unit 7, 8, and 2 of ap bio vocab

Stromatolites

Oldest known fossils formed from many layers of bacteria and sediment.

Oparin and Haldane

Oparin and Haldane were two scientists who proposed in the 1920s that the primitive atmosphere contained the following gases: methane, ammonia, hydrogen, and water. They believed that these gases collided, producing chemical reactions that eventually led to organic molecules.

Miller-Urey Experiment

Experiment that found that organic molecules can form in a strongly reducing atmosphere.

Sidney Fox

If amino acids present in the early earth, they would have to react together in just the right way to form proteins, one of the essential components of life. In the 1950's and 1960's, Sidney fox performed experiments to see if he could form proteins. He heated dry, purified amino acids that he called "proteinoid." When fox dissolved these protein-like compounds in water, they self-organized into spherical membranes that are semi-permeable and have the ability to grow and divide. These structures created by Fox and other scientists called proteinoid microspheres of protocells. Fox and other scientists believe that perhaps these types of structures were the beginnings of forming a living cell.

Montmorillonite clay

Charged clay surface attracts nucleotides to allow bonds to form and polymerization of RNA

RNA world hypothesis

Hypothesis that describes how the Earth may have been filled with RNA-based life before it became filled with the DNA-based life we see today.

morphological

the branch of biology that deals with the form and structure of organisms without consideration of function

relative age

The age of a rock compared to the ages of rock layers

absolute age

The age of a rock given as the number of years since the rock formed.

radiometric dating

the process of measuring the absolute age of geologic material by measuring the concentrations of radioactive isotopes and their decay products

carbon 14

a long-lived naturally occurring radioactive carbon isotope of mass 14, used in carbon dating and as a tracer in biochemistry.

homologous structures

Structures in different species that are similar because of common ancestry.

analogous structures

Body parts that share a common function, but not structure

vestigial structures

A structure that is present in an organism but no longer serves its original purpose

convergent evolution

Process by which unrelated organisms independently evolve similarities when adapting to similar environments

divergent evolution (adaptive radiation)

process by which a single species or a small group of species evolves into several different forms that live in different ways

similarities in embryology

In early stages of development, many organisms provide evidence that they shared a common ancestry

molecular clock

Model that uses DNA comparisons to estimate the length of time that two species have been evolving independently

Conserved processes

Organisms share many and features that evolved and are widely distributed among organisms today. Structural and functional evidence supports the relatedness of all domains.DNA and RNA are carriers of genetic information through transcription, translation and replication. Major features of the genetic code are shared by all modern living systems. Metabolic pathways are conserved across all currently recognized domains.

conserved structural features

Structures that are present in organisms that show relatedness across biological domains

Charles Darwin

English natural scientist who formulated a theory of evolution by natural selection (1809-1882)

Natural selection

A process in which individuals that have certain inherited traits (phenotype) tend to survive and reproduce at higher rates than other individuals because of those traits.

Fitness

Ability of an organism to survive and reproduce in its environment - measured by offspring produced

differential reproductive success

the tendency of some individuals to have greater reproductive success than other individuals in a population

artificial selection

Selection by humans for breeding of useful traits from the natural variation among different organisms

population

A group of individuals that belong to the same species and produce fertile offspring

allele frequency

Number of times that an allele occurs in a gene pool compared with the number of alleles in that pool for the same gene

gene pool

All the genes, including all the different alleles for each gene, that are present in a population at any one time

Hardy-Weinberg equilibrium

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

null hypothesis

the hypothesis that there is no significant difference between specified populations, any observed difference being due to sampling or experimental error.

mutation

A change in a gene or chromosome.

random mating

no selective mating in which animals chose mate depending on phenotype

natural selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

gene flow

movement of alleles from one population to another

sexual selection

A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates.

sexual dimorphism

Differences in physical characteristics between males and females of the same species.

selective pressure

when the environment pushes an individual or population to adapt or evolve

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

stabilizing selection

Natural selection that favors intermediate variants by acting against extreme phenotypes

population bottleneck

A period during which only a few individuals of a normally large population survive.

founder effect

change in allele frequencies as a result of the migration of a small subgroup of a population

immigration

Migration to a new location

emigration

Migration from a location

speciation

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

reproductive isolation

Separation of species or populations so that they cannot interbreed and produce fertile offspring

biological species concept

Definition of a species as a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but are not able to produce viable, fertile offspring with members of other populations.

punctuated equilibrium

Pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change

gradualism

A proposed explanation in evolutionary biology stating that new species arise from the result of slight modifications (mutations and resulting phenotypic changes) over many generations.

divergent evolution

when two or more species sharing a common ancestor become more different over time

allopatric speciation

The formation of new species in populations that are geographically isolated from one another.

sympatric speciation

The formation of new species in populations that live in the same geographic area

prezygotic barriers

A reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted

postzygotic barriers

Barriers that prevent the hybrid zygote from becoming a fertile adult.

temporal isolation

form of reproductive isolation in which two populations reproduce at different times

ecological isolation

species occur in the same area, but they occupy different habitats and rarely encounter each other

behavioral isolation

Form of reproductive isolation in which two populations have differences in courtship rituals or other types of behavior that prevent them from interbreeding

mechanical isolation

mating is attempted, but morphological differences prevent its successful completion

hybrid inviability

A postzygotic barrier in which hybrid zygotes fail to develop or to reach sexual maturity

hybrid infertility

hybrid offspring are sterile or have reduced fertility

hybrid breakdown

Hybrid is fertile, but when they breed the next generation is sterile.

genetic diversity

The range of genetic material present in a gene pool or population of a species.

extinction

A term that typically describes a species that no longer has any known living individuals.

