BIO Test LAP 10

Directional Selection, Stabilizing Selection, Disruptive Selection

• an extreme phenotype is favored

  • Causes allele frequency to shift over time in that direction

• Ex. Peppered Moths

• One phenotype is favored

• Eliminates the extremes of a phenotype.

• Ex. birth weight in humans - if your baby is too small (not able to survive and thrive) and if your baby is too big (might kill the mom and themselves)

  • When the middle phenotype is favored

• Favors the extremes and eliminates the middle phenotype.

• Can lead to speciation

  • Can become a new species

• Ex. Rabbits that live in an environment with black and white rocks

  • Grey is a disadvantage.

• When 2 distinct phenotypes, this can lead to a new species forming

• Random

• When an allele becomes more or less common in a population due to chance

• BY CHANCE

• 2 types:

  • Bottleneck Effect and The Founder Effect

• An externa event (natural disaster) kills off many in the population.

• The new population has different allele frequencies than previously.

• By chance

• Random what alleles go to a new place, cause by population starting a new population.

• A few individuals colonize a new habitat.

  • Can cause major changes in allele frequencies.

• how new species form

• Occurs when gene flow between 2 groups stops

  • Known as Reproductive Isolation

  • 3 types: Behavioral Isolation, Geographic Isolation, Temporal Isolation

• Reproductive Isolation #1

• If 2 populations develop different courtship rituals or behaviors, they will stop interacting/mating with each other.

• If I turn left when I dance and you turn right, we don’t match (as birds)

• WE BECOME DIFFERENT SPECIES

• Reproductive Isolation #2

• 2 populations are separated geographically.

  • Mountains, rivers, bodies of water

• When something geographical, like a natural barrier separates species causing them to adapt.

• Reproductive Isolation #3

• When populations reproduce at different times, they will eventually diverge into separate species

• Ex. Orchids in the rain forest pollinate at different times, resulting in diverse species.

• Separating by time

• show us about what date the rock is from

• Relative and radioactive dating

• Generic method of dating fossils using layers

• Lower layers = older fossils

• Index Fossils - give scientists an approximate date for other things

• Absolute dating

  • More precise than relative dating

• Relies on radioactive isotopes which break down at a steady rate.

• Half - Life = time required for half of the radioactive atoms to decay

• Carbon - 14

• 540 mya - Snowball Earth

• 250 mya - Pangea Forms

• 65 mya - meteor hits Earth

• Plate Tectonics - created mountains, volcanoes, etc. changing the environment

• Comets/Meteors - destroying ecosystems and killing a lot of animals, letting the animals with the best adaptations survive and thrive.

• Climate Change - makes it too hot or too cold in places for animals to live, either they must adapt or die.

• Life on Earth also changed in response to living organisms changing.

• Ex. Photosynthesis is allowed for carbon dioxide levels to drop and oxygen levels to thrive.

  • Allowing for more to thrive.

  • Things moving from water to land.

• May occur during an Ice Age (snowball Earth), Meteor strike, Upset ocean current (Pangea forming)

• When the meteor hit Earth since the dinosaurs were big, meat eaters, etc. they died off leaving the smaller reptiles to thrive.

• evolution of entire groups of organisms

• Big scale organisms

• Big changes in time

• Ex. Flowering plants evolved 130 mya

• Ex. Dinosaurs appeared 250 mya and existed until 67 mya

• fossil evidence shows that evolution can occur at different rates and at different times.

• Slow, steady, change over time.

• Ex. Horses

• stable periods interrupted by rapid change of species.

• Usually seen in mass extinctions.

• A single species diverges into multiple different species.

• Ex. Darwin’s Finches

• unrelated organisms evolve similar traits due to similar niches - analogous structures

• Ex. Penguins and dolphins have similar body types.

• Early atmospheric conditions + lightning can form organic compounds.

• Showed life can be made with right chemical components.

• Proved that spontaneous generation did not occur.

  • Theory at the time that said life could be created from nothing.

• Boiled liquid in a sterile flask

  • Bacteria only able to grow when it was exposed to air.

  • Life did not generate on its own.

• science of classifying and naming organisms

  • Binomial Nomenclature - Developed by Linnaeus

  • “genus species”

    • Scientific 2-part naming system

group

• • developed by Linnaeus

• “genus species”

  • Scientific 2-part naming system

• Important because it is easy to communicate.

Kingdom

Phylum

Class

Order

Family

Genus

Species

• not just based on looks → now Genetics, development/embryology, cell biology

Bacteria, Archae, Eukarya

• Kingdom Eubacteria

• bacteria in this

• No nucleus - Prokaryotic Cells

• Kingdom Archaebacteria

• Bacteria that live in extreme environments

• No nucleus - Prokaryotic Cells

• Kingdom Protista

• Kingdom Plantae

• Kingdom Fungi

• Kingdom Animalia

• Only group that has a nucleus

• 2 unicellular organisms joined together in symbiosis to form the first eukaryote

• Kingdom Protista

• Kingdom Planta

• Kingdom Fungi

• Kingdom Animalia

• “grab bag Kingdom” - contains things that don’t fit elsewhere.

• Generally unicellular

• Unicellular organisms that are not bacteria

• Ex. Algae, Amoebas

• Autotrophic - go through photosynthesis.

• Multicellular and have cell walls.

• Eukaryotic

• Ex. Trees, Ferns, Grass

• Heterotopic

• Multicellular and have cell walls

• Eukaryotic

• Ex. Mushrooms, Mold, Yeast

• Multicellular

• Eukaryotic

• Heterotrophs

• Study that reconstructs the evolutionary history of a species

• When you reconstruct the evolutionary history of a species

• Adds time into your classification

• Throws in time that the animal diverged

• Shows evolutionary relationships

• “family trees”

• Timeline showing who is related to who

• trait that arose in the most recent common ancestor

• Everything after has the trait

• Ex. seat belts on cars

• Group of similar organisms on a cladogram

• most distant organism, not in the larger clade

• NOT ALIVE

• only composed of DNA and Protein

  • Not made of cells **

• Can only reproduce by infecting living cells

  • 2 types of infections

• Quick cycle of infections

• Virus injects DNA into cell → Viral copies created → cell bursts → Viruses Escape

• Ex. Ebola, COVID - 19, Rhonavirus (common cold), Influenza

• Longer cycle due to period of dormancy

• Virus injects DNA into cell → Viral DNA incorporates with host cell DNA → the cell copies itself many times (this is dormancy period)

• Then:

  • Cell enters Lytic cycle → Viruses created → Cell Bursts → Viruses Escape

  • Ex. HIV, Herpes, Chickenpox