seeds so **spermatophytes**
70
Major event in Jurassic re life on earth
domiance of ruling reptiles and gymnosperms
origin of birds
71
Major event in Cretaceous re life on earth
origin of angiosperms
ruling reptiles and many invertebrates go extinct towards the end of period
72
when was the zenith of biodiversity?
late tertiary/early Quaternary
73
Major event in Quaternary re life on earth
origin of humankind
74
75
Outline the cambrian explosion
Happened more than 500million years ago.
When most of the major animal groupsn start to appear in the fossil record
Time of rapid expansion of different forms of life on Earth
76
List the taxanomic classes. Starting with domain....
* Domain
* Kingdom
* Phylum
* Class
* Order
* Family
* Genus
* Species
77
what does homologous mean?
homology is similarity due to shared ancestry between a pair of structures or genes in different taxa.
78
jellyfish is an example of which plylum?
cnidarians
79
what % of species through earth's history have gone extinct
over 90% (possibly close to 98%)
Gaston and spice 2004
## Footnote
q
80
why might marine species last longer in the fossil record than terrestrial
could be due to the greater buffering of marine systems to environmental change
81
when were the 5 big extinctions
Late Ordovician
Late Devonian
Late Permian
Late Triassic
End Cretaceous
82
define benthos
flora or fauna found at the bottom, or in the bottom sediments, of a sea or lake.
83
what does eukaryotic mean
organism containing cells with nucleus
84
what are protozoa
unicellular, heterotropiohc, eukaryotic species found in most habitats
84
Heterotrophic meaning
an organism that **cannot** create its own food, instead relying on nutrition from other sources of organic carbon, mainly plant and animal matter
84
Lists of described species are prone to two kinds of errors....(Gaston and Spicer, 2004)
* **homonymy** - the same species name may have been attriubted to more than one species
* **synonymy** - more than one species name may have been attributed to the same species.
85
why are fungi different to plants?
fungi are heterotrophic. this means they rely on using the matter og other plants. plants are **autotrophic** so create matter through photosynthesis
85
what are nematodes
One of the most abundant species on earth. roundworms. often parasitic
86
estimated No. extanct insect species that may have been synonyms (Gaston and Spicer, 2004)
20%
87
annual and daily rate of additional species being formally described (Gaston and Spicer, 2004)
13,000 per annum
36 per day
88
general trend of biodiversity on earth through history
radiations and stabilisations, punctuated by mass extinctions of different taxanomic groups at different times
89
Alpha diversities meaning
the number of species found within local assemblages or communities
89
beta diversities meaning
turnover of species identities between communities
89
gamma diversity
number of species occurring across a region
90
equation showing the relationship between species richness and area
S=cA^z
S = number of species
A = area
c and z = constants (Arrenhius relationship)
91
4 primary reasons to explain the species-area relationship
1. **sampling**. There may be no underlying relationship between species number and area - simply more species are sampled in a larger area
2. **habitat diversity** - larger areas are more topographically and environmentally diverse, so may contain more habitats giving more opportunities for organisms to establish and persist
3. **colonisation/extinction dynamics** - colonisation rates decrease if there are more species in an area - due to fewer species meaning to colonise and early colonisers are best suited to colonisation.
extinction rates will rise if more species in an area due to more negative interactions of competition and predation.
4. **speciation/extinction dynamics** - balance between speciation and extinction most significant. the larger the area - larger potential geographic ranges of species - thus greater liklihood of speciating and smaller liklihood of extinction.
92
what is speciation
when populations evolve to become entirely unique new species
93
2 theoretical types of relationship between the local richness an assemblage might attain and the species richness of the region in which that assemblage resides have been contrasted......
* **Type I** - local richnes may be directly proportional to, but less than, regional richness, following *a proportional sampling model*
* **Type II** as regional richness increases, local richness might attain a ceiling above which it does not rise despite continued increases in regional richness
94
what % of known classes are marine?
yet what % of known species are marine?
(Reaka-Kudla, 1997)
90%
less than 15%
95
5 sets of factors that have been suggested to explain the contrast in diversities between land and sea....
