Biology 102 Exam #1
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- What is the current population of humans on earth?
- 6.4 billion and rising
- How many new people are added every second?
- 3 people every second
- What are the 3 patterns of dispersion?
- random, clumped and uniform
- What is an age structure?
- An age structure divides into segments of 3 nations (# of individuals in each of several age categories)
- What are the 3 components of age structure?
- pre-reproductive, reproductive, post-reproductive
- What is a type 1 survivorship curve?
- Type I: Humans have a good change of living past age 50
- Type 2 survivorship curve?
- Type II: (linear line) mortality and survivorship are constant; age has no effect on survival or death (rodents, song birds, etc)
- Type 3 survivorship curve?
- Type III: inverse of type I; survivorship low in the beginning (anything that spawns; oysters, etc.)
- What is the exponential growth model?
-
what would happen to population in ideal conditions (a quantity increasing by a fixed percentage of the total in each specified interval); G=rN
N=# of organisms (population size); G=growth; r= growth rate (dN/dt) - What is the logistic growth model?
-
shows how carrying capacity can affect population size
G=rN [(K-N)/K)] - What is carrying capacity?
- the maximum number of individuals of a population that a given environment can sustain indefinitely (how many individuals can be supported in a habitat)
- What is an ecological footpring?
- How much average human takes up on the earth; average number is 24 acres
- What can be done to decrease the ecological footprint?
- Recycle, use other forms of transportation other than cars or airplanes, eat locally grown foods, less meat, use fuel efficient cars
- About how many species live on earth?
- 1.7 million species have been described; 5-30 million are still out there unnamed
- What species is most abundant?
- insects 750,000 species named
- What is the correct way to write a species name?
- Canis familiaris
- What did Linnaeus do?
-
(1707-1778) founder of taxonomy and binomial nomenclature (the two name, naming system)
In this order: Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species - Lamarck?
-
theory of evolution in 1809
 Transformism
 Need-based
 Inheritance of acquired characteristicsïƒ example/if you lose 2 fingers accidently, your children will be born without those 2 fingers; Arnold bodybuilding example - Lyell?
-
(1797-1875); Developed Uniformitarianism (1830), whatever forces that are on earth, they are uniform (volcanoes, earthquakes, etc.)
 Take home messages
• The earth is very old (much older than 6000 years accepted at the time via biblical reference)
• Slow and subtle processes over long periods of time can cause huge changes - Hutton?
- (1726-1797) developed Gradualism (1795), the earth gradually, slowly changes
- Darwin?
- Had a unique ability to think along a geological time scale (if the earth were a year old; 2 ½ months prokaryotic life forms, 11 ½ months vertebrates develop, at 9:15 Homo sapiens evolve, I’ve been around about .13 seconds; Darwin’s observations; Most species produce more offspring than the environment can support; Environmental resources are limited; Most populations are stable in size; Individuals vary greatly in their characteristics (phenotype); This variation is heritable (genotype); Natural selection is the mechanism of evolution; 1859 published On the Origin of Species by Means of Natural Selection
- Wallace?
- also developed a theory of natural selection at the same time and collaborated with Darwin
- Miller?
- first to test the abiotic synthesis hypothesis; he placed water, methane, hydrogen, and ammonia inside a reaction chamber. He kept the mixture circulating while zapping it with sparks to simulate lightning. In less than a week, amino acids and other small organic compounds had formed
- What is biogeography?
- Study of patterns of distribution of species.Animals of a given continent resemble the country more than any other country; Example/ Australia is dominated by marsupials
- What is biological species?
- is based on interfertility rather than physical similarity (the definition of species is based on its reproductive isolation)
- What is a population?
- localized group of individuals of the same species
- What is a gene pool?
- total sum of alleles in a population at one time. The genetic possibilities/diversity of a population
- What is an allele?
- an alternative form of a gene
- What is natural selection?
- a population of organisms that can change (adapt) over time as a result of individuals with heritable traits leaving more offspring than other individuals
- What is genetic drift?
- random changes in the gene pool of small population due to chance alone
- What is stabilizing selection?
- ex/ human birth weight; Intermediate forms of a trait in a population are favored and alleles for the extreme forms are not. Can counter mutation, gene flow, and genetic drift. It preserves most common phenotypes (pg 250)
- What is directional selection?
-
selected force that forces in another direction
 Ex/ a new mutation that benefits individuals also may cause a directional shift (pg 248) - What is diversifying selection?
- selecting against the average; Could eventually lead to 2 species; Occurs through error in meiosis usually
- What is sexual selection?
- a form of natural selection in which the genetic winners are the ones that outreproduce others of the population; Ex/ flashy colored male birds
- What is the bottleneck effect?
- a drastic reduction in population size brought about by severe pressure or a calamity.
- What is the founder effect?
- occurs when a new population arises from only a few individuals; Ex/ only a few fish are introduced into a lake; Ex/ only a few birds make it to an island
- What is gene flow?
- addition or removal of alleles due to individuals entering or leaving a population from another population through immigration and emigration; Ex/ blue jays keep genes flowing between separate oak populations
- What is genetic variation a product of?
- Sexual reproduction (genetic recombination); Mutations; Provide alternative alleles that may or may not be useful with changes in environment; This creates the substrate for adaptation to work with
- What is allopatric speciation?
- “geographical speciationâ€; Physical barrier that separates a species into two populations, until eventually they are so different that they cannot interbreed; Scale and type of movements, migrations, and dispersal can be key factors
- What is sympatric speciation?
- less common, form own new special species
- What is exaptation?
- evolutionary novelties are modified versions of older structures. Ex/ birds and flight; ex/ vocal cords lower down; can’t breathe and drink at the same time
- What is paedomorphosis?
- adults retain features that were juvenile in ancestors. Ex/ adult tadpole had characteristics (gills)
- What is heterchrony?
- ex/ head size and proportions. Head larger as child, something on our body that grows at different rates
- What is homeosis?
- spatial changes in developmental plan
- How old is the earth?
- 4.55 billion years old
- How old is the universe?
- 14-16 billion years old