Bio205 Chapter 1:
- Defined as the relationship between organisms and their environment
- Environment refers to all the external factors that influence an organism’s survival,
growth and or reproduction directly or indirectly.
o Surroundings, abiotic factors that work within it
o Biotic factors it interacts with
o Relationships: individuals interactions with physical surroundings and organisms
of its species and others
- Resources: consumed by organisms, making them less available for others: food, water,
- Conditions influence organism but not consumed: temperature, day length, acidity
- Organisms can compete for resources but not conditions
- Conditions can impact resources by making them tough or unavailable to organism:
freezing temp h2o into ice
- Hazards: factors that only affect organism negatively: bad weather conditions,
- Darwin natural sel theory distribution of organisms
- Organisms interact with their environment many ways. Prevailing environmental abiotic
conditions. Extracting resources from the habitat, while they protecting themselves from
predators. Organism-organism interaction allows from recognizing friend to foe; potential
- Main purpose: pass on genes and reproduce
- “stuggle for existence experienced in habitat
- Habitat: a physical location in time and space, can be large or small, but it is more then
that it consists of other organisms; Ecosystem: biotic community and its abiotic
- Car and body coexist: ecosystem has both bio and abio features that work togeather.
Composed of parts that work togeather - Abiotic: air, soil, water Biotic: organisms. Complex: each organism interacts with abiotic
parts and modifies it, by doing so, becomes a part of the biotic environment for other
- Birds eat insect and leave more resources for organisms that feed on similar food
Ecological Hierarchy: 1.4
- Group of indiv of same species occupying the same area @ same time
- Community: All populations of all species interacting with one another are called a
- Ecosystem: community and its abiotic environment
- Landscape: area of land composed of patchwork of ecosystems
- Biosphere: narrow interface at earth’s surface that contains and supports life
o Atmosphere: layers of air surrounding earth
o Hydrosphere: water at or near earth’s surface including soil solution
o Lithosphere: soil and earth
Importance of scale: 1.5
- Autecology: structural and physiological ecology
o Autecology would study polar bear size, its limb proportions and how they give it
an advantage in north
- Behaviour ecology: factors affecting species distribution
o Behavioural ecologist would study its social activities, hunting technique.
- Population ecology: population size and how it changes over time
o How are they distributed in area, differences among different populations of polar
- Evolutionary ecology: study in changes of genetics of population due to evolutionary
prccesses: natural selection
- Community ecology: community patterns. Interactions between coexisting species.
o Impacts of predation by polar bears on seals. Competition between other species - Ecosystem ecology: studies ecosystem structure and function: flow of energy and
nutrients through its abiotic and biotic components.
- Landscape ecology: factors influencing spatial extent and arrangement of interacting
o Spread of fire and disease, why do rainforests support more species then
- Global ecology: exchange of energy between the ecosystems and Atmosphere,
o Carbon transfer
Ecology as a science: 1.6
- Ecologist use the scientific method
1. Observation: all science begins here. Observations must be replicable;
observed again by different observers. Ecological pattern: there must be
2. Hypothesis Generation: propose problem; then generate a possible answer
to research question
3. Hypothesis Testing: gathering more data, x and y variable, confounding
factor; extraneous variable that can impact variable being testing
4. Experimentation: performs an experiment; field experiment (in natural state),
lab experiment (more control over surroundings)
5. Reiteration: repeat
6. Theory generation: form integrated set of hypothesis that explains more then
what the single hypothesis doe
Models in Ecology: 1.7:
- Null models: patterns are due to random factors in absence of particular ecological
process. Helps us guard that a pattern occurred when it was just by chance
- Human factor: air pollution, ecological foot print. Humans have influenced environment
- Environmental science: impacts of humans on the environment
- Human pop growth, conservation of biodiversity, sustainability of natural and human
systems, global climate change - Clearing of forests: impacts forest habitat, resulted in extinction of species
Dual Focus: 1.10
- Individuals and ecosystem are both basic units of nature.
- Individual responds to the surrounding environment and passes on genes via
reproduction, birth rate and death rate determine population. Ecosystem also a vital unit
of nature given its importance in sustaining biosphere
Chapter 2: Climate
- Most influential on ecosystem, and places greatest constraints on organisms.
- Weather: combination of precipitation, wind, cloudiness, humidity and other atmospheric
- Climate is the long term avg. pattern of weather
2.1: Solar radiation:
- Electromagnetic energy that radiates through sun, travels relatively through space
before it reaches earth’s surface.
- Molecular interactions, couples with earth’s rotation and revolution create wind patterns
and ocean currents, these air and water movements influence weather.
- Radiation: stream of photons/ packets of energy that behave in waves or particles
depending on observation
- Wavelength: distance of crescents, freq: # of crests in one second. Hotter object more
frequent shorter wavelengths
- Shortwave radiation: 0.1-4 um, thermal radiation: long wave radiation
- Solar constant: albedo; reflected radiation, insolation; direct or indirect insolation that
reaches surface without being reflected.
