E2

Question 1

What do we need to know in order to understand the distribution and abundance of a species?

Answer 1

History, environmental conditions, resources required, life histories and population dynamics, interactions with their own and other species.

Question 2

What is the definition of conditions and what are some examples?

Answer 2

Abiotic environmental factors, influence the functioning of an organism, e.g. temp, pH, salinity, humidity. May be modified by a presence of another organism. Not consumed or used up.

Question 3

What are optimum conditions? How are they measured?

Answer 3

Those under which most offspring are produced. Measure effect on key properties e.g. enzyme activity, respiration rate, growth / reproductive rate. Organisms can survive over a range of conditions. Any condition that exceeds the limit of tolerance is a limiting factor, when a species is limited in distribution it is said to be restricted according to environmental tolerances.

Question 4

What are the three types of response curves?

Answer 4

A) extremes are lethal, only optimal conditions allow reproduction
B) conditions only lethal at high intensities
C) condition required as a resource at low concentrations

Question 5

What are temperature extremes?

Answer 5

Midday sun in desert, cold Antarctic winter

Question 6

What factors can temperature effect?

Answer 6

Metabolism, growth, development, size.

Question 7

Why is temperature important?

Answer 7

To understand the role of temperature in seasonal, annual and geographical variations in productivity in ecosystems. Appreciate the knock on consequences e.g. what is this effect of changing organismal size on their role within ecological communities due to temperature.

Question 8

What are endotherms?

Answer 8

Regulate temp by production of heat within their own bodies?

Question 9

What are ectotherms?

Answer 9

Rely on external heat sources

Question 10

What is life like at low temps?

Answer 10

70% of plant is ocean, 10% of planet is polar ice caps. Two types of injury in cold. Chilling - >0 damages membranes permeability, freezing - <0 affects osmoregulation. Freeze-avoidance and freeze-tolerance. Acclimitisation is natural adaptation to temperature changes.

Question 11

What is life like at high temps?

Answer 11

High air temp, fire - lightning strikes. Thermal vents - hot fluids rich in minerals expelled from sea bed. Hot springs - geothermally heated ground water

Question 12

How does temp act as a stimulus?

Answer 12

Temp and arctic alpine plants - period of freezing stimulates germination. Interacts with photoperiod and therefore onset of growth. Egg laying stimulated by temperature and day length. Temperature stimulates breeding in many animal species.

Question 13

What does temp correlate with?

Answer 13

Plant and animal distribution.

Question 14

What are temperature interactions?

Answer 14

Humidity which has important consequences for evaporation, humidity can reach 100% under dense leaf canopies. Disease can be caused.

Question 15

What impact does pH of soil and water have?

Answer 15

pH can exert a powerful influence on abundance and distribution of organisms. Roots damaged by toxic conc of H+ pH < 3 or OH- pH < 9. Indirect effects occur, soil pH influences nutrient availability and toxin conc. acidic soil high Al3+, Mn2+, Fe3+. Alkaline soil - PO43-, Mn2+, Fe3+.

Question 16

How does soil pH influence plant species?

Answer 16

Chalk/limestone grassland have a higher diversity of flora than acid grassland. Similar for plants and animals inhabiting ponds, streams and lakes.

Question 17

What pH conditions do prokaryotes tolerate?

Answer 17

Extremes of both, they live in geothermal springs, volcanic lakes. Sulphur oxidising bacteria. Optimum pH of 2-4. Soda lakes, Cyanobacteria. Optimal pH 9-11.

Question 18

What effect does salinity have?

Answer 18

Salt conc in soils offers osmotic resistance to water uptake by plants. Halophytes are adapted to saline conditions (maintain osmolytes in vacuoles). In marine habitats organism are usually isotonic. Osmoregulation - maintenance of homeostasis, an energetic process.

Question 19

What conditions are physical forces?

Answer 19

Wind and water. Streams and rivers - water shallow and turbulent upstream, fast-flowing downstream. Sea - currents and waves. Organisms have physical adaptations to cope.

Question 20

What impact does climate change have?

Answer 20

CO2, most important greenhouse gas, has risen <300 to >400 ppm since the Industrial Revolution. Driving planetary warming rates >100% faster than natural post glacial warming. Many species cannot respond. Distribution shifts and widespread extinctions of flora and fauna are predicted. Fragmented and developed landscapes are barriers to range shifts.