Mass extinction

A large extinction of species in a relatively short period of time

Cell

smallest unit of life

Subcellular

existing or occurring within a cell

Organelle

A tiny cell structure that carries out a specific function within the cell

endomembrane system

A group of membranes and organelles in eukaryotic cells that work together to modify, package, and transport lipids and proteins

Nucleus

The most visible organelle in a eukaryotic cell that contains the DNA not found in the mitochondria or chloroplasts. Enclosed by a double membrane called the nuclear envelope and contains a nucleolus (which makes ribosomes).

Smooth Endoplasmic Reticulum (Smooth ER)

Extends beyond the nuclear envelope as a series of membranes without ribosomes attached. Functions in making lipids and detoxing the cell from toxic substances.

Rough Endoplasmic Reticulum (Rough ER)

Extends from the Smooth ER as a series of membranes with ribosomes attached. Proteins are made by the ribosomes and are transported by the rough er and vesicles to the Golgi complex to be shipped out of a cell.

Ribosomes

Made by the nucleolus and are not membrane bound or part of the endomembrane system (not considered a true organelle). Made up of ribosomal RNA and proteins. Function in producing proteins for the cell (free ribosomes in the cytoplasm) or export from the cell (attached to the rough ER).

Vesicle

A membrane bound sac that contains materials involved in transport of the cell.

Vacuole

Cell organelle that stores materials such as water, salts, proteins, and carbohydrates. Can also store food or function in pumping water out of a single celled organism.

Golgi Complex

Accepts materials enclosed in a vesicle from the rough ER. Packages and processes substances for export from the cell. Has a sidedness - the cis face accepts materials and the trans face ships materials out.

Lysosome

A membrane bound organelle containing hydrolytic enzymes used to digest macromolecules. The enzymes function best in an acidic environment.

Hydrolytic

cleavage of bonds by the addition of water

Intracellular

within the cell

Extracellular

outside the cell

Eukaryotic

A cell characterized by the presence of a nucleus and other membrane-bound organelles. Eukaryotes can be unicellular (protists) or multicellular (fungi, plants and animals).

Cell

smallest unit of life

Nucleus

Subcellular organelle that contains DNA and a nucleolus

Mitochondria

Membrane bound organelles that are the sites of cellular respiration. They produce ATP from sugars, fats, and other fuels. Found in all eukaryotic cells. Made up of an outer membrane, intermembrane space, inner membrane with folds called cristae, and a matrix in the middle. Have their own DNA and ribosomes.

Chloroplasts

Membrane bound organelles that are the sites of photosynthesis. They use carbon dioxide to produce sugars and other compounds. They contain chlorophyll and enzymes for photosynthesis. Chemical reactions are compartmentalized by the membranes. There's an outer double membrane, flattened discs called thylakoids that contain chlorophyll and organize to form stacks called grana. Thylakoids are suspended in the fluid filled stroma. Have their own DNA and ribosomes.

Compartmentalization

seen in eukaryotes; consequence of organelles being membrane-bound. - keeps functions and raw materials or chemical reactions separated

Form fits function

How something works is related to its structure

Enery

the ability to do work

Surface Area

The measurement of the outer surface of an object.

Volume

The amount of space an object takes up

Surface Area to Volume Ratio

Ratio of a cell's outside area to its internal volume.

Examples of Cell Adaptation to Increase the Surface Area to Volume Ratio

Root Hairs in Plant Cells, Guard Cells Surrounding Stomata, Epithelial Cells of the Small Intestine

Plasma Membrane

a microscopic membrane of lipids and proteins that forms the external boundary of the cytoplasm of a cell or encloses a vacuole, and that regulates the passage of molecules in and out of the cytoplasm.

Phospholipid

a lipid that contains phosphorus and that is a structural component in cell membranes

Phospholipid Bilayer

A double layer of phospholipids that makes up plasma and organelle membranes.

Transmembrane Protein

An integral membrane protein that spans the phospholipid bilayer.

Peripheral Protein

A protein loosely bound to the surface of a membrane or to part of an integral protein and not embedded in the lipid bilayer.

Steroid

lipid molecule with four fused carbon rings

Cholesterol

A lipid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids.

Glycolipid

a lipid with one or more covalently attached carbohydrates

Glycoprotein

A protein with one or more carbohydrates covalently attached to it.