Evolution Biology Unit Test

Evolution

Evolution

• the process by which different kinds of living organisms are though to have developed and diversified from earlier forms

• evolution usually refers to a process that produces a more complex organism

Aristotle

• was known for being the first attempt to classify animals into groups

Linnaeus

• extended ideas for classification of plants + animals based on anatomy/physiology

• recognized similarities and differences between organisms

• binomial nomenclature

Count Buffon

• challenged the idea that life forms are unchanging

• He noted similarities between humans and apes, speculates that they have a common ancestor

Lamarck

• compared current animal species with fossils

• observed the line of descent/progress - a series of fossils lead to modern species

• species increase in complexity overtime

• “the inheritance of acquired characteristics”

  • describes the characteristics acquired during an organisms lifetime can be passed onto its offspring

Cuvier

• catastrophism

  • catastrophes occurred which formed different species

  • developed the science of palaeontology

  • found that each stratum is characterized by a unique group of fossil species

  • the deeper the stratum, the more dissimilar from modern life it will be

Malthus

• looked at populations and graphed relationships to resources

• as population increases, there will be more competition (survival of the fittest)

Lyell

• rejected catastrophism

• proposed that geological processes occur at the same rates in the past that they do today in a process called uniformitarianism

• slow, subtle processes could result in substantial processes

Natural Selection

• describes a process of change in a population of organisms over many generations

• this chance happens because individuals who have inherited traits survive and pass alleles to offspring

Mutations

• a change in genetic material of an organism

• leads to new alleles in a species and are a source of new genetic variation

• as a result, traits are inherited among generations

Selective advantage

• genetic advantage of one organism over its competitors

• leads to an organism having the better chance for survival and reproduction

Selective Pressure

• environmental conditions may select for or against certain characteristics

Wallace

• individuals with traits that help them survive in their local environments were more likely to survive to pass these traits onto offspring

• survival of the fittest

  • organisms that are fittest leave the most offspring so those organisms win the struggle for survival

Darwin

• Individuals that are better suited to local conditions survive better to produce more offspring

• his observations become important to his theory of evolution by natural selection

• organisms produce more offspring than can survive. Therefore, organisms compete for limited resources

Adaptations

• a structure, behaviour, or physiological process that helps an organism survive and reproduce viable offspring in a particular environment

• Structural - related to physical features

• Physiological - chemical functions they perform

• Behavioural - an adaptation that involves activities that helps an organism survive

Variation

• are structural, functional, or physiological differences between individuals

• not all variations become adaptations

Non random mating

• mate selection based on a particular phenotype or due to inbreeding

• individuals choose mates based on physical and behavioural traits

Inbreeding

• when closely related individuals breed together

• increases frequency of homozygotes

• harmful recessive alleles will be expressed

Genetic Equilibrium

• a population in which an allele frequency remains the same over generations

Allele Frequencies

• the percentage of any specific allele in a gene pool

Macro Evolution

• evolution on a grand scale

• changes occur over a long period of time

Micro Evolution

• small scale evolution

• change in gene frequencies within a population overtime

• changes may form and lead to new species

Embryology

• the study of early, pre-birth stages of an organisms development

• we use embryology to study relationships between animals

• different organisms will show similar stages of embryonic development

Homologous Structure

• have similar structural elements and origin, but serve different purposes

Analogous Structure

• structures that do not have common evolution origin, but serve the same purpose

Biogeography

• study of past and present geographical distribution of organisms

• geographically close locations will have populated species more closely related than locations distant from each other

Fossil Records`

• reveals 3 pieces of evidence that support evolution

  • Fossils found in young layers of rock are more similar to modern species

  • Fossils appear chronologically by rock layers

  • not all organisms appear in the fossil record at the same time

Transitional Fossils

• certain types of fossils that show links between groups of organisms

Artificial Selection

• humans can select for specific traits, reducing genetic diversity

• the organisms that are produced, are produced with the goal of containing the same genetic information in order to produce similar organisms

Prezygotic Isolating Mechanisms

• prevent species from mating or prevent fertilization of eggs if individuals from different species attempt to mate

Postzygotic Isolating Mechanisms

• prevent the hybrid zygotes from developing into a viable and fertile organism

Species

• a population whose individual members can interbreed and produce viable offspring who can also interbreed

Speciation

• is how a new species is formed, and its a continuous process

Sexual Selection

• a mode of natural selection based of competition between male completion and female selection

Natural Selection

• certain individuals have a better chance of survival based on their fitness

Stabilizing Selection

• favours intermediate phenotypes

• reduces variation and improves adaptation

Directional Selection

• favours one extreme over the other

Disruptive Selection

• favours extremes

• intermediate phenotypes become eliminated

The Bottleneck Effect

• changes in gene distribution that result from a rapid decrease in population size

• only a fraction of the alleles are still present after the population decrease

• gene pool loses diversity

The Founder Effect

• a change in the gene pool that occurs when a few individuals start a new isolated population

• founders will carry some, but not all alleles from the original gene pool

• diversity in the new gene pool is limited

Genetic Drift

• changes in allele frequencies due to chance events in a breeding population

• when there is a small population, you are less likely to see gene pool of population

• when there is a large population, you are more likely to see gene pool of population

Mutations

• changes that happens in the DNA of an individual

• Heritable mutation has potential to affect an entire gene pool

Gene Flow

• movement of alleles from one population to another

• new alleles are brought into the population

Sympatric Speciation

• populations within the same geographical areas diverge and become reproductively isolated

• chromosomal changes and non-random mating influence gene flow

Evolutionary Change

• evolutionary biologists are constantly trying to determine the speed at which evolution occurs

Gradualism

• evolutionary change is slow and steady

Punctuated Equilibrium

• long periods of stasis that are interrupted by periods of divergences

Divergent Evolution

• species who are once similar to an ancestral species diverge or become increasingly distinct

Convergent Evolution

• similar traits arise due to different species having to adapt independently to similar environmental conditions

Allopatric Speciation

• a population split into groups by a geographical barrier, causing change in allele frequencies

Adaptive Radiation

• the diversification of a common ancestral species into a variety of differently adapted species

Zygote Morality

• interbred species may stop the development of the zygote

Hybrid Inviability

• first ten hybrid might be viable, but gen 2 isn’t

Hybrid Infertility

• aka. Hybrid Sterility

• Meiosis doesn’t produce normal gametes

Habitat Isolation

• species live nearby to another, but different habitats

Mechanical Isolation

• anatomically, the organisms are incompatible

Gametic Isolation

• gametes are unable to fuse to form a zygote

Behavioural Isolation

• different species have matin rituals specific to their species

Temporal Isolation

• temporal = time

• timing of mating affect the mating of species