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Biology Exam 4 (new)

Limnology Study of inland waters
Scientific Method "Science as a way of knowing" 1. Observation 2. Question 3. Hypothesis 4. Test 5. Conclusion
Important for hypotheses Come up with many possible answers so that you don't just look for results that supports your hypothesis
Common Question about Organisms Origin of species
Divine Creation Aristotle's 'scala naturae', species are perfect and permanent
Descent with modification Species change. Strong support
First inspiration leading to decent with modification Geologists ask how the earth changes over time-it was obvious that the world is very old and constantly changing- he proposed natural selection. He studied fossils to prove this as well.
Lamarck Use and disuse. Body parts that are used often get stronger, whereas body parts that aren't use deteriorate and both of these adaptions are inherited
Testing Lamarck's Hypothesis Matthias Schliite didn't pass on his strong arm to his offspring
Decent with modification by natural selection STRONG SUPPORT: Darwin and Wallace. New observations, new and very different species. Species today descended from ancestral species due to natural selection
Natural Selection A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rate that other individuals because of those traits. Darwin and Wallace said that traits that an enhance survival are not possible within a lifetime
Observation 1 of Darwin's Hypothesis Organisms reproduce a lot leading to over reproduction
Observation 2 of Darwin's Hypothesis Population sizes remain relatively stable
How can observation 1 and 2 both be true? More are produced than can survive. "Struggle for existence" the weakest ones or the ones with the least desirable traits don't survive
Observation 3 of Darwin's Hypothesis Struggling successfully; there is a lot of variety in the population
Observation 4 of Darwin's Hypothesis Traits are heritable and passed onto offspring
Conclusion of Observations 3 and 4 Individuals were heritable traits that enhance survival and reproduction are passed onto offspring
Overall Conclusion of Darwin's Hypothesis Traits become common over time
Artificial Selection Evidence supporting Darwin; we pick favored traits and control survival
Homology Evidence supporting Darwin; Similarity is due to common ancestry. Homologous structures=similar structures that are functionally different (arm, dog leg, fin, wing)
Vestigial Structures Historical remnants that serve no purpose (appendix)
Molecular homologies Similar composition of proteins, DNA
Biogeography Evidence supporting Darwin; the geographic distributions of organisms. For example, same island=more similar features in organisms than a distant island. caused by factors like the continental drift
Fossil record Near by strata more similar than separated strata ; gradual change over time; evidence of new species and extinct species
Not all genetic variation is subject to natural selection Genetic drift and gene flow are also parts of evolution
Neutral Variation Neither greatly add to nor greatly detract from organism fitness
Historical constraints Traits are only modified from existing material, selection can only edit an existing variation. Also, what works in one period of time may not be ideal in a later time (wooly mammoth)
Microevolution Generation to generation change in allele frequencies in a population
Genetic variation The raw material for evolution. If there is now variation for a gene, it will stay the same
Polymorphism 2 or more versions of a trait is present for a species; the presence of genetic variation within a population
Where do new alleles and traits come from? Mutations: change in structure of DNA (on a single gene or an entire chromosome) mutations are not always a bad thing
Step 1 for where new traits come from Creating new alleles: mistakes during DNA replication or meiosis. Point mutations and duplications. Breakage and duplications
Step 2 for where new traits come from Create new combinations are alleles to get new traits: crossing over, independent assortment, fertilization
Genetic Drift Effects of random chance on a population (luck) Important for small populations
Fixed allele The only one type of allele remaining the the rare allele is eliminated via genetic drift
3 Types of Natural Selection Directional, diversifying, stabilizing
Directional One extreme version of a trait is favored
Diversifying Either extreme phenotype is favored
Stabilizing Average is good, extremes are not
Founder Effect A few individuals start a new population, reducing overall genetic variability, some traits will be lost and a trait that was originally rare could become common
Example of the founder effect The Amish
Bottleneck Effect Population size dramatically decreases; lose genetic variability and traits, when population grows again theres still the low genetic diversity, endangered species
Sexual Selection Just because you survive doesn't mean you an reproduce; natural selection acting on sexual genes
Intrasexual Competition for mates
Intersexual Traits help individual get chosen by females
Runaway Hypothesis If big is good, bigger is better
Handicap Hypothesis Only the most robust can have costly/risky traits
Speciation Allele frequency --> trait change --> species change
Biological species concept Individuals that have the potential to interbreed and produce viable, fertile offspring
Problems with the definition for 'species' Hybridization and asexual reproducers
Hybridization Two different species reproduce. (mule, liger)
Asexual reproducers Some organisms don't do sexual reproduction. Bacteria, mayflies, plants can self-fertilize
Allopatric Speciation Part of a population gets isolated. Genetic drift, natural selection, differences between two areas (depends how strong barrier is)
Sympatric Speciation Without geographic isolation. Polyploidy, changing habits
Polyploidy Error during cell division results in change of number of chromosomes, can be catastrophic but sometimes is not.
