General Biology 2 Final Exam Reviewer

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Georges-Louis Leclerc

1. 🇫🇷 French nationalist

2. Proposed various causes of evolution with evidence

3. Wrote a 44-volume natural history series

Histoire Naturelle

George-Louis Leclerc wrote this 44-volume natural history series to describe plants and animals

Carolus Linnaeus

1. 🇸🇪 Swedish botanist

2. Developed binomial nomenclature and classification

3. Father of taxonomy

Taxonomy

Carolus Linnaeus proposed this as a way to organize biotic life into a hierarchical structure in which a scientific name was assigned to each organism (Binomial Nomenclature)

Binomial Nomenclature

• Classification system in which each species is assigned a two-part scientific name

• [ Genus ] [ Species ]

Erasmus Darwin

1. 🇬🇧 British physician and naturalist

2. First to formally theorize about evolution in Zoonomia

3. Based his conclusions on development changes in animals, artificial animal breeding, and vestigial structures

Vestigial Structures

Present body parts that lack function

Georges Cuvier

1. 🇫🇷 French Zoologist

2. Established comparative anatomy and paleontology

3. Developed Catastrophism

Catastrophism

• Developed by Georges Cuvier

• Organisms are destroyed by natural catastrophes repeatedly, causing evolution and the creation of new species

James Hutton & Charles Lyell

• Proposed Uniformitarianism

Uniformitarianism

• Hutton and Lyell's principle that geologic processes that occurred in the past can be explained by current geologic processes

• The same things that have happened before will play the same way in the future

Jean-Baptiste Lamarck

• Developed Lamarckism

• Proposed two principles: "The Law of Use and Disuse", "The Inheritance of Acquired Characteristics"

• Lamarck's hypothesis: The environment can produce physical changes in an organism which can be inherited by the next generation

Lamarckism

• An evolutionary theory by Jean-Baptiste Lamarck stating that species change over time by the use and disuse of structures and the inheritance of acquired traits

• Opposes Darwinism

The Law of Use and Disuse

A principle which states that parts of the body that are used extensively develop whilst those that are not used deteriorate

The Inheritance of Acquired Characteristics

A principle which states that an organism could pass its modifications to its offspring

Thomas Malthus

1. 🏴󠁧󠁢󠁥󠁮󠁧󠁿 English economist

2. Published "An Essay on the Principle of Population" which stated that the human population's size is limited by the availability of necessary resources

3. Malthus' principle was the basis for Darwin's natural selection

Charles Darwin

1. 🏴󠁧󠁢󠁥󠁮󠁧󠁿 English naturalist

2. Proposed his theory of evolution by natural selection

3. Formulated his theory after his voyage, and wrote the book, "On The Origin of Species"

4. Defined evolution using his idea of “Descent With Modification"

Natural Selection

A natural process resulting in the evolution and survival of organisms best adapted to the environment

The Voyage of the Beagle

Charles Darwin's famous global voyage, where he found his first evidence of evolution

Galápagos Islands

The place where Charles Darwin made his observations during his voyage

Darwin's Study of Geology and Fossils

Earth must be old

1. Darwin observed geological changes that were the result of slow processes

2. Darwin collected fossils that differed from modern species

Observations of Nature

• Genetic Variation: Genetic variation is inheritable

• Limited Resources: Essential resources (e.g. food, space) are limited in every habitat

• Overproduction of Offspring: More offspring are born than can survive. The capacity to overproduce was a characteristic shared by all species

Inferences from Observations

• Struggle For Existence: Individuals compete for limited resources that enable them to survive

• Unequal Reproductive Success: The inherited characteristics of some individuals make them more likely to survive (natural selection)

• Descent With Modification: A population’s characteristics can change by natural selection, giving rise to new species

Modern Evolutionary Synthesis

• Genes are responsible for hereditary characteristics

• Population, not individuals, that evolve

• Speciation occurs due to the accumulation of small genetic changes

Gene Pool

Collection of all genes in a certain population

Gene or Allele Frequency

The relative frequency of an allele at a particular locus of a population

Genotype Frequency

How many genotypes there are

Phenotype Frequency

How many manifestations of a genotype there are

Hardy-Weinberg Equilibrium

A population’s allele frequencies are constant unless there is an evolutionary force acting upon them

Assumptions of Hardy-Weinberg Equilibrium

1. No natural selection

2. No mutation

3. No genetic drift

4. No gene flow

5. No non-random mating

Systematics

• It is the classification and study of biodiversity

• Include

  • Taxonomy - Classification of organisms

  • Phylogenetics - Evolutionary relationships between species

Linnaean Taxonomy

Devised by Carolus Linnaeus to organize life into a hierarchy of inclusive categories

Binomial Nomenclature

• Two-part format of the scientific name (Binomial)

• Avoids ambiguity when communicating about research

Linnaean System of Classification

Linnaeus grouped organisms into a hierarchy of increasingly inclusive categories

Taxonomic Levels

• Domain

• Kingdom

• Phylum

• Class

• Order

• Family

• Genus

• Species

Taxon

• A group at any level of the hierarchy

• The more features two organisms share, the more taxonomic levels they share

The Flaw of the Hierarchy

The hierarchy does not disclose the evolutionary relationships between species

Dichotomous Key

• A method of identification wherein groups of organisms are divided into two categories repeatedly

