Biodiversity & Populations (4) + (6) Flashcards
(106 cards)
1
Q
as seral stages increases, what happens
A
Numbers increase more
During primary succession, at each stage until climax populations alter their environment enabling larger organisms to thrive.
Most rapid change at stages 3 + 4:sub-climax community
AT seral stage 5, climax community, most biodiversity, highest # of plant species, most niches, longest food chains, high biomass, high PP. Soil: low pH, large q of humus, deep with topsoil/subsoil, high q of N2
2
Q
describe 5 factors that depict LOW biodiversity in a habitat
A
- Relatively few successful species
- The nature of the environment is stressful/extreme with few ecological niches
- Relatively few species live in the habitat, often with very specific adaptations for the environment.
- Simple food webs
- A change to the environment will have a major effect on the ecosystem
3
Q
describe the steps in population size fluctuating due to intraspecific competition
A
- when resources are plentiful, population increases
- tf there will be more organisms competing for the same q of food/space
- these resources become scarce, the population decreases
- a smaller population means there’s less competition for food/space, which is better for growth/reproduction- pop. grows again
4
Q
describe the trend of a predator-prey graph
+ however?
A
- Prey population increases = there’s more food for predators, so their pop. increases
<em>Predator pop. increases AFTER prey pop.</em>
- <em></em>As predator pop. increases, greater numbers of predators consume prey, so more prey is eaten, so their pop. decreases.
- There’s tf less food for predators, so their pop. decreases after prey pop. decreases.
However, they are usually more complicated eg. due to availability of food for prey. The prey pop. size might dec. because there are too many, then predation amplifies this. -intraspecific competition + pred-prey. There may be other predators/prey too.
5
Q
explain the pitfall traps and Tullgren funnel ways of sampling animals
A
> creating a pit in the ground, with waterproof cover to prevent rainwater from filling the traps. Alcohol can be placed in the bottom to prevent invertebrates leaving.
> Soil/leaf litter placed in funnel on a sieve, with a light bulb above and a jar of alcohol below. Small organisms are collected from the jar.
Light bulb dries out soil, organisms move away from heat + light. They fall through the sieve.
6
Q
explain what happens in these stages of the carbon cycle
- CARBON into PLANTS
- CARBON into ANIMALS/CONSUMERS
- CARBON out of PLANTS/ANIMALS
- BREAK DOWN
- RELEASE
A
- Atmospheric CO2 diffuses into mesophyll cells + photosynthesis converts it to carbs/organic compounds
- Primary/secondary consumers move C to the next trophic level, (herbivores, then carnivores/omnivores) C-containing organic compounds are hydrolysed and they become part of the organism eg. lipids, proteins, carbs.
- Any organism in the food chain dies, undigested food contains C compounds & passes out of animal/plant bodies. Now part of dead remains/excretory products.
- Saprotrophic decomposers, mainly bacteria but also fungi, secrete enzymes hydrolysing the large organic molecules. C-containing compounds now in decomposers eg. lipids, protein, carbs. Some products used in respiration by bacteria.
- ALL ORGANISMS IN THE FOOD CHAIN RESPIRE, releasing CO2 into the atmosphere
7
Q
give 5 factors that depict high biodiversity
A
- Large number of successful species
- The nature of the environment is relatively benign/not stressful, with more ecological niches
- Many species live in the habitat, often with few specific adaptations to the environment
- Complex food webs
- The effect of a change to the environment is often relatively small for the whole ecosystem
8
Q
give examples of cooperation at inter and intra specific levels
A
- Intraspecific- social insects eg. ants, termites, honey bees*
- Interspecific- mutualism eg. coral + algae*
9
Q
Give the first three factors that affect genetic biodiversity (MICAIN) + one line how they affect it
A
MUTATIONS- new alleles produced increase
INBREEDING/ SELECTIVE BREEDING- only a few individuals selected for breeding decrease
CAPTIVE BREEDING PROGRAMMES- endangered species are low in number decrease
10
Q
Give the second set of three factors that affect genetic biodiversity (MICAIN) + brief description
A
ARTIFICIAL CLONING- genetically identical offspring are produced decrease
INTERBREEDING/ GENE FLOW- between 2 populations increase
NATURAL SELECTION- alleles for disadvantageous characteristics are lost decrease
11
Q
how are conservation/preservation needs balanced with human needs in the UK peat bogs
A
Areas of wet peat store water + CO2, and are home to many plants & animals eg. moss
Farmers use peat bogs to graze sheep/deer- overgrazing = loss of moss species, soil compaction (increasing water runoff, taking sediment with it), and peat bog erosion.