Reproductive Isolation Seperation and divergence of a population's gene pool. Gradual process, reproductive barriers enhance separation
Pre-zygotic barriers Prevent mating or fertilization: timing is different, habitat is different, behavior is different, mechanical isolation (gentalia doesn't fit together), gametic isolation (sperm can't survive)
Post-zygotic barriers Reduced hybrid viability (offspring can't survive and reproduce: mules, ligers)
Macroevolution Evolution on a grand scale
Gradualism Big changes reflect slow, steady, change. Lineages gently diverge and speciation: accumulation of may small changes
Punctuated Equilibrium Long periods of stasis and short periods of rapid change
Evidence for punctuated equilibrium Single gene/chromosome changes, fossil record evidence, adaptive radiations
Adaptive radiations Relatively rapid increase in new species on islands or over time. 1. Evolution of a key adaptation 2. Release from competition, predation 3. Subsequent specialization
Mass Extinctions Famous example: cretaceous extinction. large decreases in terrestrial plants/animals
Continental Drift Plates of earth's crust shifted apart. Caused extinctions, north and south separated, explains distribution of fossils, allopatric speciation
Endemism Being restricted to a specific geographic location
Abiotic factors Physical; climate, habitat
Biotic factors Other organisms; predators, diseases, competition
Convergent evolution Some species arrive at similar adaptations, unrelated species occupying the same niche in different places
Demography Population ecology, how populations change over time
Population A group of individuals of the same species in the same area
Meta-populations Spatially separated populations with some interaction
Population density Number of individuals in an area
Dispersion Spatial distribution of individuals
Age structure: pyramid shaped Lots of kids, some adults, few seniors. Kenya. Rapidly growing population
Age structure: bell shaped Some kids, many adults, some elders. US. Steady or non-growing population
Age structure: urn shaped A few kids, many adults, most elders. Italy. Non-growing or shrinking population
Rate of increase Births-deaths/population size (r=(b-d)/N)
If there is a low birth rate or high death rate... r is negative
R strategists Live fast die young, have lots of offspring. Large rates of increase. very small in size, no parental care, young when reproduce, type 3 curve, pyramid shaped age structure
K strategists Slow and steady wins the race, live in competitive places. Few offspring, big bodied, lots of parental care, delayed age of reproduction, type 1 curve, bell shaped age structure
Exponential Growth A population whose members all have access to abundant food and are free to reproduce at their physiological capacity. This occurs when r is greater than 0. J-shaped curve on a graph (not really possible, a population cannot grow forever)
Logistical Growth Population size increases, and then levels off at the carrying capacity
Density Independent Controls Affect any size population. These include factors like fire, tornado, drought-can’t keep a population at constant levels, don’t make a "correction" when the population size gets too large- abrupt shifts in population size
Density Dependent Controls Depend on the size of a population. These factors include competition for food, predation, and disease- halts population growth so that a population doesn’t continue growing forever
Ecological Footprint Amount of land and water needed to produce all the resources used
Co-evolution Adaption in one species triggers an evolutionary response in another species
Mechanisms plants use for defense against herbivores Plants minimize being eaten mainly by having spines (like a cactus), or they use chemical defenses
Mechanisms prey use against predators Be able to escape, be hard to eat, be bad to eat, be hard to see, let someone else be eaten, gang up on the predator, scare the predator, be vigilant
Predation +/- interaction
Batesian mimicry Pretending to be bad to eat. For example, predators know that a monarch butterfly is poisonous, so predators stay away. A viceroy butterfly is not poisonous, but fakes being a monarch so that they do not get eaten