- 23 units evaporate water, 21 are absorped by landmasses and oceans and emitted back
- Shortwave radiation only in day, thermal is present during day and night.
- H20 vapor and co2 absorp leaving radiation and trap it emitting it back to earth:
- PAR: photosynthetically active radiation: wavelengths that plants use in photosynthesis
- UV key role in evolution, cause of mutation, infrared: key role in habitat and climate 2.2:
- Tilt of earth’s axis influences seasonal radiation
- Mean temp. declines from tropics to poles.
2.3: Elevation and Temperature. Air temp. in Troposphere decreases with elevation
- Altitude: distance above earth’s surface
- Elevation: distance above sea level
- Force of huge mass of air molecules above a given area of earth’s surface is
atmospheric air pressure.
- Air pressure is only 0.1 at sea level. As it travels upwards for hundreds of kilometers is
thins out before going to atmosphere.
- Air pressure decreases with elevation this is because air molecules move faster at
earth’s surface, decreasing pressure with elevation results in molecules moving slower.
Additionally, warming effect of earth’s surface declines with elevation.
- Insolation from earths surface back to space, heat flows from warmer to cooler area
- Air temperature plays crucial role in exchange of water between earth and its
- Latent heat: energy absorped or released per gram during state of change. When it is
going from a ordered to less ordered state, energy is required to break the bonds; liq
- 2260 J of energy to evaporate water
- Condensation: water to liq: reverse, makes the ^ energy.
- Evaporation and condensation rate =, it is called saturated
- Saturation vapor pressure: water vapor content of air at saturation
- If pressure is exerted condensation occurs and vapor pressure decreases. Warm air has
greater capacity for holding water vapor
- Amount of water in given volume of air: absolute humidity
- Relative humidity: amount of water vapor expressed in comparison to percentage
saturation vapor pressure, which has a rel humidity of 100% - Air cooling: saturation vapor pressure decreases resulting in rel. humidity to increase.
When it exceeds saturation value cloud form which eventually precipitate with water/ice
becomes too heavy.
- Dew point temperature: a point where saturation vapor pressure is achieved. Dew is
formed when nightfall result in drop in temperature, thus the relative humidity increases.
If cool night temp reaches dew point, dew forms, lowering water content of air. When sun
comes back up, air temp up, saturation vapor pressure up. Dew evaporates. Dew can be
good moisture for small plants and animals.
- Precipitation: all forms of water reaching earth. Including mist and fog
- Not evenly distributed: it is most at equator and then declines as you go north and south
(similar to insolation)
- Decline is not continuous, there are two peaks at mid latitude then further decline N and
- As warm air travels tropical oceans it gathers moisture, northeast trades meat southeat
trades at intertroical convergence zone: two air masses meet, air piles, warm air cools.
When dew point reached precipitation falls. High rainfall in tropical regions.
- Having lost its moisture it moves N&S. Descending air warms it draws water from
surface thus arid regions are major desserts.
- ITCZ moves north and south depending on rays of sun
2.8: Snow and Ice:
- Ice forms from frozen water, and snow from crystallization of water vapor
- Snow: 25% of total precipitation, because it is much less dense
- Snow effects greater in Canada due to lake effect: greater proximity to surrounding lakes
and water bodies
- Recharging effect of snow melting soil moisture spring growth
- Effective insulator for vegetation because of low density. Snow cover greater and
established early in winter is good. If it is light then soil warms more quickly when snow
cover is gone
- Reflective: earth’s surface heats up less, allows polar ice caps to increase in size.
- Can be hazardous when comes in significant amounts: storms and avalanches destroy
trees and living plants. 2.9: effects of topography:
- Physical structure of landforms influences precipitation
- Air ascends cools, becomes saturated with water vapor( low Saturation pressure) and
releases on top at windward side. Leeward side gets air that had lost moisture and takes
from surface. Thus windward supports certain vegetation and animals.
- Leeward: rain shadow conditions.
2.10: irregular climate variation:
- Ice age and droughts occurring in same area in past
- Tilt in axis every 10 thousand years change seasonal radiation
- Sunspot activity: huge magnetic storms on the sun. occurs 11 years and makes global
climate change predictions tougher to predict.
- Normal: strong trade winds move surface water westwards. warm water from western
pacific result in maritime air to rise and cool abundant rain fall.
- Under ENSO (El Nino): trade winds slacken, reducing westward flow of surface currents
and bringing more precipitation to Peru.
- La Nina: injection of cold water causing cooling of eastern pacific. Heavy rain in eastern
Australia and cold temp. in north America.
- Actual conditions may differ at specific sites. The weather of your area may not match
the general climate of the entire city
- Define the conditions in which organisms actually live. Heat transfer can vary and affect
the localized area.
- Walking into forest, you have experience microclimate: shady area, less insolation,
cooler air, alight wind etc.
- Ex: northern hemisphere south facing slopes are targeted by a lot more solar radiation
then north facing slopes.
