Adaptations

 Individual organisms that appear more similar to one another than to the individuals of another, different species  Organisms that are slightly different from one another are a result of genetic variation  Homo sapiens

 Traits that allow plant or animal species to survive in a particular environment.  Variations- differences in genes within a species

 Each trait is determined by one of two alleles  Alleles are different forms of the same gene that contain slightly different genetic info ◦ Two types of Alleles  dominant-will produce a trait that masks the another trait for the same characteristic  recessive- produces a trait that is masked by a dominant trait

 Homozygous- when two alleles are the same either both dominant or both recessive  YY (dominant)  yy (recessive)  Heterozygous- when two alleles are different one dominant and one recessive  Yy

 Phenotype-physical appearance due to many different traits, all similar but not identical  Genotype- combination of all the different genes that determine a species phenotype  Genotype determines phenotype ◦ The combination of different genes determine the physical appearance of an organism

 Genes are responsible for all the traits that allow an organism to be adapted to its environment. The genotype of an individual determines the phenotype of the individual.  Genetic variation ensures that there are many possible genotypes and phenotypes that an organism can possess.  This genetic variation is a result of mutations, recombination of genes, and the random mating of individuals.  When an environment changes, an individual with a specific phenotype may be better suited to adapt to the new environment. This is important because this species will then be more likely to survive and pass their genes to the next generation.

 Genetic variation is the reason why there are many unique individuals of a species in a population.  Genetic variation allows a population of species to survive different environmental pressures.  In the cactus population, there were cacti with a few spines and some with many spines. All of these individuals would survive if the Sun is not too intense.  Likewise, in the penguin population, there coexist numerous penguins with different densities of bones.

Adaptations

 Environmental Pressures- changes in the environment that the individuals need to adapt to  Environmental factors effect whether or not a species will survive and reproduce effectively ◦ Weather ◦ Temperature ◦ Habitat ◦ Food ◦ Water ◦ Other organisms

 Adapting to environmental changes is necessary for a species to survive  Adaptations occur when an increase in the proportion of the individuals that possess a trait that permits survival

 When adapting to environmental factor changes, one of the slightly different traits may offer a survival advantage to those individuals that have the trait ◦ Giraffe-long neck to eat leaves off taller trees  Those individuals are able to survive and reproduce passing the trait onto the next generation

 Those who do not possess the advantageous trait do not survive  Those who do have the trait survive and continue to reproduce pass on the trait until all individuals possess the trait  Once a advantage trait is now a common gene  Natural Selection (Survival of the Fittest)  Individuals as a whole species adapting to enviro changes  Organisms that are adapted to their enviro tend to survive and pass on their genes to their offspring  Organisms that are not as well adapted to their enviro tend to not survive and to not pass on their genes

 Genetic variation is responsible for all the different traits that an individual possesses.  In our example, there was genetic variation in the trait of bone density. Before the weather turned much colder, all the penguins were living happily.  However, when the environment changed, some individuals were more adapted to the environment than others. Thus, they were more likely to survive and pass on their genes.

 If members of a species did not have different traits no natural selection could exist because all the members of that species would be equally adapted to each environmental pressure.  However, there is genetic variation in populations and some individuals are more adapted to their surrounds than others. The ones that survive are more likely to pass on their genes.

 Environmental pressures can affect the population because some members are more adapted to the new environment than others.  In the experiment, penguins with more dense bones survived at a higher rate because they were more equipped to deal with the shortage of food.  The environmental pressure can be natural causes (such as temperature and sunlight) or human causes (such as pesticide exposure or antibiotic exposure).

Adaptations

 If individuals cannot adapt to environmental factors and changes they will eventually become extinct.  And we learn about them from their Geologic Record- Fossils

 Scientists who Study the history of animals and plants by looking at fossils.  Fossils- hardened remains of previous life that are found in the crust of the earth- geologic records

 When a new environmental pressure is introduced, some organisms in a population will not survive. The organisms with the genes that are most adapted to the environment will have the highest chance of surviving and passing their genes on to the next generation.  In our example, the change in the climate severely reduced the food source of the penguins. The result was that there was not enough food for all of the penguins in the population to survive and only one penguin survived. Because this penguin cannot mate with another penguin and reproduce, the population of penguins will become extinct.