Govt. has given farmers £ to use peat in a sustainable way- to reduce water runoff, lower the number of livestock or remove them over winter. eg. Environmental Stewardship Scheme
12
Q
how are the following edaphic factors measured
- soil texture
- soil moisture content
- mineral ion content
- humus content
- mineral matter content
- soil pH
- temperature of soil
- air content
- depth of soil
A
- Pass dry soil through sieves of different mesh to find composition of gravel, sand, clay
- Drying soil to constant mass
- Conductivity of a soil solution
- Mass lost by heating dry soil to burn off organic matter
- Mass left after organic matter is burnt off dry soil
- pH of soil water, using pH meter, universal indicator paper or solution
- Temperature probe
- Add known volume of soil to water, stirring to drive off air. The expected volume of soil + water = actual volume of soil + water = AC
- Soil auger or cut a soil profile with a spade
13
Q
how can one calculate the energy in:
- secondary production*
- consumption*
- food absorbed*
A
E <em>biomass</em> = E consumed - E respired - E excreta - E egesta
the length of the food chain is limited by these losses, energy converted to biomass in consumer = secondary production. Energy is lost in metabolism, mainly in respiration.
E consumed = E biomass + E respired + E excreta + E egesta
E <em>food absorbed in alimentary canal </em>= E consumed - E egesta
14
Q
how can ABIOTIC FACTORS be divided
A
climatic eg. temperature range, precipitation
edaphic eg. features of the soil
topographic eg. altitude, aspect, gradient, shape of the land
15
Q
how can one sample using a belt transect
A
Place a quadrat along the transect, count the species inside the quadrat, giving a frequency.
(A qualititative ACFOR scale: abundant, common, frequent, occasionally, rare, N for none)
Use an identification key
16
Q
how can one study succession most easily
A
Usually difficult bc it happens over time, however
SAND DUNES
because they constantly shift, tf those nearest the shore are youngest. As one moves away from sea, the dunes are older.
17
Q
how can the proportion of polymorphic gene loci be measured
+ what does the result infer
A
number of polymorphic genes / total number of loci
eg. 2 / 8 = 0.25, tf a quarter of the gene loci are polymorphic
* The greater the proportion of polymorphic gene loci, the greater the genetic biodiversity within the population because there are greater differences in the alleles among individuals in the population.*
18
Q
what does a pyramid of numbers and a pyramid of biomass
A
Numbers: shows the relative numbers of individuals at each trophic level eg. by length of bar
whereas, Biomass shows relative amount of biomass at each trophic level eg. by length of bar
19
Q
how can population growth be summarised
A
It changes in a population over a period of time.
The population will grow exponentially if:
> the species enters an unoccupied area
> there is no food shortage
> there are no predators
The population will then always reach an equilibrium
20
Q
how do farmers ensure plants can uptake more N2
A
PLOUGHING; increases drainage + aeration,
reducing anaerobic conditions, reducing their growth on farmland
21
Q
how do farmers control disease/predation in their artificial ecosystems
A
PLANTS: fungicides, disease-resistant GM crops
fencing to exclude grazers such as rabbits/deer, using pesticides to kill insect pests/slugs etc. pest-resistant GM crops
ANIMALS: antibiotics/vaccines
ranching control predators eg. wolves + are extensive systems
intensive systems- eg. keeping animals in sheds
22
Q
how do farmers maximise energy input for maximising secondary production
A
plant - Optimum planting distances between crop plants, light in greenhouses on overcast days, early seeding
animal - providing good-quality feed, high in energy so not wasted in excretion
23
Q
how do farmers maximise growth of livestock and crop plants
A
Livestock (primary consumers)
Provide food supplements eg. vitamins/minerals, selective breeding for fast growth (kill just before adulthood)
Crop plants (producers)
Provide water (irrigation), fertilisers (containing NPK + other elements eg. S), selective breeding for fast growth, CO2 pumped into greenhouses, crop rotation
24
Q
how do farmers reduce competition + energy loss in their agriculture
A
CROP PLANTS/PRODUCERS
Ploughing + herbicides for weeds
Selectively breeding plants that maximise energy storage in edible products eg. seeds, fruits, tubers
LIVESTOCK/PRIMARY CONSUMERS
Control competitors eg. rabbits, deer
Animals kept in thermostatically-controlled sheds, less energy lost in movement/maintaining body temp.