1.**Life began in the sea** -early diversification of form that led to different taxa occured in sea, with only some of groups being able to then make it onto land
2.**continental environments are more hetergeneous than marine ones** - this promotes greater levels of speciation on land. continental drift resulted in distinct F&F assemblages on different land masses, with different speicies with similar roles
3.**ocean bed environment is less architecturally elaborate than the terrestrial environment** - would promose more speciation on land
4.**patterns of herbivory differ between sea and land** - herbivores in marine environments tend to be generalists while terrestrial are specialist, often feeding on just a single host plant in a certain part. more specialism leads to more speciation.
5.**differences in body size distributions of marine and terrestrial species assemblages** - primary production, herbivory and predation involve smaller smecies in the sea than on land. Smaller bodied species maintain the continuity of larger geographic ranges more readily through larger numbers of individuals...this might reduce liklihood of allopatric speciation
96
what is allopatric speciation
species populations become geographically isolated from each other to an extent that prevents or interferes with gene flow leading to the development of a new species
97
which biogeographic region contains the most biodiversity
Neotropics
98
the three tropical biogeographic regions contain how much of the world's extant species
over 2/3
99
tropics from most to least biodiverse
neotropics, indotropics, afrotropics
100
why are the afrotropics less biodiverse than the neo and indo tropics
* tropical forests of africa are not as extensive, well developed or rich as those in the other 2
100
**4 KEY TAKEWAYS** from the composition of biodiversity across the broad biogeographic regions
* three tropical regions are the most biodiverse
* neo tropics is the most biodiverse
* the three tropics decline in biodiversity - neo, then indo then afro
* the patterns in biodiversity of different biogeographic regions may not be consistent amongst many groups of organisms - for example distribution amongst regions of butterfly species appears to be more similar to that of birds than mammals
101
how many biomes are there according to (Olson et al, 2001)
14
101
4 primary biomes of the oceans...and how are they divided
polar, westerlies, trades, coastal boundaries
on the basis of the algal ecology of the pelagic open ocean
102
what is the pelagic zone?
the area of open ocean.
103
what is a biodiversity hotspot?
an area that contains exceptional concentrations of endemic species and is undergoing exceptional loss of habitat
104
what does it mean for a taxon to be endemic to an area?
it occurs there and nowhere else
105
how do levels of endeminism levels change with different factors
* **Area** - number and proportion of endemic taxon will increase with area, but somewhar weak trend
* **Latitude** - number of endemics increases towards lower latitudes. the mean range size of species declines from high latitudes. (Gaston, et al. 1998)
* **Species richness** - often a positive correlation but with significant outliers too. Oceanic islands have high levels of endemism but low numbers of species
106
3 reasons for the occurence of areas of high endemism.
* **unusual environmental conditions** - may cause independent evolution of local adaptations that enable species to persist under these conditions but prevent them spreading more widely
* **isolation** the separation by distance or other barriers of individuals from conspecifics enables independent evolution - thus endemic taxa
* **historical** changing environmental conditions can constrain previously more widespread species. on continents high levels of endemism in areas of ecoclimatic stability.
107
4 features of latitudinal gradient of increasing biodiversity
* **persistent feature through much of the history of LoE**.Example seen this with study of angiosperms in the Cretaceous (Crane and Lidgard, 1989).
* **peak of diversity is rarely actually the equator** rather often an inflection point somewhat further north; 20-30 degrees.
* **gradient is commonly asymmetrical about the equator** - pattern is more like a pear (increases rapidly from north to equator then declines slowly from equator to south) rather than an egg.
* **steepness of gradient may vary markedly** between different taxa - butterflies are more tropical than birds
108
3 principle mechanisms causin the patterns of latitudinal gradients in biodiversity
* **area effects** the tropics have a larger area than temperate regions so more speciation and less extinction.
* **energy availability** there is more energy available in low latitudes, giving a wider resource base and allowing more species to occur.
* **time** greater evolutionary time in the tropics. less environmental perturbations like glaciation and climatic drying.
