EVOLUTION Change in a species over time

Diversity Huge variety of animal and plant life - living organisms as well as fossils

Adaptation Plants and animals were well suited to the environments in which they lived physical and behavioral traits enabled them to survive

Galapagos Islands Finches: type of bird in the Galapagos isolated on islands so these birds demonstrated the ability to adapt to environmental changes Rosemary and Peter Grant

Other scientists support of evolution Anatomists: study of structure of adult animals Homologous Structures: similar bony structures in different organisms develop from the same type of tissue in an embryo

Other scientists support of evolution Analogous Structures: similar in function, but different in embryonic development

Other scientists support of evolution Embryology: looked at embryo’s of different organisms and noted similarities

Other scientists support of evolution Vestigial Organs: structures that appear to have lost their function in an organism

Other scientists support of evolution Geologic Explanations: the face of the Earth can change, why not life on earth?

Darwin’s Findings Overproduction: capacity of every species to produce more offspring than can survive Fitness: species have to reproduce and pass on their genes successfully to survive

Competition Struggle for existence Between species Within species For food, water, shelter

Variation Differences between the members of a species make every individual different from every other individual

Adaptations “Survival of the fittest” Those best adapted to the environment will survive longer and reproduce more successfully than individuals less adapted

Natural Selection Favorable variations will be passed on Unfavorable variations will be eliminated from future generations

Speciation Results from accumulated variations in an isolated population: new species are formed Each living species is descended from other species over time and share a common ancestor: ADAPTIVE RADIATION

How fast does evolution occur? Gradualism: occurs slowly over time (millions of years): Darwin’s theory supports this Punctuated Equilibrium: species stays the same for a long period of time. The appearance of a new species disrupts the balance allowing for a short period of rapid evolution: Steven J. Gould

How Does Variation Happen? Population Genetics: population: group of individuals of the same species, living in the same locations and capable of reproducing Gene Pool: mixture of all possible alleles within a population can determine the frequency of any allele in a gene pool (1 in one million to 100%)

How Does Variation Happen? Mutations: changes in DNA that changes the information carried by the gene can be positive or negative mutations (may or may not survive)

How Does Variation Happen? Gene Recombination: occurs during sexual reproduction when genes from two parents are mixed to produce offspring

How Does Variation Happen? Migration: when an individual leaves a population and moves to a new population bringing their genes to the new gene pool and taking away genes from the old gene pool

How Does Variation Happen? Genetic Drift: occurs in small populations, not large ones bad because decreases the variation in the gene pool if only a few organisms have certain alleles and they are destroyed before they have reproduced, the alleles are lost

How Does Variation Happen? Hardy-Weinberg Law does not exist in nature, just tells us under what conditions we can stop evolution mathematical analysis of allele frequencies No evolution under the following conditions: population must be large Individuals cannot migrate mutations cannot occur Reproduction must be completely random

Types of Speciation Isolation: something that prevents two groups of the same species from interbreeding new gene pools evolve

Types of Speciation Geographic Isolation: happens when a species is separated by some natural barrier such as a desert, mountain or body of water the species adapts to the environment in which it lives

Types of Speciation Reproductive Isolation: When a species becomes separated, goes through evolution and loses the ability to interbreed

Convergent evolution Organisms not closely related develop analogous structures due to adaptation to their environment

Coevolution When two species evolve in response to one another either competitively or cooperatively flowers and bees: flowers have adaptations that attract bees

Bacterial Resistance to Antibiotics Mutations have occurred in bacteria that allow them to resist antibiotics and survive. The bacteria that survive are able to reproduce and pass on the mutation to their offspring, creating a generation of bacteria that are resistant to antibiotics

Scientists Stanley Miller and Harold Urey: 1953 Simulated primitive conditions on earth to create organic compounds

Heterotroph Hypothesis Lynne Margulis: U Mass Amherst Primitive atmosphere: ammonia, methane, water and hydrogen gases Organic Compounds: Simple sugars and amino acids formed by combining inorganic raw materials in a “hot, thin soup” Aided by heat and electricity

Heterotroph Hypothesis Aggregates: clusters or groups of complex molecules, absorbed simple organic raw materials from the environment for food: heterotrophs Heterotroph to Autotroph: heterotrophs performed anaeorbic respiration creating CO2 because there was no oxygen in the atmosphere

Heterotroph Hypothesis Increased amount of CO2 lead to evolution of organisms who could use CO2 produce their own organic compounds Anaerobes to aerobes: Once the organisms were producing their own food through photosynthesis, oxygen was added to the atmosphere and the heterotrophic organisms evolved to be able to use the oxygen to make larger amounts of energy than they could using anaerobic respiration