BIO FINAL SG PDF

Tab 1 Biology 121 Study guide for Final Exam 100 points, about 30 mpq rest of matching, short answer Short answers on chapters we havent been on Upgrading/downgrading and role of a keystone species Figures like steps of meiosis/others called out then KNOW THEM Helpful Resources!!: - https://qui...

Tab 1 Biology 121 Study guide for Final Exam 100 points, about 30 mpq rest of matching, short answer Short answers on chapters we havent been on Upgrading/downgrading and role of a keystone species Figures like steps of meiosis/others called out then KNOW THEM Helpful Resources!!: - https://quizlet.com/user/quinnsterlingg/folders/biological-science - https://quizlet.com/985026620/bio-final-flash-cards/ Chapter 1 Scientific literacy A general, fact based understanding of the basics of biology/other sciences, the scientific method, and the social, political, and legal implications of scientific information Biological literacy: ability to use process of scientific inquiry to think creatively abt world issues that have a biological component, communicate these thoughts to others, and integrate these ideas into decision making Scientific thinking OHPEC (observation, hypothesis, prediction, experiment, conclusion) 1. O-scientists observe world around them & ask questions based on info they gather 2. H- make educated guess based on O (null or alternative) 3. P-predict what will occur 4. E-test our hypothesis (using dep, ind, control variables) 5. C-draw conclusions on experiment, analyze data Why is the process flexible, self-correcting? ○ If Hypothesis was incorrect, you can go back and revise, asking more questions/making new predictions Hypothesis vs theory ○ Theories: well-supported hypothesis backed w data, withstand time & multiple experiments, can be broader than hypotheses (ex: evolution) Test Questions: Science is: both a body of knowledge and an intellectual activity that encompasses observation, description, experimentation, and explanation of natural phenomena. The process of scientific thinking usually begins with: an observation/question  Which of the following is correct: a hypothesis that does not generate a testable prediction is not useful Short answer: 1. Describe the steps of the scientific thinking process. What makes it so flexible & why is it self-correcting? Chapter 2 Atomic structure Atoms: bit of matter that cant be subdivided any further without loosing essential properties Element: Substance made up of one type of atom Central nucleus of the atom has protons (positive charge) neutrons (no charge) electrons (negative charge) surround the atom Ions: atom with a charge (gain electrons=negative charge, loose=positive) Chemical bonds Covalent: 2 atoms share electrons Ionic: 2 oppositely charged ions attract each other (electron transfer), ionic compounds are neutral Hydrogen: Bond molecules together (forms between slightly pos hydrogen atom in one molecule and slightly negative in another, resulting in bond weaker than Cov or Ionic) Characteristics of water (result of hydro bonding, be able to explain!) 1. Cohesion: all the hydrogen bonds link together the water molecules in a chain or/network enough to give the water a surface tension with some net-like properties that can support a fishing spider. Cohesiveness results in high surface tension (why small insects can walk on water) 2. Reduced density as a solid : As temp drops and water molecules slow down & become less tightly packed ( held slightly farther apart), causing ice to be less dense than water. 3. Large Heat Capacity: When we heat water, the added energy doesn’t immediately increase movement of the water molecules, it disrupts some of the hydrogen bonds. Bc so much of your body is water, you are able to maintain relatively constant body temperatures.  4. Good Solvent: Water is able to pry ionic compounds (ex: NaCL) apart bc it carries charges as a polar molecule. Bc so many substances dissolve in water, they can be quickly and efficiently moved about—from one part of the cell or body to another part, and through the soil—distributing nutrients and other valuable resources for animals and plants. Test Questions: Two atoms are bonded together w a covalent bond. This means that: the atoms share one or more electrons Water can absorb a large amount of heat while increasing only a few degrees in temperature An atom with unequal numbers of protons and electrons; an atom with a charge: ion The subatomic particle that can be