- Microclimate influence the distribution and activities of organisms
Chapter 3: The Aquatic Environment
- Essential substance of life, component of all living things
- 95% of the mass of living cells is water - Salinity (salt concentration) major influence on adaptations of aquatic animals. There are
two divisions: Freshwater and marine (salt water).
3.1: Properties of Water:
- H20: H is positively charged, O is negatively
- Polar molecule, weak polar covalent bonding allows it to be easily broken
- High specific heat: # of calories need to raise 1 g of water by 1*C
- This means that large amounts of energy must be absorbed for the temp of lakes to go
up by 1 degree. Along with warming up, these waters cool off just as slowly during the
- Water Heat capacity also vital for thermal regulation of organism; since so many mass of
cells are made up of water
- Thus large amounts of energy are absirped and released when changing state
- Real water does not becomes denser when cooled. Because water molecules occupy
more space when frozen, ice floating on top of water makes it heavier.
- Hydrogen bonding: water molecules exhibit cohesion: tendency to stick togeather
- Water cohesiveness allow water to be on top of tree resisting transpiration
- Surface tension: taut surface, because of water attraction to eachother and the air
above, vital for some organisms and objects that can then be supported by water. Ex:
- For some organisms is can be a barrier if they get trapped or it takes them a long time to
cross they can become easy prey for fish
- Cohesion is also responsible for waters viscosity: the ability of a fluid to resist a force
from separating it, and allowing it to pass through it.
- Streamlines body of most fish and marine animals reduces resistence. Physeter
macrocephalus (sperm whale) has least resistence.
- Waters viscosity can also be beneficial: if submerged body weighs less then water it is
subject to buoyancy: ability of water to exert upward force on body in it. Most aquatic
animals are not as subject to resist gravity, thus swimming and buoyancy allows them to
utilize less energy.
- H20 density exerts constraints on deep water organisms, deep water is subject to
greater changes in pressure. Protein membrane are sensitive to pressure, thus deep
water organisms have modified versions to be able to live in deep water.
3.2: Light in Water: - Light is much more reduced in water then in air
- 1) suspended particles intercept or scatter light (can be living or dead)
- 2) water absorps light leaving only blue rays to be lost with increasing depth.
- This impacts temperature in water and organisms like phytoplankton; their pigment
composition is influenced by amount of light.
3.3 Water Temperature:
- Light absorption results in surface water being heated
- Temperatuere in deep water is still cooler, the thermocline zone is what experiences
rapid change in temperature.
- Epilimnion is the layer above thermocline. Much lower density then hypollimnion: deeper
layer of cold denser water. Thermocline prevents the two from mixing.
- Fall both layers have relatively same temp due to vertical mixing of water. In winter the
epiliminon has lower temp, due to ice frozen at top.
Chapter 4: Terrestrial environment:
- Desiccation: greatest challenge for living organisms because living cells are made up of
water, air must be saturated with moisture, or readily evaporation will occur and cell
needs to be moist to function; water balance: cell needs to maintain moisture to function.
- Many plants have evolved based on this factor: plants form cuticle to prevent water loss
and prevent damage from solar radiation, this made it tough for gas exchange, thus they
developed stomata to allow sufficient Co2 and O2 exchange by allowing it to diffuse in
- To stay hydrated we must replace water lost through evaporation; urination. Kidneys
help regulate water reabsorption when we drink water.
- Plants through evolution developed Xylem, and vascular tissue to help consume water
ans sufficient nutrients.
- Development of skeletons, cell walls, chitins, lignin
- Kelp vs. Tree (macrocytis pyrifera) and (pseudotsuga menziesii) kelp cannot grow
outside of water, but tree can grow so tall on land. Adaptation allowing it to stand upright
4.2: Light and Vegetation:
- Light gradient on land affected by absorption and reflection of light by plants
- Canopy: upper most layer of vegetation - Leaf orientation and are matters: different leaf angles are more effective at reflecting
sunlight. Many plants angle their leaves accordingly when light levels are sufficiently
high and can cause damage or overheating
- Varying leaf angle is an adaptive plant behaviour: Tranmittence activates phtochrome, a
pigment that detects shading, shade intolerant plants allocate more carbon to leaves
instead of roots elongating their shoots to access light.
- Direct sunlight can cause sunflecks and is not reflected
- Ephemerals: species that fulfill their life cycle when light and moisture are available.
4.3: Soil Defined:
- Medium for plant growth, controls fate of water, natures recycling system: breaks down
waste products of organisms and transforms them into basic elements that can be the
habitat of animals and fungi.
- Define Soil:
o Natural product of withering rocks
o Formed by actions of living organisms
o Collection of natural bodies of earth, composed of minerals and elements that
allow plant growth.
o Regolith: layer of unconsolidated debris overlaying unweathered rock.
Chapter 6: Plant Adaptations
6.7: Carbon Allocation
- Carbon balance model: describes balance between CO2 uptake in photosynthesis and
its loss in respiration
- Total photosynthetic uptake minus total respiratory loss from organs
- Carbon allocation: net carbon gain for whole plant; influences plant survival, growth and