chapter 14-19

Explain how multicellular life may have evolved in eukaryotes.

evolved from: stramenopiles (brown algae), unikonts (fungi and animals), and archaeplastids (red algae and green algae).

Advantages/Disadvantages of Water Existence

*Advantage* 1. Plentiful water 2. Support for the body of the plant *Disadvantage* 1. Maintain moisture inside their cells (gaining, acquiring, retaining issues) 2. Support the body in a non-buoyant medium 3. Reproduce and disperse offspring without water (zyogotes and gametes travelled through water in water existencre) 4. Anchor their bodies in soil Obtain resources from soil and air (new means of getting nutrients esp. through air and soil) (Some species accumulated adaptations that made life on dry land possible.)

Cooksonia

-An extinct grouping of primitive land plants -The oldest known plant to have a stem with vascular tissue -A transitional form between the primitive non-vascular bryophytes and the vascular plants (missing link for plants) -Date from the middle of the Silurian until the Early Devonian (a total time span of 428 to 398 mya) -Only the sporophyte phase of -Cooksonia is currently known (only ones that were preserved) Individuals were... --small (a few centimeters tall) --lacked leaves, flowers and roots --speculated that they grew from an --unpreserved rhizome --had a simple stalk that branched dichotomously a few times --each branch ended in a sporangium (where spores were produced)

Vascular Plants

-Dominate the natural landscape (due to the fact of specialized vascular tissue) -Contain Vascular Tissue: 1. Xylem --conducts water and dissolved minerals up from roots --Composed of strong-walled cells reinforced with lignin (usually appear larger) --supports the body of the plant against gravity 2. Phloem --Conducts sucrose and other organic compounds throughout the plant (products of photosynthesis) --composed of thin-walled cells (usually appear smaller) -Most seedless vascular plants are homosporous (identical spores) --windblown spores are dispersal agents -All seed plants are heterosporous and have male and female gametophytes --seeds disperse offspring --Ex: pollen = male spore

Plant adaptations to land

-Plant evolution is marked by adaptations for life on land (one of the first organisms to invade land and live in a Terrestrial environment) -More than 500 million years ago, the algal ancestors of plants may have carpeted moist fringes of lakes and coastal salt marshes. -Plants and green algae called charophytes are thought to: 1. have evolved from a common ancestor, 2. have complex multicellular bodies 3. are photosynthetic eukaryotes

Alternation of Generations

-Plants have an Alternation of Generations in which the haploid and diploid stages are distinct, multicellular bodies. *Look at plant, moss, and fern alteration of generation life cycles --Haploid Generation: produces gametes (called the Gametophyte) --Diploid Generation: produces spores (called the Sporophyte)

Biological Life Cycles

-Series of changes in form that an organism undergoes, returning to the starting state -Haplontic life cycle --the haploid stage is multicellular --the diploid stage is a single cell --meiosis is "zygotic". -Diplontic life cycle --the diploid stage is multicellular --haploid gametes are formed --meiosis is "gametic". -Alternation of Generations (Haplodiplontic) life cycle --multicellular diploid and haploid stages occur --meiosis is "sporic". --Preferred by most plants (not always 50/50)

Coal, Oil, Natural Gas

-Two groups of seedless plants formed vast ancient "coal" forests in low-lying wetlands during the Carboniferous period (359-299 million years ago). -When these plants died, they formed peat deposits that eventually formed coal. (Results of fossilization process of seedless plants) -Coal, oil, and natural gas are fossil fuels. --Pressure and heat gradually converted peat into coal. --Oil and natural gas formed from marine organisms --The process that produced no longer exists -Burning fossil fuels releases CO2 and other greenhouse gases into the atmosphere, which are now causing a warming climate. -As temperatures dropped during the late Carboniferous period (which ended the period) --glaciers formed and the climate turned drier and --wind-dispersed pollen and protective seeds gave seed plants a competitive advantage. (drove the evolution of pollen and seeds)

Read 4.7

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Skim through 4.9 and use this section to apply 14.8 information.