shared/donated to form a chemical bond: electrons The property of water that accounts for its high surface tension: cohesion due to hydrogen bonding Weakest type of chemical bond: hydrogen bond Glycogen and starch are examples of this type of biological molecule: carbohydrates A type of solution w a low ph: acid Chapter 3 Structures and functions of carbohydrates and lipids Glucose is a biologically important simple carbohydrate & the most common fuel source for most cells Many sugars bound together in a linear fashion form a starch molecule, which can be either a food source (glycogen) or a structural component of cells (cellulose) Lipids are oily molecules (hydrophobic) that are important components of cell membranes Proteins are made from amino acids Amino acid structure – amino group (NH2), carboxylic acid group (COOH), and sidechain that varies. Different side chains make up the 20 different amino acids Protein Structures Protein primary, secondary, tertiary, and quaternary structure. 1. Primary structure (amino acid sequence) determines protein identity & characteristics. 2. Secondary Structure: hydrogen bonds btwn amino acids in polypeptide chain cause folding 3. Tertiary structure is required for a protein to be biologically active. 4. Quaternary Structure: 2 or more polypeptide chains bound tg  Enzymes – biological catalysts. Speed up chemical reactions by lowering activation energy. The enzyme is not used up in this process Nucleic acids DNA & RNA – both polymers made of a sugar (deoxyribose or ribose), a nucleic acid, and a phosphate group. How are molecules of DNA and RNA alike? How are they different? ○ Alike: Both play central roles in directing the production of proteins ○ Diff: DNA is double-stranded. Between 2 strands, A pairs with T, G pairs with C. We can determine sequence of complementary strand from the sequence of 1st strand. ○ DNA stores hereditary information, includes the info for the cell to make all necessary molecules ○ RNA is single-stranded, involved in protein synthesis, and uses uracil (U). ○ Messenger RNA act as intermediary – copies info from DNA into an mRNA molecule and uses it to direct protein synthesis Test Questions Carbohydrates are built from many sugar molecules joined together. What role do they play in cells? Energy Storage & Cell Structure What type of lipid is the major component of the cell membrane: Phospholipid What type of macromolecule stores hereditary information: DNA A nucleotide is composed of which 3 molecular structures bound together? Sugar, Phosphate, Nitrogenous base Which is NOT a protein function? A. fight infection B. store genetic info in molecular structure C. form structural features such as hair and bone D. chief form of long term energy storage E. help catalyze chemical reactions Protiens are compromised of many Amino Acids bound together in a specific order, determining their identity. Enzymes: increase rate at which a reaction occurs Enzymes are an example of this biological molecule: proteins Cells – chap.4 Eukaryotes vs prokaryotes Eukaryotes have organelles – prokaryotes do not, not even a nucleus DNA in prokaryotes stored in cytoplasm. Ex (bacteria, archaea) Organelles: animal/plant cell Function of each of the Organelles ○ Nucleus: stores hereditary info (DNA) ○ Mitochondria: Where ATP is produced for energy of the cell ○ Rough ER: protein production ○ Smooth ER: synthesizes lipids ○ Plasma membrane: protects cell ○ Ribosome: Synthesize proteins by translating messenger RNA (mRNA). ○ Golgi Apparatus: Packages proteins ○ Lysosome: Removes waste from cell ○ Cytoplasm: Jelly-like substance that fills the cell. ○ Cytoskeleton: supports cell & aids in mvmt ○ Chloroplast: site of photosynthesis ○ Cell Wall: structural support ○ Vacuole: stores nutrients & waste Cells with greater energy needs usually contain more mitochondria Advantages of the cell wall for plant cells – limit water loss, structural support, help resist predation Plasma membrane Passive Transport: molecular movement without the input of energy. 2 types: ○ Diffusion: passive transport which a particle (solute) is dissolved in a gas/liquid (solvent) and moves from an area of high concentration to low ○ Osmosis: molecules move across a membrane, direction is determined by relative concentrations of all solutes on either side of the cell. Active transport: molecular mvmt that depends on input of energy, which is necessary when the molecules (or ions) are large and against concentration gradient. If ATP used, its active transport! Endocytosis: absorbtion of large particles into a cell/ Engulfing large particles with the plasma membrane. 