bsci 1

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Greek Philosophers

sought to achieve perfect form, influenced by views of geometry, variation is an imperfection

Heraclitus

exception to the ancient world, pre-socrates, thought everything was constantly changing

Aristotle

first great naturalist, interested in animals and plants in the natural environment, scala naturae

Scala Naturae

life-forms could be arranged on a scale of increasing complexity

Natural Theology

prevailing view up until the Renaissance, God designed a perfect earth with humans at the peak

Species Constant

prevailing view up until the Renaissance, designed by god for perfection for the environment, no change over time

No Extinction?

prevailing view up until the Renaissance, if God placed animals somewhere then they must remain alive. Fossils belong to species that moved to different places

Carolus Linnaeus

Swedish botanist who developed the first successful system for classifying living things into similar groups, a system that is still in use today: Kingdom, Phylum, Class, Order, Family, Genus, Species

James Hutton

father of modern geology, theory of uniformitarianism, earth had layers

Theory of Uniformitarianism

states that the geologic processes that shape Earth are uniform over time, erosion and sedimentation define earth's history

Charles Lyell

a geologist who popularized uniformitarianism, rocks show a time sequence and earth is old, species can change over time and extinction exists

Georges Cuvier

father of paleontology, functional integration of organisms, extinction established as a fact (but he still believed in species constant)

Jean-Baptiste Lamarck

he proposed that by selective use or disuse of organs, organisms could acquire or lose certain traits which are then passed on to their children and future generations, eventually changing the species

Gregor Mengel

Pea man, had laws of inheritance, father of genetics

Functional Integration of Organisms

species could not change into a different species and still function, change would be fatal

Thomas Malthus

Growth potential of human population vs food population

Robert Chambers

Vestiges of the Natural History of Creation, had weak evidence for evolution

Alfred Wallace

evolutionary ideas and natural selection ideas at the same time as Darwin, difficulties getting published, father of biogeography

Wallace's Line

a faunal boundary line drawn in 1859 by the British naturalist Alfred Russel Wallace that separates the ecozones of Asia and Wallacea, a transitional zone between Asia and Australia.

Charles Darwin

English natural scientist who formulated a theory of evolution by natural selection (1809-1882)

Darwin's Points

Variation, Heritable, Struggle for survival, Differential reproduction, changes in characteristics of the population

Differential reproduction

those that struggle most successfully leave more offspring with that trait

Theory of Natural Selection

Heritable changes in the population over time as a result of the struggle for survival and differential reproduction of the fittest

Evidence for Evolution

\-Groups within groups (common descent) \n -Homology (common ancestor) \n -Vestigial structures \n -Fossil record \n -Biogeography \n -Direct observation

Law of Succession

living species in an area are frequently closely related to fossils in that area providing evidence that the species evolved there

5 Types of Natural Selection

directional, stabilizing, disruptive, frequency-dependent, sexual

Directional Selection

reduces variation

Stabilizing Selection

variations over time but no net change

Disruptive Selection

form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle

Frequency-Dependent Selection

selection in which the fitness of a phenotype depends on how common the phenotype is in a population

Sexual Selection

A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates.

Darwin: How to increase variation in a population?

Inheritance

Gene

a discrete unit of DNA (or RNA) that codes a particular trait

Chromosomes

hold genes, long DNA molecules

Locus

location of a gene on a chromosome

Diploid

individuals have 2 copies of each chromosome (homologous pairs)

Alleles

control a single trait category but may have different expressions

Mitosis

interphase, prophase, metaphase, anaphase, telophase

Interphase

period of the cell cycle between cell divisions

Prophase

chromosomes condense

Metaphase

chromosomes line up in the middle

Anaphase

chromosomes pull apart

Telophase

divides

Meiosis

produces haploid daughter rather than a diploid, meiosis I and meiosis II

Haploid

having a single set of unpaired chromosomes

Interphase I (Meiosis)

period of the cell cycle between cell divisions

Prophase I (Meiosis)

chromosomes form tetrads

Metaphase I (Meiosis)

tetrads line up willy nilly

Anaphase I (Meiosis)

pairs pulled apart

Telophase I (Meiosis)