25
how do humans affect biodiversity
_Deforestation, agriculture + climate change_ due to **human population growth** requiring housing, industry and farming.
26
how do the words *habitat, niche, population, species & community* interact
SPECIES is a group of organisms interbreeding to produce **fertile offspring.** A group of the *same species* in a give space is a POPULATION, and they *inhabit* a HABITAT, a **place** within the ecosystem. NICHE is **where** they live and **how** they live i.e. which **specific factors** influence it; only one SPECIES inhabits a niche, often the role of the organism within an ecosystem.
A COMMUNITY is a group of POPULATIONS interacting in a habitat/ecosystem.
27
how does succession progress
Succession begins with low mineral ions due to farming/new land/no soil profile, then seeds/roots grow from previous crops etc., followed by **herbaceous shrubs/plants (high leaf area = increasing NPP)** then trees (large tress = **decrease in NPP** due to more dead parts/non-photosynthetic tissue = less photosynthesis compared to rate of respiration)
Increased plant biodiversity = **more niches** for animals, increasing index of diversity, then stabilises and decreases as trees shade areas, decreasing herbaceous abundance. Mineral ion content increases as humus/decaying matter increases and microorganisms release minerals from it. SUBCLIMAX COMMUNITY HAS HIGHEST PRODUCTIVITY.
Will also **reduce mineral ion content** due to large trees shedding fewer leaves for decay/humus/microorganisms.
28
how does _agriculture_ affect the environment and what is its effect on *biodiversity*
*To feed growing populations, **monocultures** are established.*
* **DEC.** as only a few species are farmed
* **Deforestation + removal of hedgerows** to allow for large farming machinery- **loss of habitats/plant species** eg. for *mice, hedgehogs, birds, invertebrates etc.*
* **Herbicides/pesticides dec. species diversity**
* M supports v few species
29
how does intraspecific competition affect population size
Organisms of the **same species competing** for the same resources. *Population 'booms and busts' as it moves towards and away from/fluctuates around the **CARRYING CAPACITY; the maximum stable population size** of a species that an **ecosystem can support***
30
how is genetic biodiversity *measured*
By measuring **polymorphism; polymorphic genes** have *more than one allele at a locus.*
The greater the **proportion** of *polymorphic gene loci,* the *greater the genetic biodiversity within the pop.*
eg. Multiple alleles; *blood groups IA IB IO*
* Dominant/recessive A, a*
31
how is _genetic biodiversity_ *reduced*, and what occurs if it is
In **isolated** populations, GB is often decreased eg. in captive breeding programmes, leading to problems from **in-breeding**.
32
In Ecology, what is _reclamation_
**restoring ecosystems** that have been _damaged/destroyed_
33
In the Carbon cycle, what is the unnatural route?
What do *Saprotrophs do to decaying matter.dead organisms?*
Dead matter forms _sediment_ and under _special geological conditions_ becomes _fossil fuels_. These are mined by humans and _combustion_ returns large quantites of CO2 to the atmosphere.
