Flashcards in What is Evolution? Deck (20):
what is evolution?
a change in allele frequencies in a population over time
ex. insects are exposed to insecticide and only the organisms with the red chromosome that has the gene that creates resistance to insecticide survive and go on to reproduce
what is a genotype?
all the genetic characteristics that determine the structure and functioning of an organism
what is a phenotype or trait?
the physical expression in an organism of the interaction between its genotype and its environment
what is a population?
the group of organisms of a particular species that inhabit a particular area
what is microevolution?
a change in a population's gene pool
- small scale
- happens within a single population
- can be accomplished by natural selection --> a trait within a species is selected
what is macroevolution?
evolution change on a grand scale
- major evolutionary changes over time
- origin of new organisms/species
- whales descending from land mammals
what are the four rules of evolution?
1) variation exists in a population BEFORE any selection
2) populations evolve, NOT INDIVIDUALS
3) selection is NOT random
4) changes (ex. evolution) happen across generations, not within a generation
what four things can cause evolution? can cause allele frequencies to change?
2) genetic drift (random events)
3) gene flow (migration)
4) natural selection (adaptive evolution)
what are three examples of things that are NOT biological evolution?
1) individual development:
changes in form, behavior, or physiology as an individual grows
- changes occur within individuals, not populations or species
2) ecosystem change:
changes in species composition and abundances, ecological succession
3) cultural evolution:
changes in ethics, politics, economics, technology, ideas
- ideas are transmitted through learning, not genetic change
- things that you have to learn are not evolution, it's cultural evolution
what is cultural evolution? what is an example?
Researchers in 1950’s left sweet potatoes on beaches to lure macaques out of the forest.One young macaque discovered that she could wash sand off potatoes by rinsing them in water (new behavior).Her siblings and mother soon learned the behavior, and over time the entire macaque population gradually learned to wash potatoes by imitation.Macaques also learned how to “season” potatoes with saltwater, use water to sort wheat from sand, bathe in hot springs, and even make snowballs for fun!This is cultural evolution by learning, not biological evolution (in which change occurs because heritable traits are passed from parents to offspring).
why study evolution? (6 reasons)
1) to understand the diversity of life
2) conservation biology
- identify genetically distinct lineages that warrant conservation status
- population size, inbreeding depression, genetic variation
3) fisheries management
fish populations evolve in response to fishing “selection”
6) forensics and paternity analysis
what is effective population size?
is 1000 turtles enough? If there’s a lot of genetic diversity then it’s probably okay but if not then….idk
what is inbreeding?
what is inbreeding depression?
Inbreeding depression is the reduced biological fitness in a given population as a result of inbreeding
Relatives more likely to mate in small populations. Relatives more likely to share copies of deleterious alleles. They produce offspring with 2 copies of deleterious allele. Inbred European viper populations have more birth defects and stillborn young
what is a genetic bottleneck? what are the consequences?
Low genetic variation!
genetic variation accumulates via mutation and recombination...after population crashes, population size may recover quickly BUT…
Genetic variation remains low because mutation and recombination require more time.
Consequence: Populations with low genetic variation cannot evolve in response to changing environments.
ex. cheetah’s are basically clones of each other because such little genetic variation = bad…they’re so similar that they can accept skin graphs from each other
what is fisheries management?
If you’re removing tiny fish then you’re removing the fish that grow slowest, leaving behind the ones that grow the fastest and then they pass on their fast growth rate to the next generation --> Removing the largest fish removes the ones that grow the fastest so the remaining fish will grow slower over time
Fishing not only depletes populations, it can change their life history and cause an evolutionary response
Management recommendation: set both lower and upper limits on size in order to offset effects of selection
agriculture and evolution
- artificial selection has produced or enhanced most of our important agricultural crops and livestock
- genetically engineered crops developed as a means to facilitate weed and pest control
medicine and evolution
- antibiotic resistance: what is actually happening is that the antibiotics are killing vulnerable bacteria, which selects for any mutations that produce resistant bacteria. In other words, the patient is not changing, the bacteria are evolving.
- viruses: evolutionary trees help us understand where a virus came from and how it may have evolved so that we can treat various strains of it (strains are derived from single lineages)
- genetic disorders
how can you screen for genetic diseases?
- determine pathways and proteins impacted by the gene
- look for correlations between diseases and the presence of a specific allele
AKA try to find biological pathways of that gene and if the pathway links to a disease