Evolution Flashcards
A modified structure seen among different groups of descendants
Analogous structure
Exemplified by forelimbs of bats, penguins, lizards, and birds
Homologous structure
The forelimbs of flightless birds
Vestigial structure
DNA and RNA comparisons may lead to evolutionary trees
Genetic comparisons
Birds and Butterfly wings have the same function but different structures
analogous structures
A body structure reduced in function but may have been used in an ancestor
Analogous structure
(A) Ink of octopus
Behavioral
(A) Hummingbirds long bill
Structural
(A) Honeybee’s dance
Behavioral
(A) migration of geese
Behavioral
(A) plant stems growing towards light
Physciological
(A) Proteins in spider’s web
Physciological
(A) Gila monsters venom
Physciological
(A) efficiency of birds lungs in high altitudes
Structural
(A) Bird’s song
Behavioral
The hardy Weinberg Principle
- Large population
- No mutations
- random mating
- no movement
- no natural selection
The more individuals in a population, the smaller effect of genetic drift
Large population
No changes to genes means new alleles are not introduced into the population’s gene pool
No mutations
Each individual in a population has the same chance of passing on its alleles
Random mating
No new alleles are introduced into the population’s gene pool by new individuals
No movement
No phenotype can have a selective advantage over another- all individuals have equal fitness
No natural selection
H-W equalibrium
- occurs when population is not evolving
- allele frequencies are constant from one generation to the next
- occurs when a population meets 5 conditions
What conditions can alter the H-W principle of equalibrium
- Mutations happen
- Gene flow
- Select mating
- Small population
- A mode of selection
Mode of selection
Any selection for or against alleles will alter their frequencies in a population
Adaptation
- Characteristics that give an organism a better chance of survival
- Special traits that help living organisms survive in a particular environment.
Reasons for Adaptation
- To suit their habitat
- For protection
- For attack
- For feeding
- For movement
Structural Adaptation
external characteristics
Behavioral Adaptation
differing ways of reacting to the environment
Physiological Adaptation
internal characteristics
Gene pool
total genetic information available to a population of organisms
Allele frequency
number of times an allele occurs in a gene pool
Species
a group of organisms that can interbreed and produce viable offspring
- example of gene pool
Natural selection on single gene traits
can lead to changes in allele frequencies and, thus, to change in phenotype frequencies
Natural selection on polygenic gene traits
can affect the relative fitness of phenotypes and thus produce three types of selection
Stabalizing selection
when natural selection chooses the average form of a trait as most fit.
Directional selection
when natural selection chooses an extreme form of a trait as most fit.
Disruptive selection
when natural selection chooses both extreme forms of a trait as most fit. Could cause two different species
Gene flow
Migration of organisms from one population to the next increases the genetic variation of the population
founder effect
a few individuals from a population start a new population with a different allele frequency than the original
Genetic drift
A change in the gene pool of a population
Genetic Bottlenecks
- some disaster wipes out the majority of a population
- By chance, the survivors may only represent a certain part of the old gene pool
- This population will have a different makeup than the original population
over reproduce
Predators eat the runts so the animal needs to overpopulate to ensure the population stays the same
Variation
There is variation among individuals of the same species
Darwin’s Adaptation
The ones with the advantages will out compete the others and live to reproduce and pass on their advantage to their offspring.
Survival of the fittest
Because more organisms are produced that can survive, they must compete
Natural Selection
Organisms with variations most suited to their environment survive and leave more offspring
Principle of common descent
All species living and extinct are descended from ancient common ancestors
all living things are linked
There is a heterozygous advantage to being a carrier of sickle cell anemia
Stabalizing
Brown fur is (p) dominant over white fur (q). White mice are more easily seen by predators
Directional
What is meant by “Natural Selection”
- The survival of the fittest
- The organism with the best traits will live the longest
- Adaptation
- able to interbreed and have viable offspring
- variation
Does natural selection act upon an organism’s genotype or phenotype in a population
Genotype (makes you the way you look and gene pools and allele frequencies are changing)
What was Darwin’s first observation when he traveled to the Galapagos that made him begin to think about the world around him
The species on each island. The sizes and shapes of the beaks on the finches were different. Connections w/ ancestors and lving organisms
What conclusions can be drawn based on the evidence of the Fossil Record
- provide a record of species
- shown records of evolution
- shows ancestory
What evidence for change over time exists int the study of BioGeography
The location where we find animals and plants
What evidence for change over time exists in the knowledge of Vestigial Structures
- certain structures that we don’t use anymore
2. shows evolution
What evidence for change over time exists in the knowledge of homologous structures
They all came from the same ancestors because they have similar structures
What evidence for change over time exists when comparing biomolecules
- compare blood samples of organism to get DNA sample to see if these animals are related
refers to the situation where different species may live in the same area, but properties of individuals prevent them from interbreeding
reproductive isolation
The black birds mating call is odd compared to the red bird so they wont mate
Behavioral isolation
There is a mountain between the two species
Geographical isolation
it keeps individuals of different species from interbreeding, even if they live in the same environment
fall cricket v spring cricket
Temporal isolation
artificial selection
s the intentional breeding of plants or animals
