H. Biology - Unit 9: Evolution

Who is Charles Darwin?

A British scientist that created the theory of evolution and natural selection

What are the three requirements of evolution?

1. Lots of time
2. Evidence that organisms have evolved
3. A common pattern/mechanism that can bring about the change

What are the four eras of Earth?

Pre-Cambrian, Paleozoic, Mesozoic, and Cenozoic.

What is the endosymbiotic theory?

Some eukaryotic organelles started out as single-celled prokaryotes but were engulfed by early prokaryotic cells. This created a symbiotic relationship and eventually became integrated into the cell.

What is the order of existence of all life on Earth?

prokaryotic bacteria, cyanobacteria, aerobic bacteria, eukaryotic single-celled bacteria, multicellular organisms

what are homologous structures? what are analogous structures? what are vestigial structures?

homologous structures have the same structure but different functions, and this supports a common ancestor. analogous structures have different structures but the same function, and this doesn’t support a common ancestor. vestigial structures are useless structures.

how do you tell the age of a fossil?

through absolute dating, which is determining the exact age using radiometric dating of rock and ash, or relative dating, which is approximating the age through its surrounding rock layers.

what is the law of superposition?

older rocks are always beneath younger rocks

what is evolution?

the theory that all living things' populations will change over time

what were the four observations that led Darwin to create the theory of evolution? what are their definitions? (think Outraged Chickens Vilify Iguanas)

1. overproduction, organisms create more offspring to survive,
2. competition, organisms compete for resources as populations increase
3. variation, all organisms differ and variation is inherited
4. inheritance, organisms with advantages survive to pass their genes to their offspring:

what is the mechanism for evolution?

natural selection

what is natural selection?

change in a population that occurs when organisms with favorable traits for a specific environment reproduce and pass on these traits to their offspring

what is genetic variation?

differences of traits between offspring

what are adaptations?

traits that improve an organism’s’ chance of survival and reproduction

what are species?

related organisms that common characters and are capable of breeding to create fertile and healthy offspring

what is adaptive radiation?

when species evolve to occupy all the ecological jobs or niches of a new area

what does divergence lead to? what is its definition?

speciation, the formation of a new species

what are the two reasons for a new species?

reproductive isolation and allopatric or sympatric speciation

what is reproductive isolation?

there is a reason why the group will not mate with other groups

what is allopatric speciation? what is sympatric speciation?

allopatric speciation is when they are in two different places and can’t breed. sympatric speciation is when they don’t breen because they don’t want to, such as mating season, preference, or body size

what is coevolution?

when two or more species evolve in response to each other as a result of their symbiotic relationship

what is a phylogenetic tree or cladogram?

diagrams that show the relatedness of organisms and also show what traits they and and the order the traits evolved

what is genetic equilibrium?

the frequency of alleles in a population’s genome doesn’t vary over generations

what’s the difference between genetic equilibrium and evolution?

genetic equilibrium has no change in allele frequency while evolution does have a change in allele frequency

what is macroevolution?

Evolution that happens to groups of organisms above the level of an individual species over a relatively long period of time

what is microevolution?

Evolution that happens over a relatively short period of time

what are the requirements for natural selection? (think Vile Snakes Inspect Turtles) what are its definitions?

1. variation, different traits in a population
2. selection, traits that give higher chance of survival and reproduction in a competitive environment
3. inheritance, genetic traits that are passed on to offspring
4. time, certain trains will become more common over time

what are some reasons for natural selection?

overpopulation, changing environment or habitat, resource competition, and predators

what are the types of natural selection? (think Deranged Seahorses Damage Ships) what are their definitions?

1. Directional Selection, the average shifts toward one of the extreme, homozygous phenotypes
2. Stabilizing Selection, the average, heterozygous phenotype is most favored
3. Disruptive Selection, both extreme, homozygous phenotypes are favored
4. Sexual Selection, males and females in a population have different phenotypes

what are the agents/mechanisms of evolution? (think Never Make Noodles Greasy)

1. Natural selection, organisms with helpful traits pass them on to their offspring, which helps them with their survival and reproduction
2. migrations, individuals and their genetic material move between different populations
3. non-random mating, inbreeding or organisms choose mates based on traits
4. genetic drift, change in genetic frequency due to random chance

what is the bottleneck effect?

an event like a natural disaster significantly reduces the population, creating random genetic changes without regard to adaptation

what is the founder effect?

when a small group splits off from the main colony, causing the allele frequency to change

what are some good evidence of evolution? (think Elongated Horses Find Berries) what are their definitions?

1. embryology, studying early embryos of animals to look for similarities
2. homologous structures, structures that look similar but have different functions,
3. fossils, preserved traces of prehistoric life
4. biochemistry, DNA sequencing for similarities between species

what is phylogeny?

the evolutionary history of organisms

what is allele frequency?

how common a specific allele is in a population expressed as a fraction expressed in decimal form