Unit 1: Evolution Flashcards
Basic Face Concerning Life on Earth (4)
Earth formed 4.3 to 4.5 Ga (billion years) ago; first life 3.5 to 3.8 Ga
Stromatolites as one of the first organisms on Earth at ~ 3.7 Ga.
3 Distinct Lineages of Organisms: Bacteria, Archaea, Eukarya
Ursus spelaeus vs. Panthera leo spelaea: former is genus but latter is a subcategory of that genus
Eukarya: General Characteristics, [X]-karyon, Life Cycle
aka Fungi – comprised of filaments (hyphae), where many hyphae together become mycelium
General Characteristics: non-motile filamentous (not-moving, thin, long) absorb nutrients; cell walls composed of chitin; a/sexual reproduction; heterotrophic decomposers
MONOkaryon: each cell contains a single nucleus
DIkaryon: cells of different hyphae fuse with each nuclei remaining distinct within the new hypha (present in Karyogamy)
Fungi Life Cycle: 1. Meiosis (division of cells into four haploids); 2. Plasmogamy (cytoplasm of two parent cells fuses together without the fusion of nuclei, effectively bringing two haploid nuclei close together in the same cell); 3. Karyogamy (final step in the process of fusing together two haploid eukaryotic cells to create a diploid)
Plants: General Characteristics, Algae Groups
General Characteristics: cellulose cell wall, photosynthesis, possess alternation of generations
Algae: both a/sexual reproduction where alternations of generations occur in the sexual cycle
Algae Group 1: unicellular only (eg. plankton); common types include diatoms and dinoflagellates
Algae Group 2: unicellular AND multicellular (eg. seaweeds); most common being red, green, and brown algae
4 Plant Life Cycles to Know
Byrophytes, Ferns, Gymnosperms, Angiosperms
BYROPHYTES – eg. mosses and liverworts; small, alternation of generations, dominance of gametophyte, development of archegonium and antheridium; 1. Meiosis (produces haploids wiht sexual being antheridia; asexual being archegonia), 2. Fertilization (fusion of haploids to create diploids)
FERNS – 1. Meiosis (release of spores; sperm use flagella to swim form the antheridia to eggs in the archegonia); 2. Fertilization (zygote develops into new sporophyte w reproductive leaves w spots called sori w clusters of sporangia)
GYMNOSPERMS – 1. Meiosis (female gametophyte w sperm nucleus) 2. Fertilization (ovulate cone and pollen cone as parents to create megaspore; pollen is microsporangia)
ANGIOSPERMS – 1. Meiosis (ovary into megasporadium; microsporocytes into microspore w male gametophyte); 2. Fertilization (egg nucleus germinates)
Chauvet Cave
Aristotle
Great Chain of Being
CHAUVETCave: located in Ardeche River Valley, Southern France( ~ 32 ka); has paintings of animals, footprints, cranium on a pedestal
ARISTOTLE: “father of biology”; did dissections
GREAT CHAIN OF BEING: aka scala naturae; an idea of a universal hierarchy; metaphysical concept with gods tiered at the top, humans in the middle, and animals underneath
Nicholas Steno
Law of Superposition
Age of Discovery
Nicholas STENO: studied genealogy from theological point of view; provided insight into fossil record: “tongue stones” were sharks teeth, realizes that it must’ve represented something that lived and died
Law of SUPERPOSITION: discovered by Steno; lower levels of stratification are older than upper layers
AGE OF DISCOVERY: Joseph Banks brought botanist James Cook on European exploration (15-17th century)
Natural Theology
Carl Linnaeus
Argument from Design
NATURAL THEOLOGY: school of thought to prove the existence of God and divine purpose through observation of nature and the use of human reason; not dependent on revelations
Carl LINNAEUS: created system of binomial nomenclature in Latin; transcended scientific category for all languages → now called taxonomy: inventory of life
ARGUMENT FROM DESIGN: founded by William Paley; organisms exist and function well therefore they were created by a being of high intelligence → watch example (if you go outside and find a watch, you would think that someone had made it because it functions well; same with organisms)
Adaptation
Gradualism
Extinction
Uniformitarianism
ADAPTATION: “form fits function” → bird beak example
