• Lichens= fungi and blue green algae 
• Legumes and bacteria 
• Rhizobium N₂ fixation 
• Mycorrhizae and higher plants Lichens Legumes and bacteria
• Hyphae; act as extension of root hairs
• Some are obligate and some facultative 

• Response (+,0) 
• Definition - one species benefits,the other is neither harmed or benefited

• Epiphytes: plants growing on one another simply for support
• EX:orchids, Spanish moss, ball moss 
• roots do not extend into xylem and phloem 
• EX: cattle Ingrid 
• hang around cattle eating bugs that are stirred up

• Response (-,0) 
• Definition: one species inhibited by a second, which is unaffected No good examples

• Response (+,-) 
• Definition: one species benefits (often derives its nourishment) at the expense of a second

• Tapeworms of birds and mammals 
• Mistletoe and some woody plants
• Phoradeudron= thief of tree
• has modified roots (Haustoria) to embed into xylem and phloem of host 
• Can be Hemiparasitic if green 

• Response (+,-) 
• Definition: parasite causes the host to rear the parasites young

• Pied billed grebe (facultative)
• Cuckoos 
• obligate: chicks knock eggs out 
• Ring-necked pheasant (facultative)
• Redhead duck (facultative)
• Cowbird
• aggressive and monopolizes nest 

• Response (0,0) 
• Definition - no direct effect

• Response (-,-) 
• Definition: the interaction of two or more individuals of the same or different species that causes adverse effects for both; often for mutually required resources in limited supply

1. Intraspecific - within a species  
2. Interspecific - between two different species 
3. Exploitative - for a resource (water, nutrients, sunlight, etc). 
4. Interference - involvesa toxin (usually); called Allelopathy
• Black walnut, creosote, Australian Pine
• not purple sagebrush from chaparral CA

1. Black walnut 
2. Creosote bush 
3. Australian Pine
4. the chaparral region of California*

• Not purple sage brush, CA sage brush: rodents were using it as canopy 

• Radiant energy from the sun
• Behaves as a wave and a particle 
• Drives the climatic and biological cycles of the earth

• low energy/photon 
• long (760nm – 1 mm) 
• heat energy 
• thermal effects 
• drives the climatic cycles

• higher energy/photon 
• shorter (760-380 nm) 
• vision 
• photosynthesis 
• control of reproduction (photoperiod) 
• seed germination

• highest energy/photon 
• shortest (100 nm-380 nm) 
• oxidation reactions (degradation)
• mutations

50%: reflected,scattered, absorbed

• 30% reflected by clouds, atmosphere, and surface of earth 
• 20% absorbed by clouds and atmosphere 

• 50% IR 
• 50% Visible 
• 0.1% UV

Tremendous variation (Latitude, altitude, atmospheric conditions) 

1. Hadley Cell 
• 90/30
2. Ferrel Cell
• 30/60
3. Polar Cell
• 60/90

1. the same IR intensity from the sun spreads over an increased area 
2. IR that penetrates the atmosphere at a steep angle must travel through a thicker layer of air 

• Weather - short term
• Sun over 
• Equator = Autumm/Spring
• Tropic on cancer23.5N= Summer (N)
• Tropic of capricorn 23.5S= Winter (N)
• Climate - long term weather patterns

• Latitude= gradient of IR 
• ↑Dust = ↓ IR
• ↑SO₄=  ↓IR
• gas that acts as particulate matter
• Altitude, Moisture, O₃, C0₂
• Green House Effect 

• forces created by the rotation of the Earth
• causes the general flow to break up into three distinct cells in each hemisphere

further complicate the picture because of differential heating of land and water:

• land heats and cools faster than water
• Temperature change is greater over land than water 
• Oceans act as great heat sinks or reservoirs 
• Coastal (cooler) vs. continental

• Poikilothermic 
• Body temp changes with external environment
• regulates tem by behavior
• EX: reptiles, fish, amphibians, bacteria, invertibrates, plants 
• Advantages: low energy requirement 
• Disadvantages: limited distribution 
• Homeothermic
• Maintains content body temperature 
• regulates temp by metabolism 
• EX: mammals & Birds
• Advantages: not limited by external environment 
• Disadvantages: High energy required  

• Global
• Latitudinal 
• Altitudinal 
• Temporal
• differing rainy seasons: bimodal, unimodal, constant 

• Relative Humidity 
• Global Air Movement 
• Cold Water Currents 
• Relief or Rain Shadow

• At equator: 
• Air at 500 ft,85o F, 95% RH. Air rises to 15,000 ft 7oF, 100%. Result= Rainfall 
• At Tropic of Cancer: 
• Air at 16,00ft, 2oF, 85% RH. Air descends to 500 ft, 85o, 35% RH. Result= No Rain

• Must control H2O loss through leaves or, skin and lungs. 
• Must have H2O to carry out metabolism 
• Must have H2O to cover respiratory surface 
• Must have H2O to operate their excretory system

• Improve water uptake 
• Reduce water loss 
• Become dormant 
• Store water

• Lower plants/organisms 
• When water is available, they are active 
• EX: Lichens, Nostoc (soil algae), desert fern, Resurrection plant,

• Higher plants, flowering plants 
• Survive drought in special resistant form 
• Two types: Annuals & Perennials

• Live only 1 season 
• resistant form is a SEED
• Texas bluebonnets, wine cups, mallows

• Live multiple seasons 
• resistant form is a bulb, underground structure
• wild onion, rain lily, sego lily