109
how does elevation affect species richness
species richness declines with elevation
110
what is the *peninsula effect*
terrestrial species richness declines towards the tips of peninsulas
110
what is chemosynthesis
process by which food is made by bacteria or other living things using chemicals as the energy source, typically in the abscence of sunlight
111
from the ocean surface downwards....
how do
* mean temperature and variability in temperature
* hydrostatic pressure
* light fluxes
* nutrient fluxes
change??
* decreases
* increases
* decreases
* decreases
112
what shape is the trend of species richness in pelagic and benthis communities with depth
decreasing, **hump shaped**
113
what is the *bay effect*
marine species richness declines as further into the bay
114
speciose meaning
rich in species
115
where are most marine groups more speciose?
* in tropical than temperate regions
* at intermediate than extreme depths
* in coral reefs than the pelagic zone
116
where are most terrestrial and freshwater groups more speciose?
* in tropical than temperate
regions
* lower elevations
* in forests than deserts
117
what is the local-regional richness relationship
local species richness tends to be positively correlated with regional species richness
118
the 17 mega-diversity countries possess what share of the worlds species
65-75%
119
where is the peak of marine species richness in regard to depth
intermediate depths
120
3 broad groups of *value* of biodiversity
direct use values
indirect use values
non-use values
121
two major components of *use value* of biodiversity
direct use value
indirect use value
122
what is direct use value
* derives from the direct role of biological resources in consumption or production
* essentially concerns biological commodities
123
broad types of direct use values of biodiversity (gaston and Spicer, 2004)
food, medicine, biological control, industrial materials, recreational harvesting and ecotourism
124
estimated amount of species of flowering plants and the amount edible to humans
300,000 +
12,500
125
x % of the worlds food supply is obtained, directly or indirectly, by x kinds of plants
75%, 12 plant types
126
which groups of animals are mainly used, directly or indirectly, for consumption
* insects
* crustaceans
* molluscs
* echinoderms
* vertebrates
127
more than 60% of the human population rely almost entirely on.... (Harvey, 2000)
plant medicine for primary health care
128
outline what is the planetary boundaries framework
* draws upon Earth system science
* 9 processes that are critical for maintaining the stability and resilience of Earth system as a whole
* aims to quantify levels of anthropogenic perturbation that would allow Earth to remain in Holocene like state
129
what is the geosphere
energy flow and nonliving materials in Earth and atmosphere
130
what are control variables in the planetary boundaries framework
* Each boundary has a control variable that captures the most important anthropogenic influence at the planetary level
131
list the 9 planetary boundaries
* climate change
* novel entities
* stratospheric ozone depletion
* atmospheric aerosol loading
* ocean acidification
* biogeochemical flows
* freshwater change
* land system change
* biosphere integrity
132
what is the biosphere integrity wedge divided into...and briefly explain the two sub wedge boundaries
* genetic diversity - rate of extinction needs to be compatable with preserving the genetic basis of the biospheres ecological complexity
* function integrity - is the HANPP at a level that does not start to diminish the biosphere
133
what is the zone of increasing risk on the planetary boundaries framework
zone where Earth system risks losing Holocene like characteristics
134
what is wrong with the 1.5 degree target set by Paris agreement
* this temperature is associated with substantial risk of triggering irreversible
* zone of risk is 1-2 degrees, so this target is in the ZoR
135
what are the *core boundaries* in the planetary boundaries framework
* climate change
* biosphere integrity
136
how much more is the current rate of extinctions than the average rate of the last 10 million years
10s-100s times larger
137
why do we use NPP as a measure of biosphere integrity
it is a computable proxy for photosynthetic energy and material flow into teh biosphere
138
what must NPP flows into human societies **not** do
substantially compromise the energy flow into the biosphere
139
what should planetary boundary limiting HANPP be set in relation to and why?
* HANPP limit should be set to **preindustrial Holocene NPP** not current potential NPP
* this is because global increase in NPP due to anthropogenic carbon fertilisation is negative feedback from Earth system on warming.
