Biology - Unit 8 {Evolution}

Punctuated equilibrium

Short periods of rapid evolutionary change

Gradualism

Slow, steady, and gradual change into another species

Allopatric speciation

Turning into different species due to being in separate areas, “*aloha*”

Sympatric speciation

Turning into different species while being in the same area, “*same*”

Ecological isolation

When species live in the same region but occupy different habitats

Reproductive isolation

When the members of two populations cannot interbreed and produce fertile offspring

Temporal isolation

When species reproduce at different times

Geographic isolation

When two populations are separated by geographic barriers such as rivers or mountains

Behavioral isolation

When two populations are capable of interbreeding but have differences in courtship rituals that involve behavior

Adaptations

the biological mechanism by which organisms adjust to new environments or to changes in their current environment. {Adaptations arise from random mutations}

Stabilizing Selection

When genetic diversity decreases and a population stabilizes on a particular trait {EX: Robins lay only four eggs because too many eggs = malnourished chicks & too little chicks = no viable offspring}

Divergent evolution

Interbreeding species are diverged into two or more evolutionary groups {two species evolving from the same organism}

Natural Selection

The process through which populations of living organisms adapt and change throughout the changes the environment faces.

Evolution

Species adapting over time in response to changing in the environment.

Population Genetics

The study of the genetic composition of populations. Distributions and changes in genotype & phenotype frequency.

Convergent evolution

distantly related organisms evolving similar traits to adapt to similar environments & necessities.

Analogous Structures

Features of different species that are similar in function but not similar in structure {Don't evolve from common ancestors}

Homologous Structures

similar physical features in organisms that share common ancestors but serve for different functions.

Genetic Drift

Migration / variation in genotypes within a small population, allowing it to disappear. {Smaller populations, random events, sudden.}

Selection Pressures

Factors that contribute to natural selection, {which traits will survive better than other traits and why?}

Sexual Selection

the evolution of certain conspicuous physical traits \[such as pronounced coloration, increased size, or striking adornments\] in animals may grant the possessors of these traits greater success in obtaining mates. {Phenotype / behaviors}

Disruptive Selection

When extreme versions of a trait are favored over normal versions of a trait {EX: Gray & Gray and White rabbits are able to blend into rocky entrances better than white rabbits, so white rabbits die off}

Directional Selection

When a single phenotype is favored, causing the allele frequency to continually move in one direction {EX: light colored moths are better camouflage against pristine environment, dark colored moths are better in sooty environment. When england because darker the population shifted from light to dark.}

Fitness

The ability of an animal to survive and reproduce {The quantity of offspring had doesn’t really matter if none of them survive to reproduce themselves}

Charles Darwin

An English naturalist and biologist who transformed the way that humanity thinks about life

Antibiotic Resistance

when germs like bacteria and fungi develop the ability to defeat the drugs designed to kill them.

Transitional Forms

A fossil that shows an intermediate state between an ancestral trait and that of its later descendants is said to bear a transitional feature.

Homologies

similarity of the structure, physiology, or development of different species of organisms based upon their descent from a common evolutionary ancestor.

Vestigial structure

Various cells, tissues, and organs in a body which no longer serve a function.

Artificial Selection

identification by humans of desirable traits in plants and animals, and the steps taken to enhance and perpetuate those traits in future generations.

Cladogram

A diagram used to represent a relationship between a group of animals {Most often based on traits… number of limbs, presence of fur or hair, wings, etc.}

Hardy Weinberg Conditions

Environment having no mutation, random mating, no gene flow, infinite population size, and no selection.

Hardy Weinberg formulas

p^2 + 2pq + q^2 = 1

p + q = 1

Bottleneck effect

Events that limit genetic variation in a population and result in founding populations can lead to genetic drift. {Ex: a lot of rabbits die in a fire, and the remaining rabbits aren’t as genetically diverse.}

Founder effect

the reduced genetic diversity which results when a population is descended from a small number of colonizing ancestors. {When a few individuals find a new area.}

Genetic flow

Any movement of individuals, and/or the genetic material they carry, from one population to another. {Larger population, through migration.}

biogeography

Studies where species live now and where their ancestors lived in the past.

Comparative Anatomy

The study of similar body structures indicating common ancestry.

Comparative Embryology

The study of similarities in developmental stages from fertilization to birth.

Paleontology

Studying fossils that document the intermediate evolutionary stages of many different species groups.

Molecular Biology

The study of all living things on Earth sharing the same universal code in DNA and RNA molecules, which indicates that they share a common ancestor.