EXAM 1: History of Life, Evolution & Speciation

Strata

Layers of rock in which fossils can be found.

Abiotic Synthesis

Living cells came from non-living origins.

Catastrophism

Local catastrophes in the past had caused later strata to have a new mix of fossils; after each catastrophe, the region was repopulated by species from surrounding areas.

Traditional Systematics

Mainly uses anatomical data; classify organisms using assumed phylogeny w/ emphasis on phenotype; stress both common ancestry and degree of structural difference among divergent groups.

Inbreeding

Mating of two genetically related individuals; chose a mate from the same genetic lineage.

Stromatolites

Mats of mineralized cyanobacteria.

Carboniferous Period

Period 354-290 mya; rich coal deposits formed; cooler w/ land covered by forested swamps; plants and animals further diversified; very large plants and trees prevalent; first flying insects; amphibians prevalent; amniotic egg emerges (reptiles).

Devonian Period

Period 417-354 mya; north was dry, south was wet (oceans); many more terrestrial species; gymnosperms emerge; insects emerge; amphibians emerge from fish-like ancestors; invertebrates flourish in the oceans; The Age of Fishes.

Silurian Period

Period 443-417 mya; stable climate, glaciers melted; significant vertebrates (many fishes) and plants; coral reefs appeared; large colonization by terrestrial plants (seedless, vascular) and animals (arthropods).

Ordovician Period

Period 490-443 mya; warm temperatures and atmosphere was very moist; diverse marine invertebrates including trilobites and brachiopods; primitive land plants and arthropods first invade land; at the end, abrupt climate change (large glaciers) resulted in mass extinction (60% of marine invertebrates).

Cambrian Period

Period 543-490 mya; Warm, wet climate, oxygen, no ice at poles; all existent phyla developed, no major reorganizations of body plans since; many marine inverts w/ shells; first vertebrates ~520 mya.

Tertiary (Paleogene) Period

Period 65 - 1.8 mya; tropical conditions replaced by a colder, driver climate.; mammals continued adaptive radiation (birds, fishes, insects diversified).; flowering plants already diverse and plentiful; primate evolution began.

Postzygotic Mechanisms

Prevent hybrid offspring from developing or breeding.

Carolus Linnaeus

Proposed the fixity of species (species don't change); proposed that species have an ideal structure and function, and a place in the scala naturae; created the binomial system of nomenclature.

Why did RNA probably come before DNA?

RNA has great functional flexibility.

Negative Frequency-Dependent Selection

Rare individuals have higher fitness.

Uniformitarianism

Rates and processes of change are constant.

Fossils

Remains and traces of past life.

Hox Genes

Responsible for the patterning of animal bodies.

Adaptive Melanism

Rock Pocket Mouse on lava flows.

Intrasexual Selection

Same sex; males directly compete for mating opportunities or territories.

Gamete Isolation

The sperm may not be able to fertilize the egg.

Cladogenesis

The splitting of one species into two.

Systematics

The study of biological diversity and evolutionary history of life on Earth.

Population Genetics

The study of genes and genotypes in a population.

Biology

The study of living organisms and how they have evolved.

Paleontology

The study of the fossil record.

Biogeographical Observations

The study of the geographic distribution of life forms on Earth.

Anagenesis

The transformation of one species into a new species over time.

Hybrid Inviability (Zygote Mortality)

The zygote dies before being born.

Extraterrestrial Hypothesis

Theory of Panspermia; organic carbon from asteroids and comets stocked prebiotic soup

Cladistic Systematics

Traces evolutionary history of the group under study; uses synapomorphies and cladograms.

Sedimentation

Traces of organisms embedded in sediment eventually turn into rock.

Temporal Isolation

Two different species may have reproductive cycles at different times in the year.

Habitat Isolation

Two different species may live in different places and won't meet to mate.

Allopatric Speciation

Two geographically isolated populations of one species become different species over time, for gene flow is interrupted; can be due to different selection pressures in differing environments.

