Biology- Evolution

gradualism

(HoET) geologists hutton and lyell first suggested that the planet was much older than previously thought; began to find evience that changes were slowly, but constantly taking place

lamarck

(HoET) one of the first scientists to propose a mechanism for evolution; changes in a population or organisms over time. included tendency towards perfection, use and disuse, and inheritance of aquired traits

malthus

(HoET) published an essay that had a huge impact on Darwin. proposed that organisms over-reproduce

darwins 4 basic principles

1) members of a polulation often vary greatly in their traits 2) variations (traits) can be inherited from parents to offspring 3) all species are capable of producing more offspirng than environment can support 4) variations that increase reproductive success will have greater chance of being passed on than those that do not incerase reproductive success

darwins theories

1) organisms with favorable traits tend to survive and reproduce; thereby leaving more descendents than other indiviuals 2) this will result in an accumulation of these traits in the offspring, changing the original genetic makeup of the population

species

a group of similar organisms that breed with one another and produce fertile offspring.

scientific theory

a well supported, testable explanation of phenomena that have occured in the natural world

isolating mechanisms

allow for gene pools to become seperate so they can form a new species.

natural selection

allows evolution to occur, a mechanism for change that occurs when organisms with favorable charcteristics for a partiular environment survive, reproduce, and pass these characteristics on to offspring. called survial of the fittest by darwin

adaptation

any trait that aids in the survival and reproduction of an organism. Ex: cactus thorns, camouflage, antibiotic bacterial resistance. a positive mutation that provides a survival advantage

reproductive isolation

as a new species evolves, polulations become reproductively isolated from each other. prezygotic or postzygotic

bottleneck effect

cause of genetic drift where large portion of polulation destroyed in a disaster, so the remaining organsims are the only alleles, leading to a change

founder effect

cause of genetic drift where segment of population moves to new habitat, like the religious communities where they exchange brides

artificial selection

choosing to breed cows that produce the most milk or the fastest horses

homologous structure

comparative anatomy. appendages that are very similar in structure, but differ in function. different mature forms, but develop from the same embryonic tissues. ex: human arm/dolphin fin/bat wing

analogous structure

comparative anatomy. not all similar features are evidence of common ancestry. they can be used for the same purpose and can be superficially similar in construction but are not inherited from a common ancestor. they show that functionally similar figures can evolve independently in similar environments. ex: wings of birds/insects (same purpose, different structure)

vestigial structure

comparative anatomy. structure that is reduced in function of a living organsim, but may have been used by an ancestor. a structure may become this when organism changes in form or behavior. homologous structure that is so reduced in size that they no longer function. ex: ostrich wing, cave fish eyes, human appendix

darwins legacy

did not publish findings for years. released "origin of species" still considered one of the greatest scientific studies ever

history of evolutionary theory

during 1700s several scientists challenged idea of world without changes. very important to darwins work

charles darwin

english naturalist who collected data on a 5 year journey around the world on the USS beagle. made observations and collected data. used data to propose hypothesis about how life changes over time to explain diversity he saw. are that had the greatest impact on him was galapagos islands due to differences in same animals living on different islands

charles lyell

explained that the geological processes seen happening on the earth now have shaped earth's geological feature over long periods of time

alfred wallace

formed identical hypotheses based on his research. sent his manuscript to darwin. and finally darwin was persuaded to publish his own conclusions. published own theory of evolution by natural selection about the same time as darwin

evolution

heritable changes in population of organisms over time. founder of modern [term] theory is Charles Darwin. theory of it is one of he most fundamental concepts in Biology (simple dogma). must be mechanisms for genetic changes to occur. process by which modern organisms have descended from ancient organisms

descent with modification

idea that each living species has descended with changes over time from other species

use and disuse

lamarck; changes in size and/or shape of a structure in an organism was a response to this. structures used a lot grew bigger and things used less got smaller

inheritance of acquired traits

lamarck; one of the crazier ones; traits such as getting a tattoo or getting buff will be passed on to offspring (PD mutations). ex: a giraffe stretches its neck to get food, and its offspring also have long necks

tendency toward perfection

lamarck; organsims were continually changing in order to live more successfully

speciation

may occur as organisms survive and adapt. formation of new species. for it to occur, population must diverge and then be reproductively isolated. two types: allopatric and sympatric

mutation

mechanism for evolution; change in DNA. although people are most aware of harmful ones, sometimes resulting change in phenotype may be beneficial to an organism under certain conditions. if the change occurs in the gametes, this change will be passed onto the offspring of that organism

genetic drift

mechanism for evolution; describes a situation in which change in a population is magnified because the population size is very small. causes include bottleneck effect and founder effect

diploidy

mechanism for evolution; most organisms are diploid, which allows for increased genetic variation in a population. heterozygote advantage- seen in sickle cell allele and malaria. recombination- leads to increased genetic variation as a result of crossing over during prophase of meiosis