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Study the figure 14.3A and use text for specific examples to give you context for information in Figure 14.3A

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Describe five types of prezygotic barriers barriers that prevent populations of closely related species from interbreeding.

1 Habitat isolation-two species live in the same general area but not in the same kind of place. 2 Temporal isolation- two species breed at different times (seasons, times of day, years). 3 Behavioral isolation-there is little or no mate recognition between females and males of different species. 4 Mechanical isolation-female and male sex organs are not compatible 5 Gametic isolation- female and male gametes are not compatible

4 Major Groups of Plants

1. Nonvascular plants: (bryophytes) include the mosses, hornworts, and liverworts. 2. Vascular plants: have lignin-hardened (protein that solidifies and hardens) vascular tissues that provide strong support. 3. Ferns: are seedless vascular plants with flagellated sperm (need moisture for sexual reproduction) 4. Seed plants: Have sperm-transporting pollen grains and protect embryos in seeds. -Gymnosperms (i.e pines): produce seeds in cones. -Angiosperms: --Seeds develop within protective ovaries (fruit). --Have flowers. --Aid in pollination. --Protect developing female gametophyte.

Describe three types of postzygotic barriers that prevent populations of closely related species from interbreeding.

1. Reduced hybrid viability- most hybrid offspring die. 2. Reduced hybrid fertility- hybrid offspring are sterile. 3. Hybrid breakdown- the first-generation hybrids are viable and fertile but the offspring of the hybrids are feeble or sterile

Describe the major protist clades, noting characteristics and examples of each.

Algae protozoan parasites mixotrophs

Explain segmentation and what kind of animals they occur in. Explain implications of this

Arthropods have distinct body segments, each of which is specialized. Because they (especially insects) have an external skeleton, each segment is very modular, meaning each body segment develops independently, modification of how genes and switches of downstream tool box genes can modify the development of each body segment without affecting the other segments. A huge diversity of body forms has resulted because there's much less developmental constraint on body form. Chordates also have distinct body segments. Because they have internal skeletons, development body segments are more integrated and thus do not occur independently, putting more constraints on body form

What implications does the exoskeleton have for arthropods?

As the arthropod grows, it must periodically shed its old exoskeleton and secrete a larger one, a complex process called molting. This means that they cannot grow beyond a certain size without the exoskeleton crushing them. Must go through soft shell phase.

Compare the characteristics of the three domains of life.

Bacteria-prokaryotic, can survive harsh climates, chlorophyl based photosynthesis Archae- prokaryotic, can survive harsh climates, Eukaryotes- eukaryotic, cant adapt to harsh climates, organelles

Describe the discoveries made by Peter and Rosemary Grant in their work with Galápagos finches.

Birds with stronger beaks had greater reproductive sucess during the dry season when seeds were scarce and larger seeds must be consumed. During wet years, birds with smaller beaks are more efficient at eating the abundant amount of small seeds so reproductive rate of birds with smaller beaks increased.

Describe the evolution of larger brain size in hominins.

Brain size didn't begin to evolve until climate became variable. Increased brain size adaptation is thus to become adaptable to constantly changing environments. Increased use of tools enabled hominids to not be as dependent on jaws for processing food and obtaining nutrients and thus jaw muscles reduced in size, making room for bigger brains. Selected for bigger brains (relative to body size) and more complex brains (more interconnectedness of brain regions( for better tool making (anticipate flaws in stone) and tool use (more refined tools and throwing spears).

morphological species concept

Classifies organisms based on observable physical traits applied to asexual organisms and fossil

phylogenetic species concept

Defines a species as the smallest group of individuals that shares a common ancestor and forms one branch of the tree of life

ecological species concept

Defines a species by its ecological role or niche and unique adaptations to particular roles

Biological species concept and disadvantages

Defines species as a group of populations whose members have the potential to interbreed in nature, and produce fertile offspring. -Reproductive isolation:prevents gene flow between species, and maintains separate species

Explain why a diagram of the tree of life is difficult to construct.