3 types: ○ 1. Phagocytosis-cell eating ○ 2. Pinocytosis-cell drinking ○ 3.Receptor-mediated endocytosis: cells engulf specific particles ○ Exocytosis – export of large particles out of a cell Test Questions: How do prokaryotic cells (bacteria) differ from eukaryotic cells: prokaryotes don't have a nucleus The transport of very large, bulky molecules into the cell is accomplished via: endocytosis The hallmarks of passive transport are: No ATP used, molecules move down their concentration gradient The golgi apparatus: processes & packages proteins, lipids, and other molecules Which organnele is responsible for degrading unwanted molecules/structures within the cell: Lysosome Which organelle generates most of the ATP energy for a eukaryotic cell: Mitochondrion You measure the concentration of a molecule inside and outside of a cell. You find that the concentration is high inside the cell and still increasing. At the same time the ATP concentration inside the cell is dropping. Your best hypothesis for the process for the product would be: active transport Protiens within cells are synthesized by the: ribosomes What makes the rough endoplastic rectiulum rough: it is covered in ribosomes The passive movement of water across a membrane is called: osmosis Chap 6 – DNA & gene expression What is DNA ○ nucleic acid, a macromolecule that stores information.  ○ It consists of individual units called nucleotides, which comprise a sugar, a phosphate group, and a nitrogen-containing base. ○ The sequences of bases on one side of the ladder-like molecule (one strand of the DNA) complements that of the bases on the other side (the second strand) Define: ○ genome: an organisms complete set of DNA ○ Chromosome: one/more unique pieces of DNA ○ Gene: a specific sequence of DNA ○ Locus: position of a gene on a chromosome ○ Allele: different versions of a gene that code for the same feature ○ Trait: any single feature/characteristic of an organism Most eukaryotes have a large amount of noncoding DNA. Introns – within a gene; exons – between genes Transcription a copy of a gene’s base sequence is made, and translation, in which that copy is used to direct the production of a protein. Occurs in nucleous in eukaryotes gene’s base sequence, or code, is copied into middle-man molecule called mRNA. This is like copying the information for the chocolate chip cookie recipe out of the cookbook and onto an index card. In translation, the mRNA moves out of the nucleus and into the cytoplasm of the cell where the messages encoded in the mRNA molecules are used to build proteins. 4 steps: ○ Step 1. Recognize and bind. RNA polymerase (the enzyme) finds the promoter site (start signal) on DNA and unwinds it so that only one strand of the DNA can be read. ○ Step 2. Transcribe. RNA polymerase moves along the DNA strand and builds a copy of the gene called mRNA. This mRNA is made up of adenine (A), uracil (U), cytosine (C), and guanine (G) (U replaces T). ○ Step 3. Terminate.RNA polymerase reaches a termination sequence (stop signal) at the end of the gene.It stops making mRNA and detaches from the DNA. ○ Step 4. Cap and edit. Cap and tail are added to protect the mRNA and help it get recognized for protein-making. Editing: Noncoding parts of mRNA called introns are removed, leaving only the useful coding parts (exons). ○ The final mRNA is now ready to leave the nucleus and be translated into a protein. Translation Step 1: Initiation. The mRNA leaves the nucleus and enters the cytoplasm. The ribosome attaches to the mRNA. Step 2: Elongation. tRNA reads the mRNA's three-base sequences called codons.Each tRNA carries a specific amino acid.The tRNA’s three-base sequence (anticodon) matches with the  codon on the mRNA, ensuring the right amino acid is added. The ribosome moves along the mRNA, reading codons and adding amino acids to the polypeptide chain. Step 3: Terminate. The ribosome reaches a stop codon on the mRNA. The finished protein is released & mRNA and ribosome detach. Operon/Gene expression Operon= a group of several genes and the elements that control their expression as a unit, all within one section of the cell’s DNA. how does this influence gene expression in bacteria? ○ Bacteria have specific regulatory molecules that control whether a particular gene will be transcribed into