* therefore NPP contribution to carbon sink due to CO2 fertilisation should be protected and sustained rather than considering for harvesting
140
how much the NPP for future HANPP be generated
additional production of NPP above the Holocene baseline, not including NPP generated for carbon sinks
141
what is the drifference in tropic levels of HANPP between land and sea
* and what does this mean
* HANPP on land is mainly lowest tropic level- plant material
* HANPP in sea at higher trophic levels - fish
* means when high trophic level organisms are reduced, structure of energy flows will change, as opposed to amount of energy
142
what are the control variables of climate change boundary
annual averages of atmospheric CO2 concentration and changes in radiative forcing
143
what is the CO2 concentration boundary
and what is the currnet amount
350ppm
417ppm
144
what are `novel entities` in the planetary boundaries framework
truly novel anthropogenic introductions into the Earth system
* includes synthetic chemicals and substances, anthropogenic mobilised radioactive materials like nuclear waste, human modification of evolution like GM organisms.
145
at its crux, what is the planetary boundaries framework concerned about
the stability and resilience of the Earth system, not human or ecosystem health
146
what should the planetary boundary be set for untested chemicals like CFC
0%!
147
what is the dobson unit
measure of amount of trace gas in a vertical column through the Earths atmosphere - mainly used in study of Ozone
148
where are we operating in the Stratopsheric ozone depletion boundary
* Since the Montreal Protocol of 1987, the trend and extent of ozone depletion has recovered slightly,
* currently within the boundary - we are at 284 DU
149
what are green and blue water on the freshwater change boundary - and their proxies
* BLUE - streamflow as a proxy for **surface and groundwater**
* GREEN - root zone soil moisture is a proxy for **plant available water**
150
control variables for freshwater change in Planterary boundaries framework
global ice free land area with stramflow/root soil moisture deviations from preindustrial levels
151
what is the AOD measure
Aerosol Optical Depth
* inegrated measure of the overall reduction in Sunlight reaching the Earths surface casued bt all absorption and scattering in the vertical air column
152
what do increases in the AOD effect
* regional climate and precipitation
* asymetries in AOD between N and S hemispheres affects monsoon systems - relative cooling in N Hemisphere pushing precipitation southwards
153
what is the control variable in aerosol loading - planetary boundaries framework
interhemispheric difference in AOD
154
what is the control variable for ocean acification - planetary boundaries framework
carbonate ion concentration in surface seawater
155
what 3 major forest biomes are focused on by the land system change boundary and why
tropical, temperate and boreal
they play the largest role in driving biogeophysical processes
156
what is the control variable for land system change - planetary boundaries framework
forest cover remaining compared to the potential area of forest in the Holocene
157
what are the elements considered in biogeochemical flow boundary, and why
Nitrogen and Phosphorus - they constitute the fundamentla building blocks of life and their global cycles have been markedly altered through agriculture and industry
158
why are N and P important elements to the P boundaries framework
the anthropogenic release of reactive forms to land and oceans is of interest, * altered nutrient flows and element ratios have profound effects on ecosystem composition and long term earth system effects
159
160
how many Planetary boundaries have been transgressed
6
161
why is the land system change boundary so important
* respecting the boundary is one of the most powerful means that humanity has against climate change
* bringing global forest cover back to levels of late 20th century would provide a substantial carbon sink by 2100
162
examples of recently developed drugs from biodiversity
* **taxol** - compound found in pacific yew tree which kills cancer cells - one of best drugs for breast and overian cancer
* **cone snail venom** - peptide compounds found which help keep nerve cells alive. can be used as an effective painkiller
* **ACE-inhibiting drugs** - found in tropical pit viper venom that kills its prey by causing a drop in blood pressure - this drug has declined the death rate from heart attacks and stroke
163
it has been suggested that what proportion of plant species have produced a major drug (and cite!)
1 in 125 (Dobson, 1995)
164
what species prevent and treat osteoporosis and why (Cite!)
bears - they are the only animals in which the problem does not ocur (Chivian, 2001)
* during the 3-7 months that black bears den, they do not eat, drink, urinate or defectate yet can deliver and nurse young and maintain bone density
165
what is biological control
use of natural enemies to control species regarded as problems.