Evolution is complex due to how genes change, how quickly tey change...shouldnt be a straight tree branch at the beginning of evolution- should be a twisted mess

4 Evolutionary events w/ 4 major groups

Evolution of plants is marked by four evolutionary events associated with four major groups of plants: 1. Nonvascular Plants (Bryophytes: mosses, hornworts, liverworts) --Advent of nourishment of a multicellular embryo within the body of the female plant. (retain it in the female plant, nurture it) 2. Seedless Vascular Plants (Lycophytes: ferns) --Advent of vascular tissue. (xylem and phloem, don't make seeds) 3. Gymnosperms (conifers) and Angiosperms (flowering plants) --Produce seeds. (a little container that has everything the empbryos need to make their own food) 4. Flowering Plants --Attract pollinators and produce fruits. (enhances the life, by increasing the rate of production/survivsl) --Fruit = enlarged ovaries

How does evolutionary change often occur? How do starfish relate to evolution?

Evolutionary change often occurs through paedomorphosis. The starfish embryo is bilateral and the common ancestor of starfish and all other deuterosomes is thought to most resemble the larval form of the starfish. Starfish larva are not the common ancestor of chordates because it has been continually evolving since starfish split from the line that would become chordates, but they are most similar among living organisms.

Distinguish between bacterial exotoxins and endotoxins, noting examples of each.

Exotoxins- are proteins that bacterial cells secrete into their environment. Endotoxins- Endotoxins are components of the outer membrane of gram-negative bacteria that are released when the cell dies or is digested by a defensive cell. Can cause a fever, aches, or a serious drop in BP

Explain how reproductive barriers might evolve in isolated populations of organisms. (Refer to study of laboratory-raised fruit flies and monkey flowers. Refer back to Fig 14.3A when needed. Fig 14.5A & 14.5B are useful)

Fruit flies whose primary food source was maltose as opposed to starch were more likely to mate with those who shared the same food preference .

Briefly describe the history of life on Earth. Describe the key events that serve to divide the eras.

Hadean, archaean, proterozoic, phanerozic- Paleozoic, Mesozoic, and Cenozoic.

*** Describe the characteristics of hagfishes/lampreys.

Have a head because the notochord doesn't continue into the head making it a distinct structure. They are vertebrates *** They have mouths but they are not hinged, so their jaws do not work.

Distinguish between homologous and analogous structures and provide examples of each. Describe the process of convergent evolution.

Homologous structures= similarities due to shared ancestry, evolving from the same structure in a common ancestor but perform many functions. analogous structures= many forms for one function

What happened as humans left Africa? Are humans still evolving?

Huge bottleneck that reduced population of humans to between 2 and 10 thousand. As a result humans have very little genetic diversity as compared to other primates. Lack of genetic diversity helps explain why we haven't split into multiple species, also that we completely fill our nice. Humans are still evolving as evidenced by "hitchhiker" genes onto genes related to immunity to diseases.

What four features do we share with invertebrate chordates, such as lancelets?

Human embryos and invertebrate chordates all have (1) a dorsal, hollow nerve cord, (2) a notochord, (3) pharyngeal slits; and (4) a post-anal tail

What characteristics prompted the discoverers of the "hobbit" to classify it in the genus Homo?

Humanlike skull characteristics and the apparent use of stone tools

*** Compare the phylogenetic relationships in Figures 18.4 and 18.15, noting similarities and differences.

In the morphology-based tree, annelids and arthropods are hypothesized to be more closely related to each other than to mollusks, largely based on their segmented bodies. In the molecular-based tree, arthropods are separated from both annelids and mollusks and are placed in the ecdysozoan clade. *** both are chordates but not vertebrates

Explain why evolutionary trends do not reflect "directions" or "goals."

It is a reflection of how genes interact with their environment

Define exaptation and describe two examples in birds.

It is when a feature evolves in one context but become co-opted for another function in another. Feathers- insulation to begin with but then turned useful in flight

What is the distinction between larva and adult stages?