gene flow

mechansim for evolution; occurs when organisms from one commuity migrate to another. this introduces new alleles into the population which can lead to a change in the genetic make-up of the population. (when you migrate you take your genes with you)

polygenic traits

natural selection can affect the distributions of phenotypes in three ways: directional selection, stabilizing selection, and disruptive selection

single gene traits

natural selection on these can lead to changes in allele frequencies and therefore to evolution. ex: color change in lizard population

diploid

organism with double set of chromosomes

over-reproduce

organisms reproduce at a greater rate than resources can supply. if, in that species, it is less likely to reach adulthood, more offspring are produces as a precaution. if an animal is at the top of the food chain they generally only have one or two babies at a time

punctuated equilibrium

pattern of evolution characterized by long periods of stability interrupted by brief periods of rapid change. it is controversial but known that evolution does occur at different rates

allopatric speciation

physical barrier divides on polulation into two or more. ex: abert and kaibab squirrels of grand canyon

directional selection

polygenic trait where individuals at one end of the bell curve have higher fitnes that those in the middle or other end. ex: birds with bigger beaks selected over medium and small

disruptive selection

polygenic trait where individuals at the ends of the curve have the higher fitness. if it lasts long enough it can cause the curve to split and create ends distinct phenotypes. ex: finches have beak sizes- large and small selected over the medium beak sizes

stabilizing selection

polygenic trait where individuals in the middle have the highest fitness causing the curve to narrow. ex: birth weight- babies in middle are more likely to survive than smaller or larger

thomas malthus

predicted that the human population would grow faster than the resources needed to sustain it and organsims over reproduce. population brought down by war, famine, and disease

fossils

preserved bones and traces of organisms that provide evidence for how life changes over time. provide a record of earlier life and evidence that evolution has occurred. provide evidence about the earths climate, geography, and life forms. almost 90% of earths history occurred during the precamlorian time. there are two major classes or traits when studying transitional [blank] derived traits and ancestral traits

prezygotic reproductive isolation

prevents reproduction by making fertilization unlikely becuase of geographic, ecological, behavioral, temporal, or other differences. ex: meadowlark in same range with different mating calls

james hutton

proposed that the earth is shaped by geolgical forces over extremely long periods of time, and that earth is very old (gradualism)

jean-baptiste lamarck

proposed that the selective use or disuse of an organ led to a change the organ that was then passed on to the offspring

macroevolution

refers to large-scale evolutionary pattern and proccesses that occur over long periods of time. extinction, adaptive radiation (divergent evolution), convergent evolution, coevolution, and punctuated equilibrium

comparative biochemistry

scientist use DNA studies to determine the evolutionary relationship between organims. the more similar the DNA, the closer the evolutionary relationship

comparative anatomy

scientists use anatomical studies of different organsims for evidence of evolutionary relationships

embryology

similarities in the structures of developing embryo of different orgamisms are considered to be proof of a close evolutionary relationship

sympatric speciation

species evolves into new one without a physical barrier. seen in insect and plant species

fitness

the ability of an organism to survive and reproduce in its environment. based on adaptations. inablility of an organism to adapt to changes in its environment will lead to its extinction becuase of natural selection

common descent

the idea that all species, living and extinct, were derived from common ancestors linked by a single "tree of life"

adaptive radiation or divergent evolution

the process where a single species has evolved through natural selection into diverse forms in a short period of time that live in different ways. often folows mass extinctions. ex: finches and tortoises of galapagos

extinction

the species has died out. more than 99% of all species that have ever lived are. darwin proposed possible reasons with competition for resources and environmental change. mass [term] has occured several times, wiping out entire ecosystems. meteorites, volcanic action, and tectonic plate movement have been blamed. mass extinctions clear the way for evolution of other species, ex: mammals

ancestral traits

trainsitional fossil. more primitive features such as teeth and tails, that do appear in ancestors

derived traits

transitional fossil. newly evolved featres such as feathers, that do not appear in the fossils of common ancestors

dna sequencing

used to determine evolutionary relationships

biogeography

variations are seen in the same types of animals based on their environment. also, there are some organisms that live in very different locations but they have similar characteristics because their environments are similar (climate, food sources, etc)

coevolution

when a change in one organism leads to a corresponding change in another organism. ex: orchid/bee/moth

postzygotic reproductive isolation

when fertilization has occurred but a hybrid offspring cant develop or reproduce; prevents offspring survival or reproduction. ex: mule, liger

convergent evolution

when unrelated species evolve similar traits even though they live in different parts of the world becuase of similar ecology and climate. ex: maraots of south america and rabbit of england. or dolphins, penguins, and sharks are distantly related species that share similar characteristics which help them live in water