• Perennials= 
• capable of continued metabolic activity during dry periods, but at reduced rates. 
• Two Types: 
• Fluctuating persistents & Stationary persistents

• drop their leaves 
• EX: ocotillo, leather stem, palo verde

• No specific change in morphology 
• EX: range ratany
• desert shrub w/ narrow short hairy leaves 
• creosote bush: small shiny leaves
• mesquite: tiny leaflets = reduce surface area 

• small leaves
• EX: cat claw
• thick cuticle (prevent moisture loss)
• store water
• stem photosynthesis
• stomatal control
• fix CO2 at night
• deep roots (EX: mesquite) 
• shallow roots
• spines
• pubescence
• EX: teddy bear cholla

• many similar to plants. 
• water loss may be constant up to a critical temp., but above that temp., the greater the temp., the greater the water loss

1. ESTIVATE
2. MIGRATION
3. RETREAT

• heat or drought induced dormancy estivation by 
• some vertebrates- 
• ground squirrels
• spadefoot toads 
• (DIAPAUSE)

• form of estivation; 
• 8-9 month dormancy
• annual life style
• period of quiescence 
• EX: eggs of most invertebrates

• by certain vertebrates (birds and mammals) 
• EX: 
• phainopepla (elevational migration)
• wildebeest (mammal, circular migration) 
• sandgrouse (fly long distances for water)
• springbok (mammal, follow rains) 

• short term escape -a daily rhythm
• usually two peaks of activity 
• EX: tenebrion beetle
• Sand diving lizard
• bimodal activity pattern
• thermo-regulatory dance 
• stilt walking 
• Social weaver: birds hide in apartment nests 
• antelope ground squirrel: lay on groung to lose excess heat, allow temp to spike to 42^oC
• bimodal with spikes in temp 

1. physiological: 
• daily torpor (low body activity), use of all metabolic water, production of uric acid, slow respiration rate, osmoregulation, adaptive heterothermy 
2. BEHAVIORAL: 
• norcternal habits, use of shade, closing/sealing burrow 
3. Anatomical: 
• ears as radiatos, large size, light color, waxy cuticle

• tenebrionid beetle
• withholding moisture from beetle and measuring osmolarity of Hemolymph 
• osmolarity stays constant, but Hemolymph decreases 60-70%

• can get rid of nitrogenous wastes as ammonia, urea, or uric acid
• also have extreme forms that don't use any water 
• When dehydrated; allow 2 maintain osmolarity of [blood] by ↑ [urine]

• hydrated camel body temp fluctuates from 36-38^oC
• dehydrated camel 42-34^oC
• controls body temp by evaporative cooling 

• duration of an organisms daily exposure to light 
• predictable and very constant 

1. Dryas flower and beetle
2. underneath juniper tree
3. Darkling Beetle 

• temp at surface changes the most 
• Temp below the surface changes very little 

• North facing slope
• generally cooler and more moist 
• woody plants found here 
• more fluctuation 
• sun rays almost parallel to surface
• South facing slope 
• retains snow; mostly grasses
• greater IR intensity; dryer 

• Morphological 
• Jackrabbit= big ears that act as radiators
• Arctic hair= small ears flat on back 
• plants= open growth to lose excess heat
• plants= dense low growth, pin cushion structure, dark pigment to abs. more IR 
• Physiological 
• biochemistry pathway  
• Behavioral
• nocturnal when in hot climates 
• using shade 

• cold water = cold air = 99%RH
• warm land mass = Air warms= 80%RH

• cool air= 95% RH
• moves up mountain= air cools further= 100%RH
• rain
• other side air warms= 90% RH = No Rain

• Kangaroo rat
• gets all moisture from food they eat
• seeds have some moisture and oxidizing the seeds give more moisture 
• California pocket mouse
• daily torpor
• reduced metabolic activity 

• uses energy
• requires nutrients
• self regulating or homeostatic 
• natality (birth rate)
• mortality (death rate)
• age structure 
• density (#/unit area) 

• varies across a particular space
• Heterogeneous b/c environment is heterogeneous 
• resources vary; a habitat is never uniform 
• light, temp, moisture, nutrients, nesting sites
• Results:patchy environment= patchy distribution 

1. Random: each individual is independent of all others 
• need very high levels of resources and no establishing territory 
2. Uniform: evenly spaced (EX creosote bush)
3. Clumped/Aggregated/Contiguous 
• most common 
• clump around resources 

• mortality and natality 
• M=N
• M>N
• M<N
• Mortality= death rate/ probability of dying  
• Often expressed as survival/ life expectancy 
• # or yrs to be lived by individual 

• account for deaths in a population 
• Types 
1. Dynamic= records the fate of a group all born at the same time 
2. Time specific = records the mortality of each age class in a population 
• Birth rate and death rate must be consistent: population stable/stationary 

1. mortality curves 
2. survivor curves
• used more 

1. Type I (large mammals) 
• most juveniles survive to reach reproductive, die in post-reproductive
• excessive care of small # of young
2. Type II (birds, rodents) 
• constant rate of mortality
• many young, still care for them 
3. Type III (fish, invertebrates, plants) 
• huge # of young 
• most death occurs during juvenile stage 
• oyster

1. pre-productive
2. reproductive 
3. post reproductive 

• productivity 
• survival 
• growth 
• EX: expanding, aging/stable, declining 

• industrial nations have stable/aging growth curve 
• base is equal to that of midpoint 
• US, France 
• Developing/ third world nations have rapid growth 
• base is much larger than the midpoint 
• Kenya, India, Argentina 
• Very small base means declining/zero growth 
• Japan, russia, Italy