Evolution

Evolution

the change in traits in population over time

What does evolution lead to

leads to biodiversity in populations and species

How does evolution occur

through changes in allele frequencies

What does evolution allow for in terms of survivalbilit

gives organisms the best opportunity to survive

Microevolution

Small Changes in traits within a population over time

Examples of microevolution

Mutation, natural selection, gene flow, genetic drift

What can microevolution lead to

speciation

Macroevolution

Major evolutionary changes over a long period of time that can lead to new species forming

Examples of macroevolution

speciation, mass extincition, adaptive radition

Speciation

formation of a new species

Phylogeny

Evolutionary Relationships between organisms

What is the big picture of phologeny trees

macroevolution

Phylogentic trees

a diagram used to present evolunary relationshsips

Are phylogentic trees always true

no they are hypothesis

Nodes or Branch Points

Point where common ancestors split into different species

Cladogram

a diagram used to show hypothesized relationships between groups of organsims how they may diverge from each other

Is there a time axis for cladogram

No, because cladogram shows shared traits/charactersitcs

Phylogenetic Tree vs Cladogram

Cladogram is based on shared charactersitics and traits while a phylogenetic tree is based on the genetic and evolutionary history

What does phylogentic tree represent better than cladogram

it represents more directly the common ancestors and how much change occured over time rathar than just divergence of features

Phylogenetic Groups

Monophyletic, Paraphyletic, Polyphyletic

Monophyletic

Group of organims with one common answers

Paraphyletic

Group of organims that conisist of some ancesotrs but not all descendents

Polyphyletic

Group of organims that do not share a recent common ancestor

Early earth atmostphere

gases in atmoshpehere released from volanos such as H2 NH3 CO2

little to no oxygen

Why are teh molecules in early earth important

because they would bond together in chemical reactions that would form bigger molecules

Earth Cooling

Life use to very hot, but earth cool down very slowly from heat losing energy to space

water in the early atmosphere condensed into rain as earth cooled

Earliest formation of molecules

inorganic molecules formaed organic molecules

monomers condensed into polymers

Oparin and Haldance Hypothesis

earth atmoshphere was likely reducing and suggest thes ebuilding blocks was from radition energy or lighting

Haldance suggested moleucles formed in the ocean

Or tidal pools formed these molecules

How these tidal pools theory work

when the tidal pools go out some water is trapped and then the UV radiation would evaporate the water. this leaves behind moleucles and then when tide comes in it take these organic molecules back out

Miller and Urey experiement

take chemicals such as amonioa and water in a flask and simulated lighting or energy and see what moleucles form

it worked and saw amino acids formed

RNA world hypothesis

scientist hypothesize this was the first form of genetic material to arise

Protocells

possible precursor to cells and were able to absorb particles from a membrane

RNA was not able to intially self replicate

therefore ribozymes were able to catalyze reactions and create a possibility of self replications

RNA shifts to DNA

RNA is very unstable so it used RNA as a template to create DNA in order to store genetic inofmraition and more genomes possible

first anaerobic heterotrohic prokaryotes

first organism and consed other organic substances for energy

Autotrophic prokaryotes

formed through mutation of heterotrophic prokaryotes that created their own energy from photosynthesis

Transformation of earth atmosphere

autotrophic prokaryotes like cyanobacteria release oxygen into air

atmosphere becomes more oxygenated and ozone later formed through interaction of oxygen and UV light

UV light absorbed in atmosphere blcoked and allows safer enviorment

What did the transformation of earth atmosphere allow for

allow for eukaryotes to form because more O2 used and cells adapted to aerobic atmosphere

Eukaryotes have

nucleus, membrane bound organelles, and cytoskeleton

Endosymbiotic Theory

expalins how eukaryotic cell orgin

Endosymbiotic theory hypothesis

Mitochondria and chloroplast were small prokaryotic organisms and were engulfed by other prokaryotes

they then created a symbiotic relationship

Evidence for Endosymbiotic theory

Interior features resemble prokaryotes

Mitochondria and chloroplast both have circular DNA

Independent Genome

Have their own prokaryotic like ribosomes

Replicate independently

Which of the following best describes Oparin & Haldane’s hypothesis regarding the formation of organic molecules on early Earth?

Organic molecules formed from inorganic molecules interacting with lightning & UV radiation

Which of the following were the first living organisms on Earth?

