Warm Up 10/12: Accessing old pathways! Refer to notes OR text for Topic 4/Option C (Ecology) to match the following terms with the correct definitions. Term Definition Organism A) All members of one species in a given area 2) Species B) All populations in a given area 3) Population C) One member of a species 4) Community D) All members of a community plus abiotic factors in the area 5) Ecosystem E) A group of organisms that can potentially interbreed to produce fertile offspring

Term Definition Organism C) One member of a species 2) Species E) A group of organisms that can potentially interbreed to produce fertile offspring 3) Population A) All members of one species in a given area 4) Community B) All populations in a given area 5) Ecosystem D) All members of a community plus abiotic factors in the area

Biological Variation Notes Objectives: -What is biological variation? -What is the relationship between genotype and phenotype? -What are the two types of variation? What are examples of these types of variation?

What is a species? Definition: a group of organisms with similar phenotypes and genotypes, that are capable of producing fertile offspring in the natural environment

What does variation mean in biology? Any difference between cells, individual organisms, or groups of organisms of any species Caused by genetic differences and/or environmental factors Variation in Donax variabilis species (Coquina)

Intraspecific Variation: differences in characteristics within a given species Example: Canis lupis familiaris What are other examples of intraspecific variation?

Examples of Intraspecific Variation

What is genotype? Definition: Genetic makeup of an individual Offspring inherit genotypes from parents Also used to refer to the pair of alleles present at a single locus With alleles A & a, there are 3 possible genotypes : -AA -Aa -aa http://biomed.brown.edu/Courses/BIO48/5.Geno.Pheno.HTML

What is phenotype? Definition: Observable physical, physiological, and behavioral traits of an organism Ex: size & shape, metabolic activities (Ex: lactose intolerance), blood type, etc. Natural selection acts directly on phenotype, and indirectly on genotypes

How to we get from genotype to phenotype How to we get from genotype to phenotype? (AKA How does genotype determine phenotype?)

What are examples of variation in our population? -All members of a single population vary in both physical and behavioral traits Phenotypic traits are either discrete or continuous Physical and behavioral traits differ in how they are defined, measured, and how environmental factors affect them

What phenotypic features do all of these horses have in common with each other?

How are all of these horses’ phenotype different from each other?

Measuring Hand Spans Spread your fingers apart as far as you can Using a ruler, measure the distance between the tips of your thumb and pinky fingers What do you notice about the class’s data?

What if we took class data for biological sex? How many possible categories are there for classifying biological sex in humans? How does this type of characteristic differ from hand span measurements?

Continuous Traits Discrete Traits Traits that change along a continuum; Individuals differ by small degrees. Traits that can only be one of two things; are either present or absent What are other examples of continuous traits? What are other examples of discrete traits?

Continuous Traits Discrete Traits Ex: Height, eye color, hair color, nose shape Ex: widow’s peak, closed vs. open ear lobes, tongue rolling, PTC gene, blood type

Why are some traits continuous? Some traits require multiple genes to be “turned on” Traits are continuous because phenotypes can be affected by environmental factors Ex: Height – nutritional differences can play a role in variation Ex: Skin color – exposure to sun can modify phenotype

Intraspecific Variation What are examples of variation that are NOT heritable? Dyed hair Colored contact lenses Painted nails Tattoos Dogs w/ trimmed ears or cut tails Traits can also be behavioral or biochemical (physiological)

Novelty Seeking Survey: Intraspecific Variation in Behavior Keep individual scores private Complete graph on lab activity sheet Now identify the high and low scores and estimate the average. How would you describe the shape of the graph? What could explain the shape of the graph? Novelty seeking trait: Continuous or discrete? Why?

How are physical traits different from behavioral traits? What are some problems with defining phenotypes for behavioral traits? Compare the graphs from the Novelty-Seeking Survey and the Hand-Span Measurements and Distribution graph. How were the two graphs the same or different?

Some scientists think that many core behaviors (eating, breathing, etc Some scientists think that many core behaviors (eating, breathing, etc.), even personality traits, are inherited at birth, in much the same way as physical traits. Many other scientists share the opinion that differences in the behavior of individuals arise from the interaction of heredity and experience, especially where environmental influences are strong; however, it is sometimes difficult to separate heredity and environmental factors. Why would it be a good idea to be skeptical of simplistic explanations for behavioral traits?