Mullerian mimicry Strength in numbers. Two different unappealing species resemble each other. The more bad prey there are, the more quickly predators learn to avoid them
Aposematic coloration Animals that are poisonous often exhibit bright colors as a warning
Co-evolutionary arms race When prey organisms develop an effective defense against predation, predators must adapt to the change and find a way around the defense, or find a new organism to prey on
Herbivory +/- interaction
Symbiosis An interaction between organisms of 2 species that involves direct physical contact
Parasitism +/-, the parasite derives its nourishment from another organism, its host. Some parasites even live within the body of their host (endoparasites or endosymbionts)
Mutualism +/+, both species benefit (flowers and bees) often leads to co-evolution
Commensalism +/0, not very common, burrs are an example
Competitive Exclusion Principle 2 species that share the same resource cannot coexist indefinitely, some one is always going to lose.
Niche The total range of resources that species needs in its environment: fundamental niche and realized niche
Fundamental niche The greatest possible range of resources an organism can use
Realized niche The range of resources an organism actually uses
Character displacement Greater differences in a trait when 2 species co-occur than when isolated, thought to be a mechanism for driving speciation.
Causes of modern extinction Habitat loss, invasive species, invasive meltdowns, the anthropogenic blender, over-exploitation
Invasive species Species introduced to an area outside of their native range, can alter habitat, outcompete and displace the local species
Common features of invasive species Wide environmental tolerances, large native range, r-strategists, reduced negative species interactions
Common features of places susceptible to being invaded Disturbed ecosystems, low predator abundances, "naive" prey
Photosynthesis Plants convert solar energy to chemical energy Light + CO2 + H2O ---> glucose +O2
Respiration Organisms break down glucose to use the chemical energy Glucose + O2 ---> CO2 + H2O + growth and activity
Primary producers Self-feeders (autotrophs)
Secondary producers Heterotrophs
Energy flows Some usable energy is lost as heat in each step and is only used once, which is why energy flows
Nutrients cycle Carbon and nutrients get used and reused and move from place to place, which is how nutrients cycle
P=R Organic carbon production (molecule, materials made by organisms) and consumption are in balance CO2 production and consumption are in balance
P>R More CO2 consumed than produced, more organic carbon produced than consumed, organic matter accumulates and CO2 declines, dead plants on forest floor, CO2 goes down in the summer as plants grow
P<R CO2 goes up in the winter as plant growth slows
Ecosystem Respiration (E) The total carbon dioxide produced by the ecosystem Organic carbon ---> CO2 + H2O
Primary Production (P) Synthesis of organic compounds from carbon dioxide. It principally occurs through the process of photosynthesis, and is caused by primary producers. Sunlight + CO2 + H2O ---> organic carbon
Key determinants of the distribution of biomes are Temperature and precipitation
Gene flow Populations can gain or lose alleles when individuals enter or leave a population, unlikely to lead to speciation
Prokaryotic biodiversity is substantially______ eukaryotic diversity Greater than
The focus on ecosystem services in the Millenium Assessment is based on the logic that these services... Are central constituents of human well-being
Autogenic Engineers Change the environment via their own physical structures, i.e. their living and dead tissues." As they grow and become larger, their living and dead tissues create habitats for other organisms to live on or in
Darwin's influences World travel, fossils, geology
U.S uses about ____ of all the raw materials consumed each year, but has less than _____ of the population of the world 1/3, 1/15
Created by: knuepril



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