Anaerobic heterotrophic prokaryotes

Aerobic

Requires oxygen

anaerobic

does not require oxygen

autotroph

makes its own organic molecules from inorganic carbon sources

heterotroph

obtains energy and carbon by consuming other organisms

What was the significance of the formation of the ozone layer for evolution?

absorbing harmful UV radiation from the sun, creating a less harsh environment that allowed new forms of life to evolve and thrive on land.

fossils

Fossils show evidence of new species by showing the timeline of it

Scientific evidence for evolution

fossils, embryology, comparitive anatomy, moelcular biology

Embryological Evidence for Evolution

similar development in related species

Homologous Strucutres

anatoomical feautures in species that originate from a common ancestor

may not have the same function

could be from sharing similar physiological structure

Analogous Structure

Anatomical features with similar function but do not share a common ancestor

Strucutre is not fundamentally similar

points to similar adaptions to similar enviorment

Vestigial Strucure

strucutre that appear useless but had ancestral function

Evidence from Molecular Biology for Evolution

analyzing different species of nucletodies and amino acid sequence

closely related species have higher percentage of shared sequeunces

Palentology

study of fossils

Catastrophisms

Earth was shaped by major gelolgic cathostrophes meaning most changes happen from violent events leading to extincition

Georges Cuvier

Proposed Catastrophism

Gradualism/Uniformitarianism

opposing thoery of catatostriphsm states that changes to earth and its organism happen from very small process over long period of time

Lamark Theory

Inheritance of acquired characterics

Inhertiance of acquired characterisitcs

acquired traits are passed on

unused traits will leave

What else did lamark believe

natural transformation of species

natural transofrmation of species

offspring are more complex than the preceding generation and organisms do not become extinct

Darwin Wallace Theory

Survival of the fittest or Natural Selection

Descent with modification - variation present in populations

Inidivduals dont evolve

populations do

Neo Dawrinism

Darwin theory with genetic understanding

genetic mutations produce the varaitions within a population

therefore advanatgeous genes are passed on, not phenotypes

Variations exist within population due to

difference in genomes

Variation exist within all populations

Variations in a population is due to genetic varation and increased by genetic mutations

Selection Pressure

elements within an enviroment that prompt organisms to adapt

Selection Pressure examples

resource scarity - resources limited

Competition - favorable traits will be selected and indiviudal who have them will thrive and those who lack will be eliminated

Do individuals adapt or populations?

Adaptation and evolution occur over generations at the population level, not within a single individual’s lifetime.

source of variation within a population

differences in alleles.

Stabilizing Selection

Narrowing the distribution towards the mean

removes extreme variants

Normal Bell Curve goes to a more centered bell curve

Directional Selection

One extreme phenotype is favored over the others

shift towards one end of the distribution

Disruptive Selection

Occurs when intermediate trait is selective against

the enviorment favors exterme or unsual trait and shfit toward both ends

Sexual Selection

Different mating of males and females in population

traits that are attractive to te opposite sex or look for different traits

Intrasexual Selection

Selection within the same sex

indiviudals directly compete for mating opportunities

usally a male behavior

Intersexual Selection

Mate choice

individuals of one sex select for traits in the opposite sex or increase alleles selected with evolve

Fitness

The ability to survive and successfully reproduce

Fitness and Natural Selection related

natural slection cna increase the odds of survival if adapations are present therby increasing allele frequency and resulting in adaptive evolution

Therefore natural selection for traits with greater fitness

Overproduction

every species tends to produce more individuals that can survive to maturity

Variations

the indivudals of a population have many charactersitics that differ

Selection

some individuals survive longer and reproduce more than others do

Adaptations

the traits of those inviduals that survive and reproduce will become more common in a population

Natural Slection favorability can change

based on the enviorment which can result in a new species a group of organisms

what is main purpose of evoution

to increase fitness and increase reproduction

Artificial Selection

driven by human choice and favors a specific phenotype

human select for or against traits through breeding

Sexual dimorphism

a term used to describe differences in the appearance between male and female members of the same species.

what determines high fitness

The individual that produces the most offspring, with the greatest number surviving to adulthood, has the highest fitness

Evolution is the change of what

allele frequencies in a population over time

Gene Pool

all copies of alleles within a population a

allele

alternative version of a gene

Allele frequency

how often did a certain version of a gene occur in a population

Natural Selection

Increases or decrease alleles based on whether they increase fitness

Gene Flow

The transfer of allele from populations when indiviuduals leave or enter populationsG

Genetic Drift

the random increase or decrease of allele by chance. smaller population the larger the effectg

genetic drift the smaller population

the larger the effect

Founder Effect

When a small group of individuals become isolated from a larger population

Bottle neck effect

occurs when population undergoes a significant reduction in size due to a natural catastropheG