mRNA. Often, these molecules act by binding to DNA near the gene and helping or blocking the transcription enzyme, RNA polymerase. Mutations Mutation: an alteration to the sequence of bases in DNA Point mutations: a single nucleotide in the DNA sequence is changed ○ Effects = no change in protein (silent), diff amino acid is added and can alter function(missense), or stop codon created (nonsense) ○ Insertions and deletions can be much more harmful than substitutions because they can alter the reading-frame for the rest of the gene. frameshift mutation: A shift in the "reading frame" of the genetic code caused by a deletion or insertion not in multiples of 3. Most harmful= frameshift or nonsense bc they can change amino acid seuence/protien structure and function Gene mutations can be spontaneous (errors in DNA replication or repair) or they can be caused by environmental factors including radiation, UV light, or chemicals such as cigarette smoke Test Questions: Which type of macromolecule stores hereditary info: DNA Smoking cigraretes (does/does not) increase risk of spontaneous mutation: DOES Which of these occurs during transcription: the information is copied into mRNA A group of several genes in a baterial cell, along w the elements that control their expression as a unit is called an: operon What is the typical sequence of events in gene expression and protein synthesis: DNA>RNA>PROTIEN Short Answer: 1. In the process of creating new proteins from the instructions in DNA, the first step is transcription. What happens during transcription, list them briefly explain each step.  2. Errors in DNA can lead to serious diseases for organisms. Give 3 examples of DNA mutations/chromosomal aberrations that are likely to be harmful to an organism, and explain why they are harmful. 3. Why is DNA considered to be the universal genetic code for all living things? - All living cells have the same, identical codon AUG (methionine) that has been conserved through evolution. Chap 7 – Biotechnology Biotechnology is the use of technology to modify organisms, cells, and their molecules to achieve practical benefits Many types of biotechnology modify DNA in part by using restriction enzymes. What do these enzymes do, and why is this useful? ○ Cut DNA at specific sequences, important because they allow short lengths of DNA to be inserted into other chromosomes ○ CRISPR is a system for editing DNA. It allows “cut and paste” gene editing A genetically modified organism: organism that has at least 1 gene of another species inserted into its DNA. ○ Example: Bt corn – corn that includes a gene from a bacterium that makes the corn resistant to an insect predator, the corn borer. What is a benefit of growing Bt corn? What is a possible concern? ○ Benefit : increased crop yields to feed more ppl, concern: environmental impact, could develop an insect resistance ○ Why is DNA useful to the Criminal Justice system? Helps to identitfy suspects more accurately bc each person’s is unique & presents objective scientific evidence Test Questions: You are working in a biotechnology lab and only have a small amount of DNA available for analysis. Which could you use to duplicate that small piece of DNA repeatedly: polymerase chain reaction (PCR) Restriction enzymes perform which of the following functions: cut DNA at specific sequences Why have scientists inserted the human insulin gene into the genome of E-coli bacteria: Bacteria express the human insulin gene & produce large quantities of the insulin protien, which is sold pharmaceutically. Chap 8 – Chromosomes & cell division Eukaryotic cell cycle – know the 5 steps and what happens in each step (Fig 8.5) ○ G1 (growth), S (DNA replication), G2 (growth and preparation for mitosis), M (mitosis and cytokinesis), G0 (resting phase). Mitosis: type of cell division that generates 2 daughter cells that are genetically identical to each other and to the parent cell. Nearly all body (somatic) cells undergo mitosis Before mitosis begins, chromosomes replicate to form 2 identical copies (sister chromatids) Know the steps of mitosis and what happens in each one – prophase, metaphase, ○ 1. Prophase: sister chromatids condense. Prophase begins when the sister chromatids condense. At this point, the spindle forms and the nuclear envelope breaks down. ○ 2. Metaphase: sister chromatids line up at the center of the cell ○ 3. Anaphase: sister chromatid pairs are pulled apart by spindle fibers. One set of chromosomes go to one side of the cell and another identical set goes to the other. ○ 4. Telophase: chromosomes begin to uncoil, nuclear membrane reassembles, cytokinesis starts and the cell begins to pinch in two.  