EVOLUTION FINAL EXAM PREP

What is the slope of the mid parent and mid offspring regression?

h^2 (a.k.a narrow sense heritability)

Macroevolution

evolution above the species level

Microevlolution

evolution within populations

Macroevolution includes…

the origin, diversification, and the extinction of species

Two distinct phenomena

\-Large scale evolutional change (ex: Major morphological change)

\-Evolutionary process above species level

Macroevolution relies on

reconstruction of the past

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i.e. paleontology, comparative phylogenetic studies, and evo-devo studies

Speciation

the divergence of lineages

lineages can…

further diversify into clades, and then these clades can be traced back to a speciation event

Stasis

a timeperiod when little to no evolution change is occuring in a lineage

When Stasis ends it can end suddenly with

cladogenesis

Gradualism in a evolutional sense

evolution occurs bit by bit in a lineage (anagenesis)

Anagenesis

type of evolution in which a species gradually changes over time, eventually becoming a new and distinct species. It involves the accumulation of small genetic changes over a long period of time, rather than the branching of one species into two or more distinct species.

Extinction (4 different definitions)

1. When a species dies out
2. When reproduction in nature is not longer able to occur
3. Death of last individual
4. disappearance from the fossil record (though the record is incomplete)

How many mass extinctions have occured (number discussed in class)

5

Species Concept

The species concept is a fundamental idea in biology that defines what constitutes a species. It is a way of categorizing organisms based on their shared characteristics and evolutionary history. There are several different species concepts, including the biological species concept, morphological species concept, and phylogenetic species concept. Each concept has its own criteria for defining a species, but all aim to capture the essential features that make a group of organisms distinct from others.

Why are species concepts important

for clear communication

What are the different species concepts

Morphological Species (Morphospecies) concept

Biological Species Concept

Phylogenetic Species Concept

General Linkage Concept

What is Morphospecies based on?

Phylogenetics and based on expert opinion

What are the Pros and Cons of Morphospecies concept?

Pro: Widely applicable

Con: arbitrary, and the presence of cryptic species

What is Biological Species Concept based on?

Reproductive Isolation

What are the Pros and Cons of Biological Species Concept

Pro: confirms the lack of gene flow, and is testable

Con: can’t apply to asexual lineages/fossils/plant hybrids, difficult to apply in nonoverlapping locations

Phylogenetic Species Concept defines a species as:

the smallest possible monophyletic group, that is recognized by unique traits

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this is useful for systematics

What are the Pros and Cons of Phylogenetic Species Concept

Pro: Applicable to most organisms, stat testable

Con: Data-intensive, can cause a large reorganization of taxa and species names

What is General Linkage Species concept definition of a species

a metapopulation that exchanges alleles to comprise the gene pool

What concept is best for fossils?

Morphospecies

What concept is best for bacteria

General Linkage Species Concept

What can differentiate bacterial species?

specific adaptations and observing a microbial mat

Which of these is the most likely sequence of events in allopatric speciation?

First, geographic separation; then, genetic divergence; finally, reproductive isolation

*Penstemon* (beardtongues) are wildflowers with a high degree of pollinator specificity. Suppose that two closely related populations of *Penstemon* have diverged in isolation, adapting to different species of bee pollinators. When the two populations come into secondary contact, hybrids have flowers that aren't efficiently pollinated by either species of bee and therefore have lower fitness than either parent. What is the likely outcome?

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Reinforcement

What best describes Allopolyploidy:

\-It Results from interspecific hybridization

\-Is common in plants

\-It Can generate new species in a single generation

\-All of these

All of these

Speciation involves….

barriers to reproduction

Types of isolating barriers

Extrinsic and instrinsic

Extrinsic barriers

Geographic, landscape that prevents gene flow

Intrinsic Barriers

Reproductive, these are barriers when the populations are still with eachother

Allopatric Speciation

type of speciation that occurs when a population of a species is geographically separated from other populations and evolves independently, leading to the formation of a new species. This can happen due to physical barriers such as mountains, rivers, or oceans, or due to human activities such as deforestation or urbanization. Over time, genetic differences accumulate between the separated populations, eventually leading to reproductive isolation and the formation of distinct species.

Sympatric

process of speciation that occurs when two or more populations of a species live in the same geographic area and become reproductively isolated from each other, leading to the formation of new species without any physical barriers separating them. This can occur through various mechanisms such as polyploidy, hybridization, and disruptive selection.

Parapatric Speciation

speciation is a type of speciation where two populations of a species evolve into distinct species while sharing a common border. This occurs when there is limited gene flow between the two populations due to factors such as geographic barriers or differences in habitat. Over time, genetic differences accumulate and the two populations become reproductively isolated, leading to the formation of two distinct species.

Allopolyploid leads to….

extremely rapid speciation, because hybrids are able to mate

What are two patterns that explain the distribution of taxa

Dispersal and Vicariance

Dispersal

movement of population from 1 region to another with little to no return exchange

Vicariance

formation of a geographic barrier that divides a once whole population

Vicariance leaves a

distinct phylogenetic signature

Punctuated equilibria

periods of stasis punctuated by brief periods of rapid change

Few fossil series are complete enough to test between stasis and gradualism, what are the best?

Marine invertebrates

What is the mode of speciation?

