AP BIO: NATURAL SELECTION

Orthogenesis

-Mutations are not random. -Changes are predetermined (already set in their genes)

vestigial structures indicate

-ability to change -common ancestry

microevolution

-change in allele frequencies in a population over time -results from natural selection -ex: brown and blue eyes -goes with hardy Weinberg

natural selection

-environment provides the criteria for survival -organisms with traits suited to that environment will survive

Uniformitarianism theory

-evolution is continuous -organisms are conducting the same processes over time (processes that occurred in earths history continues to happen)

descent with modification

-genetic changes occur within species and the better of those changes can be seen in future generations (best characteristics get passed on only) -"survival of the fittest"

Requirements for Equilibrium

-no genetic drift: bottleneck effect -founder effect -no natural selection -no mutations -no gene flow -large population size -no sexual selection (no random mating)

punctuated equilibrium theory

-organisms evolve(change) after long periods of stability -sudden large change in a short time (punctuated)

Catastrophism Theory

-species are not capable of changing but of replacement (replaced by other organisms) -eliminates an entire species population. A new species then migrates to that area.

homologous structures

-structures that seem to be derived from a common origin -structures from common ancestor that are modified to perform different functions

analogous structures

-structures with a common purpose but not a common origin -look the same, perform same function but not from common ancestry because evolved on their own

Q. Which of the following is the correct sequence of events in the origin of life? 1. formation of protobionts 2. synthesis of organic monomers 3. synthesis of organic polymers 4. formation of DNA-based genetic systems

2,3,1,4

if 200 hawks how many alleles are there?

400

In a particular region, a species of lizard lives in the lowlands. Even though there are numerous mountains in the region, the climate on the mountains is too cold for the lizards to survive. Scientists are concerned that the lowlands will become much warmer by the end of the twenty-first century and will become unsuitable for this lowland lizard species. Which of the following best predicts the impact on the lizard species if there is a gradual increase in the average temperatures found in both the lowlands and mountains in this region? A Some lizards will migrate to new habitats in the mountains and become isolated, leading to allopatric speciation. B The species will undergo artificial selection, as the genes will adapt to warmer temperatures. C The species will experience a genetic bottleneck, and sympatric speciation will result in the development of several new species. D The lizards will hybridize with a different lizard species that is adapted to a warmer environment, leading to increased genetic variation in the species.

A

vestigial structures

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

Genetic Drift: Bottleneck Effect

A rapid decrease in population size due to a disturbance or natural disaster reduces the abundance of a species and removes individuals with some alleles from the population, altering gene frequencies through drift.

monophyletic

ALL descendants came from one common ancestor

comparative biochemistry

DNA is similar in species that share a common ancestor Ex: gel electrophoresis, chromatography

Natural selection can alter the frequency distribution in what 3 ways

Directional, disruptive and stabilizing

convergent evolution

Evolution toward similar characteristics in unrelated species

Homozygous vs. Heterozygous

Having identical alleles for the same gene vs. having different alleles for the same gene.

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In a phylogeny the number of nodes separating organisms indicates how closely related they are. The less the more closely related

inheritance of acquired characteristics theory

Organisms could modify their traits based on their needs/fit their environment

Natural selection can act more directly on the ___ and indirectly on the ___

Phenotype , genotype

Which of the following constitutes the smallest unit capable of evolution ? -individual -family unit -population -community

Population

homologous structure example

The arm of a human, the wing of a bird or a bat, the leg of a dog and the flipper of a dolphin or whale are homologous structures. They are different and have a different purpose, but they are similar and share common traits.

homoplasy example

The legless condition found in various types of extant lizards

comparative anatomy

analysis of structures can imply relatedness among groups of organisms -homologous structure, analogous structure and vestigial structures

genetic drift

any random event that changes the frequency of alleles

Homoplasy

any structure found in two organisms but not their common ancestor. -due to convergent evolution

analogous structure example

bat wings, bird wings, and butterfly wings are all used to fly but have different structures

Cladogenesis

both species live during the same time period. coexist

A widely accepted hypothesis about the origin of life on Earth is that life arose approximately 3.5 billion years ago as the result of a complex sequence of chemical reactions that took place spontaneously in Earth's atmosphere. Another hypothesis about the origin of life suggests that life began somewhere else in the universe and arrived on Earth by chance. Which of the following questions might scientists ask to most reliably determine if there has ever been life on Mars? A How far from Earth was Mars 3.5 billion years ago? B Is there scientific proof that Earth ever had an oxygen-free atmosphere? C Did Mars have the elements present in its atmosphere to support life? D Was there oxygen gas on Mars 3.5 billion years ago?

c

Because cheetahs, Acinonyx jubatus, experienced a bottleneck event about ten thousand years ago, living cheetahs exhibit very little genetic variation compared to other living species of large cats. Which of the following principles best justifies a claim that cheetahs, compared to other large cats, have a relatively low resilience to environmental perturbations? A A captive population of cheetahs kept in a confined area will have a greater risk of contracting and passing on a virus. B When a population is reduced, new niches become available in the environment, which can trigger adaptive radiation. C Populations with little genetic diversity are less likely to contain individuals that can withstand different selective pressures. D Populations with low genetic diversity are more likely to contain individuals that can withstand different selective pressures.