How are cancer cells different from healthy cells? List & explain ○ 1. Loss of Contact Inhibition: Normal cells stop dividing when they come into contact with other cells, but cancer cells ignore this signal and continue to divide uncontrollably. ○ 2, Unlimited Division: Cancer cells can divide indefinitely, unlike normal cells, which have a limited number of divisions. ○ 3. Reduced Stickiness: Cancer cells have weaker adhesion molecules, making them less sticky. This allows them to break apart more easily and spread, unlike normal cells that stick together tightly. Meiosis – occurs only in gametes (eggs & sperm cells). It starts with a diploid cell and generates 4 haploid cells that are genetically distinct. Later when fertilization occurs, the newly fertilized egg will be diploid, with one set of genetic info from each parent. Know the steps of meiosis and what happens in each step. Use Fig 8-22 as your guide Meiosis I Prophase 1: chromosomes condense & crossing over occurs Metaphase 1: chromosomes line up Anaphase 1: homologues pulled to either side of cell Telophase 1 & cytokinesis: nuclear membranes reassemble around sets of sister chromatid pairs, 2 daughter cells form Meiosis 2 Prophase 2: chromosomes recondense Metaphase 2: sister chromatids line up at center of cell Anaphase 2: sister chromatids pulled to opposite sides of cell Telophase 2 & cytokinesis: nuclear membranes reassemble and 2 daughter cells pinch into 4 haploid gametes  Crossing over (genetic recombination) occurs when homologous chromosomes swap genetic information. Test Questions: In asexual reproduction, daughter cells inherit DNA from: a single parent A karyotype: can be used to diagnose down syndrome (Trisomy 21) in humans A diploid cell undergoes meiosis. What are the final products of this division: four haploid gametes In the __ stage of meiosis, the sister chromatids line up down the middle of the cell: metaphase The majority of a eukaryotic cell’s life is spent in a nondividing state referred to as: interphase The eukaryotic cell cycle consists of 5 phases, in the following order: Gap1, S phase (DNA synthesis), Gap 2, mitosis, and cytokinesis If a cell w 18 chromosomes divides by mitosis, how many chromosomes will each daughter cell have: 18 During meiosis, which processes lead to genetic variability in gametes: crossing over of sister chromatids & random assortment of homologous pairs In eukaryotic cells, where does DNA replication occur: before mitosis, during S phase The color of a daisy’s petals is a __, the instructions for which are found in a gene that controls the petal’s color. There may be many alternative versions of the gene, which are called __: trait; alleles What processes must occur before mitosis begins: cell receives signals from neighboring cells that it is time to divide, cell passes G1/S checkpoint, DNA replicated, DNA damage repaired.  A diploid cell undegoes meiosis. What are the final products of this process: 4 haploid cells In the __ stage of mitosis, the daughter chromatids of the cell have reached the poles and the nuclear envelopes re-form: telophase Mitosis produces 2 daughter cells that: are genetically identical to each other and the original parent If a cell containing 16 chromosomes divides by mitosis, how many chromosomes will each daughter cell have: 16 In peas, tall plants are dominant to short plants. A heterozygous plant is crossed w a homologous recessive plant. What fraction of the offspring would you expect have the short phenotype: 1/2 Chap 9 – Genes & inheritance Explain the difference between genotype and phenotype ○ Genotype: genetic makeup ○ Phenotype: observable characteristics Mendel’s Law of Segregation – diploid organisms have 2 copies of each gene, but eggs or sperm cells (gametes) have only 1 copy: during formation of gametes, the 2 alleles for a gene separate so half gametes carry one allele and half the other Observed traits depend on 2 copies (alleles) of a gene in an individual, one from each parent Know how to make, interpret a Punnett square: Used to predict the genotypes and phenotypes of offspring from a cross between two parents. ○ Test Cross: Used to determine the genotype of an individual with a dominant phenotype. It involves crossing the individual with a homozygous