Mode can vary for different traits within a lineage

What term did Dawkins use?

variable speedism

Adaptive Radiation

Rapid diversification of many species from few • Single or small group of ancestral species • Numerous descendent species • Wide variety of ecological niches

When does adaptive radiation occur?

when there is increased ecological opportunity

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\-abundant resources, extinction of competition, morphological innovations

Key innovations pave the way for

adaptive evolution

Background Extinction

the normal rate of extinction

Mass Extinction

a statistically significant increase above background extinction rates

Mass extinction main points

its a rapid event where anywhere from 20%-90% of species die

Affect organisms across…

phyla, habitats, and geography, and affect them all differently

Causes are typically _________

Extrinsic

What are the big 5

• Late Ordovician

• Late Devonian

• End-Permian

• End-Triassic

• K-Pg Boundary

Causes of the “Great Dying”

• Ultimate cause: Volcanism

• Evidence suggests that the Siberian Traps eruptions drove the end- Permian extinction event

What was the biggest of the big 5

End Permian

K-pg is thought to be due to….

big ateroids

\-evidence: layer in earths surface with increased leves of Iridium (rare metal on earth, but is common in space rocks) and the crater in the Gulf of Mexico

After K-pg what type of organisms flourished?

Mammals

\-birds, snakes,and frogs also survived

Aristotle

Scala naturae:

which ranked things by complexity

James Hutton

Gradualism

Alfred Russel Wallace

“Father of biogeography”

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Plato

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•Theory of Forms

•Deduction from principles

•Emphasis on the eternal and unchanging

Carl Linnaeus

was "the father of modern taxonomy",

Systema Naturae (1735), he used binomial nomenclature and homologies. Ranked in order of kindom,class, order, genus, and species.

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Jean-Baptiste Lamarck

proposed the 1st cohesin theory of biological evolution. He determined thatenviromental conditions give rise to changes and he is remembered for the inheritance of aquired traits. Phylum and family were added later on.

Thomas Henry Huxley

Book: Evidence as to Man’s Place in Nature

Darwins most influential books

On the Origin of species by means of Natural selection

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The Descent of man, and selection in relation to sex

Cuvier

•Pioneer of biostratigraphy

•Established the fact of extinction

**•Catastrophism**

•Fixity of species

Lyell

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Uniformitarianism

Thomas Malthus

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Book: An Essay on the Principle of Population (1798)

•Left unchecked, human population growth will outpace resource availability

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Ernst Haeckel

Neo-Lamarckism

Hennig

Was the Founder of phylogenetic systematics / cladistics

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What are the 8 lines of evidence for evolution

Homology, Vestigial Traits, artificial selection, direct observation of microevolution, speciation, the fossil record, biogeography, and the age of the earth.

Homology

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similarity due to the inheritance of traits from a common ancestor

Vestigial Traits

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A special case of homology,

Inheritance of traits from ancestors explains cases of “poor design” and vestigial or “leftover” traits

Artificial Selection

Direct Observation of Microevolution

Moth coloration patterns in polluted/ashy areas

Speciation

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the formation of new and distinct species in the course of evolution.

How The Fossil Record proves

•Extant life forms resemble forms found in the fossil record •Transitional fossil forms •Macroevolution •The fact of extinction

Biogeography

•Law of Succession

•Distributions of living species

•Fairly sharp barriers that match for many taxa: biogeographic regions

What are the 3 definitions of evolution?

Broadest sense: change over time

Darwin’s definition: descent with modification

Genetic definition: change in allele frequencies over time

What are the 4 alternatives to natural selection:

Theistic evolution

Neo-Lamarckism

Orthogenesis

Saltation / Mutationism

Theistic Evolution

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view that God acts and creates through laws of nature.

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Asa Gray

Neo-Lamarckism

theory of evolution that suggests that acquired traits can be passed down to offspring. This theory is an extension of Lamarckism, which proposes that organisms can pass on traits that they acquired during their lifetime to their offspring. However, Neo-Lamarckism also incorporates the idea of genetic inheritance, which was not part of Lamarck's original theory.

Orthogenesis

suggests that evolution is directed towards a predetermined goal or endpoint.

Saltation / Mutationism

no selection, evolution by mutational drive

What are the 2 sources of homoplasy

convergence and reversals

4 Steps to inferring phylogenies

1\.Collect data 2.Identify possible homologies 3.Tree reconstruction 4.Tree comparison

What are the 3 domains of life?

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1\.Archaea

2\.Bacteria

3\.Eukarya

4 Geological Eons

• Hadean

• Archean

• Proterozoic

• Phanerozoic

Hadean Eon 4.6-4 bya

Formation of the earth \~4.6 BYA

Liquid h2o 4.4 BYA

Plate tectonics 4 BYA

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\*Hellish conditions, high CO2 atmosphere

Archean Eon 4-2.5 BYA

Contenents, little free O2, LIFE BEGINS, FIRST FOSSILS (STROMATOLITES), PHOTOSYNTHESIS BEGINS 3.4 BYA

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Oxygen Catastrophe 2.4-2 BYA

What were the 3 Geological Eras within the Phanerozoic Eon

• Paleozoic

• Mesozoic

• Cenozoic

What were the 6 geological Periods within the Paleozoic Era

• Cambrian

• Ordovician

• Silurian

• Devonian

• Carboniferous

• Permian

3 geological Periods within the **Mesozoic Era**

• Triassic

• Jurassic

• Cretaceous

3 geological Periods within the **Cenozoic Era**

• Paleogene • Neogene• Quaternary

2 geological Epochs within the Quaternary Period

• Paleocene

• Holocene

Analogy

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similarity due to shared function

Biases in the fossil record

•Fossilization depends on many variables

•Durability of the tissue

•Burial timing and conditions

•Oxygen level

•Geographic bias

•Associated with ancient environments / habitats

•Lowland and marine environments dominate

•Taxonomic bias

•Marine organisms, bony/shelled organisms

•Temporal bias

•Old rocks are rare

Sir Francis Bacon

created the Scientific method, gives order to expirementing