c

Mollusk fossils were excavated and collected from a coastal cliff. Scientists studying the fossils observed patterns of changing shell shape in the mollusks. The scientists identified a period of stability or stasis, followed by rapid change, and then stasis again with regard to shell shape. Which of the following statements best predicts the result of a comparison between the fossils found before and after the period of rapid change? A The same species will be found in both static periods, but they will have different shell shapes. B The same species will be found in both static periods, but the species in the second static period will have smaller shells due to the stress of undergoing rapid change. C Most of the species found in the first static period will be absent in the second static period. D Most of the species found in the second static period will resemble each other more than the species found in the first static period.

c

Some plant species flower in response to increasing daily temperatures in the spring. Many of these species rely on pollinators that migrate based on changes in day length and the position of the Sun. The current global warming trend is placing new selective pressures on the species involved in these relationships. Which of the following best explains the impact of these new selective pressures on the organisms involved? A If the environment for the plant species becomes too warm, the pollinators will no longer migrate to that area in the spring, continuing on to a more northern environment instead. B The warmer temperatures will lead to a drier environment, so the plants will no longer produce enough nectar to attract the pollinators. C The plant species will flower earlier in the spring in response to rising temperatures before the arrival of the pollinators, so seeds will not be produced. D Migrating pollinators will start migrating later in the year, switching from spring-flowering plants to summer-flowering plants.

c

taxonomy theory

classify organisms on similarities and differences

paraphyletic

common ancestor with SOME of its known descendants

A researcher hypothesizes that RNA molecules were present in the most recent common ancestor of all living organisms. Which of the following scientific questions would best test the hypothesis? A Is it possible to produce an RNA polymer in a laboratory setting? B How many distinct functions can a particular RNA molecule perform in a cell? C How many different monomers of RNA are found in a eukaryotic cell? D Do any known organisms function entirely without RNA?

d

A scientist wishes to provide experimental evidence to support the model shown in Figure 1 by demonstrating the ability to synthesize an RNA molecule. Which of the following is an alternative hypothesis that can be tested to support the RNA World Hypothesis? A A protein template that matches proteins found on the primitive Earth added to a mixture of deoxyribonucleotides will produce double-stranded DNA molecules. B Double strands of DNA placed in a harsh environment will unwind and form RNA molecules for long term information storage. C A pool of amino acids can spontaneously form into single‑stranded RNA, which would then code for proteins. D A mixture of ribonucleotides such as adenine and uracil will spontaneously form single-stranded chains of RNA.

d

Which of the following questions about the origin of life on Earth is most scientifically testable? A Why were the earliest life-forms created using only twenty amino acids? B Did life originate to make the universe a better place? C Was catalytic RNA used by ancient organisms as a stepping stone to acquire protein enzymes? D Can simple organic molecules form spontaneously in an oxygen-free atmosphere?

d

Which of the following statements best summarizes organic evolution as it is viewed by modern evolutionists? a)It is goal directed. b)It represents the results of selection for acquired characteristics. c)It is the descent of humans from the present-day great apes. d)It is the differential survival and reproduction of certain phenotypes.

d

mutations are fuel for

evolution

disruptive selection

favors individuals at both extremes of the phenotypic range

stabilizing selection

favors intermediate variants

directional selection

favors one extreme

Hybrid Inviability

fertilized egg doesn't survive, such as when male horses and female donkeys mate

Macroevolution

formation of a new species following the accumulation of changes -speciation (allopatric vs sympatric)

Heterozygous advantage + ex

heterozygous organisms are selected by the envirornment ex: sickle cell trait in humans

Analagous Structures can demonstrate

homoplasy

vestigial structure example

human appendix

hybrid sterility

hybrid is unable to produce compatible sperm cell or egg cells with other organisms

molecular clock example

if humans, pigs, rats and cats all produce galactosidase small differences in the enzymes can be used to infer a timeline for their evolution

Fitness

measured by an organisms ability to survive, reproduce and have offspring that survive

close branching represents

more related. Recent ancestor

Darwin's Theory

natural selection and descent with modification

What can alter allele frequencies in a population?

natural selection, genetic drift, gene flow

anagenesis

new species replaces the old species

Genetic Drift: Founder Effect

occurs when a few individuals become isolated from a larger population; can affect allele frequencies in a population

Hardy-Weinberg equation

p2 + 2pq + q2 = 1 p=frequency of dominant allele q=frequency of recessive allele ****p+q=1

Hardy-Weinberg Principle

principle that states that allele frequencies in a population remain constant unless one or more factors cause those frequencies to change

post zygotic barriers

reduced hybrid viability, reduced hybrid fertility, hybrid breakdown

polyphyletic

related species WITHOUT a common ancestor (not all of descendants either). Different ancestors and not all ancestors are in the tree.

comparative embryology

similarities in the development patterns of organisms implies relatedness -least reliable option

Gradualism Theory

small changes occur over time , many small changes can become big changes -can be observed in the fossil record with similar but different species

pre-zygotic barries

temporal isolation behavioral isolation mechanical isolation gametic isolation habitat isolation spatial isolation

hardy Weinberg is used to

test whether a population is evolving

hybrid breakdown

the offspring of hybrids do not survive

Parsimony

the simplest explanation is the best

Phylogeny (Theory)

the use of tree diagrams to find the distant or close relatives. -closer branches=closer relationship

Overproduction theory

there are no good or bad traits but when population reaches a carrying capacity they all begin fighting for resources ---> competition -in competition the ones with better traits will survive

molecular clock

when a specific molecule is common to more than one species it can be used to infer a time period , in which organisms branched apart from a common ancestor