AP Bio Summer Textbook Reading

Intro & 15.1-15.4

(Scientists can use/generalize research found on __model organisms__ for other organisms b/c) All life shares a …

common ancestor.

C.O.L.T.s

* Homeostasis (Maintains homeostasis)
* Organization (Displays organization and has DNA)
* Grows and develops
* Reproduces
* Adaptation/Evolution
* Cells (Made up of one or more cells)
* Energy (Requires energy)
* Responds to stimuli

Nucleic acids

molecules that can reproduce themselves and encode proteins/contain info for protein synthesis

Photosynthesis

chemical reactions that turn sunlight energy into glucose (sugar) and other small biological molecules; the energy can then be used internally for synthesis/building

sunlight + carbon dioxide (CO2) + water (H2O) → glucose (C6H12O6) + oxygen (O2)

Aerobic metabolism

“a set of chemical reactions that %%releases energy%% from life’s molecules by %%using oxygen%%;” more efficient than anaerobic metabolism pg. 3

Anaerobic metabolism

“a set of reactions that %%extracts energy%% %%without using oxygen%%” pg. 3

Organelles

“membrane-enclosed compartments” inside cells; led to “specialized cellular functions” pg. 4

Nucleus

organelle that contains genetic information

Difference between eukaryotes and prokaryotes

Eukaryotic cells DO have a nucleus

Prokaryotic cells have NO nucleus; all prokaryotes are unicellular

Endosymbiosis

means “living inside another;” larger cells ingested smaller cells; hypothesized origin of some organelles including mitochondria and chloroplasts

Genome

“the sum total of \[an organism’s\] genetic material” pg. 4

What is Homo sapien an example of?

Binomial- an organism’s scientific name; made up of 2 Latin words, 1st is genus and 2nd is species

Phylogenetic tree

Diagram that shows evolutionary relationships

Domains

3 major branches in the phylogenetic tree of life:

* %%Archaea%% = single-celled prokaryotes
* %%Bacteria%% = single-celled prokaryotes
* %%Eukarya%% = species have eukaryotic cells whose mitochondria and chloroplasts originated from endosymbiosis with bacteria

Unicellular eukaryotes

Protists

Levels of organization for internal systems

cells, tissues, organs, organ systems, (multicellular) organism

Levels of organization for external systems

population, community, landscape, biosphere

Positive feedback

amplifies the initial response *try not to say increase; keeps a system/process going; can destabilize a system; ex. Climate change/global warming, Blood clotting

Negative feedback

working opposite of the stimulus (negative = opposite) *don’t focus on speed; the mechanism to maintain homeostasis; (helps stabilize a system; very common in regulatory systems); ex. regulating body temp.

Systems analysis

uses equations to understand biological systems; creates a computational model of a biological system; can be used to make predictions

Gene

segment of DNA

DNA nucleotide bases

adenine, thymine, cytosine, guanine

A nucleotide sequence encodes…

information/instructions to build certain proteins.

True/False: All cells of a multicellular organism contain the same genome

True

Causes of mutations

mistakes during DNA replication (spontaneous), chemicals, radiation

Bioinformatics

the study of biological information (biologists and computer scientists work together)

Evolution

the genetic change that occurs in populations over time

Natural selection

the process through which individuals in a population with beneficial traits will survive and reproduce

Who came up with natural selection?

Charles Darwin and Alfred Russel Wallace

Adaptation

a trait that helps an organism survive and reproduce in their environment; “describes both the trait itself and the process that produces the trait” pg. 304

What crucial evolutionary process leads to adaptations?

Natural selection

Tree frogs with toe pads for climbing vs aquatic frogs with webbed feet for swimming are examples of what?

Adaptations

Proximate explanations

explains how an adaptation works

Ultimate explanation

explains why an adaptation exists / what led to it

Scientific theory

“a body of scientific work in which rigorously tested and well-established facts and principles are used to make predictions about the natural world” pg. 11

Natural history

how a group of organisms “get their food, reproduce, behave, refute their functions, and interact with other organisms” pg. 12

Quantified observations

Data; observations that were turned into explicit counts or measures

Hypothesis–prediction method

1. make observations
2. ask a question
3. form a hypothesis
4. make predictions based on the hypotheses
5. test the predictions by making additional observations or conducting experiments / design and conduct an experiment that uses quantifiable data to test your prediction

Controlled experiment

“changes, or manipulates, one or more of the factors being tested;” has an independent variable, dependent variable, and a control group pg. 13

Comparative experiment

“compares unmanipulated data gathered from different sources“ pg. 13

Null hypothesis

the hypothesis that any differences are due to random differences from drawing two samples from the same population; what many statistical tests start with

The hypothesis that says there is no relationship between the IV and DV.

It is deemed valid until proven untrue by statistical experiment — By testing your (alternative) hypothesis through an experiment, you are trying to disprove/reject the null hypothesis. (Similar to ‘innocent until proven guilty;’ null hypothesis = status quo, alternative hypothesis = change/innovation)

Evolutionary theory

“our understanding and application of the processes of evolutionary change;” pg. 323 “has many useful applications” such as diseases, agriculture, and “the development of industrial processes that produce new molecules with useful properties” pg. 299

Darwin’s 3 major propositions for evolutionary theory

1. Species change over time (they don’t stay the same)
2. Descent with modification
3. Natural selection

Descent with modification

the concept that divergent species share a common ancestor and have diverged from one another gradually over time

Whose work helped scientists understand genetic inheritance?

