AP Biology Unit 1

Aristotle

Aristotle

First “Biologist”, Scala Naturae: Life forms organized from most complex to least complex

Carl Linnaeus

Grouped organisms based on what he perceived as their similarities, developed the taxonomy binomial nomenclature (Genus species)

John Baptise de-Lamarck

Man who developed an early theory of evolution based on use and disuse and inheritance of acquired characteristics

Lamarck’s use and disuse

What organisms use grow stronger, what they don’t use deteriorates

Lamarck’s inheritance of acquired characteristics

Theory that said characteristics acquired during a lifetime can be passed onto offspring (if you lose an arm, your offspring would be born without an arm)

Thomas Malthus

Wrote essay on Principle of Population: Populations tend to increase towards overpopulation, resulting in individuals facing a struggle to get resources

Georges Cuvier

Opposed to evolution because he thought Earth had to be young, argued for catastrophism

Catastrophism

Past occurred suddenly and differently from mechanisms today

Charles Lyell

Wrote Principles of Geology, developed uniformitarianism, thought Earth was very old, opposed Cuvier

Uniformitarianism

The processes that shaped the Earth are the same as those at work today: if there are no entire world floods today, there never were

Alfred Wallace

Studied the same thing as Darwin, came up with mechanism of evolution, sent his article to Darwin to fact check, then Darwin published first

Charles Darwin

Sailed on HMS Beagle and collected lots of organisms and rocks, came up with idea of natural selection, published The Origin of Species by Means of Natural Selection

Natural selection

Organisms better adapted to their environment tend to survive and produce more offspring, the advantaged adaptation takes over

Basics of Natural Selection

Overpopulation leads to competition for resources, variations arise in population, variations that give organisms an advantage get passed on, eventually entire population will have advantage

Descent with modification

Darwin used this term instead of evolution, said organisms share attributes that came from ancestor in the past

Adaptation

Heritable characteristic that increases an individuals ability to survive in an enviorment

Artificial selection

When humans modify a species (GMOs, dog breeding, etc.)

Direct observation

When we can see evolution taking place, in small organisms with short generations (bacteria, insects, etc.)

Homology

Shows us there is a common ancestor, includes homologous structures, vestigial structures, embryology, genetics

Homologous structures

Similar structures that show evidence of evolution, ex. the one bone, two bone, lots of bones structure in the limbs of many animals

Vestigial structures

Structures that were once used but aren’t anymore, show evidence of evolution, ex. tailbone in humans

Embryology

The embryos of many species look very similar and become more distinct as they develop, evidence for evolution

Ontogeny recapitulates phylogeny

Theory from early 1800s, development of embryos follows evolutionary history, quickly found to be false, would mean if we were born early we would not be human

Genetic evidence for evolution

All organisms share a similar genetic code, which is evidence for evolution, the more similar the code, the more related the organisms

Convergent evolution

Comes from organisms adapting to similar environments in similar ways, is NOT due to a common ancestor, ex. wings of bats and butterflies

Tiktaalik

Transition to land animals, one of the first tetrapods (4 limbs), fish → reptile

Biogeography

The geographic distribution of species, species in more similar areas tend to be more closely related

Endemic species

Species only found in one area of the world, specialized to their area

Microevolution

Small changes within a population, due to mutations (changes in DNA)

Point mutation

Changing a single nucleotide, which can then change the gene

Hardy-Weinberg formula

Formula to calculate the gene pool of a non-evolving population

Requirements for Hardy-Weinberg

1. No mutations

2. Random mating

3. No natural selection

4. Large population

5. No gene flow

Random mating

No trait looked for by opposite sex

Gene flow

Population gains or loses alleles due to migration in an area (immigration: coming in, emigration: going out)

Genetic drift

Individual’s genes not being passed on (maybe due to random death) more pronounced in small populations, alleles may become lost or fixed

Founder effect

When a few individuals from a population start a new population with a different allele frequency than the original population, evolve differently from the original population

Bottleneck effect

Sudden change in environment drastically reduces population size, survivors may not represent the original population’s alleles

Directional natural selection

One extreme form of a species favored by natural selection

Stabilizing natural selection

Middle form of a species favored by natural selection

Disruptive natural selection

Two extreme forms of a species successful in separate environments

Sexual selection

Changes in secondary characteristics, gives organisms an advantage in mating, ex. brighter birds get more mates

Analogous Structures

Shared features between organisms that have a similar appearance and function but are not from a common ancestor