Balancing Selection (Balanced Polymorphism)

Two or more alleles are kept in balance, and therefore are maintained in a population over the course of many generations.

Disruptive (Diversifying) Selection

Two or more extreme phenotypes are favored over intermediates; bimodal distribution.

Allele Frequency

(# of copies of a specific allele in a pop.)/(Total # of alleles for that gene in a pop.)

Genotype Frequency

(# of individ. w/ a particular genotype)/(Total # of individ. in a pop.)

6 Periods of the Paleozoic Era

1. Cambrian 2. Ordovician 3. Silurian 4. Devonian 5. Carboniferous 6. Permian

6 Characteristics of Living Organisms

1. Cells & Organization 2. Energy Use & Metabolism 3. Response to Environmental Change 4. Regulation & Homeostasis 5. Growth, Development, Reproduction 6. Biological Evolution

Eras within the Phanerozoic Eon

1. Cenozoic

6 Factors Which Influence the Pattern of the Geological Time Scale

1. Climate/Temperature 2. Atmosphere 3. Land masses (continental drift, 1-10 cm/yr) 4. Floods/Glaciation 5. Volcanic Eruptions 6. Meteorite Impacts

When did the 6 mass extinctions take place?

1. End of Ordovician 2. End of Devonian 3. End of Permian 4. End of Triassic 5. End of Cretaceous (KT) 6. Currently

5 Core Concepts of Biological Literacy

1. Evolution 2. Structure & Function 3. Information Flow, Exchange and Storage 4. Pathways and Transformations of Energy and Matter 5. Systems

5 Causes of Microevolution

1. Genetic Mutations 2. Gene Flow (Gene Migration) 3. Nonrandom Mating 4. Genetic Drift 5. Natural Selection

The 4 Eons

1. Hadean 2. Archaean 3. Proterozoic 4. Phanerozoic

5 Conditions of the Hardy-Weinberg Principle

1. No Mutations 2. No Gene Flow 3. Random Mating 4. No Genetic Drift 5. No Selection

4 Stages of Developing Life

1. Nucleotides and amino acids produced prior to existence of cells. 2. Nucleotides and amino acids became polymerized to form DNA, RNA, and proteins. 3. Polymers became enclosed in membranes. 4. Polymers enclosed in membranes evolved cellular properties.

2 Periods of the Cenozoic Era

1. Paleogene (Tertiary) 2. Neogene (Quaternary)

Eras within the Proterozoic Eon

1. Paleozoic 2. Mesozoic 3. Cenozoic

3 Periods of the Mesozoic Era

1. Triassic 2. Jurassic 3. Cretaceous

Reducing Atmosphere Hypothesis

1920s, Oparin & Haldane; Hypothesis that spontaneous formation of organic molecules occurred in Earth's primitive atmosphere, due to the lack of oxygen; monomers evolved and joined to form polymers.

Miller & Urey Experiments

1953; an apparatus was used to simulate environment of primitive Earth's atmosphere w/ strong energy sources; showed that biochemicals could be produced from simple nonbiological sources.

Deep-Sea Vent Hypothesis

1988; hypothesis that key organics arose at deep-sea vents, due to the extreme temperature differential between the vent and the surrounding water.

Polymorphic Genes

2 or more alleles in a population.

The KT Extinction

76% of marine species, 50-75% plants/animals became extinct (including non-avian dinosaurs); paved the way for a lot of the ancestors of our current species; marks the end of the Mesozoic and the beginning of the Cenozoic era.

Monomorphic Genes

99% take the form of 1 allele.

Phylogenetic Tree

A diagram indicating lines of descent; each branching point is a divergence from a common ancestor, and represents an organism that gibes rise to two new groups.

Creationism

A god is absolute greater of heaven and earth, out of nothing, by an act of free will (Christians, Jews, Muslims).

Species

A group of related organisms that share a distinctive form.