Gregor Mendel

Who discovered the structure of DNA?

Watson and Crick

Point mutation

addition, deletion, or substitution of a single base

Alleles

different forms of a gene

Gene pool

sum of genetic variation (all alleles at all loci) in the population

Allele frequency

proportion of each allele in the gene pool; decimal

Genotype frequency

proportion of each genotype among individuals in the population

Gene flow

“Migration of individuals and movements of gametes (in pollen, for example) between populations;” “can change allele frequencies in a population;” pg. 305

Genetic drift

“random changes in allele frequencies from one generation to the next;” “may cause large change in small populations;” *not mutation* — strictly environmental events pg. 305

Population bottleneck

when a (sometimes larger) population “passes through environmental events that only a small number of individuals survive;” can cause loss of genetic variation (conservation/endangered species issue) pg. 305

Founder effect

the resulting change in genetic variation when a few individuals (who likely don’t have all the alleles in the gene pool of its source population b/c it’s such a small group) colonize a new region; (some individuals get separated from their original population and form a new small population in a different place and as this founder population grows, there is less variation b/c it started from a few individuals with only a few alleles from the gene pool) the change is equivalent to if a large population got reduced by a bottleneck

Similarities and difference between founder effect and bottleneck

Similarities:

• population goes large→small→large

• forms of genetic drift

• reduce genetic variation

Difference: Original population

• Founder effect- original population still exists, just in a different location (so the original genetic variation is only lost in the new population)

• Bottleneck- original population is gone (so the original genetic variation is lost completely)

Sexual selection

when individuals choose specifically which individual of the opposite sex they want to mate with instead of mating randomly; also suggested by Darwin

True/False: Sexual selection will enhance an organism’s chance of reproduction and survival.

False, it will enhance an organism's chance of reproduction but %%not necessarily their chance of survival%%

Intrasexual selection

when certain features improve “the ability of their bearers to compete for access to mates” Pg. 306

Intersexual selection

when certain features make “their bearers more attractive to members of the opposite sex” Pg. 306

Checkpoint question: How do self-fertilization and sexual selection differ in their expected effects on genotype and allele frequencies over time?

Self-fertilization will not affect genotype or allele frequencies over time while sexual selection will. Self-fertilization will result in more homozygous and less heterozygous genotypes, while sexual reproduction will result in more heterozygous and less homozygous genotypes.

If the offspring are equally able to survive from nonrandom mating (sexual selection) or random mating, it will not change allele frequencies.

Fixed allele

when it is the %%only allele at a given locus%% in a population; “the population is monomorphic \[one form\] at that locus” pg. 308

Fixed allele frequency

1

Genetic structure (of a population)

the frequencies of the different alleles at each locus and the frequencies of the different genotypes in a population

Hardy–Weinberg equilibrium

“a model in which allele frequencies do not change across generations and genotype frequencies can be predicted from allele frequencies” pg. 308

5 principles of Hardy–Weinberg equilibrium

[only apply to sexually reproducing organisms]

• There is no mutation.

• There is no natural selection (selection among genotypes).

• There is no gene flow.

• Population size is infinite.

• Mating is random.

Results/consequences if these conditions hold:

1. Allele frequencies remain constant

2. Genotype AA, Aa, aa

   Frequency p^2, 2pq, q^2

Checkpoint question: Why is the concept of Hardy–Weinberg equilibrium important even though the assumptions on which it is based are never completely met in nature?

You can use the model to predict genotype frequencies of a population from its allele frequencies, and you can see evolutionary processes/how a population evolves through “the specific patterns of deviation from HW equilibrium.”

Qualitative traits

“often distinguished by discrete qualities;” “influenced by alleles at a single locus;” ex. black vs white, smooth vs wrinkled pg. 310

Quantitative trait

“likely to show continuous quantitative variation rather than discrete qualitative variation;” influenced by alleles at more than one locus; ex. distribution of body sizes of individuals in a population; bell-shaped curve on a graph pg. 310

Stabilizing selection

“preserves the %%average%% characteristics of a population by favoring average individuals;” @@reduces variation@@ pg. 310

When talking about specific genes stabilizing selection is often called ___ because it gets rid of any deleterious mutations.

purifying selection

Directional selection

“changes the characteristics of a population by favoring individuals that vary in one direction from the mean of the population;” %%favors one extreme%% pg. 310

When talking about a single gene, directional selection is called…

positive selection

Disruptive selection

“changes the characteristics of a population by favoring individuals that vary in both directions from the mean of the population;” %%favors extremes instead of the average/mean%%; @@increases variation@@; bimodal (two-peaked) distribution pg. 310

Below are examples of what types of natural selection?


1. Black-bellied seedcracker (West African finch)
2. Surface proteins of influenza
3. Human birth weight
4. Texas Longhorn cattle

1. Disruptive selection
2. Directional selection
3. Stabilizing selection
4. Directional selection