recessive individual. Works best with organisms producing many offspring because it increases the chance of observing the recessive phenotype. ○ Understand how a test-cross can help reveal an unknown genotype (chp 9 section 7). This process works best for organisms that produce large numbers of progeny (hundreds of seeds or eggs at a time). Why? ○ Test Cross: Used to determine the genotype of an individual with a dominant phenotype. It involves crossing the individual with a homozygous recessive individual. Works best with organisms producing many offspring because it increases the chance of observing the recessive phenotype. What is a pedigree and what kind of predictions can we make from it? ○ Family trees used to track the inheritance of traits.  What are codominance and incomplete dominance? Give an example of each ○ Codominance: Both alleles are fully expressed in the heterozygote (e.g., AB blood type). ○ incomplete: Heterozygote shows an intermediate phenotype (e.g., pink flowers from red and white parents). Multiple allelism – a single gene has 3 or more alleles in a population(ex: blood type) Polygenic traits like human height result from the additive effects of multiple genes, and vary continuously Pleiotropy – one gene influences multiple traits. Ex sickle cell trait and resistance to malaria. This is very common Why are some traits sex-linked? Why does the sex of the offspring determine their chances of inheriting the trait? ○ Some traits are sex-linked because the genes that control these traits are located on the sex chromosomes (X or Y chromosomes). In humans, females have two X chromosomes (XX) and males have one X and one Y chromosome (XY). Genotypes are not blueprints - Environmental factors can have major effects Most traits are inherited independently (not influenced by other traits). One exception – linked traits that result from crossing over of chromosomes. If genes are located close to each other on a chromosome they will frequently be inherited together. Test Questions: How many sex chromosomes does the normal human male inherit from his father: 1 In peas, tall plants are dominant to short plants. A heterozygous plant is crossed w a homologous recessive plant. What fraction of the offspring would you expect have the short phenotype: ½ The phenotype of an organism is: its physical characteristics A true breeding purple flowered plant is repeatedly mated w a true breeding white-flowered pea plant. All of their offspring are purple flowered. If these 2 purple flowered offspring are mated, what percent of their offspring will be white flowered: 25% A plant can have either blue or yellow flowers. If blue flowers have the genotype CC and yellow flowers have cc, what color will the flowers of the heterozygous plant Cc be: blue Traits that vary continuously, such as human height, often result from: additive effects of multiple genes Genes that are frequently inherited together, like red hair and freckles, are known as linked genes. Which characteristic makes 2 genes likely to be linked: they are located very close together on a chromosome Aunt Maud had her cat cloned. She expects it to be identical in every single way to the OG pet. Is she right: no, bc the clone will not experience the same exact environment and experiences as the OG one. Short answer: List/Explain 1 advantage and disadvantage of asexual & sexual reproduction. What type of organisms typically reproduce by asexual reproduction (binary fission)? ❖ Advatage: quick/more offspring at a faster rate -> good for producing identical cells that are helpful in healing like skin cells ❖ Disadvantage: bc of identical cells, less genetic variation, making pop more susceptible to disease if none are resistant ❖ Sexual advantage: more genetic variation-> diversity and resistance ❖ Disadvantage: slower, need more energy ❖ Organisms like bacteria & prokaryotes use asexual, mammals use sexual All your roses have thorns on the stems except for one which has a smooth stem. You would like to breed more roses without Thorns. You know that the allele for Thorns (T) is dominant and the allele for smooth stems (t) is recessive, so you perform a test cross to determine the genotype of one of your thorny roses. How will you know if the Thorny Rose is TT or lowercase Tt? draw punnet squares to show how this analysis works Chap. 10 Evolution and Natural Selection Evolution occurs when allele frequencies in a population change Understand and be ready to explain