
College Biology Review #3
12/1 Concept Mapping
Visual organization that shows how things are connected
Pre- Darwin 12/3
Plato- Interpreted variations as imperfections and believed only perfect forms were real
Aristotle- “scala naturae”- organisms could be arranged in increasing complexity, but were placed here, not evolved
Linneas- created taxonomy (system of classifying organisms), didn’t believe in evolution, but believed taxonomy would reveal God’s plan
Lamark- believed things evolved to become more complex, and complexity = perfection
Darwin- Figured out how evolution occurred
- Theory of Natural Selection- those best suited to the environment survive
- Natural resources (such as food) are limited
- Variation in a population
- Most variations are inherited
- In certain environments, some variations are more favorable
- Those with favorable traits will survive and reproduce to pass on favorable traits
- Background info:
o Was supposed to be a doctor like his father, but turned to ministry and later zoology and geography
o 1831- 1836 spent aboard the Beagle surveying South American coast
o Most data from Galapagos Islands (W of Ecuador and very isolated)
o Important because he proved how evolution works, revolutionizing biology
o Read up on all conflicting theories in order to better support his own and was an excellent observer and recorder
o Equated to Copernicus, Galileo and Newton
12/4 The Signs of Evolution
- Darwin used only geographic distribution and fossil records to support his theory
Biogeography- Geographical distribution of species
Endemic- native (found nowhere else)
- examples- only marsupial mammals are endemic to Australia. Placental mammals do fine there, but they didn’t evolve there.
Darwinian interpretation- modern species are found where thy are because they evolved from ancestor inhabiting the same region
The Fossil Record
- Oldest fossils are prokaryotes, followed by fish, amphibians, reptiles, mammals and birds. This chronologic order supports the theory of increasing complexity in evolution.
- Darwin’s interpretation- evolutionary transitions should leave signs in the fossil record
Taxonomy
Taxonomy- classifying organisms. Developed by Linnaeus, who believed in placement, not evolution
Darwin’s interpretation- saw in taxonomy evidence for common descent. Organisms at different taxonomic levels share ancestors
Comparative Anatomy
- common descent is evident in anatomical similarities (if two organisms look alike, they probably share an ancestor
Homology- common ancestry
Homologous structures- anatomical signs of evolution supporting common ancestry
Vestigial organs- unneeded structures; remnants of ancestral structures that were essential.
- Example- pelvis and leg bones in snakes or a person’s appendix
Comparative Embryology
- Closely related organisms develop similarily
o It is difficult to distinguish between a fish, human or rabbit in early embryotic stages (for example, all have gills)
Otogeny- embryonic development of an individual organism
Phylogeny- evolutionary history of a species
- In the 18th century embryologists believed embryotic development was a replay of evolutionary development. “Ontogeny recapitulates phylogeny.”
o Inaccurate- there’s not a “fish stage,” “amphibian stage,” etc.
Molecular Biology
- Evolution reflected in DNA. DNA is passed from one generation to the next, so similar DNA on separate organisms indicates common ancestry.
Darwin’s Interpretation- he believed all forms of life were related through branching descent from the earliest organisms.
- Darwin wrote the Origin of Species in 1859
- Darwin toured on a ship named the Beagle and was constantly seasick. He spent as much time as possible off the ship, which is how his studies began.
Flora- plants
Fauna- animals
12/8
Genetic Drift- an agent of evolution- random event kills off a small population opposite of natural selection
Resource Partitioning- how environment is divided among co- existing species
Sexual Selection- choosing a mate based off of specific characteristics, which are then passed down to future generations
Carrying Capacity- number of individuals an environment can support
Gradual Evolution- very small, consistent changes over a period of time
Punctuated evolution- very drastic changes in a short amount of time followed by periods of no change
Species- individuals that can mate and produce viable (fertile) offspring
Taxonomy- created by Linneas
- Named by Genus, species
- The five kingdoms are Monera, Protista, Fungi, Plantae, and Animalia
Reproductive Barriers- any barrier that impedes the production of viable offspring
- Prezygotic- changes that occur before the egg and sperm combine. The animals are physically unable to mate. Causes:
o Different environments
o Different mating times
o Mismatched mating behavior
o Mismatched anatomy
- Postzygotic- a barrier occurring after egg and sperm meet. May produce hybrids (ex. mule), but doesn’t produce viable offspring.
o Hybrid- a cross of two different species
§ Offspring is usually infertile
§ Sometimes first generation offspring are fertile, but the second generation will be infertile
12/9 How Populations Evolve
Holes in Darwin’s theory- Darwin had no concept of molecular level
Hardy and Weinberg- created an equation for frequency in a population. P = dominant, q = recessive. P + q = 1. p² + 2pq + q² = 1.
