Evolution Chapters 15/16

Intro Video =PLISBHwlJXpn2bmLjfiShKcIHpBP cov24Ohttps://youtu.be/FpfAZaVhx3k?list =PLISBHwlJXpn2bmLjfiShKcIHpBP cov24O =PLISBHwlJXpn2bmLjfiShKcIHpBP cov24Ohttps://youtu.be/FpfAZaVhx3k?list =PLISBHwlJXpn2bmLjfiShKcIHpBP cov24O

Evolution A change over time A process by which modern organisms have descended from ancient organisms Theory- a broad, well tested explanation that unifies a broad range of observations A change over time A process by which modern organisms have descended from ancient organisms Theory- a broad, well tested explanation that unifies a broad range of observations

Earth’s History More than 4 Billion years old Fossils- preserved remains of ancient organisms Many modern life forms appear to be modifications of fossil forms More than 4 Billion years old Fossils- preserved remains of ancient organisms Many modern life forms appear to be modifications of fossil forms

Theories of Evolution Three Scientists Lamarck Malthus Darwin Three Scientists Lamarck Malthus Darwin

Lamarck French Scientist Proposed that acquired traits were passed on to offspring

Acquired Trait- one that is not determined by genes, instead arises over time by experience or behavior –Example- developing large muscles Disproved by current knowledge of genetics Acquired Trait- one that is not determined by genes, instead arises over time by experience or behavior –Example- developing large muscles Disproved by current knowledge of genetics

Malthus Stated that if the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone

Charles Darwin British Scientist Sailed on ship HMS Beagle on trip to explore S. America Was the Naturalist on board, collecting plant and animal samples British Scientist Sailed on ship HMS Beagle on trip to explore S. America Was the Naturalist on board, collecting plant and animal samples

Darwin’s Work While on the Beagle, Darwin collected and recorded information about all types of living species Back in Britain he analyzed his observation and published The Origin of Species While on the Beagle, Darwin collected and recorded information about all types of living species Back in Britain he analyzed his observation and published The Origin of Species

Darwin’s Theories Descent with Modification- newer forms of life are modified descendents of older species Modification by Natural Selection- states how evolution is occurring Descent with Modification- newer forms of life are modified descendents of older species Modification by Natural Selection- states how evolution is occurring

Theory Part 2 Concepts Natural Selection- organisms best suited to their environment will reproduce more successfully Adapt- a change in a population in response to the environment Natural Selection- organisms best suited to their environment will reproduce more successfully Adapt- a change in a population in response to the environment

Fitness- an individual’s genetic contribution to the next generation –High fitness= more offspring Survival of the fittest- competition for food and living space will only allow for those best suited to environment to reproduce Fitness- an individual’s genetic contribution to the next generation –High fitness= more offspring Survival of the fittest- competition for food and living space will only allow for those best suited to environment to reproduce

Evidence of Evolution Homologous Features Analogous Features Vestigial Structures Conserved Genes Similarities in Embryos Macromolecules Homologous Features Analogous Features Vestigial Structures Conserved Genes Similarities in Embryos Macromolecules

Homologous Features Similar features that have slightly different mature forms but originated from a common ancestor –Example- forearm of mammals Similar features that have slightly different mature forms but originated from a common ancestor –Example- forearm of mammals

Analogous Feature Have same function, but have different development –Example: Wings on bird and insect

Vestigial Structures Organ that serves no current purpose in organism, but is believed to have one in ancestor –Examples: Tailbone in humans Appendix in humans Pelvic bones in whales Organ that serves no current purpose in organism, but is believed to have one in ancestor –Examples: Tailbone in humans Appendix in humans Pelvic bones in whales

Conserved Genes A gene that remains unchanged within DNA, but is turned off and not used –Example: hind legs in whales

Similar Embryos During early fetal development, vertebrates all appear the same

Macromolecules All have DNA as basis Similar amino acid sequence that make up proteins –More similarities the closer related the two organisms are

Patterns of Evolution Co-evolution Convergent Divergent Co-evolution Convergent Divergent

Coevolution Changes in two or more species in close association with each other –Example- plant and animal pollinators Changes in two or more species in close association with each other –Example- plant and animal pollinators

Convergent Occurs when the environment selects for similar phenotype, even though ancestry is very different –Example- body shape of dolphins and sharks

Divergent Two related species becoming different from one another Two Types –Adaptive –Artificial Two related species becoming different from one another Two Types –Adaptive –Artificial

Divergent Adaptive- change is in response to habitat –Example: Galapagos finches Divergent Adaptive- change is in response to habitat –Example: Galapagos finches Divergent Artificial- other interference speeds up differences (breeding) –Example: Dog breeding

Genetic Equilibrium Population Genetics- looking at evolution from a genetic point of view Population- members of a species that live in the same area and make up a breeding group Population Genetics- looking at evolution from a genetic point of view Population- members of a species that live in the same area and make up a breeding group

In normal circumstances the percentages of a particular trait remain constant –Equilibrium In normal circumstances the percentages of a particular trait remain constant –Equilibrium

Disruption of Equilibrium Mutation Genetic Drift Migration Non-random Mating Natural Selection Mutation Genetic Drift Migration Non-random Mating Natural Selection

Mutation- any change to DNA –Can affect the protein made which can affect the individual and their offspring Mutation- any change to DNA –Can affect the protein made which can affect the individual and their offspring Genetic Drift- allele frequencies (%) change due to chance or random events –Example- Natural disasters

Migration- net movement in or out of a population –Immigration- moving into a population –Emigration- movement out of a population Migration- net movement in or out of a population –Immigration- moving into a population –Emigration- movement out of a population Migration creates gene flow Gene Flow- movement of genes from one population to another

Non-random Mating- mating in small populations –Leads to higher occurrences of disorders –Example- Amish Non-random Mating- mating in small populations –Leads to higher occurrences of disorders –Example- Amish

Natural Selection Traits being selected for or against Three Types –Stabilization –Directional –Disruptive Traits being selected for or against Three Types –Stabilization –Directional –Disruptive

Stabilization Selection Type of natural selection in which the average form is being selected for

Directional Selection Type of natural selection in which one extreme is being selected for, creating movement in one direction

Disruptive Selection Type of natural selection in which the average is being selected against and both extremes are being selected for

Formation of Species Speciation- process of forming new species Morphology- internal and external structure and appearance –Scientists use this as basis for classifying species Speciation- process of forming new species Morphology- internal and external structure and appearance –Scientists use this as basis for classifying species

Biological Species Concept- A species is a population that can interbreed, but not breed with other groups

Isolating Mechanisms Mechanisms that can cause new species to form Two Types –Geographic –Reproductive

Geographic Isolation- having a physical barrier between groups –Example: river, canyon, mountain

Reproductive Isolation- barrier to successful breeding Examples: different mating calls, different mating seasons Reproductive Isolation- barrier to successful breeding Examples: different mating calls, different mating seasons

Rates of Speciation Gradual- slow change over time –Lots of intermediates in fossil record Punctuated- sudden shift in fossil record –Could be caused by natural disaster or other sudden change to environment Gradual- slow change over time –Lots of intermediates in fossil record Punctuated- sudden shift in fossil record –Could be caused by natural disaster or other sudden change to environment