166
successes of biological control
* approx 30% and 40% of weed and insect controls have been successful
* econ retruns can be huge, with huge monetary values of annual gains in food production
167
what is biomimicry and examples
biological materials providing the models for many industrial materials and structures
* japanese bullet train modeled on the beak of a kingfisher bird for its aerodynamics
* tiny hooks on bur fruits inspired velcro
168
what does the indirect use value of biodiversity derive from
derives from the many functions that it performs in providing services that are crucial to human wellbeing
169
3 principle ways that ecosystem processes might respond to reductions in species richness
* *redundancy* - beyond some min number of species necessary, most species lose their significance
* *rivet popping* - loss of a few species has no effect, but beyond some threshold losses, the ecosystem processes will fai
* *idiosyncrasy* as diversity changes so does ecosystem function, but the magnitude and direction of change is unpredictable
170
3 mechanisms proposed to explain why there should be a relationship between biodiversity and ecosystem functioning
* **Sample effect -** if in a regional pool of a large number of species, some have strong impacts on ecosystem processes, the more species drawn from the pool the greater chance it includes strong impacting species
* **Species complementarity** - if species differ in resource use, then the more species that are included in a local assemblage the thoroughly resources will be exploited as species compliment each other
* **positive interactions** - increasing numbers of species in a local assemblage could result in increases in the number of interactions, thus increasing ecosystem functioning
171
4 components of non use value of biodiversity
* option value
* bequest value
* existence value
* instrinsic value
172
what is option value of biodiversity
* biodiversity should also be retained for the options for future use or non use that it provides
* includes huge potential for medicinal and industrial uses
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what is bequest value of biodiversity
* value of passing on a resource intact to future generations.
* John Locke - each generation should bequeath enough and as good for others to future generations, because **justice demands it.**
* **justice is opportunity**
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what is existence value of biodiversity
* all other values consider marketable commodities in terms of human wellbeing
* but biodiversity also values on its existence
* biophilia - humans have empathy with other bearers of life
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what is intrinsic value of biodiversity
* the value the entity has in itself, regardless of meeting human needs or even being quantified
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why may have extinctions declined since 1950
* could be due to more conservation activities
* but more likely - introduction of more stringent criteria for deciding that a species is genuinley extinct
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why does extinction data underestimate true levels of species losses
* available info on extinctions is strongly biased towards higher plants, birds and ammals which have been better studied.
* available info on extinctions is strongly biased towards islands (72% of mammalian species extincitons since 1500 are for islands) and developed nations. because its easier to document
* available info on exinctions is strongly biased towards terrestrial and freshwater species, away from marine ones.
* almsot invariably assumed that a described species is extant unless sufficient evidence shows they are extinct - museums contain specimens of species not seen since collected, yet no active research means we assume they are extant
* unless a species is known to science their extinction will pass unrecorded. most species are unkown
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4 main causes of species losses and declines in biodiversity
* direct exploitation
* habitat loss and degredation
* introduced species
* extinction cascades
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what does CFC stand for
**chloroflourocarbon**
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what proxy tells us CO2 levels were stable for thousands of years up to 1800
air bubbles in ice cores from Antarctica and Greenland
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how has human activity affected the Nitrogen cycle
altered it, fixing N2 by combining it with C, H or O2
happens deliberately when making fertiliser or as a by product such as from fossil fuels
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Williamson (1996) rule on species invaders
10% of introduced invaders become established and of those 10%, 10% become bests
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what negatives can introduced species cause
alter nutrient regimes, fire regimes, hydrology, energy budgets, change vegetation or habitat, drive changes in abundance and distribution of native species
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what is the most frequent extinction caused by introduced species
predation and parasitism
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outline the concept of extinction cascades
extinction of a key species may trigger a series of secondary extinctions.
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since 1600 how many recorded extinctions of plants and animal species have there been
over 1000
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what are the **ultimate** causes of biodiversity loss
the size of human population, the rate of human population grown and the scale of the human enterprise
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What is the Convention on Biological Diversity and key points
mutlinational treaty signed in 1992. aka **rio convention**
* first time biodiversity was comprehensively addressed in a binding global treaty
* first time that genetic diversity was specifically covered
* first time conservation of biodiversity was recognised as the common concern of mankind
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what are the 3 objectives of the convention on Biological diversity
1. conservation of biological diversity
2. sustainable use of its components
3. fair and equitable sharing of the benefits arising from the utilisation of genetic resources
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what are peverse subsidies and examples
subsidies that are adverse in the long run to both the economy and the environment.