Convert it to **humus** in the soil (**dead organic material**, formed from *leaves, plant & animal material* by soil microorganisms)
34
name a Seed Bank & its aim/uses
**Kew Millenium Seed Bank Project**
**-***aims to store a representative sample of seeds from every known species of plant*
* AIMS: to maintain **viability** of seeds, tf kept in **cold/dry** conditions. Samples are periodically **germinated** to test viability.*
* USES:*
1. ***Provide food crops** + building materials*
2. *Maintain **genetic biodiversity** in wild species of crop*
3. *For **habitat reclamation/repopulation** of endangered habitats*
35
name the 3 factors limiting PG that are *density independent* or *both*
_Independent-_ **climate**
*_both-_* shortage of food, water, oxygen
lack of light
36
name the 5 limiting factors for PG that are *density dependent*
1. **_Predators_**- critical to carrying capacity
2. **_Lack of shelter_**
3. **_disease_**
4. Accumulation of _toxic waste_
5. _Psychological_ factors eg. overcrowding. reluctance to breed
37
name the 5 phases of the *population growth curve*
**LAG
LOG
PG DECELERATES
STATIONARY
DECLINE**
38
name the 8 methods of regulating sustainable fisheries
1. ***exclusion zones***
2. ***limiting boats***
3. ***banning*** *in season*
4. ***nets/hook rules***
5. ***quotas***
6. ***inspection** of catches*
7. ***restocking***
8. ***ecosystem approach:** no trawlers, no-catch zones, leave oldest fish + youngest fish*
39
name the BIOTIC factors in an ecosystem
1. **Members of a food chain- *producers, consumers (10, 20, 30), decomposers***
2. **Competition- *intraspecific, interspecific***
3. **Cooperation- *intraspecific, interspecific***
4. ***Parasitism***
5. ***Predator-Prey***
40
name ways of catching insects for sampling from *long grass, trees* and *river beds*
**long grass;** sweep net, used to catch insects from long grass + crops
**trees;** tree beating or bushes, a large white cloth is placed under the tree
**river beds;** kick sampling- net is placed downstream, current carries material into the net, including organisms living in river bed
41
On a *xerosere* eg. bare rock, name the *seral stages*, the plants that grow at that time + the *abiotic changes* incurred
_Abiotic factors dominate._
1. **PIONEER SPECIES eg. lichen.** Simple soil forms
2. **eg. dominance by moss/small hardy plants** an increase in _organic matter_ + mineral particles, increase in _moisture retained_, _shading_ = lichen outcompeted
3. **MID-SUCCESSION eg. dominance by herbaceous plants/shrubs** soil build up, _pH decreases_ as _humic acid increases_ from humus in soil
4. **SUB-CLIMAX COMMUNITY eg. dominance by tree seedlings.** increase in soil profile, increase in _moisture_, _rate of change_ of species is _rapid_
5. **CLIMAX COMMUNITY eg. mature woodland.** increase in _shade_, _smaller trees/shrubs outcompeted_
_Biotic factors dominate._
42
STAGE **4** for nitrogen-fixing bacteria in the Nitrogen cycle
*Nitrogen-fixing bacteria **reduce** atmospheric N2 to **NH3**, using **nitrogenase** enzyme.*
Two types of N-F B:
1. _Free-living bacteria_; bacteria living soil, 90% of N2-fixing eg. _Azobacter_
2. Bacteria in _root nodules_ of _leguminous plants_ eg. _Rhizobium_
43
STAGE **1** for nitrifying bacteria in the Nitrogen cycle
***ammonification & putrifaction***
The *nitrogen* in plants and animals **re-enters by -death** **-excretion + egestion** and is broken down by **decomposers/bacteria** which carry out " to form **NH3** (usually proteins & aas released into soil which are broken down).
44
STAGE **2** for nitrifying bacteria in the Nitrogen cycle
**Nitrification =** *oxidation of ammonia to nitrite NO2-by _Nitrosomonas._ then oxidation of nitrite to nitrate NO3-by _Nitrobacter._*
## Footnote
*Nitrates are very **soluble** and are easily taken up by **plants**- **soil fertility INCREASES***
45
STAGE **3** for denitrifying bacteria in the Nitrogen cycle
* denitrifying bacteria remove the nitrates from the soil by converting it into **atmospheric nitrogen NO3- → N2***
* these bacteria are **facultative anaerobes;** they can use NO3- instead of O2 to carry out the equivalent of resp. on an ETC*
* tf they thrive in **anaerobic conditions/water-logged soil***
46
what are the aims of *CITES*
*_Convention on International Trade in Endangered Species_*
1. *Regulate/**stop trade** in endangered species*
2. *Make **killing** of endangered species **illegal***
3. ***Limit trade** in less endangered species i.e. only w/ a permit/licence*
4. ***Trade in products** of endangered species **illegal***
5. Stop trade in **wild plants** for **commercial** purposes
47
what are the axes for a population growth curve and what is the maximum called
x axis = time
y axis = population size
The *carrying capacity* is the maximum the population grows to
48
what are the effects of the following _abiotic factors_ on _adundance_ and _distribution_
1. **Temperature**
2. **pH**
3. **Depth** of water
4. **Flow** rate
5. **O2 conc.**
6. **Turbidity**
7. Dissolved solid eg. conc. of ion
8. **Light intensity**
9. Type of subtrate
1. Temp. **range** determines the **species which can survive**
2. Many species cannot survive in _waters of low pH_
3. Determines **size of fish** that can survive
4. Some species prefer *high flow rates*, others cannot survive
5. Few species survive **low O2 conc.**
6. Makes vision difficult for predators
7. Ions provided for physiological processes
8. Influences **rate of photosynthesis** of submerged plants
9. eg. species burrows in mud, woodlice survive under stone
49
what are the two types of food chainnn
_Grazing chain-_ based on *living* plants
_Decomposer or detrital chain-_ based on *dead plant material*
50
what are the two levels of _primary productivity_
*gross primary productivity (GPP)*
## Footnote
The *rate* at which the *solar energy absorbed* by the plant is *converted* to *chemical energy. Normally _1%_*
***net primary production (NPP)***
**NPP = GPP - respiration**
Some of GPP is lost in respiration, leaving energy stored in the **biomass of producers** (NPP), which is the energy available to the **next trophic level**
51
what are the types of *non-random/selective sampling*
* opportunistic*
* systematic*
* stratified*
52
what are the *two types* of **belt transect**
*continuous belt transect*
## Footnote
*-place the quadrat all the way along the tape measure*
**interrupted** line transect
-place the quadrat at **fixed intervals** along the tape measure
53
what are *density dependent* and *density independent* factors
Factors that _limit population growth._
Density dependent depend on the **number of individuals** present in the population.