Endosymbiotic Hypothesis

A hypothesis that two different species or organisms once lived close together as a favored condition, which carried out over time; eventually forming a nucleus; mitochondria/chloroplast.

Phylogenic (Evolutionary) Species Concept

A species in an irreducible group of organisms diagnosably distinct from other such groupings and within which there is a paternal pattern of ancestry and descent; uses morphological, chromosomal, and molecular characters.

Biological Species Concept

A species is a reproductive community of populations (reproductively isolated from others) that occupies a specific niche in nature; interbreeding with common gene pool to produce viable, fertile offspring.

Index Species

A species to which we compare fossils to find out when they existed.

Metabolism

All the chemical reactions in a cell.

Molecular Homologies

Almost all living organisms: ...use the same basic biochemical molecule. ...utilize the same DNA triplet code. ...utilize the same 20 amino acids in their proteins. ...utilize ATP as an energy source.

Clade

An evolutionary branch that includes a common ancestor, together with all of its descendant.

Phylogeny

An organism's evolutionary history.

Homologous Structures

Anatomically similar because they are inherited from a common ancestor; may or may not be functionally similar

7 Factors that Affect the Fossil Record

Anatomy, Size, Number, Environment, Time, Geological Processes, Paleontology

Industrial Melanism

Before Industrial Evolution: Peppered Moths were 10% dark colored; 90% light colored. After Industrial Evolution: soot in atmosphere, three trunks darkened, lichens killed, birds act as selective agents. Peppered Moths were 80% dark colored; 20& light colored. Today: after regulations have been put in place on air pollution Peppered Moths have flipped back.

Protobiont

Cell-like structures; contain a boundary (i.e. membrane), polymers inside which contain information, polymers inside w/ enzymatic function; self-replication.

Genetic Drift

Changes allelic frequency due to random chance; can cause the gene pools of two isolated populations to become dissimilar.

Abiotic Natural Selection

Changes due to climate, water availability, minerals.

Biotic Natural Selection

Changes due to competition, predation, sexual selection.

Microevolution

Changes in a single gene in a population over time.

Adaptations

Changes that help a species become more suited to its environment.

Primitive Characters

Characteristics that are present in all members of a group, AND present in the common ancestor.

Divergent Characters

Characters that are present in some members of a group, BUT NOT present in the common ancestor.

Charles Lyell

Earth is subject to slow but continuous cycles of erosion and uplift; wrote Principles of Geology; proposed Uniformitarianism.

Hierarchy of Dating (from largest to smallest)

Eon -> Era -> Period -> Epoch -> Year

Mesozoic Era

Era 248 - 65 mya; Age of Reptiles; consistently hot climate, dry terrestrial environments; little if any ice at poles.

Cenozoic Era

Era 65 mya - present; Age of Mammals

Paleozoic Era

Era spanning 543-248 mya; 3 major mass extinction events

Plato

Essentialism, Theory of Forms; objects are temporary reflections of ideal forms.

Precambrian Time

~87% of geologic time; spans the Hadean, Archaeon, Proterozoic Eons; little or no atmospheric oxygen; first cells came int existence in aquatic environments; eukaryotic Cells arise; multicellularity arises; Ediacaran/Vendian Periods take place.

Ecological Species Concept

Using the ability of organisms to successfully occupy their own ecological niche or habitat, including their use of resources and impact on the environment, to distinguish species.

Founder Effect

When a new population is started from just a few individuals; the alleles carried by the population founders are dictated by chance; formerly rare alleles with either occur at a higher frequency in the new population OR be absent in the new population.

Nonrandom Mating

When individuals do not choose mates randomly.

Adaptive Radiation

When members of a species invade several new geographically separate environments (niches); the populations become adapted to different environments; many new species evolve from the single ancestral species.

Sympatric Speciation

When one population develops into two or more reproductively isolated groups, with no prior geographic isolation.

Emergent Property

When two interacting materials perform a new function that wouldn't be possible for each part to perform on its own.