* support for agirculture - may cause overloading of cropland leading to soil erosion, pollution from fertilisers and pesticides, and release of GHG
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what is in-situ conservation
methods of conserving all the living species especially in wild and endangered species in their natural habitats and environment. includes biosphere reserves, national parks, sancturies etc
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what is ex situ conservation
methods of conserving all living species in the artful habitats that reflect their natural living habitats,
eg - aquariums, botanical gardens, DNA banks, zoos
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2 major aspects of geographical diversity of the physical environment that allow living things to become numerous:
* habitat heterogeneity at different scales
* history - physical and ecological barriers have allowed for allopatric speciation
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where are the most endemic species
oceanic archipelagos
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what % of angiosperms and insects in Hawaii is endemic
89% angiosperm
99% insects
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what are species flocks
* groups of up to hundreds of species all clearly derived from a single ancestor from which they diversified without perceptible geographical isolation
* now all living in the closest geographical proximity within a restricted geographical area
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what % of biological diversity on Earth is insects
more than 50%
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how does the size of insects mean they are so numerous
* most insects are 1-20mm long
* means do not require large areas for populations to sustain themselves
* no long distance displacements are needed for feeding or reproduction
* also too heavy/fragile for long distance transport
* this facilitates isolated populations - leading to allopatric speciation
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what was life only from 3000ma-1000ma
prokaryotic, mostly unicelluar forms, later accompanied by the first unicellular eukaryotes
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what were the first multicellular organisms
simple algal threads composed of chain linked single cells
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when was the cambrian explosion
550 Ma
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what was the most severe of all mass extinctions
End Permian - 70-90% of marine invertebrate species extinct.
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what was the K-T extinction
* boundary of Cretaceous and Tertiary
* disappearances of amonoids and dinosaurs
* most widely investigated extinction
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what were the amanoids
extinct spiral shelled cephalapods which appeared during the Devonion and disappeared in K-T extinction
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largest and second largest invertebrate phylum
arthropods and Mollusca
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what are phylogenetics
the study of evolutionary relationships among biological entities - often species, individuals, genes (taxa)
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how many species are annually described as new
1500
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sympatric speciation meaning
the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic regions
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define biota
the sum of all living species found in a given region or at a given time in the history of life
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when did the crust first solidify
4.5 billion years ago
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what is naturgemalde
* the scientific approach of Von Humboldt to all natural phenomena
* views nature in its most holistic form - a constellation of interconnected phenomena whose patterns can be best envisioned and causes understood - when explored in synergy
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what is phytogeography
the geography of plants
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what was William Smith's map
*the map that changed the world*
* the first geological map of England
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how did Darwin discover evolution
* tortoises from the Galapagos islands - all had different carapaces - the phenotypes had best adapted for the environment on the specific island
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what is the taxon cycle theory
biogeographical theory of how species evolve through range expansions and contractions over time associated with adaptive shifts in the ecology and morphology of species
* formulated by E O Wilson
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what is Buffons law
* biogeographys most fundamental pattern and 1st principle
* *different regions of the globe, even those with similar climatic and environmental conditions, are inhabited by different species*
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3 fundamental processes of biogeography
evolution,
immigration/dispersal
extinction
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what is adaptive radiation
organisms diversify rapidly from an ancestral species into a multitude of new forms - particularly when a change in environment makes new resources available, alters biotivc interactions or opens new environmental niches
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prototypical example of adaptive rdaiation
finch speciation on Galapagos - *darwins finches*
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what are macro and micro evolution
* **macro**evolution is diversification above the species level
* **micro**evolution is evolutionary diversification within a species
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what does geographic template mean
very regular spatial patterns of variation in environmental conditions across the planet
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what are the two component patterns of non random variation across the geographic template
* **spatial autocorrelation** - the tendency for similarity in environmental conditions between sites to decrease with distance from those sites
* **Enviro-geographic gradients** - particular trends in environmental conditons along the principal geographic dimensions
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what are the principal geographic dimensions
latitude, elevation, depth, area, distance, isolation
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what are the Earth's three great engines driving the environmental variation forming the geographic template
* **energy of the sun** - provides the energy used by nearly all biological communities and drives climatic conditions
* **immense heat of the core** driving plate tecctonics and associated phenomena
* **gravitational forces** influence earths revolution on axis, rotation about the sun, tides, currents etc
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what distinguishes biomes from each other
their principal forms of vegetation which in turn form under particular climatic conditions and soils
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why do we have heavy precipitation above the tropics
* solar radiation is at its most intense
* creates hot air masses that rise above surface high into atymosphere
* as pressure decreases, the air masses cool
* colder air cant hold as much moisture, water condenses and heavy precipitation occurs
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how do air masses create hot desert biomes
* tropical hot air masses will reach upper atmosphere and forced split to form two cells of currents - Hadley cells - flowing N and S
* these air masses cool, become more dense and descend, as they do the column of air above becomes bigger, thus more air pressure
* more air pressure means warmer temperatures and increased capacity for moisture - but the air has already lost most moisture above tropics!
