Biology 1603 I- Evolution

Biology

natural sciences that studies life and living organisms

Materialism

that the material world— matter— exists, and everything in the universe, including consciousness, is made from or is a product of matter

Methodological Naturalism

experiments are conducted and observations are made through the natural or material world that is open to our five senses

Philosophical Naturalism

claims that science has falsified the fundamental notion of the supernatural or the spiritual

Adaptation

a trait or integrated suite of traits that increases the fitness of its processor

Fitness

reproductive success and reflects how well an organism is adapted to its environment

Descent with Modification

evolution

Natural Selection

changes in allele frequency due to differential reproductive success

• Unifying Theory

Historical Constraint

a limitation on an organism’s evolutionary potential that arises from its past evolutionary history, mainly its existing phylogeny and developmental pathways

• descent with modification causes this

Aristotle

viewed species as fixed and arranged them on a scala naturae

Scala naturae

“The Great Chain of Being” and “The ladder of life”

Humans > Animals > Plants

Aquinas

wrote natural theology

Natural Theology

catalog “links” as a means of revealing and appreciating the wisdom of God

Paley

The watch on the Heath

• Un aliveness objection- the creator is God

• Argument from Design

• natural theology

Teleological Argument

asserts that the apparent order, complexity, and purpose in the natural world indicate the existence of an intelligent creator

Hume

Hume argues that the inference of a designer from the order of the universe is based on a weak analogy. We know watches are made by humans because we have observed the process of human watchmaking

• the weak analogy objection

3 Objections to the teleological argument

• The Weak Analogy Objection

• The Uniqueness Objection

• The Designer Without God Objection

Lyell

Wrote “Principle of Geology”

• Uniformitarianism

• Deep Time

Lamarck

Lamarck Evolution

1. Different things have descended from common ancestors (scala naturae becomes an ancestor

2. Spontaneous Generation of Simple Organisms

3. Inherent trend from simple to complex

4. Use/ disuse

5. Environmental influence (Inheritance of Acquired Characteristics)

Darwin

The struggle for existence

• The Origin of Species by Means of Natural Selection

What is the origin of species about?

All organisms have descended with modification from common ancestors

Beagle

Voyage of HMS beagle

Malthus

wrote an essay of the principle of population— limits the human population expansion

Artificial Selection

an evolutionary process in which humans consciously select for or against particular features in organisms

Wallace

wrote “on the tendency of varieties to depart indefinitely from the original type”

• wrote letters Darwin about evolution

Mayr

observed Darwin’s “Origin”

• all species have high reproductive material

• populations tend to remain stable

• Environmental resources are limited

• Individuals of a population vary in their characteristics

• much variation is inherited

What is a model for artificial selection?

brassica oleracea

• wild mustard » cabbage, cauliflower, broccoli

Homology

the fundamental similarity between biological structures, genes, or other traits in different organisms that are inherited from a common ancestor

• similar by descent

  > humans, cats, whale, bats

• in a molecular sense— hemoglobin genes and coding sequence

Biogeography

the science of studying the geographical distribution of plant and animal life, including the factors that influence this distribution over time and space

Law of Succession

similarities between fossil and extant taxa from the same geographical region

Transitional Fossil

any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group

Cetacean Example

Tetrapods— hind limb buds are present in early embryos of Dolphin

allele

one of two or more different versions of a gene found at a specific location on a chromosome

genotype

the genetic makeup of an organism

what are the five assumptions of hardy- weinberg

1. large population size

2. random mating

3. no selection

4. no mutation

5. no migration

Genetic Drift

changes in allele frequency due to chance (sampling error)

• decline in diversity

Bottleneck Effect

population's size is drastically reduced, often by a natural disaster, leading to a severe loss of genetic variation

Founder Effect

population is established by a small number of individuals from a larger parent population

Non-random mating

mating choice is biased

• changes in genotype frequency

Inbreeding

mating with close relatives and selfing

Assortative Mating

• like attracts like

• opposites attract

Migration (gene flow)

emigration or immigration

• exchange of DNA between geographically discrete populations

Directional Selection

one extreme phenotype is favored over all other phenotypes, leading to a shift in the population's mean trait value in one specific direction over time

