Chapter 2 Flashcards
the ecosphere
- Lithosphere
- Hydrosphere (and cryosphere)
- Atmosphere
atmosphere includes
- Troposphere
- Stratosphere
- Mesosphere
- Thermosphere
energy
- Energy is the capacity to do work and is measured in calories (nutrition) or Joule (work required to produce one watt of power for one second (W⋅s) W=J/s
- Cal = 4.2 joules.
potential energy
is stored energy that is available for later use (e.g., gasoline)
kinetic energy
-Energy derived from an object’s motion and mass is known as kinetic energy (e.g., engine using gas)
low quality energy
- Most of the energy available for use is called low-quality energy.
- diffuse, dispersed at low temperatures, difficult to gather.
heat vs temp
- The total energy of all moving atoms is referred to as heat, a low-quality energy
- vs. temperature, a measure of average speed of molecules or atoms in a substance.
high quality energy
such as a hot fire, coal or gasoline, is easy to use, but the energy disperses quickly.
the first law of thermodynamics
- The first law is the law of conservation of energy
- energy can neither be created nor destroyed; it is merely changed from one form into another
- The total amount of energy in the universe is constant
the second law of thermodynamics
-The second law of thermodynamics (law of entropy) tells us that when energy is transformed from one form into another, there is always a decrease in the quality of usable energy; some energy is ‘lost’ as lower-quality, dispersed energy to the surrounding environment, often as heat
second law and organisms
- The second law of thermodynamics is important for organisms:
- because they must continuously expend energy to maintain themselves; whenever they use energy, some is lost
- because it tells us that energy cannot be recycled; it is constantly being degraded; the more we transform energy, the more is dispersed becoming less useful and lower quality
energy flow in ecological systems
- About 30% of the energy received is reflected by the atmosphere back into space.
- Of the remainder, about 50% provides heat to the Earth’s surface, 20% absorbed in the atmosphere, and less than 1% forms the basis for our ecological systems.
how plants produce O2
- Green pigments in plants, chlorophylls, absorb light energy from the sun.
- Plants combine carbon dioxide and water, using energy from the sun, into high-energy carbohydrates such as starches, cellulose, and sugars, during photosynthesis.
- Photosynthesis produces oxygen.
producers or autotrophs
Organisms with the ability to capture energy and manufacture matter are known as autotrophs, or producers.
heterotrophs or consumers
All other organisms are known as heterotrophs, or consumers.
two types of autotrophs
phototrophs and chemoautotrophs.
-Phototrophs get their energy from light, while chemoautotrophs obtain their energy from chemicals in the environment.
cellular respiration
- carbohydrates are broken down into inorganic molecules, carbon dioxide, and water.
- energy is released and can be used for many purposes by the organism.
aerobic organisms
must have access to oxygen for cellular respiration to take place, or they will die.
-Some species, anaerobic organisms (such as some bacteria), can survive even without oxygen.
food chains
- Each level of the food chain is called a trophic level.
- Herbivores eat producers and are the energy source for higher-level consumers, or carnivores.
- Omnivores, such as humans, raccoons, sea anemones, and cockroaches, can get their energy from multiple trophic levels.
consumers
- Primary Consumers: eating plants
- Secondary Consumers: eating herbivores
- Tertiary Consumers: eating animals that are secondary consumers or higher
food chain
Linked feeding series
trophic levels
An organism’s feeding status in a food web. Plants are at the producer level while animals are consumers
food webs
Network of food chains or feeding relationships
are all plants autotrophs
no Carnivorous pitcher plant gain their energy from ingesting the bodies of insects that trapped
detritus
These chains are based on dead organic material called detritus, which is high in potential energy but difficult for typical consumer organisms to digest.
decomposer food chains
play a key role in breaking down plant and animal material into products such as carbon dioxide, water, and inorganic forms of phosphorus and nitrogen and other elements.
detrital food chains
-Detrital food chains tend to dominate in forest ecosystems, and freshwater ecosystems.
grazing food chains
- Grazing food chains dominate in marine ecosystems.
- Producers are photosynthetic phytoplankton
- Zooplankton graze on the phytoplankton
species numbers and climate
The number of species increases from the poles to the tropics as conditions become more amenable for life
energy efficiency
portion of energy entering system that is transformed into useful form of energy or work.
- In natural food chains may be as low as 1%; 90% lost at each trophic level.