* therefore hot dry air descends leading to desert biomes
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where are some of Earths most expansive deserts found
latitudes 30degrees N and S - where the air masses from Hadley cells descend
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example of mountain influences on rainforest/desert biomes
* where mountain ranges occur along coast and prevailing winds are from ocean islands -
* air masses rising and condensing along mountain slopes create rainforests on the windward slope -
* once air passes over peak and descends it promotes the formation of deserts on leeward side
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how does proximity to the coast influence local to regional climates
* high heat capacity of water means oceans vary less in temperature compared to land or air
* coastal and island environments tend to be thermally buffered - experiencing more mild summers and winters and less seasonal variation
* in contrast interior regions tend to experience much more seasonality in climate, and less rainfall than needed for forest, leading ot praire, savannah and grasslands.
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how do biomes change as we go up a mountain
* we see changes to pressure, temperature and precipitation as we climb
* mimics the latitudinal changes in a local scale - a tropical mountain will go from tropical to polar.
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how much of earths surface is marine realm
70%
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what is bathymetry
the measurement of the depth of water in oceans, rivers and lakes
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where is Alfred Russel Wallace study evolution
Malay achipeligo of Indonesia
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when did Pangaea start to break up
early Mesozoic, 240-220 million years ago
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what was Gondwana
large landmass - supercontinent - today part of Africa, Americas, Australia and India
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why is there a relatively high similarity of plants an animals in southern continents
much longer history of Gondwana than northern continents allowed for evolution and dispersal of species
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what are seamounts
large underwater mountains rising from sea floor, often formed from volcanic activity
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how were Hawaii and the Galapagos islands formed
hotspots above mantle plumes that pushed through oceanic crust
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what is a guyot
also called a tablemount - an underwater volcanic mountain with a flat top - eroded by marine processes
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why did global warming occur when the continents were concentrated in the tropics
* Land absorps more solar radiation than the reflective waters
* Earths total heat budget was accentuated
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what was the mid Eocene sauna
* 55ma
* average global temp was well over10 degrees of todays
* earth was devoid of any significant ice sheets and tropical climates extended deep into arctic and antarctic latitude
* replacement of ancient mammals with modern orders of today
* surge in evolutionary radiations of animals and plants
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what is the solar constant
the total energy emitted by the sun
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3 main features of the cyclical changes in earth's orbit
* eccentricity
* obliquity
* precession
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how did ice sheets feedback during earths cooling in Pleistocene
* ice sheets expanded, increasing amounts of solar radiation reflected back into atmosphere - **albedo**
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how were species ranges changed during Pleistocene
would shift by 10 degrees in latitude
* in mountainous regions by 1000m elevation
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what is confusing about the Pleistocene megafauna
* these large mammals and bird lineages surged in diversity and ecological dominance even during intense glaciation
* yet at the end of Pliestocene they collapsed
* caused by humans, who spread across land bridges, rather than climate
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when and how were the plant and animal extinctions of pleistocene
plants - towards the start, with the changing climates cycling into glaciations
animals - towards the end with the rise of humans. not instantaneous, but with the spead of humans into different continents
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what does it mean that adaptive radiations are inherently *autocatalytic*
they are driven largely by interactions among the species themselves,
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what does comparing Galapagos finches and Hawaiian honeycreepers tell us and why
* both are from the same ancestral species of finch that colonised the archipelgo
* more than 50 species in hawaii, and 14 in galapagos
* hawaii's isolation, age, time since ancestral finches arrived is greater leading to more adaptive radiation
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what is the `adaptive zone`
optimal range of isolation leading to adaptive radiation. island must be within dispersal range of a few species, but well beyond range of most others