Protocell

The first cells, they had a single layer lipid membrane instead of a lipid bilayer membrane

Oparin and Haldane’s synthesis of first molecules

When Earth’s Oceans were primordial soup, chemicals slid past each other and with the energy of lightning or UV light, bonds were able to form, creating the first molecules

Miller and Urey’s contribution to synthesis of first molecules

Created the Oparin/Haldane conditions in a lab and were able to get amino acids to form, which proved the Oparin/Haldane theory true

RNA

Most likely the first genetic material, plays role in protein synthesis, smaller than DNA and single stranded, can act as an enzyme

Relative Fossil Dating

Determining the age of a fossil by how far in the ground it is

Radiometric Fossil Dating

Measuring the decay of an isotope to determine fossil age

Prokaryotes

Simplest cells, bacteria, no nucleus or true organelles other than ribosomes, 3.8-2.1 BYA were the only life forms

Eukaryotes timeline

Atmosphere changed 2.8 BYA, eukaryotes emerged around 2.1 BYA, multicellular organisms around 1.2 BYA

Endosymbiotic theory

Scientific explanation for the origin of eukaryotic cells, certain organelles, particularly mitochondria and chloroplasts, originated as free-living prokaryotes that were swallowed by simple, ancestral eukaryotic cells. Over time, this led to more complex cells.

Evidence for endosymbiotic theory

Mitochondria and chloroplasts have their own DNA and ribosomes, they can make copies of themselves, they have membrane transport systems similar to those in prokaryotes

Molecular clock

Hypothesis that evolutionary changes occur in regular intervals, potentially could predict future evolutionary changes

Archeopteryx

Fossil that shows dinosaur to bird transition

Heterochrony

Change in timing or rate of development

Homeotic genes

Genes that control placement and spatial organization of body parts

Hox

A homeotic gene that provides positional information in the embryo

Eukarya, Archaebacteria/Archaea, and Eubacteria

Three Linnaean domains

Kingdom, Phylum, Class, Order, Family, Genus, Species

Seven levels of classification within Eukarya

Eukaryote

A cell with a Nucleus

Archaea, Eubacteria, Plant, Animal, Protist, Fungi

Linnaean kingdoms

Morphology

Body shape

Phylogeny

Based on morphology and systematic, show evolutionary time

Systematics

Evolutionary history grouping

Clade

Group of species that includes ancestral species and all descendants

Monophyletic

If we have the common ancestor and all of the descendants

Paraphyletic

Common ancestor and some of the descendants

Polyphyletic

Pulling from multiple places in a evolutionary history diagram

Speciation

When a new species forms

Macroevolution

Big enough changes in genetics to create a new species

Biological definition for species

Group of populations whose members can reproduce and have offspring that can reproduce

Morphological definition for species

Species definition based on shape

Ecological definition for species

Species definition based on environments

Phylogenetic definition for species

Species definition based on evolutionary trees

Prezygotic reproductive isolation

Things that keep fertilization from happening

Postzygotic reproductive isolation

Things that happen after fertilization that prevent reproduction

Zygote

Fertilized egg, first cell of organism

Prezygotic habitat isolation

Organisms can’t reproduce together because they live in very different environments

Prezygotic temporal isolation

Organisms can’t reproduce together because they are out at different times of day or their reproduction happens at different times of year

Prezygotic behavioral isolation

Organisms can’t reproduce together because they don’t have the same mating behaviors

Prezygotic mechanical isolation

Organisms can’t reproduce together because their reproductive organs have different shape/size

Prezygotic genetic isolation

Organisms can’t reproduce together because they have a different number of chromosomes

Postzygotic reduced hybrid viability

When two organisms attempt to reproduce and the offspring doesn’t survive very long or is never born

Postzygotic reduced hybrid fertility

When two organisms attempt to reproduce and the offspring is born but is unable to reproduce

Postzygotic hybrid breakdown

When two organisms attempt to reproduce and the offspring genetic start to break down, over generations, the fertility declines

Allopatric speciation

Gene flow becomes disrupted due to geographic barrier so the population splits into two species

Sympatric speciation

Speciation without geographic isolation (most common in plants)

Polyploidy

Wrong # of chromosomes

Gradualism

Species descend from common ancestors and gradually change more and more over a long period of time

Punctuated equilibrium

Not much change occurs and suddenly lots of change occurs

Stasis

Periods of no evolutionary change