• Usually represented in two ways

  • Descriptive Representation

  • Diagrammatic Representation

Descriptive Representation

A series of paired statements laid out in numbered sequences

Diagrammatic Representation

A branching flowchart

Phylogeny

Evolutionary history of a species or a group of species

Cladistics

• A phylogenic system that categorizes groups into ancestral and derived characters

• A phylogenic system that categorizes groups into clades

Ancestral Characters

Inherited traits that resemble the ancestor’s

Derived Characters

Features that differ from the ancestor’s

Cladogram

A treelike diagram built using shared derived characteristics

Features of a Cladogram

• Clade

• Outgroup

• Root

• Node

Clade

• Includes a common ancestor and all of its descendants

• Is monophyletic

Outgroup

The most distantly related species and functions as a reference group

Root

An initial ancestor common to all organisms

Node

A common ancestor tied to two or more taxa

Monophyletic

• “Single tribe”

• A single common ancestor and all of its descendants

Paraphyletic

• “Beside the tribe”

• A common ancestor and some of its descendants

Polyphyletic

• “Many tribes”

• A group with no recent common ancestor

Phylogeny Based On Molecular Data

1. DNA Sequence Comparisons

2. Protein Sequence Comparisons

DNA Sequence Comparisons

The DNA sequences of a gene are aligned to determine the evolutionary relationships among some mammals

Protein Sequence Comparisons

The number of differences on the amino acid sequences of different species are used to measure relatedness

Fossil Records

• Support evolutionary theory

• Fossils are remains or traces of past organisms that are mostly found in sedimentary rocks

• Display the evolution of organisms

Fossil Formations

• Compression

• Petrifaction

• Impression

• Cast

• Intact Preservation

Compression

Sediments accumulate on top of organic material and compress it

Petrifaction

A decaying organism gradually turns into stone

Impression

An organism leaves imprints in mud that harden to rock

Cast

An organism is covered by mud and rots away, leaving a hollow interior once the mud has hardened

Intact Preservation

A whole organism is preserved in material (e.g. tree resin)

Transitional Fossils

Fossils that resemble two groups that are classified separately in the present-day

No Fossil Traces

• A reason for incomplete fossil records

• Most organisms never leave a fossil trace

Plates Are Constantly Moving

• A reason from incomplete fossil records

• Decomposing organisms are usually destroyed by plate motions

Hard To Discover

• A reason for incomplete fossil records

• Scientists will never find fossils buried deep in the Earth or the ocean

Biogeographical Evidence

• Supports evolutionary theory

• The study of the geographic distribution of fossils and species

Wallace’s Line

Patterns of organic life on either side of an imaginary boundary

Anatomical Evidence

• Homologous Structures

• Analogous Structures

• Vestigial Structures

Homologous Structures

Structures that have the same set of bones

Analogous Structures

Structures that have similar functions but different embryological development or sets of bones

Vestigial Structures

Anatomical features that are present in one group of organisms but are nonfunctional in other, similar groups

Embryology

The study of an organism’s development from an embryo to an adult

Molecular Evidence

Many organisms share similar molecules (RNA, DNA, proteins) that suggest a descent with modification from a common ancestor

Microevolution

The evolutionary change within a population

• Natural selection

• Mutation

• Gene flow

• Genetic drift

• Non-random mating

Five causes of microevolution

Natural Selection

This process results in the adaptation of a species to its environment

• Variation

• Increased fitness

• Inheritance

Three factors in natural selection

Variation

• A factor of natural selection

• Members of a population differ from another

Increased Fitness

• A factor of natural selection

• Organisms that are greatly adapted to their environment are more likely to survive

Inheritance

• A factor of natural selection

• Genetic differences are inheritable

Types of Natural Selection

• Directional Selection

• Disruptive Selection

• Stabilizing Selection

Directional Selection

The extreme phenotype is favored and the frequency distribution curve shifts toward it

Disruptive Selection

Two or more extreme phenotypes are favored

Stabilizing Selection

The intermediate phenotype is favored

Types of Sexual Selection

• Intrasexual Selection

• Intersexual Selection

Intrasexual Selection

Members of one sex compete for access to the opposite sex

Intersexual Selection

Members of one sex choose their partners from the opposite sex

Mutation

Occurs when a DNA sequence is randomly modified to cause genetic variation

Gene Flow

• The movement of alleles between populations through migration

• When a foreign allele is brought into a gene pool, the allele frequency distribution changes

Genetic Drift

• Changes in allele frequency due to random events

• Include

  • Bottleneck Effect

  • Founder Effect

Bottleneck Effect

A type of genetic drift in which catastrophes cause the loss of genetic diversity

Founder Effect

A type of genetic drift in which the loss of genetic diversity occurs when individuals separate from a population and create new ones

Non-Random Mating

• Affects how the alleles assort into genotypes

• Include

  • Assortative Mating

  • Disassortative Mating

Assortative Mating

Individuals of a similar type mate

Disassortative Mating

Individuals of a different type mate

Descent With Modification

As the descendants of an ancestral organism migrated, they obtained diverse modifications to adapt

Macroevolution

• Large-scale evolutionary change

• Creating an entirely different species due to evolution (speciation)

Ernst Mayr

• Defined a biological species as having members that can interbreed and produce fertile offspring