Pearson Environmental Science: Your World Your Turn: Chapter 5: Evolution and Community Ecology
Evolution
"Change over time"
Heterotroph
"other feeder"
Autotroph
"self feeder"
Pyramid of Energy
(Figure 22, page 145) 3rd level Consumer---------0.1% energy_______Heat---> ______________________^ ^ ^ ^ 2nd level Consumer---------1% energy________Heat---> ______________________ ^ ^ ^ ^ 1st level Consumer---------10% energy________Heat---> ______________________^ ^ ^ ^ Primary Consumers--------100% energy_______Heat---. ______________________^ ^ ^ ^ ______________Light Energy/Chemical Energy
Consumers
(heterotrophs) organisms that rely on other organisms for energy and nutrients
When does extinction occur?
-when environmental condition change rapidly or severely enought that a species cannot adapt to the change. -occurs gradually one species at a time.
Timespan of a specie
1 million to 10 million years The number of species on earth at any given time = the number added through speciation - the number removed by extinction.
Allopatric speciation
1. Single population >2. Geographically isolated populations >3. Divergence due to long-term geographical isolation. >4. Isolated populations come together; two populations can no longer interbreed and are now two species.
Photosynthesis Equation
6CO2+6H2O+sun's energy-->C6H12O6 (sugar) +6O2
Keystone Species
A species that has strong or wide-reaching impact on a community than others EXAMPLE: Sea Otter eats urchins which eat kelp. Sea otters keep urchin population controlled, keeping kelp alive kelp serves as habitat for many animals and plants
Advantages/disadvantages of generalist category
Advantage: live in many different places and variable weather conditions Disadvantages: may not be as successful
Advantages/disadvantages of specialist category
Advantages: successful in their niche because they are good at what they do Disadvantage: cannot adapt well
Artificial Selection and Dogs
All dogs are a single species Any two dogs can produce offspring Dog breeders maintain differences among varieties by allowing only like individuals to breed.
Survival of the fittest
An individual with high fitness produces more offspring and therefore passes on its genes more frequently than an individual with lower fitness Next generation will have a higher proportion of fitter individuals organisms evolve in a way that maximize their success in a given environment
trophic level
An organisms rank in a feeding hierarchy
Omnivores
Animals that eat both plants and animals
Genetic Drift
Biological evolution that happens by chance Unusual events such as natural disasters kills/separates all but few individuals from a population --> next generation has different gene pool
Primary producers (Autotrophs)
Capture energy from the sun or from chemicals and sort it in the bonds of sugar, making energy available to the rest of the community
Intraspecific competition
Competition among the same species
The Ten Percent Rule
Each trophic level contains 10% of the energy of the trophic level below it (See Pyramid of energy term 90)
Food Webs and Keystone Species
Feeding relationships have both direct and indirect effects on organisms in the community
(CNS) 3. Individuals vary in their fitness
Individuals with helpful variations are better suited for their environment than individuals without them organisms better suited for their environment are more likely to succeed --> reproduce
Scavengers
Large detritivores vultures
disequilibrium
Limiting factors shift, altering carrying capacities. Population size changes, community enters a period of adjustment
Population Cycles
More prey=more food=more reproduction of predators then-->more predators= more consumption of prey, less predators then--> more prey=more food=more reproduction of predators...
Energy Transfer in Communities
Organisms consume food and "burn it" through cellular respiration Energy is used for life activities but in the process much is released as waste heat. only a small amount of energy is transferred to next trophic level
Generalists
Organisms with wide tolerance ranges able to live in a wide array of habitats or recourses
Trophic Cascade
Predators at hight trophic levels (sea otters) indirectly help organisms at low trophic levels (kelp) by limiting populations at intermediate trophic levels ( urchins).
Speciation
Process by which new species are generated -geographical separation
Photosynthesis
Process by which primary producers use sunlight to convert CO2 and water into sugars, releasing O2 along the way
Primary mechanisms
Processes of biological evolution mutation migration genetic drift natural selection
(CNS) 2. Individuals of a species vary in their characteristics
Some individuals of a species have better qualities than other members of a species. Variations are described as heritable when passed from parent to offspring
Conditions of Natural Selection
Three conditions: 1. Organisms produce more offspring than can survive 2. Individuals of a species vary in their characteristics 3. Individuals vary in their fitness
Sun
Ultimate source of energy for nearly all of earth's ecological systems Releases radiation from large portions of the electromagnetic spectrum
Competition
When multiple organisms seek the same limited resource, such as food, light, water, or space.
(CNS) 1. Organisms must produce more offspring than can survive
a "struggle for existence" among organisms in their environment, (Carrying capacity)
Biological Evolution
a change in a populations gene pool overtime leads to changes in the frequency of an appearance or behavior from generation to generation EXAMPLE: 1st generation of mice 40% brown 60% tan 2nd generation of mice 28% brown 72% tan
Equilibrium
a generally stable and balanced community
Adaptation
a heritable trait that increases an individual's fitness
Symbiosis
a long-lasting and physically close relationship in which at least one organism benefits "living together"
*****commensalism (+/0)
a relationship in which one species is benefited while the other is unaffected.
Mutualism:
a relationship in which two or more species benefit (+/+) many are symbiotic EXAMPLE: some plants and fungi together form symbiotic associations called mycorrhizae. plant provide protection and energy to fungus. fungus assists plant by absorbing nutrients from the soil. Not all in close proximity: butterflies
*****mutualism (+/+)
a relationship in which two or more species benefit; often symbiotic
Resource partitioning
adaption to competition by using slightly different resources or their shared resources in different ways species divide the resources the y use in common by specializing in different ways
Migration
aka gene flow if after a mutation occurs some with/without mutation immigrate/emigrate, biological evolution occurs
Gene Pool
all of the genes present in a population
First trophic level
always made up of primary producers
Niche
an organism's use of resources and its functional role in a community Includes the habitat, food it eats, how and when it reproduces, and what other organisms it interacts with. summary of everything an organism does and when and where it does it.