2 haploid daughter cells form

Meiosis II

same as mitosis (but no duplication in interphase)

Segregation

alleles of a single trait, individual units that are not blending

Independent Assortment

different traits on different chromosomes

Recombination

the genetic process by which one chromosome breaks off and attaches to another chromosome during reproductive cell division

Monohybrid Cross

A cross between individuals that involves one pair of contrasting traits (Ex: Rr x Rr

Homozygous

An organism that has two identical alleles for a trait

Heterozygous

An organism that has two different alleles for a trait

Dihybrid Cross

A cross between individuals that have different alleles for the same gene, if alleles are ondifferent chromosomes they will assort independently

Punnett Square w/o Independent Assortment

non-9:3:3:1 ratio

Mutations

creates variation, random errors in genetic arrangements

Point Mutation

Gene mutation involving changes in one or a few nucleotides

Larger scale chromosomal rearrangements

deletion, duplication, inversion, translocation

Chromosome number mutation

non-disjunction \= duplicated homologous chromosomes

Complete Dominance

a relationship in which one allele is completely dominant over another

Incomplete Dominance

Situation in which one allele is not completely dominant over another allele

T or F: Dominant alleles are more common than recessive ones

F

T or F: If a dominant allele is deleterious, it is more uncommon in the population

T

Co-Dominance

heterozygotes express a different phenotype that is not intermediate, variegated

Linked Genes

same chromosome

Pleitropy

one gene may affect many different traits

Epistasis

Genes influence each other's expression

Quantitative genetics

traits are determined by many genes that show additive or continuous variation across the population

Polygenetic inheritance

most traits are affected by many genes (ex: height in human populations)

Environment Effects

genes often interact with the environment to affect phenotype (ex: height)

Random Development Effects

change phenotypic expression

Hardy Weinberg Equilibrium

condition that occurs when the frequency of alleles in a particular gene pool remain constant over time

Gene Pool

complete set of all unique alleles in a species or population

Allelic frequency

The proportion that a particular allele represents out of the total num of alleles in a population

Genotypic frequency

the proportion that a particular genotype represents out of a total number of individuals in a population

Use of Hardy-Weinberg

Allows you to determine if evolutionary agents are acting

Bottlenecks

Extreme reductions in population size due to catastrophic environmental changes or disease

Genetic Drift

random change in allele frequencies that occurs in small populations

Founder Effect

Small founding population may have allele frequencies that differ from the parent population, deleterious alleles may become fixed

Sex

sexual reproduction, 2 parents create genetically unique offspring through the fusion of haploid gametes

Why not to have sex

Inefficient, costly, risky

Facultative Asexual Reproducers

Asexual when conditions are good, sexual during times of stress

Tangled Bank Hypothesis

Sex provides genetic variability in offspring, variability comes from new gene combinations (independent assortment and recombination) variability promotes niche differentiation.

Red Queen Hypothesis

sexual selection allows hosts to evolve at a rate that counters the rapid evolution of parasites

Fundamental Asymmetry of Sex

females usually invest more in their offspring than males do, results in men being competitive and females being choosey

Sexual Dimorphism

Differences in physical characteristics between males and females of the same species

Intra-Sexual Selection

competition between members of the same sex for mates

Inter-Sexual Selection

members of one sex choose mates on the basis of certain traits

Sexy Son Hypothesis

the female receives indirect genetic benefits through her sons, who will themselves be attractive to females and produce many grandchildren

Runaway Selection

a form of sexual selection that occurs when female mating preferences for certain male attributes create a positive feedback loop favoring both males with these attributes and females that prefer them

Good Genes Hypothesis

the hypothesis that an individual chooses a mate that possesses a superior genotype

Handicap Hypothesis

a male that can support a costly and unwieldy ornament is likely to be a vigorous individual whose overall genetic quality is high

Parasite Hypothesis

males that can produce/maintain elaborate displays must be resistant to parasites

Developmental Stability Hypothesis

stress causes asymmetry

Edward O. Wilson

coined the term sociobiology and was its major advocate as an explanation of human behavior

4 Types of Social Interactions

Selfish, cooperation, spiteful, altruistic