Some factors can be both, depending on the species and its environment.
54
what are *producer+consumers* and *predators+prey*
Producer: _green plants_ that produce _organic material_ by the process of _photosynthesis_
Consumer: _animals feeding_ on plants or other animals- they can be Predators: an _animal_ that lives by _killing_ and _eating_ other animals or Prey: an animal _hunted or seized for food_, especially by a _carnivorous_ animal
55
what happens to the _net primary productivity_
Energy + biomass are transferred along the food chain as carnivores consume food. The *energy that remains* is incorporated into the biomass of the consumer = *secondary production/productivity.*
*eg. if net primary production of grass = 21,135, food eaten is 3,153, and heat loss in respiration = 1,020 faeces = 1,970 urine would be 38 kJm-2yr-1 and energy efficiency = 3.964%*
Energy + biomass are lost at every trophic level by:
**Egestion, excretion, respiration, death.**
56
what happens when *abiotic factors* are *optimum* and when they are *not ideal*
**WHEN OPTIMUM FOR THAT SPECIES:** organisms can **grow fast/rate of reproduction increase/is more successful**.
*eg. when temp. of organism's surroundings is ideal, does not use energy to maintain core temp. but for growth/reproduction/seeds- **pop. size increases***
_CONDITIONS NOT IDEAL-_ organisms grow more _slow_/reproduction is _less successful_.
*eg. is temp. of surroundings sig. higher or lower than their optimum body temp., they use a _lot of energy_ to maintain core temp, less for growth/repro., _pop. size decreases_*
57
what is *a keystone species*
A species that has a **disproportionate effect** on its environment **relative to its adundance** (often a *top predator*). If this species is **removed**, the **ecosystem changes dramatically** and may cause other species numbers to change. *eg. wolves in yellowstone park.*
58
what is an *abiotic factor*
A **non-living** condition/thing, as **climate** or **habitat**, that **influences or affects an ecosystem** and the organisms in it.
59
what is an *ecosystem*
The **sum total** of **biological life + non-biological components** within an area i.e. **biotic + abiotic components**, which are interacting and where **energy flows** in food chains/webs and **nutrients cycle eg. C, N, minerals, water.**
60
what is a *decomposer*
A **heterotrophic microorganism** that **breaks down dead organic matter** to simpler **organic/inorganic** matter.
61
what is a _detritivore_
Organisms that _break down/feed on detritus_ i.e. Dead organic matter. into simpler molecules for decomposers. They preceed *decomposers* in the process of decomposition.
62
what is a *pooter* (2)
A sampling technique: one tube pointed at invertebrate, the other one inhales with, invertebrate enters jar
63
what is a *transect*, from which you can *sample*
how do you sample
A **line across a habitat** made by a long **tape measure.**
Species which **touch the transect/tape** are counted.
64
what is dry biomass + how is measured
Dry biomass is an _accurate measure_ of the _organic_ material in organisms/living things.
Dry the organisms in an **oven at 80'C**. Weigh sample until _mass remains constant_
(not practical for higher trophic levels)
65
what is rAnDoM SaMpLiNg and what are the adv/dis of it
* **Random coordinates are generated** to choose which sampling sites to use, and a **portable global-positioning satellite** to find exact positions of #s.
