physical limits on biota kga172 space, place and nature presented by associate professor elaine...
TRANSCRIPT
Physical limits on biota
KGA172 Space, Place and Nature
Presented by Associate Professor Elaine Stratford
Semester 2
Limiting Conditions for Life
(with apologies to Schultz)
LOOKING BACK, LOOKING FORWARD
Part 1
Revising Lecture 2.8
1. In what ways is glaciation related to processes of Earth’s orbit, wobble, and tilt?
2. Glaciers are classified, first, by two fundamental characteristics. What are these?
3. In terms of thermal character, there are two kinds of glacial feature. Again, what are they and what are their principal characteristics?
4. Describe the difference between an ice sheet and an ice cap.
5. Define the following term for a landscape feature in a glacial environment and explain how each arises or operates:
a. Cirqueb. Arête c. Truncated spurd. Horne. Morainef. Glacial troughg. Roche moutoneeh. Hanging valleyi. Glaciofluvial sedimentj. Till k. Outwash fansl. Meltwater m. Ablation n. Solifluction
Auguste Rodin, A man thinking
Learning Objectives
Module 2 Lecture 9• be able to
– explain why scale and context are essential elements of all biotic patterns and processes
– describe key interactions of organisms with their environments
– appreciate and convey the importance of the multidisciplinarity of environmental studies
KGA172• Know and be able to (a) employ basic
geographical terminology and concepts, (b) find, evaluate, analyse and reference appropriate literature, (c) contribute to debates about development and sustainability
• Comprehend and be able to explain spatial patterns, generate basic maps, field sketches and graphs, and communicate in written and graphical forms
• Apply key academic skills and (a) engage in critical thinking, discussion and listening, and in self-reflection and reflection upon the viewpoints of others and (b) research, plan and conduct fieldwork to collect data
• Analyse and interpret basic spatial, numerical and qualitative information
• Synthesize and integrate knowledge of social and Earth systems
Textbook Reading
Bergman and Renwick (2008)
Critical reading1.What is the author’s purpose?2.What key questions or problems does the author raise?3.What information, data and evidence does the author present?4.What key concepts does the author use to organize this information, this evidence?5.What key conclusions is the author coming to? Are those conclusions justified? 6.What are the author’s primary assumptions?7.What viewpoints is the author writing from?8.What are the implications of the author’s reasoning?[from Foundation for Critical Thinking]
A man in a library
PHYSICAL LIMITS ON BIOTAPart 2
ECOSYSTEM FUNCTION Productivity Energy Transfer
Disturbance Change
Diversity Scale
-
ECOLOGYDefinition and historic development
(G L Unwin)
Niche= a species’ function in an ecosystem= a species’ lifestyle
Habitat = where a species lives= a species’ address
Kerry Bridle
Kirkpatrick 1999
HOW BIOTA FIND PLACE – potential vs actual niche
Biodiversity = the variety of life, including genotypes, species, communities and ecological processes.
Ecosystem function … Ecosystem processes and population dynamics
Reproduction Regeneration
Growth Competition
Senescence Mortality
Disturbance, change and succession
Abiotic and biotic (including human) conditions, resources and Interactions:
Physico-geo-chemical and biological conditions (that is, the “environment” for establishment, survival, growth and reproduction)
Available resources (materials and energy)
… all depend on
conditions and resources which are limited and limiting for life
Conditions - physical or chemical
attributes of the environment that
influence the organism’s growth and reproduction
Resources - substances that are
consumed by an organism
Unknown photographer
What are the major elemental constituents of life – that is, for nutrition and growth?
Damien Catchpole
Strahler and Strahler Geography and Man’s Environment
Liebig's law of the minimum (populations are limited in their growth and distribution by the resource in greatest scarcity)
Shelford's law of tolerance (populations are limited in their growth and distribution by the resource closest to excess or deficiency)
Adrian Pyrke
Processes and dynamics of biological interactions with the environment
Biotic and abiotic interactions which determine the distribution and abundance of organisms
Krebs 1985
Processes and dynamics of biological interactions with the environment
Biotic and abiotic interactions which determine the distribution and abundance of organisms
Krebs 1985
Influence of topography and soil characteristics on the limits of species,
species’ distributions
Via moisture, light and temperature regimes, nutrient availability, fuel and fire patterns
Kirkpatrick and Marks
Growth and Productivity
(G L Unwin)
(G L Unwin)
(G L Unwin)
SUNLIGHT
Direct and diffuse radiation
Shortwave (solar) and longwave (far red) radiation
Light quality (wavelength)
Light quantity (photon irradiance)
Light duration, periodicity (diurnal / seasonal) and disturbance effects (red / far red and blue light effects)
Competition for light, light compensation point, shading
Grant Dixon
Atwell, B., Kriedemann, P., and Turnbull, C. (1999) Plants in Action. ASPP / Macmillan, Melbourne, p. 385.
Sun/shade light response in
photosynthesis (including light-
compensation point and quantum yield)
…or what about such response in a pond?
(G L Unwin)
(G L Unwin)
(G L Unwin)
Conclusions
Scale and context are implicit in biotic patterns and processes and intrinsic to any proper definition of the limits on biota
Ecosystems contain and depend on interactions of organisms with their environment, hence ecosystem function requires a supply of resources and energy (nutrition) within a matrix of competitively limiting conditions for life
(G L Unwin)
ConclusionsYour environmental studies will need to be multidisciplinary in order to define and demonstrate important functional links between environmental physics and physiology at the smaller scale and the structural, evolutionary and demographic patterns and dynamics of whole ecosystems at the larger regional scale.
(G L Unwin)