Rev. Thomas Malthus

Wrote Essay on the Principle of Population: each generation has the same reproductive potential as the previous; reproductive potential is greater than the environment can support; death, disease, and famine were inevitable if population is to have stability.

Count George Buffon

Wrote a 44-volume catalog of all known plants and animals; suggested that life forms change over time.

Hardy-Weinberg Equation

p + q = 1 p2 + 2pq + q2 = 1 (expansion)

Directional Selection

Individuals at one extreme of a phenotypic range have greater reproductive success in a particular environment, and the curve shifts in that direction.

Assortative Mating

Individuals select mates with the phenotype and reject opposites; increases # of homozygotes.

Reproductive Isolating Mechanisms

Inhibit gene flow between species and maintain distinctiveness of species.

John Ray

Conducted the first thorough study of the natural world.

Holocene (Anthropocene) Extinction

Current mass extinction; caused not by natural causes, but by human activity (increasing population, and depleting habitats).

What are the advantages of a DNA/RNA/Protein world?

DNA and Protein are able to specialize some of the functions that RNA used to handle, making all of them more efficient.

Genetic Homologies

DNA base-sequence differences. When very similar, suggest a recent common ancestor. When more different, suggest a more ancient common ancestor.

Sexual Selection

Directed at certain traits of sexually reproducing species that make it more likely for individuals to find or choose a mate and/or engage in successful mating.

Prezygotic Mechanisms

Discourage attempts to mate.

Disassortative Mating

Dissimilar phenotypes mate preferentially; increases # of heterozygotes.

Alfred Russel Wallace

Father of Biogeography

Aristotle

Father of Classic Taxonomy; all living things can be arranged in a linear hierarchy.

Lamarck

First biologist to propose evolution and link diversity w/ environmental adaptation; concluded more complex organisms are descended from less complex organisms.; proposed Inheritance of Acquired Characteristics (Lamarckianism)

Cuvier

First to use comparative anatomy to develop a system of classification founded Paleontology; proposed Catastrophism

Heterozygote Advantage

For a single gene, heterozygote is favored.

Transitional Fossils

Fossils which may link two separate organisms in their line of evolution.

Tetrapods

Four-legged animals.

p in the Hardy-Weinberg Equation

Frequency of the dominant allele.

2pq in the Hardy-Weinberg Equation

Frequency of the heterozygotes.

p² in the Hardy-Weinberg Equation

Frequency of the homozygous dominant genotypes.

q² in the Hardy-Weinberg Equation

Frequency of the homozygous recessive genotypes.

q in the Hardy-Weinberg Equation

Frequency of the recessive allele.

Vestigial Structures

Fully-developed anatomical structures w/ reduced or obsolete function.

Hardy-Weinberg Principle

Genes remain in equilibrium (constant frequency) over time (in each succeeding generation of a sexually reproducing population) as long as 5 conditions are met.

Which is the oldest metabolic pathway?

Glycolysis

Mechanical Isolation

The reproductive structures of different species may not fit together.

Scala Naturae

Great chain of being; establishes man as dominate and perfect form of life; sets man above and apart from nature; incorporated into the religious belief that the earth and its creatures are the result of special creation, that they have not changed since they were created.

Evolution

Heritable change in one or more characteristics of a population or species from one generation to the next.

Clay Hypothesis

Hypothesis that simple organics polymerize on solid surface (clay, mud, inorganic crystals) into more complex organics.

Equilibrium Population

Hypothetical population in which evolution doesn't occur.

Hybrid Breakdown (Reduced F₂ Fitness)

If two hybrids do breed, their offspring doesn't develop.

Population

Members of the same species that are likely to encounter each other and thus have the opportunity to interbreed.

Controversy of the Extraterrestrial Hypothesis

Most meteors are destroyed by the intense heat of impact.

Edicarian & Vendian Periods

Multicellular animals appear, including sponges; mudflat animals, unusual forms, no internal organs, no shells or bones; mass extinction occurred

Intersexual Selection

Opposite sex; females choose males possessing a particular phenotype.