GRADUALISM: founded by James Hutton; earth changes slowly but incrementally, thereby creating large changes with time → eg. Grand Canyon
EXTINCTION: discovered by Georges Cuvier; realized that some species die off without branching out to other forms of life
UNIFORMITARIANISM: founded by Charles Lyell; says that we can’t assume anything that we can’t see, therefore he pushed for concrete evidence to prove theories
Jean Lamarck (2)
Erasmus Darwin
Alexander von Humboldt
Jean LAMARCK:
- Principle of Dis/Use: parts of an organism’s body that are used become more developed; parts that are not used become smaller and may disappear
- Inheritance of acquired characteristics: changes achieved over an organism’s lifetime are passed on to its offspring
ERASMUS Darwin: writings inspired his grandson; came up with Zoonomia, aka laws of organic life (deals with pathology, anatomy, psychology and the functioning of the human body)
Alexander von HUMBOLDT: discovered biological changes in altitude by surveying plants along the way to the top of a volcano; inspiration to Darwin
Charles Darwin (4)
HMS BEAGLE: five year contract; discovered many things; read Lyell and Humboldt; collected fossils and specimens through hunting expeditions; saw world in comparison framework
LAW OF SUCCESSION OF TYPES: finding that living species generally resembled fossil forms of species from their same location
GALAPAGOS ISLANDS: endemic fauna; volcanically created chain of islands that was a good distance from South American coastline, preventing most species from traversing the coast; created an insular habitat and exclusive species with differences in form and behavior
SUBSIDENCE OF LAND HYPOTHESIS: refers to the creation of coral atolls (eg. Mo’ orea in the Southern Pacific); coral grows upward and outwards as the inner island disappears → Volcanic island - fringing reef - barrier reef - coral atoll
Morphological convergence
Alfred Russel Wallace
Fecundity
MORPHOLOGICAL CONVERGENCE: observed similarities across species in similar but distant environments → e.g. sugar glider and flying squirrel
Alfred Russel WALLACE: unsung hero who collected specimen in the Amazon and worked with Darwin that came up with same ideas but in a different area; working class naturalist who published The Geographical Distribution of Animals
FECUNDITY: large amount of offspring but only a few survive; AKA surplus production of offspring
Individual variation
inheritance
“Struggle for Existence”
INDIVIDUAL VARIATION: Genetic differences that are usually heritable; lead them to survive better in the wild (natural selection) or be chosen for animal husbandry (artificial selection)
INHERITANCE: preservation of favored traits thru process of genetic transmission of characteristics from parent or ancestor to offspring
“STRUGGLE FOR EXISTENCE”: leads to differential survival / reproduction with successful traits as heritable and preserved due to the characteristics of nature
Pattern of evolution Explanatory power (6)
PATTERN OF EVOLUTION: from Darwin; continuous, slow, gradual; change by “insensible degrees” → eg. Darwinian giraffes
EXPLANATORY POWERr:
- Analogy: similarity of function and superficial resemblance of structures that have different origins e.g. wings in different organisms
- Convergence: organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches
- Homology: shared descent from a common ancestor
- Vestigial structures: rudimentary organs
- Embryology
- Fossil record
Difficulties on Theory (3)
missing links exist bc of poor preservation of the past
AGE OF THE EARTH: Ussher; Biblical Chronology: Oct 6, 4004 BC, 9:00AM
ORGANS OF EXTREME PERFECTION: critics asked how does a highly functioning organ come to be thru evolution → Darwin argues that the final form came about thru minor steps that have been perfected bc whole parts are developed in useful and gradual stages (Eg. hawk eyes)
BLENDING inheritance: offsprings uniformly blend the features of the parents; theory of pangenesis → eg. two extremes have offsprings who have offsprings… until offsprings “wash out” with no genetic variation
Gregor Mendel Genetic locus Gene Gene pool Inbreeding coefficient