Gene Pool- aggregate of genes in a population
Word of the Day: Aggregate- total/ sum of
Richard Dawkins—Evolutionary Biology
- Richard Dawkins was born and raised in East Africa. He came to Oxford as an undergraduate in 1959 and taught at Berkely and Oxford
- Is one of the leading evolutionary thinkers and has popularized Darwinism. Uses digital technology to test Darwinism
- Says that genes are in control; organisms are simply “vehicles” for genes, and the gene that can build the best “vehicle” survives
- Critics say that he over- simplifies the theory of evolution
o The Selfish Gene- 1976
o The Extended Phenotype- 1982
o The Blind Watchmaker- 1986
o River out of Eden- 1995
o Climbing Mount Improbable- 1996
o Unweaving the Rainbow- 1998
Ecology 12/15/03
Ecology- study of the interaction of organisms, with each other and the environment
Abiotic components- non- living things (rocks, air, water, etc.)
Biotic components- living things (plants, animals, fungi, etc.)
Levels of study (for Ecology)- Organism, population, community, ecosystem
Population- group of same organism
Community- several coexisting populations
Ecosysem- community with abiotic components
Biome- major type of community found in broad geographic areas
I Terrestrial Biomes- land biomes, ordered from most to least rain
A. Tropical rainforest- over 60” rain annually
a. Usually rains every day
b. Found near equator (very warm)
c. More plants/ animals than all the other biomes combined
d. Cold rainforest—Seattle
B. Temperate Deciduous Forest-
a. Trees with large, broad leaves (lose leaves in fall)
b. Found in mid- latitude regions (30- 45° North and South)
C. Coniferous Forest
a. Conifer trees
b. Just North (or South below Equator) of Temperate Deciduous Forests
c. Also called Taiga
D. Grasslands
a. Grass is prominent growth
b. Three types (ordered more-> less rain and warmer-> colder)
i. Savanna- just grass- warm
ii. Temperate- some trees
iii. Chapparral/Steppe/ Scrubland- spiny bushes- cold
E. Desert- 10” or less precipitation per year
a. Hot deserts
b. Cold deserts (also called tundras)
12/16/03
II Aquatic Biomes
A. Freshwater- less than 1% salt
a. Standing water- ponds and lakes
i. Pond- light can reach bottom
ii. Zones:
1. Littorial zone- shallow, well- lighted, close to shore
2. Limnetic zone- open, away from shore, well- lighted
3. Profundal zone- no light, below limnetic (abiotic, no photosynthesis)
iii. Eutrophic- nutrient- rich from nitrogen in fertilizer runoffs. Less oxygen, green, cloudy, no fish, becomes marsh.
iv. Oligiotrophic- blue, clear, lots of oxygen and fish
b. Flowing water- rivers and streams
i. Stream- light can penetrate to bottom
B. Salt Water- Greater than 1 % salt content
a. Zones:
i. Benthic- sea floor
ii. Pelagic- open water- most of ocean
iii. Contenental shelf- shallower, juts out from land
iv. Intertial- land meets water- shallow
v. Neritic- right where the continental shelf ends
vi. Oceanic- on top of Pelagic- shelf to shelf
b. Photic- light can penetrate
c. Aphotic- light can’t penetrate
C. Estuaries- salt water meets fresh water
a. Also called “brackish” water
12/17/03 Food Web
Trophic levels- depends on rank
Levels from highest to lowest and examples
- Keystone predator/tertiary: Humans
- Secondary consumers: Fox, Wolf, Owl
- Primary consumers (Heterotroph) low- level predators/ herbivores: Rabbits, Mice
- Producers/autotrophs: Grass, Shrubs
- Scavengers- ready- made nutrients: Vultures
1/5/04 Population Ecology
Population density- number of individuals per unit area
Population dispersion- spacing pattern of these individuals. Can be clumping, uniform, or random.
3 factors of population size
1. Clutch size- number of offspring produced
2. Number of times an organism can reproduce
3. Age at first reproduction
Demographics- study of statistics involving human population growth
- Age structure- how old the people are
- Sex- male or female
Population Growth Patterns
Artithmetic- increasing by a constant number every year, resulting in a linear graph. A very atypical pattern
Exponential- increases by a given percent every year, resulting in a curved graph. Example: human population.
Logistic- Most natural. Increases are controlled by carrying capacity. There will generally be an exponential curve to the carrying capacity, where it will level off
1/12/04 Community Ecology
Community- several populations coexisting
Characteristics:
- Form of vegetation
- Trophic structure (food webs)
- Species richness- different populations, #s
o Rainforest high, tundra low
- Diversity- different types within larger groups (Ex. Frogs)
- Stability- Abiotic (climate) and biotic (species)
4 Things Determine Characteristics
1. Role of competition
2. Role of predation
3. Role of environment- resources
4. Role of humans
Succession- transition in species over time (ex. Number, diversity)
Primary- lava flow, soil destroyed. Basic to more complex
Secondary- when soil is okay, but a fire, for ex. Has occurred. Basic to complex a lot faster