- Some ecosystems have an inverted biomass pyramid (natural grasslands, oceans).
natural food chains are inefficient
Only 10–20% of biomass is converted to food for next level
- Energy is released as heat during cellular respiration
- The longer the food chain, the less efficient
- The energy pyramid has important implications for humans
- In terms of energy efficiency, it would be better to operate as low on the food chain as possible—as primary consumers or vegetarians
productivity
-The rate at which energy is changed into biomass; usually expressed in kilocalories/m2/yr
gross primary productivity (GPP)
is the overall rate of biomass production. GPP=NPP+R
net primary productivity (NPP)
- Cellular respiration (R), must be subtracted from the GPP to reveal the net primary productivity (NPP); the amount of energy available to heterotrophs.
- Humans use 40% of all terrestrial NPP for their own use
ecosphere broken down
- At the smallest level is the individual organism.
- A group of individuals of the same species is a population.
- All the populations of all species in an environment are known as a community.
ecosystems
are collections of communities interacting with their physical environments.
-Ecosystems are open systems in that they exchange material and organisms with other ecosystems.
ecozones
- Ecozones are groups of ecosystems with similar dominant vegetation and animal communities.
- Ecozones can be grouped into biomes, based upon dominant vegetation and adaptations of other organisms to that particular environment.
abiotic components
- Key abiotic factors: light, temperature, wind, water, and soil characteristics
- Soil type is critical in determining the kind and extent of vegetation growth of an area
soils
- Soils are composed of inorganic materials decaying organic matter, water, and air
- Most soils form mainly from the parent material where they are found
- Various processes result in different layers forming in the soil, called soil horizons
- A soil profile is the view across these horizons
- Time is also a critical factor in soil development
humus
decomposed organic material
loams
soils that contain a mixture of humus and clay, silt, sand, and gravel.
texture
Texture is a main determinant of soil permeability, the rate at which water can move through the soil.
pH
Soils differ in chemical characteristics such as pH.
limiting factors
factors that determine whether an organism can survive in a given ecosystem e.g. rainfall, essential nutrients
dominant limiting factors
the weakest link in the chain of various factors necessary for an organism’s survival.
range of tolerance
the range of conditions that different organisms can tolerate and still survive
optimum range
the range of conditions that is ideal for a species
zone of physiological stress
conditions can be tolerated by certain individuals within the population, but are not optimal, so fairly few individuals can exist
extinction
Entire species ceasing to exist. Natural Extinction According to fossil record > 99% of all species are now extinct. Earth has experienced periodic mass extinctions.
- Nearly half of all plant and animal families died out 250 million years ago.
- Dinosaurs disappeared 65 million years ago.
niche
Each species needs a specific combination of the physical, chemical, and biological conditions for its growth, known as the niche of that species.
habitat
The habitat is simply where the species lives
competitive exclusion principle
According to the competitive exclusion principle, no two species can occupy the same niche in the same area
fundamental niche
potential range of conditions a species can occupy
realized niche
the range actually occupied
specialized species
have narrow niches and are vulnerable to environmental change, e.g., Panda
generalist species
may have a very broad niche, e.g., black bear, coyote
intraspecific competition
occurs among members of the same species; regulates population size; may lead to establishment of territories
interspecific competition
occurs between different species
resource partitioning
resources are used at different times, or in different ways, by species with overlaps of fundamental niches, possibly reducing competition
optimal foraging theory
recognizes that there is a point of compensation between the benefit of obtaining the prey and the costs of doing so, and predator behaviour adjusts to optimize benefits
parasitism
a special type of predator–prey relationship, where the predator lives on or in its prey (host).
mutualism
the relationship benefits both species
e.g., nitrogen-fixing bacteria and their host plants.
commensalism
interactions that seem to benefit only one partner but do not harm the other
e.g., epiphytes.
keystone species
Species with a strong influence on the whole community are known as keystone species
e. g., Beaver
- It is very significant when a keystone species is removed from an area, or extirpated, by human activity; a cascade of affects typically ensue
biodiversity
is the result of all the interactions between abiotic and biotic factors throughout evolution.
genetic diversity
variability in genetic makeup among individuals of the same species; the ultimate source of biodiversity at all levels.
species diversity
the total number of species in an area.
-Global estimates 5 to 20 million.
ecosystem diversity
the variety of ecosystems in an area.
biodiversity hotspots
areas with high numbers of endemic species; found mainly in tropical areas.
endemic species
are particular to a certain area, and found nowhere else on Earth.
In Canada there are approximately 54 endemic species of vascular plants, mammals, freshwater fish, and molluscs.
-In terms of protecting biodiversity, it is especially important that endemic species are given consideration, e.g., Vancouver Island Marmot.
