Biology Review: History of Evolutionary Thought

• Provides a Biology Review for Term 3, Cycles 2, 3, and 4

History of Evolutionary Thought

• Aristotle believed species are unchanging and individuals within a species are identical
• Hutton proposed changes in nature are gradual, known as uniformitarianism
• Buffon suggested species change as they spread from their original location
• Lamarck theorized new species arise from existing ones through environmental forces
• Cuvier proposed species reappear after catastrophes, with fossils representing extinctions
• Lyell stated all changes in nature are gradual, renewing uniformitarianism
• Darwin & Wallace suggested individuals within a population differ, and species arise through natural selection

Contributions of Past Scientists

• Georges-Louis Leclerc: A French naturalist describing plants and animals in a 44-volume natural history series, also providing evidence of evolution and proposing various causes
• Carolus Linnaeus: A Swedish botanist developing the binomial system of nomenclature and a system of classification for living organisms, while believing in scala naturae and the fixity of species
• Erasmus Darwin: A British physician and naturalist formulating one of the first formal theories on evolution in Zoonamia, basing conclusions on changes in animals during development, animal breeding by humans, and the presence of vestigial structures
• Georges Cuvier: A French zoologist establishing the sciences of comparative anatomy and paleontology, further developing the theory of catastrophes where animal and plant species are destroyed time and again by natural catastrophes, and that new species evolve after that
• James Hutton & Charles Lyell: Hutton, along with Lyell, developed the concept of uniformitarianism

Jean Baptiste Lamarck

• Best known for the idea that acquired characteristics are inheritable, also known as Lamarckism
• He proposed two principles:
  • The law of use and disuse
  • Inheritance of acquired characteristics
• Lamarck's theory of evolution explains that the environment can produce physical changes in an organism during its lifetime which can be inherited in the next generation

Thomas Malthus

• An English economist published an "Essay on the Principle of Population," proposing the size of human populations is limited by available resources
• Charles Darwin: Used Malthus's principle to formulate his idea of natural selection

Charles Darwin

• An English naturalist whose scientific theory of evolution by natural selection became the foundation of modern evolutionary studies
• He formulated his theory after returning from his voyage and wrote the book “On the Origin of Species”

Darwin Theory of Evolution

• During the voyage of the Beagle Darwin observed life and geology throughout the world
• The journey aboard the HMS Beagle, led Darwin to observe life and geology throughout the world
• Observations made on the Galapagos Islands gave him many ideas about natural selection and evolution

Darwin's studies

• Darwin observed massive geological changes, realizing Earth's changes result from slow processes, and Earth must be very old
• Darwin collected fossil specimens differing from modern species, like the Glyptodon, an armadillo-like animal

Biogeographical Observations

• Animals on different continents differed, however similar environments had similar-looking animals, ex. Patagonia hares in South America instead of rabbits
• Each Galapagos island's tortoise type descended from a common ancestor [ex. Long-necked tortoises inhabiting dry areas scarce of low vegetation while short-necked types inhabit moist regions with ground vegetation.]
• Darwin observed finches exhibited beak size/shape variation [He speculated a mainland Finch was the ancestor of all types on the Galapagos Islands.]

Publication

• Darwin received a manuscript from British naturalist Alfred Russel Wallace
• Wallace collected and identified thousands of species in the Malay Archipelago for 8 years

Natural Selection and Adaptation

• Individuals in a species differ, and some variation is heritable
• Essential resources like space and food are limited in every habitat
• There are more offspring born that can survive
• Darwin realized the capacity to overproduce was characteristic of all species

Modern Synthesis (New-Darwinian Theory)

• Modern evolutionary synthesis unifies DNA, mutations, inheritance, and natural selection ideas
• The Modern Synthesis Theory of Evolution States:
  • Genes lead to hereditary characteristics
  • Populations, not individuals, evolve via natural selection and genetic drift
  • Speciation occurs because of the accumulation of genetic changes

Microevolution

• Evolution involves changes in gene frequency within a population
  • Microevolution refers to evolutionary changes within a population
  • Five forces can cause shifts in genes

Causes of Microevolution

• Variation arises as members of the population differ from one another
• Increased Fitness: Individuals better adapted to their environment reproduce more
  • Survival traits are passed down to avoid distinction