* **Random number tables for where to place quadrat within specified area.**
* Data are *not biased* by *selective* sampling, but it may not *cover the habitat equally*, leading to **under/overestimation** of biodiversity because a *high presence/low presence is missed.*
* Each individual has the **same probability** of being selected.
66
what is the definition for _conservation_
**Maintenance** of **biodiversity** through *human action + active management*.
## Footnote
eg. Forests managed as a sustainable source of timber; controlled grazing.
67
what is the definition for _preservation_
**Protection** of an area by **restricting/banning human interference**. Visitation is not allowed except for those who **monitor** the area.
## Footnote
*eg. Galapagos islands, Virgin caves, marine conservation zones*
68
what is the difference between a _herbivore_, a _carnivore_ and an _omnivore_
An animal feeding _only on plants only_ compared to one that _feeds on other animals_, and one that eats _both_ animals and plants.
*They create a food chain, i.e. a _linear sequence_ of _eating_ and _being eating_. Interacting chains = food web.*
69
what is the difference between a *sustainable resource*, *sustainability* & *sustainable management*
70
what is the difference between *bacteria* **cultured separately** and **cultured together**
Cultured separately = they have normal growth curves. One grows more rapidly than the other.
*Cultured together = One experiences a high rate of growth, whilst the other has an initial increase followed by negative growth-* they have **similar niches** and the '**competitive exclusion principle** applies- abiotic factors favour one species over the other.
71
what is the difference between _in-situ_ and _ex-situ_ conservation
& examples
*_IN-SITU:_* active management to *maintain biodiversity in the natural environment*
* eg. wildlife reserves, marine conservation zones*
* nature reserves, natural parks*
*_EX-SITU:_* conservation _outside_ the _normal environment_ of the species
(plants are easier to conserve e-s because as part of their life cycle, they have a dormant stage/seeds)
eg. _captive breeding programmes, zoos_
_botanical gardens, seed banks_
72
what is the difference between *species diversity, habitat diversity + genetic diversity*
* Habitat diversity:* **number of different habitats** in an area
* Species diversity:* **number of different species** and **relative abundance** in an area
* Genetic* diversity: **variety of alles within a species (or pop. of species)** in an area
73
what is the Simpson's Index of Biodiversity
A *measure* of *species biodiversity - (*including evenness+richness), carried out by *taking a sample* and/or *animals in an area.*
74
what is the _biosphere & biome_
Biosphere; *inhabited* part of the Earth
Biome; life-zone determined by **temperature & rainfall,** characterised by the **dominant plant species present** (*plant species may determine animal life present in biome because the producer starts the food chain, all other energy is gathered from it*)
75
what is the difference between *conservation & preservation*
CONSERVATION: recognises that *humans need to live **within ecosystems** + **interact** with other species*
PRESERVATION: recognises that nature has _intrinsic values_ which are _diminished by the presence of humans_. *All species* should be conserved regardless of whether they are of value or harmful to humans. Protection of ecosystems = _protection from encroachment by humans._
76
what is the **Maasai Mara** and how does it _work?_
The Maasai Mara is a **national reserve** in **Kenya**, supporting a large area of **grassland/savannah**, for populations of **cheetah, wildebeest, zebra, lions.**
Traditionally _Maasai people_ _raised livestock_, such as cattle, for a living. This led to _overgrazing_, destroying grassland for _wildlife_.
Conservation trusts work with Maasai people to make money through _conservation/ecotourism projects_ to meet their _economic needs_, and teach _sustainable farming_ for _ecological needs._
77
what is the *result* of the burning of fossil fuels and what is the effect on *biodiversity*
* An increase in global temperature, acid rain destroying forests, sea levels causing loss of land/habitats*
* Loss of ice caps/habitat*
* **# of Non-drought species decrease, animals feeding/dependent on them decrease**
* **Salt water moves upstream in rivers, decrease habitats for freshwater species**
* **Extinction of polar species**
78
what is the *result* of **deforestation**
what is its effect on *biodiversity*
Deforestation leads to **loss of forests/habitats** to provide wood for fuel/construction + create space for construction/agriculture.
* **decrease in # of trees**, habitats, food sources, potential medicines
* **#s of animals dependent** on trees **decreases**
* **animals migrate** to nearby ecosystems
79
what is the _Terai Arc_ and how has management led to a balance between _conservation/preservation & human needs_
An area of **forest/grassland** on the border of *India/Nepal*.**Endangered** **species** inhabit it eg. *Bengal tiger, Asian elephant*. 7 million people inhabit it too.