Carnivores
animals that kill and eat other animals
Specialists
animals with very restricted tolerance ranges EXAMPLE: panda bear
(+/-)
beneficial for one participant, but harmful for the other
Decomposers
break down nonliving matter into simpler parts that can then be taken up and reused by primary producers fungi and bacteria
Mutation
changes in DNA
Interspecific competition
competition among 2 or more members of separate species
Detritivores
consume detritus (nonliving organic matter including leaf litter, waste products, and the dead bodies of other community members. millipedes, soil insects
What does cellular respiration occur in?
consumers (heterotrophs) as well as primary producers (autotrophs)
Tertiary Consumers
consumers of secondary consumers
Extinction
dissapearance from a species on Earth 99% of all species that ever lived are now gone.
Arms race
each species develop stronger and stronger "weapons" in response to the other
2nd Law of thermodynamics
energy tends to change from a more-ordered state to a less order state; systems tend to move toward increasing disorder (entropy)
Ecological Succession
following a disturbance, communities may undergo succession
Fundamental niche
full niche of a species
Thermal energy
high entropy very difficult to capture and convert to something else generally "lost" when released as heat
Fitness
how reproductively successful an organism is in its environment
Entropy
increasing disorder
Predation and Evolution
individual predators that are better at capturing prey will likely be more successful than less skilled predators. natural selection often leads to the evolution of adaptations that enable predators to be better hunters. Prey have evolved an elaborate array of defenses against being eaten
Energy and Biomass
inefficient energy transfers between organisms shapes the structure of a community
Herbivory
interaction in which an animal feeds on a plant insects are the most common herbivore does not directly kill the plant but can affect growth and reproduction
Food chain
linear series of feeding relationships EXAMPLE: Algae-->Small fish--> Large fish-->Bird-->Alligator
2nd, 3rd, and 4th trophic level
made up of primary, secondary, and tertiary consumers
(-/-)
negative effect on both organisms as each takes resources the other could have used
Newt v. Garter Snake arms race
newt has enough poison to kill 100 people garter snake can still eat them
Realized niche
niche restricted by competition
Result of 2nd law of thermodynamics
no process involving energy conversion is 100% efficient EXAMPLE: Only 14% of energy from gas in a car is used to move the car. The rest is converted into thermal energy and releases as heat.
What would happen if there were no detritivores or decomposers?
nutrients would be lost to the ecosystem when organisms die.
Primary consumer
organism that consumes producers
Secondary Consumers
organisms that feed on herbivors
Artificial Selection and Agriculture
our entire agricultural system is entirely based on artificial selection Corn is sweeter with larger kernels, oranges, apples, and pears have better taste, wheat and rice with larger and more numerous grains, brassica oleracea has given rise to broccoli, cauliflower, cabbage, and brussels sprouts
herbivors
primary consumers that only eat plants deer and grasshoppers
Predation
process by which an individual of one species (a predator) hunts, captures, kills, and consumes an individual of another species (prey). Interactions between predators and prey influence community structure by helping determine the relative number of predators and prey.
Chemosythesis
process by which energy stored in the bonds of hydrogen sulfide convert CO2 and water into sugars
cellular respiration
process by which organisms use oxygen to release chemical energy of sugars such as glucose, releasing CO2 and water as a byproduct
Natural Selection
process by which traits that improve an organism's chances for survival and reproduction are passed on more frequently to future generations than those that do not Charles Darwin ---> On the Original Species Alfred Russel Wallace
Coevolution
process by which two species evolve in response to changes in each other change in one species therefore, is usually followed by a change in another
Background extinction rate
rate at which gradual extinction occurs
Parasitism
relationship in which one organism, the parasite, depends on another, the host, for nourishment and some other benefit host is harmed in the process
Commensalism
relationship in which one species benefits and the other is unaffected. (+/0) Palo verde trees in desert provide shade which keeps ground cool and moist and thus young plants thrive in its shade.
Gene
sequence of DNA that codes for a particular trait
"0"
symbolizes the relationship in which there is no effect or the effect is neutral
Tolerance
the ability to survive and reproduce under changing environmental conditions influences where and how an organism lives
Succession
the process by which a plant or animal community successively gives way to another until a stable climax is reached.
Artificial Selection
the process by which humans choose and bread animals and plants with appreciated traits rather then letting nature "select" what traits are best suited for a given environment
Biomass
the total amount of living tissue contained within a trophic level EXAMPLE: snakes eat mice 1 snake's weight > 1 mouse's weight 1 snake's weight < All mouses weight
Competitive exclusion
the winner of competition may exclude the weaker completely. occurs when two or more species try to occupy the exact same niche.
How many trophic levels are typically in a community and why?
typically only three or four the relative amounts of nutrients available at each trophic level put restrictions on a community's structure
Chemosynthesis v. Photosynthesis
use different energy sources each use water and CO2 to produce sugars
Chemosynthesis energy support what?
various species of mussels, shrimp, crabs, fish, enormous clams, and tubeworms
Food Web
visual map of feeding relationships and energy flow, showing the many paths by which energy and nutrients pass among organisms as they consume one another
Energy From Chemicals
water heated by magma deep-sea vents host large communities primary producers such as bacteria use energy stored in the bonds of hydrogen sulfide to convert carbon dioxide and water into sugars (Chemosynthesis)
Character displacement
when resource partitioning leads to the evolution of physical characteristics among the competing species that reflects their specialized role in the environment
