Biol 301 Exam 2

On the Origin of Species

Charles Darwin's book that describes how evolution occurs

Natural Selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates

Adaptation

A trait that helps an organism survive and reproduce

Greek Essentialism

Variation observed were imperfect copies of the transcendental ideal form of the subject

Catastrophism

Successive catastrophies create sudden change

Gradualism

The theory that evolution occurs slowly but steadily

Lamarck's Mechanism

Internal forces and inheritance of acquired traits

Internal Forces

Unknown internal mechanism causes differences between parent and offspring

Inheritance of Aquired Characteristics

Use or disuse of trait alters trait through lifetime, which is then passed to offspring

Alfred Russell Wallace

independently came to same conclusions as Darwin about evolution

Descent with Modification

Each living species has descended, with changes, from other species over time

Mechanism for the Evolutionary Process

Adaptation by natural selection

Blending Inheritance

Early concept of heredity proposing that offspring possess a mixture of the traits from both parents

Mendellian Genetics

Discontinuous Variation; Major mutations were the key to evolution since they cause large phenotypic effects

Biometrician Genetics

Continuous Variation; Evolution proceeded by the gradual accumulation of small changes

Biometricians vs Mendelians

Biometricians were correct

Neo-Darwinism

A revision of Darwin's original theory of evolution to include modern genetics; Heritable Variation x Selection

Speciation

The formation of new and distinct species in the course of evolution.

Systematists

Scientists specializing in describing and categorizing organism groups

Three (Four?) Requirements for Natural Selection

1. More offspring produced than survive
2. Variation among individuals
3. Inheritance of individuals
4. Individuals with favorable characteristics are more likely to survive and reproduce

DNA

A molecule composed of two strands of nucleotides that are wound together into a double helix

Chromosomes

Compact structures consisting of long strands of DNA wound around proteins

Alleles

Different forms of a particular gene

Polygenic

Trait controlled by two or more genes

Pleiotropy

The ability of a single gene to have multiple effects

Epistasis

When the expression of one gene is controlled by another gene

Heterozygous

When an individual has two different alleles of a particular gene

Homozygous

When an individual has two identical alleles of a particular gene

Codominant

When two alleles both contribute to the phenotype

Dominant

An allele that masks the expression of another allele

Recessive

An allele that is masked when a dominant allele is present

Gene Pool

Collection of alleles from all individuals in a population

Random Assortment

The process of making haploid gametes in which the combination of alleles that are placed into a given gamete could be any combination of those possessed by the diploid parent

Haploid

An organism or cell that has only one complete set of chromosomes

Gametes

Sex cells

Mutation

A random change in the sequence of nucleotides in regions of DNA that controls the expression of a gene

Recombination

The reshuffling of genes that can occur as DNA is copied during meiosis and chromosomes exchange genetic material

Evolution

Change in allele frequency over time

Migration

Movement of individuals from one place to another

Genetic Drift

A process that occurs when genetic variation is lost due to random variation in mating, mortality, fecundity, and inheritance

Bottleneck Effect

A reduction of genetic diversity in a population due to a large reduction in population size

Founder Effect

When a small number of individuals leave a large population to colonize a new area and bring with them only a small amount of genetic variation

Selection

The process by which certain phenotypes are favored to survive and reproduce over other phenotypes

Stabilizing Selection

When individuals with intermediate phenotypes have higher survival and reproductive success than those with extreme phenotypes

Hardy-Weinberg equilibrium

condition that occurs when the frequency of alleles in a particular gene pool remain constant over time

Where do Hardy-Weinberg numbers come from

Punnett Squares

Fitness

Genetic contribution to the next generation

Relative Fitness

Fitness compared to other individuals

Directional Selection

Form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve

Disruptive Selection

Form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle

Microevolution

Change in allele frequencies in a population over generations

Artificial Selection

Selection in which humans decide which individuals will breed for particular traits

Industrial Melanism

A phenomenon in which industrial activities cause habitats to become darker due to pollution

Macroevolution

Evolution at higher levels of organization including species, genera, families, orders, and phyla

Phylogenetic Tree

Hypothesized patterns of relatedness among different groups such as populations, species, or genera; depict which groups evolved from other groups

Allopatric Species

The evolution of new species through the process of geographic isolation

Sympatric Speciation

The evolution of a new species without geographic isolation

Polyploid

Condition in which an organism has extra sets of chromosomes

Viscosity

The thickness of a fluid that causes objects to encounter resistance as they move through it

Why is water a solvent

Water is polar

Acid Rain

Rain containing high amounts of chemical pollutants

Solutes

Dissolved substances in water

Semipermeable membrane

Membranes that allow only particular molecules to pass through and reduces free movement of solutes

Osmosis

Movement of water through a semipermeable membrane

Osmotic Potential

The force with which a solution attracts water by osmosis

Osmoregulation

Mechanisms organisms use to maintain a proper solute balance

Hyperosmotic

Tissue solute concentrations are higher than the surrounding water

Hyposmotic

Tissue solute concentrations are lower than the surrounding water

Diffusion of oxygen and carbon dioxide

from high to low concentration
oxygen - high in alveoli
carbon dioxide - low in alveoli

Alveoil

Air sacs in the lungs

Countercurrent Circulation

An adaptation where blood and water flow in opposite directions

Anareobic

A process that does not use oxygen

Thermophiles

Heat loving organisms

Thermal Optima

The range of temperatures in which an organism best performs

Isozymes

Different forms of an enzyme that catalyze a reaction

Cohesion

Attraction between molecules of the same substance

Root Pressure

Transpiration

Evaporation of water from the leaves of a plant

Cohesion-tension theory

Theory that explains how the physical properties of water allow it to move through the xylem of plants

Stomata

Small openings on leaves that are entry points for CO2 and exit points for water vapor

Electromagnetic radiation

Energy from the sun, packaged in small particle-like units called photons

Photosynthetically Active Region

Wavelengths of light that are suitable for photosynthesis

Chloroplasts

Specialized structures within plant cells that allow for photosynthesis to occur

Chlorophyll

Green pigment in plants that absorbs light energy used to carry out photosynthesis

Carotenoids

An accessory pigment, either yellow or orange, in the chloroplasts of plants

Photosynthesis

Conversion of light energy from the sun into chemical energy.

C3 photosynthesis

The most common form of photosynthesis in which atmospheric CO2 is used to form 3-phosphoglycerate, a three-carbon sugar.

C4 photosynthesis

process that first converts CO2 into a 4-carbon molecule in the mesophyll cells

CAM Photosynthesis (Crassulacean Acid Metabolism)

CO2 converted to 4-carbon molecule. Stomata open at night

Homeostasis

Process by which organisms maintain a relatively stable internal environment

Negative Feedback

The action of internal response mechanisms that restores a system to a desired state when the system deviates

Radiation

The emission of electromagnetic waves from a surface

Conduction

The direct transfer of heat from one substance to another substance that it is touching

Convection

The transfer of heat by the movement of a fluid

Evaporation

Liquid to gas

Thermal Inertia

The ability of a material to maintain its temperature

Thermoregulation

Process of maintaining an internal temperature within a tolerable range.

Homeotherms

Organisms that maintain a consistent body temperature

Poikilotherms

Organisms that do not have constant body temperatures

Ectotherms

Organisms that rely on the environment for body temperature