Areas of the forest are *destroyed* for **housing/development** + humans uses **forest resources** to survive. This leads to *destruction of habitat, and brings animals/humans into closer contact eg. elephants tramping crop fields/tigers killing livestock and being shot.*
**WWF conservation charity** work with locals to bring them **solar cookers/biogas generators** to reduce usage of **wood** from the forest. They encourage farmers to plant **mint hedges** around crops to *keep animals away bc they dislike the taste of mint!*
80
what is *autotrophism + heterotrophism*
A process of **obtaining carbon** from CO2 using **energy** from **light or chemical reactions.**
Heterotrophs **obtain carbon** from the **breakdown** of **organic** compounds.
81
what is **BIODIVERSITY**
The _variety of different organisms in an area._
Levels: species diversity, habitat diversity, genetic diversity
82
what is *biomass*
**Total quantity** of **dry mass** in organisms, commonly measured for a trophic level, a population or a community inhabiting a certain region.
83
what is **deflected succession**
Succession deflected/arrested directly or indirectly due to _human activity_.
*eg. agriculture, grazing, burning, conservation management, mowing. Acidic conditions (climate change) can deflect communities- acid soil/peat results in moorland.*
leading to a _sub-climax community_ called a **plagio climax.**
84
how does *interspecific competition* affect population sizes/growth
Organisms of **different species compete for limited resources** eg. red/grey squirrels for food sources/habitats in the UK.
This reduced the resources available to both pops., leading to population sizes reducing because there is less energy for growth/reproduction.
It also affects **distribution of species**, i.e. if one species is **better adapted to its surroundings** than the other, it will **out-compete** the less well adapted species- cannot exist alongside it because it has a lower chance of survival.
85
what is **opportunistic sampling** and give its advs/disadvs.
*A type of selective/non-random sampling, Choice of sampling sites is based on **prior knowledge/research** eg. deliberately sampling an area with species X, or because subjects are easily accessible eg. questioning passing people in a pilot study.*
**Placing the quadrat where you feel/know is best/easiest.**
- It is _quicker/easier/cheaper_
- Can lead to over/underestimation due to small sample size, bias. A large proportion of the population is excluded.
86
What is predation and what effect does it have population size
= where an organism/the **predator** kills and **eats** another organism/ the **prey**
eg. *lions killing and predating on buffalo*
The population sizes of predators and prey are **interlinked**- as the pop. of one changes, it causes the other to change.
87
what is **primary succession**
+ types: xerosere, hydrosere, psammosere, halosere
Succession that occurs on **bare rock (*newly formed land*)**. eg. due to *cooled volcanic lava, a sand dune, river delta/retreating lake*.
Initially there is **no soil profile**.
**Sere** = where succession occurs.
* Xerosere =* succession on **dry land** (*pioneer species is **xerophytes***)
* Hydrosere =* succession originating on *water* (" hydrophytes)
* Psammosere* = **sand dunes***Halosere =* **salt marshes**
88
what is ***secondary succession***
Succession on **soils** that have *already been formed* but have *suddenly lost* their community.
eg. due to *fire, harvesting/fallow fields*
Secondary S is **much quicker** than 10 because *soil is already present.*
89
what is **stratified** sampling and give advs./disadvs.
*A type of non-random/selective sampling. Dividing a habitat into areas that **seem different**, sample each separately. Strata should be **mutually exclusive**, individuals should be assigned to **one stratum only**. Individuals are then randomly sampled from the strata.*
Sample in the different area/vegetation of a habitat.
\> All areas sampled- *species not under-represented*
\> possible *over-representation* i.e. disproportionate #s because small areas look different
90
what is **succession**
The **progressive change**, **over time**, in the **composition** of a **community** of organisms from initial colonisation by a **pioneer species** towards a largely stable **climax community.**
91
what is systemic sampling and give its advs./disadvs.
A type of *non-random/selective* sampling.
Samples are taken at **fixed intervals** across a habitat- **line/belt transects**.
Sample every n metres along a line/belt transect.
\> Useful in showing a _gradient across a habitat_ of an environmental factor eg. *drier further away from a pond/the sea.*
\> Only the _species on the line is recorded_, and species may be _missed_ leading to an _underestimation_ of biodiversity
92
what is *trophic level*
A stage in a **food chain** at which organisms obtain their **food** in the same general manner.