Natural Selection

• Ability to adapt to the environment and having increased chance of survival

Types of Selections

• Directional Selection: One certain phenotype is favored/selected
• Disruptive Selection: Two phenotypes are favored/selected
• Stabilizing Selection: Intermediate phenotype is selected
  • Disruptive selection favors small or large rather than medium favors medium
• Sexual Selection: Adaptive changes gives a higher chance of finding a mate
• Intrasexual Selection: Selection in self
• Intersexual Selection: Selection in male and female or with others

Mutation

• Mutation is a random change in the genetic sequence of a living thing's DNA, or any changes on base
• Anything with RNA or DNA can have mutations, such as animals, humans, plants, bacteria, and fungi
• Not all mutations affect the genetic equilibrium in a population

Gene Flow (Migration)

• Gene flow is the movement of alleles between populations
  • New/rare alleles occur when gene flow brings a new allele and affects the allele frequency

Genetic Drift (Chance)

• Changes in the allele frequencies of a gene pool due to chance events, like habitat change
• Such events remove individuals and their genes from a random population

Types of Genetic Drift

• Bottleneck Effect: The loss of genetic diversity is due to natural disasters, disease, overhunting, overharvesting, habitat loss
• Founder Effect: Genetic variation is lost when a few individuals break away and populate

Non-Random Mating (Preference)

• Affects how the alleles in a gene pool assort into genotypes
  • Assortative mating occurs when similar types of individuals mate more
  • Dissortative mating occurs when dissimilar types of individuals mate more

The Hardy-Weinberg Principle

• A population is in genetic equilibrium, allele frequencies do not change by overtime
• Assumes that the genetic pool of the parent stays as it is if there were no external factors
  • No natural selection
  • No mutation
  • No migration
  • No large population
  • No random mating

Terminologies

• Gene Pool: A combination of all the genes present in a reproducing population or species
  • A large gene pool has extensive diversity, & it is able to withstand greater environmental disruption
• Gene or Allele Frequency: It is the relative frequency of an allele at a particular locus in a population
• Genotype Frequency: Fraction of individuals with a given combination of alleles (ex WW, Ww, or ww)
• Phenotype Frequency: How often we see each color whether it's Purple is 7/9 or how often White 2/9
• Alleles (Formula Equation): p+q=1 must always equal to 1
• Genotypes (Formula Equation): p²+2pq+q² must always equal to 1

Macroevolution

• Darwin's voyage to the Galapagos Islands led him to observe different groups of finches

Macroevolution Definition

• Processes associated with evolutionary change at the species level and above
• Often results in speciation or the formation of new species
  • Speciation: the creation of new species, which some members cannot interbreed within their group

Patterns of Macroevolution

• Divergent Evolution: interbreeding species diverge into two or more groups due to changing environmental factors
• Convergent Evolution: distinctly different species become more alike in structure and function in order to adapt to similar environments
• Parallel Evolution: two species from a common ancestor develop

Co-evolution

• Occurs when one species evolves, causing another species to evolve to ensure that a relationship can continue

Reproductive Isolating Mechanisms

• Pre-Zygotic Isolation: Occurs before the formation of a zygote and prevent mating -Habitat Isolation: No mating due to space between species in the same geographic range -Temporal Isolation: No mating due to different times of reproduction -Behavioral Isolation: No mating due to unique mating patterns -Mechanical Isolation: Mating is incompatible due to reproductive structures -Gametic Isolation: Mating cannot fertilize due to incompatibility
• Post-Zygotic Isolation: Occurs after the formation of a zygote -Hybrid Inviability: Hybrids develop but cannot survive -Hybrid Sterility: Development of a zygote but cannot form more -Hybrid Breakdown: First generation are able, but incapable of producing more

Modes of Speciation

• Allopatric Speciation: A geographic barrier separates a population into two groups that cannot interbreed
• Parapatric Speciation: Two populations living in neighboring areas but share a border zone
• Sympatric Speciation: A population develops into reproductively isolated groups without geographic isolation

Evidence of Evolution

• Fossil Records: Fossils are the remains of organisms lived long ago found on sedimentary rock
  • The deeper the rock, the older the fossils remain