Gregor MENDEL: came up with theory of particulate inheritance through pea plants are bi-allelic (only 2 alleles are observable / important); used findings towards the genetic foundation of evolution
Genetic LOCUS: position on the chromosome
GENE: unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring; made of 2 alleles
Gene POOL: represents all the alleles at all loci in all individuals
INBREEDING coefficient: has negative correlation with verbal IQ due to the probability that a person with two identical genes received both genes from one ancestor → eg. incest
Rules of Probability
Rule of MULTIPLICATION: the probability that independent events A and B will occur simultaneously is the product of their individual probabilities
Rule of ADDITION: the probability that event A or event B will occur is equal to the probability of A plus the probability of B
Hardy-Weinberg principle
5 Population Assumptions
mathematical method to determine whether a species was evolving → p2 + 2pq + q2 = 1
Population assumptions: under these assumptions, allele frequencies in the gene pool will not change aka evolution isn’t happening
- No mutations
- Large (infinite) population
- Isolated (no gene flow)
- Random mating
- No natural selection
Microevolution Forces (5)
MODERN SYNTHESIS: aka neo-darwinism; articulated a new field of biology where you can identify the driver of the evolutionary process
MUTATION: random change in DNA
GENETIC DRIFT: drift to loss or fixation occurs faster and is more likely in smaller populations; occurs bc populations are not infinitely large → produces random changes in allele frequencies that may lead to a loss of genetic varation
- Founder effect: higher incidence in population due to founding population having high frequency of the allele (lack of gene flow) → e.g. Amish of Lancaster County, PA where Ellis-van Creveld syndrome allele frequency is, PA vs. World: 0.07 vs 0.01
- Bottleneck effect: large population shrinks to smaller population which leads to diversity loss → e.g. greater prairie chicken and northern elephant seal
GENE FLOW: the movement of genes among populations due to migration and interbreeding → e.g. copper tolerance in bent grass near a mine, where the wind carries copper-tolerant alleles to non copper-tolerant plants, resulting in the the spread of this tolerance as a result of reproduction (not adaptation)
NON-RANDOM MATING: can lead to changes in genotype frequencies
- Assortative: individuals tend to mate with individuals that are phenotypically similar to them
- Disassortative: individuals breed with individuals unlike themselves
Fitness
Directional selection
Stabilitizing selection
Disruptive selection
FITNESS: relative contribution an individual makes to the gene pool of the next generation; an individual’s ability to produce viable and fertile offspring; environmentally dependent
DIRECTIONAL selection: select away from original ideal towards one phenotype better adapted to the environment → i.e. dark mice living on dark lava flow
STABILIZING selection: individuals in the middle are most advantageous; select against extremes; actively maintains genetic diversity
DISRUPTIVE selection: select against intermediate phenotypes; extremes are favored while anything in between is no → Eg. seacracker birds with heavy/large bills exploit large seeds and birds with small/fine bills exploits small seeds BUT middle bills can’t exploit either
Normal Distribution
Bimodal distribution
Phenotypic variation
Normal distribution: aka Gaussian distribution; bell shaped curve
Bimodal distribution: two distinct peaks
Phenotypic variation : bimodal because gender based → eg, men are typically taller than women
Sickle-cell anemia (2)
“Good Genes” hypothesis
SICKLE-CELL ANEMIA: brought questions as to why diversity existed if “lesser” traits were destined to die out
- Point mutation: changed the shape of blood cell due to incomplete dominance (aka heterozygous)
- Heterozygote advantage: allowed for higher tolerance / immunity to malaria but can clog in bloodstream / lead to other health consequences
“GOOD GENES” hypothesis: questioned whether displays were allowing poor survival fitness genes to be passed OR display showcase both plumage and fitness