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what does **parallel** and **hierarchical** adaptive radiations mean (lobeliads in Hawaii)
* **parallel** - temporal-spatial patterns of divisions were repeated on each island
* **hierarchical** - in that each separate insular lineage underwent a similar succession of further splits on progressively finer spatial scales (habitat, montane slopes, along the slope, growth form and habit)
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what is the concept of functional isolation
species with limited dispersal powers and greater site fidelity are likely to have higher diversificiation rates and higher levels of endemicity
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what does it mean if a species has a high site fidelity
it is more likely to stay in that place
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why do mammalian carnivores have much lower rates of radiation
high energy demands, more specialised dites, broader home ranged and longer generation times
* means evolution happens much slower than herbivores
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what are two forms of maps used in biogeography and describe them
* **systematic maps**- static, they portray the geographic range(s) of species during a particular time period
* **chorological maps -**dynamic as they reconstruct the evolutionary development and geographic expansions og a focal lineage over time
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what is philopatry
the tendency of an animal to remain in or return to the area of its birth
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what are geophylogenies
geographically explicit reconstructions of the evolutionary development of lineages across time and space
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4 Reasons why the tropcs have more biodiversity than anywhere else
1. **solar radiation** - there is more intense solar radiation, supporting higher rates of plant productivity and growth.
2. **climatic stability** - tropics are less variable in climate over long time periods - eg glacial cycles in pleistocene - allowing species to develop niches
3. **surface area** ; tropical landmasses are bigger provifing more resources, habitats and niches, to support more plants and reduce extinciton rates
4. **the tropics are older** unlike the terrestrial or marine systems of higher latitudes, the tropics have been around for more time, allowing more species to accumulate through evolution and immigration.
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why does terrestrial biodiversity peak at intermediate elevations
* colder air means there is more precipitation
* more isolated leading to more divergence and endemic species
* less likely to be affected by parasites, competitors and predators. (including humans)
*** combination of the beneficial and negative factors**
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why does occeanic biodiversity peak at intermediate depths
* a **balance of the beneficial and unbeneficial factors**
* solar radiation will decrease with depth, meaning less light and temp
* but there is more stability deeper, as more isolated from storms
* more nutrients deeper due to marine snow
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Where have most of human species extinctions taken place
islands
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3 types of island
continental islands - part of continental shelf but become islands when land bridges are covered by rising sea levels like Doggerland
continental fragments - broke off by tectonic drifts ie Jamaica, Cyprus
oceanic islands - islands in middle of ocean that are formed from submarine volcanism
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when will a species have larger leaves
when light is a limiting factor
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if we are studying a small a local area and we see different patches of differnet plants, what could we infer
if we know their tolerances, we could infer soil characteristics
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what is the difference between ecological and realised niche
ecological - all the resources a species needs to survive and reproduce, as well as its interactions with other species. the full range of conditions and resources that a species could potentially use or occupy in its habitat.
realised - This is what actually happens in nature. It’s the specific set of conditions and resources that a species uses or occupies in its habitat due to competition, predation, and other factors. Essentially, it’s the part of the ecological niche that a species actually occupies in reality.
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what is competitive exclusion
complete competitors cannot exist, as they use the same resources. one will drive the other to extinction.
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what do trees aim for in the UK compared to the Med
Trees in the Med aim for water as it is scarcer
UK trees aim to light due to it being the limiting factor
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2 example of spatial autocorrelation
Oak trees have their acorns distributed by the eurasian Jay, meaning they will likely be growing close to each other. the jay tucks at the acorn, causing it to auto germinate
ash tree - seeds are wind dispersed. so trees will grow close
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