Diversifying/ Disruptive selection

individuals with extreme traits at both ends of a phenotypic spectrum are favored over those with intermediate traits

Stabilizing selection

average, or intermediate, phenotype for a trait is favored, while extreme variations are selected against

Sexual Selection

changes in allele frequency due to differential mating success

• secondary sexual trait dimorphism

Mutations

changes in DNA

Point mutation

change in a base

GAT CGA TCG A

GAT GGA TCG A

Indel Mutations

insertion or deletion mutations

Duplication

DNA containing a gene is copied, creating one or more identical or similar copies of the gene within the same genome

Polyploidy

whole gene duplication

Recombination

can shuffle existing alleles into new combinations

• random assortment

• cross over during meiosis

what is more important than mutations in organisms that reproduce sexually?

recombination

Biological Species

what oragnisms are reproductively cohesive?

single species

Reproductive Cohesion

the protein complexes, cohesins, that hold sister chromatids together after DNA replication until they are separated during cell division (mitosis or meiosis)

what organisms are reproductively isolated

distinct species

Reproductive isolation

an event or phenomenon creates a split in the cohesive population

Pre-Zygotic Barriers

• Habitat Isolation
• Temporal Isolation
• Behavioral Isolation
• Mechanical Isolation
• Gametic Isolation

Habitat isolation

populations are separated by their differing habitat preferences, preventing them from encountering each other and interbreeding, thus leading to genetic divergence and potentially new species

Temporal Isolation

prevents different species from interbreeding because they reproduce at different times

Behavioral Isolation

distinct species fail to interbreed due to differences in their courtship behaviors, such as unique mating calls, songs, dances, or visual signals

Mechanical isolation

prevents two different species from interbreeding due to physical incompatibility of their reproductive organs or structures

Gametic Isolation

gametes (sperm and egg) of two different species are incompatible, preventing fertilization and the formation of a zygote

Post-Zygotic Barriers

• Reduced Hybrid Viability
• Reduced Hybrid Fertility
• Hybrid Breakdown

Reduced Hybrid Viability

genes of the different parent species may interact and impair the hybrid’s development

Reduced Hybrid fertility

even if hybrids are vigorous, they may be sterile

Hybrid Breakdown

Some first-generation hybrids are fertile, but when they mate with another species or with either parent species, offspring of the next generation are feeble or sterile

Allopatry speciation

populations become genetically isolated from the parent population

Sympatry Speciation

populations become genetically isolated but share a geographic range

Allopolyploid

polyploidy by hybrid formation and subsequent restoration of hybrid fertility

Law of Superstition

sedimentary strata reveal the relative age of fossils

Radiometric Data

used to determine the absolute ages of fossils

Half Life

time required for half the parent isotope to decay

Extinction

• permian

• - k/ pg (creatcenous/ paleogene)

Permian

known as the most severe extinction in history

Cretaceous/ Paelogene

mass extinction that wiped out 75% of species on Earth — dinosaurs

Allometry

the study of how different body parts or traits change in size or form relative to the overall size of an organism

Heterochrony

change in timing or pace of development

» the juvenile ape hypothesis

Homeosis

genes that control other genes

• alteration of major anatomical features

  » body parts

Homeotic

a regulatory gene that controls the development of specific body segments

Homeobox (HOX)

control of major developmental programs in animals

Pitx1 Example

Pitx1 is expressed in the ventral spine and mouth regions of developing marine sticklebacks but only in the mouth region of developing lake sticklebacks

Linnean Hierarchy

taxa of Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species

Binomial Nomenclature

the formal, universal biological system for naming species with a two-part Latinized name

Phylogeny

study of genealogical relationships among living organisms

Monophyly

the complete set of descendant taxa and their most recent common ancestor

Non- monophyly

a set of taxa that fails the test for monophyly

(Apomorphy) — Derived Trait

diagnose monophyletic groups

(Plesiomorphy) — Ancestral Trait

diagnose non- monophyletic groups

Taxa/ Taxon

organisms at any Linnean rank

Sister Taxa

pair of taxa that form monophyletic group

Ingroup

set of taxa under study

outgroup

reference taxa for assessing trait status

• derived or ancestral