Question 21

What are resources?

Answer 21

All things consumed by an organism, consumed does not necessarily mean eaten. Resources are entities required by an organism that may be reduced by the activity of other organisms.

Question 22

What are photosynthetic autotrophs and chemosynthetic autotrophs?

Answer 22

PA - Green plants and algae
CA - bacteria and archaea.
All other organisms use the bodies of other organisms as food sources
In each case the consumed resource is no longer available to another consumer.
The consequence is competition.

Question 23

How are resources other dimensions of the ecological niche?

Answer 23

Green plants assemble inorganic resources into organic compounds - photosynthesis. CO2, H20, sunlight, and mineral nutrients converted into biomass. Consumers reassemble these packages at each successive stage in a web of consumer-resource interactions.

Question 24

What is solar energy as a resource?

Answer 24

Must penetrate the atmosphere, absorption, reflection and scattering by water vapour, water surfaces, clouds, atmospheric particles. Varies with circumstance (latitude, season, time of day).

Question 25

What is solar radiation as a resource?

Answer 25

Only source of energy green plants and algae use. A resource continuum of different wavelengths. PAR 400-700. Radiation intensity and quality varies continuously. Shade effects decreases resource. Woodland canopy, light attenuation by phytoplankton.

Question 26

What is CO2 as a resource?

Answer 26

Used in photosynthesis obtained from the atmosphere. Availability to plants and algae varies according to position in habitat. C3, C4, CAM photosynthetic pathways.

Question 27

What is water as a resource?

Answer 27

Critical resource, hydration is necessary for metabolic needs, must be replenished, plants and the transpiration stream. Terrestrial animals drink water or generate it from metabolism of food and body materials.

Question 28

What is mineral nutrients as a resource?

Answer 28

Macronutrients - N, P, S, K, Ca, Mg, Fe
Trace elements - Mn, Zn, Cu, B, Mo
Plants obtain nutrients in inorganic forms from soil or water
Some groups have special requirements ; diatoms
Animals obtain nutrients as organic forms in their food

Question 29

What is oxygen as a resource?

Answer 29

Diffusion and solubility of O2 is low in water
Limiting in aquatic and waterlogged environments.
Aquatic plants modify their roots and shoots
Aquatic animals either - maintain a constant flow over respiratory surfaces, have LSA:V ratio, specialised respiratory surfaces, low respiration rate

Question 30

What are organisms as a resource - autotrophs?

Answer 30

Autotrophs - assimilate inorganic resources into organic packages consumed by heterotrophs

Question 31

What are generalists and specialists?

Answer 31

Generalists are polyphagous - they take a wide variety of prey species. Specialists are monophagous or polyphagous - specialising on certain parts of prey. Resource use patterns reflect consumer lifespan. Must match food demands to prey timetable. Evolution of specialised structures.

Question 32

What organisms as a resource - plants and animals?

Answer 32

Provide different nutritional contents, consequence on consumer, plant cells rich in cellulose, lignin. C:N plants 40:1. Animals and fungi 10:1. Diff parts have differing compositions - a variety of resources.

Question 33

What organisms as a resource - defences to predators?

Answer 33

Physical and chemical defences. Behavioural and morphological defences. Animals have more options than plants.

Question 34

What is the ecological niche?

Answer 34

Framework within each condition should be understood. A niche is not a place it is an idea. A summary of an organism tolerances and requirements. Niche describes how, rather than just where an organism lives.

Question 35

What did Hutchinson say an ecological niche was?

Answer 35

A multi-dimensional hypervolume of resource axes. Temp is one dimension, relative humidity, pH, wind speed, flow rate, salinity. In 2 dimension of food size and behaviour, 3 dimensions of food size, temperature and humidity. In reality many more factors define an organisms niche. We call this the n dimensional hypervolume.

Question 36

What is the fundamental niche?

Answer 36

Where an organism could live in abscence of competitors and predators.

Question 37

What is the ecological niche?

Answer 37

Where an organism actually lives, when competitors reduce resources available

Question 38

What are the dimensions of the niche?

Answer 38

Includes both conditions and resources, conditions considered as continuous variables. Some resource dimension can be plotted like condition dimensions : upper and lower limits. Predators can only handle a certain prey size. But many resources are discrete entities not continuous variables. Certain species can only use limited resources. Therefore have to consider as a discrete factor.