Fossil Formation

• Compression: Compresses fossils preserving the plant
• Petrification: Mineralized bones are considered fossils
• Impression: Fossil that reveals an anatomical footprint
• Cast: Once living material is dissolved and replaced
• Intact Preservation: Tree resin preserves and hardens to form amber

Transitional Fossils

• Transitional fossils are those that classify separately

Biogeographical Evidence

• Biogeography is the study of the geographical distribution of fossils as organisms live with them
  • Wallace's Line: As Alfred Russel Wallace traveled around the Malay Archipelago and noticed different species on either line

Anatomical Evidences

• Homologous Structure: Same set of bones who descended from common ancestor
• Analogous Structure: Same function, different development or bones
• Vestigial Structure: Anatomical features that is not useful

Other Evidences

• Embryology is the study of where organisms develop from an embryo to adult
• Molecular Biology states that the molecules are similar in life

Linnaean Taxonomy

• Carlous Linnaeus, organizes the life by hierarchical scheme that classifies
• He grouped organisms to form DOMAIN > KINDOM > PHYLUM > CLASS > ORDER > FAMILY > GENUS > SPECIES

Taxonomic Levels

• Archaea > Bacteria > Eukarya
• Then divided into kingdoms > phyla > classes > order > families > genera > species

Binomial Nomenclature

• Carlous Linneaus instituted naming the two-part

Dichotomous Key

• Identify objects that classify the organisms

Phylogeny

• Evolutionary history of ancestor as their lineage
• It indicates lineages

Cladistics

• Distinguishes species with ancestral characters
• Way of classifying cladistics
• Ancestral inherited attribute
• Different derived figures

Reading a Cladogram

• Tree-like diagram that shared derived charts
• Origin initial ancestor that spreads
• The most distorted species and its function
• Clades are a shared ancestor as descendants

Monophyletic

• Shared common ancestor, it is single

Paraphyletic

• Shared common ancestor, it is beside

Polyphyletic

• No shared common ancestor, it is many

Phylogeny based on Morphology

• Similar body parts that evolves in common
• Same part but different function due to ancestry

Phylogeny based on Molecular Data

• Small genes that align to determine evolutionary relationship
• Several species that used amino acids that used to measure the relationship

Transport and Circulation in Plants

• Evaporation of water transports from the environment through water

The Water transport in Xylem

• Water's ability to stay in a chain known as cohesion
• Adhesion means Water's ability to stick to any tube
• For transpiration to occur which closes to ensure water is released

The Sugar Transport in Phloem

• Source is like where the sugar store
• Location where sugar uses what the sink's purpose
• The amount of sugar stores from each of their parts

Transport and Circulation in Animals

• Bathes the tissues which returns to the heart

Open and Close Circulatory System

• Open Circulatory System bathes the tissues
• Close Circulatory System pumps vessel

One Circuit and Two Circuit Circulatory System

• Single One System is that where heart pumps blood to gills
• Two Circulatory System were cardio that consisted pulmonary circuit

The Human Heart

• Circulates blood
• Has an atrium that receive
• A ventricle pumps
• Septum separates
• One moves blood to the correct direction and aterioles move away while vein moves to heart

Two Major Circular Pathways

• Oxygen blood moved to capillaries
• Then from the aorta leads through the lung

The Tracing Pathway

• Consist of parts where contraction moves as the capillary moves throughout body

Types of Vessels

• Arterioles which have cells where vessel merges
• Gas Exchanges which take uptake from o2 outside

Types of Restoration

• Expel waste with air and blood
• Transport to internal respiratory such as water

Hydras

• Outer layer of calls contacts the environment and inners can exchange gastro activity

Earthworms

• Body surface can exchange

Insects

• Insects have wind passage

Aquatic Animals

• Have grills from water

Mammals

• Vertebreak and lungs in surface

Respiratory Medium

• Substance where animals can exchange gas
• Sudden animal death

Ventilation

• Flow where air spreads in lungs

Pressure

• Flog draws to nostril of force towards lungs

Humans Exchange

• Lungs expand and contract when exhaling

Respiratory Proteins

• Increases oxcygnation