93
what occurs during the _deceleration_, _stationary_ & _decline_ phases
**3.POPULATION GROWTH DECELERATES**
*Environmental resistance increases i.e. limiting factor increases, increasing death rate or inhibiting birth rate.*
**4.STATIONARY PHASE**
_birth rate = death rate_
(*if applicable, immigration rate = emigration rate, i.e. _equilibrium reached_) = **carrying capacity,** the _maximum pop. size_ that can be maintained in a habitat*
**5.DECLINE PHASE**
If/Due to **limiting factor** eg. new predator, unfavourable climate, natural disaster, accumulation of toxic waste eg. in yeast in closed system
94
what occurs in the LAG + LOG phases
_Lag: reproduction begins_. *Slow* because *few individuals*are present and may be widely spaced and acclimatising to the environment, leading to a decreased rate of reproduction. Some components required for growth may not yet be at optimum conc. eg. primary metabolites.
**Log: rapid/maximum growth rate** under **optimum** conditions. i.e. There is **no environmental resistance**. *Birth rate \> death rate. **Struggle** for existence is **low**, **survival** is **high**.* The species realises its full reproductive potential.
95
what were the aims of the *Countryside/Environmental Stewardship Scheme*
1. Sustain the **beauty/diversity** of the countryside
2. Improve, extend + create _wildlife habitats_
3. _Restore neglected land_ + conserve **archaeological** & **historical** features
4. Improve countryside _enjoyment_ by public eg. creating **footpaths**
5. Giving money to _farmers_ to manage their land with _biodiversity_ in mind
96
what were the aims of the _Rio Convention for Biodiversity_
1. Provide *_guidance to governments_* on how to conserve biodiversity
2. *_Promote sustainability_*
3. *_International sharing_* of/access to genetic resources/benefits from them
4. Sharing of _scientific knowledge/discoveries_
97
what apparatus is used to sample plants
**QUADRAT: 'frame' or 'point'**
* frame is 0.5m, split into smaller squares. Each square/25 is worth 4%.*
* point has two vertical legs, pin inserted to find smaller areas*
98
where in a food chain is energy transfer *least efficient*
SUN → PRODUCER
99
where is nitrogen found in the ecosystem, and how is it obtained by animals and plants
**Proteins & nucleic acids** contain **N**, which are found abundantly in living organisms.
Animals **consume** plants/animals, whilst plants obtain it from the **soil**. The **availability** is highly dependent on the action of **bacteria** in the soil.
100
which characteristics show _continuous & discontinuous variation_
SINGLE GENE/ _monogenic_ = _dis__continuous variation_ due to very limited number of variants
MANY GENES/ very **polygenic** = **continuous variation** because large number of phenotypes
*Environmental influences may also affect phenotype*
101
which terms are used to discuss energy transfer through a food chain
The **rate** at which **energy flows** through the food chain = **_productivity_**
Energy enters the food chain through the **producers**
The **rate** at which energy is **stored by producer** in the form of their **biomass** = ***primary productivity***
102
why do ecosystems have the potential to be *self-supporting*
The **interrelationship** between *producers, consumers + decomposers* eg. producers/green plants need the Sun for energy, all other organisms need the producers, who also depend on decomposers + weathering of rocks for their supply of inorganic nutrients.
All ecosystems influences by nearby ecosystems.
103
why does *population size* vary **1**
Due to **abiotic factors** i.e. non-living features of the ecosystem.
* **light intensity**
* **water/shelter availability**
* **temperature**
* **chemical** composition of surroundings eg. soil pH
eg. because there's only enough shelter for a certain # of individuals
104
why does *population size* vary **2**
Due to **BIOTIC FACTORS**
* *interspecific competition- reduces q of resources available to species*
* *intraspecific competition*
* *predation (predator and prey population sizes are linked)*
105
*why is the Simpson Index effective*
because it takes into account the _species richness_ and _species evenness_, i.e. the number of *different species* and their *relative numbers*
* IMAGE: A : high evenness, high richness- higher biodiversity*
* B : high richness, low evenness*
106
why is *genetic biodiversity* necessary (5)
Genetic biodiversity will lead to **survival** of the species; *Individuals have little **variation** in their DNA. A population has different **versions** of a gene; **alleles**; creating diversity within the pop. The **more alleles present**, the more **genetically diverse.***
*These pops. can **adapt to changes** in their environment, tf **less likely** to become **extinct** bc some organisms will likely **carry an advantageous allele**, enabling them to **survive** eg. a fatal disease, and **reproduce.***