the 4 different mechanisms of evolution: ○ Mutation: Random changes in DNA sequence ○ genetic drift: Random changes in allele frequencies due to chance events. ○ Migration: Movement of alleles between populations ○ Natural selection: differential survival and reproduction of individuals based on their traits. Fitness – reproductive output of an individual with a particular phenotype compared to the reproductive output of another individual with an alternate phenotype Fitness is a relative term – a comparison of individuals Depends on the environment – an animal of superior fitness in one environment may not be as fit in a different environment Natural selection allows populations to adapt to their environment This is always ongoing, and never reaches “perfection”. Why not? ○ bc environments change, so organisms adapted td might not be tmw Chapter 17 Ecosystem: communities of biological organisms plus the living and nonliving components in the environment with which they interact Biome: all living organisms within an area, often referred to as community Trophic levels – energy flow and the 10% rule  ○ Levels in a food chain or food web. Energy flows through trophic levels, with about 10% transferred from one level to the next (10% rule). ○ Energy from the sun passes through an ecosystem in several steps known as trophic levels in a food chain ○ Detritivores and decomposers then extract energy from organic waste and the remains of dead organisms. ○ At each step in a food chain, some usable energy is lost as heat. How the earth’s shape determines global weather patterns ○ Global climate patterns are largely determined by the earth’s round shape. ○ Solar energy hits the equator at a more direct angle than at the Poles ○ This temperature gradient generates atmospheric circulation patterns Ocean movements and el niño ○ Every 2-7 years, a dramatic climate change driven by ocean currents, called El Niño, causes a sustained surface temperature change in the central Pacific Ocean Niche: species role in a community Fundamental vs realized. What happens when two different species compete for the same niche in a single location? ○ Fundamental niche is the potential niche, while realized niche is the actual niche occupied. Competitive exclusion principle: two species cannot occupy the same niche in the same location. Competition: ○ Competitive exclusion: 2 species battle for resources in the same niche until the more efficient one wins and the other species is driven to extinction in that location ○ Resource partitioning is a COMPROMISE. Individual organisms and species can adapt to changing environmental conditions, and resource partitioning can result from an organism’s behavioral change or a change in its structure. When this occurs, one or both species become restricted in some aspect of their niche, dividing the resource. ○ Character displacement: an evolutionary divergence in one or both of the species that leads to a partitioning of the niche. Ex in 2 species of seed-eating finches on the Galápagos Islands where both species live, their beak sizes differ significantly. Adaptations – predator vs prey, parasitism ○ Predators use mimicry (ex: snapping turtle that has physical structures that mimic something—usually a food item—of interest to potential prey.) ○ Prey: use physical (mechinical, chemical, camo) and behavioral (alarm defenses) ○ an interaction between two species in which one species eats the other. Predators are a strong selective force, Predators & prey co-evolve ○ Parasitism: symbiotic relationship in which one organism (the parasite) benefits while the other (the host) is harmed. Primary and secondary succession  Succession = change in species composition of a community over time, not continuous 1. Primary Succession: begins after disturbance leaves an area barren of soil and w no life. Starts with Colonizers-fungai/bacteria-that are easily distributed, usually photosynthesizers (producers) that arrive first, can take many yrs 2. Secondary Succession: begins when a disturbance opens up a part of a community to the development and growth of species previously outcompeted by other species in the area/after disturbance like flooding or fires. Life and soil are present (faster than PS) organisms colonize decaying remains of another organism, formerly cultivated land is colonized by weeds Keystone species= species within a community whose presence has huge affect on what other species can survive in an area