Inheritance of Acquired Characteristics (Lamarckianism)

Organisms can change their traits during their life and pass the adaptation to their offspring.

Anaximander

Organisms evolve over time.

Quaternary (Neogene) Period

Period 1.8 mya - present; Age of Man (Hominids); Homo sapiens appear 130,000 years ago; 6th Mass Extinction.

Cretaceous Period

Period 145 - 65 mya; dinosaurs began precipitous decline; mammals began an adaptive radiation and moved into habitats vacated by the dinosaurs.

Jurassic Period

Period 199 - 145 mya; dinosaurs achieved enormous size; mammals remained small and insignificant; first bird.

Triassic Period

Period 248 - 199 mya; nonflowering seed plants become dominant.; gymnosperms dominant; reptiles abundant (1st dinosaurs appear); first true mammals.

Permian Period

Period 290-248 mya; continental drift formed supercontinent Pangaea; interior regions dry w/ seasonal fluctuations; forests shift to gymnosperms; amphibians prevalent, but reptiles became dominant; first mammal-like reptiles appeared; at the end, the largest known mass extinction event occurred.

Analogous Structures

Serve the same function, but not constructed similarly and don't share a common ancestor; similarity due to convergence.

Synapomorphies

Shared, derived characters.

Convergent Evolution

Similar evolutionary experiences in different species due to similar environmental pressures the acquisition of a feature in distantly related lines of descent; the feature is NOT present in a common ancestor.

Genetic Mutations

Source of new alleles; new combinations of alleles; source on which other evolutionary forces can act; random events; they are good, bad, or neutral depending on environmental conditions.

Phyletic Gradualism

Speciation occurs gradually; stasis is apparent, but not real; transitional links are found; ancestral species transformed into new species.

Punctuated Equilibrium

Speciation occurs rapidly; species experiences stasis; transitional links NOT found; subpopulation becomes a new species.

Drawbacks of the Biological Species Concept

Species have dimensions in space and time; what about asexual production?; unit of evolution and taxonomic category.

Typographical (Morphological) Species Concept

Species is defined by fixed, essential features; each species has a unique structure that makes it distinct.

Behavioral Isolation

Species may only respond to the calls or signals of their own species and ignore others.

Biogeography

Study of geographical distributions of plants and animals across Earth; different mixes of plants and animals in areas separated by water, continents, islands, etc.; consistent w/ origin in one locale and then spread to accessible regions.

Erasmus Darwin

Suggested common descent; evidence in developmental patterns, artificial selection, vestigial organs.

Monophyletic

Taxon whose units all evolved from a single parent stock; most recent common ancestor and all of its descendants.

Parsimony

The arrangement requiring the fewest assumptions is preferred; this would leave the fewest number of shared, derived characters unexplained; minimize the number of assumed evolutionary changes; the reliability of a cladogram is dependent on the knowledge and skill of the investigator.

Hybrid Sterility

The born hybrid cannot reproduce.

Taxonomy

The branch of biology concerned w/ identifying, naming, and classifying organisms.

Macroevolution

The formation of new species or groups of species.

Bottleneck Effect

The idea that, for whatever reason, a population has passed through a bottleneck, so that the ones who make it on the other side have very less genetic variability.

Parallel Evolution

The independent evolution of similar traits, starting from a similar ancestral condition; several species respond to similar challenges in a similar way.

Stabilizing Selection

The intermediate phenotype is favored; the peak of the curve increases and the tails decrease.

Half-Life

The length of time required for half the atoms to change into something else; unaffected by temperature, light, pressure, etc.

Homeostasis

The maintenance of internal conditions within certain boundaries.

Gene Flow (Gene Migration)

The movement of alleles between populations when gametes or seeds (in plants) are carried into another population, OR breeding individuals migrate into or out of population.

Fitness

The relative reproductive success of an individual.