Larva isn't capable of sexual reproduction but adults are.

Compare the three main groups of living primates.

Lemurs, lorises, and tarsiers= primates bc have basica primate characteristics of joints that are flexible for climbing trees and swinging on branches, hands that are flexible for climbing trees and swimming Anthropoids (monkey and apes) have opposable thumb. New World and Old World monkeys split. New World Monkeys have prehensile tails. Apes split from old world monkeys. Apes don't have tails. Chimpanzees and bonobos are most closely related to apes but we didn't evolve from chimps, we share our most recent common ancestor with them.

Describe the unusual characteristics of the newly discovered Homo floresiensis.

Many different waves of hominids left Africa. Fossil evidence shows that other hominid species could have persisted until as recently as 13 TYA

Distinguish between microevolution and speciation.

Microevolution is the change in the gene pool of a population from one generation to the next. Speciation is the process by which one species splits into two or more species.

Describe the circumstances that led to the adaptive radiation of the Galápagos finches. Define founder effect. Does it apply to adaptive radiation on Galapagos?

Multiple speciation events are more likely to occur in island chains that have physically diverse habitats, islands far enough apart to permit populations to evolve in isolation, and islands close enough to each other to allow occasional dispersions between them.

Relationship between plants and fungi

Mutually beneficial symbioses between plants and fungi began 500 million years ago, when plants first occupied land. -These intimate associations allow plants to tap a vast underground network of fungal filaments into which water and mineral nutrients flow (fungi are good absorbers which help plants absorb nutrients into their roots, the sugars created by the plant are given to the fungi) -Plants supply mycorrhizae with sugars and other organic molecules. -At least 90% of all plants form such relationships

Describe the relationships between Neanderthals and modern humans. Describe the evidence that suggests that all modern humans share a common ancestor that lived 160,000-200,000 years ago.

Neanderthals and humans both evolved in Africa but Neanderthals migrated to Europe first. Humans followed and outcompeted/interbred with Neanderthals leading to Neanderthals extinction. Humans were hunter/gatherers so ate a wider variety of foods. Humans had smaller stature and so didn't have as hight energy demands as Neanderthals did.

Explain how sympatric speciation can occur, noting examples in plants and animals.

Occurs when a new species arises within the same geographic area as a parent species. (occurs mostly in plants). Many plant species have evolved by polyploidy in which cells have more than two complete sets of chromosomes.

Explain how hybrid zones are useful in the study of reproductive isolation.

Over time in hybrid zones reinforcement may strengthen barriers to reproduction, such as occurs in flycatchers, or fusion may reverse the speciation process as gene flow between species increases, as may be occurring among the cichlid species in Lake Victoria. In stable hybrid zones, a limited number of hybrid offspring continue to be produced.

To which mammalian order do we belong? What are the three main groups of this order?

Primates: 1. lorises, pottos, and lemurs 2. tarsiers 3. anthropoids

Distinguish between the subgroups of the domain Bacteria, noting the particular structure, special features, and habitats of each group.

Proteobacteria-are all gram-negative, share a particular rRNA sequence, and represent all four modes of nutrition. Gram-positive bacteria- actinomycetes common in soil. Streptomyces are often cultured by pharmaceutical companies as a source of many antibiotics, including streptomycin. Cyanobacteria-Cyanobacteria are the only group of prokaryotes with plantlike, oxygen-generating photosynthesis. Chlamydias- Chlamydias live inside eukaryotic host cells. Spirochetes-are helical bacteria and notorious pathogens, causing syphilis and Lyme disease.

Describe the extremely diverse assortment of eukaryotes.

Protists, protozoans, algae

List the characteristics that arthropods have in common.

Segmentation, exoskeleton, specialized jointed appendages

Describe the four stages that might have produced the first cells on Earth.

The abiotic (nonliving) synthesis of small organic molecules, such as amino acids and nitrogenous bases. The joining of these small molecules into polymers, such as proteins and nucleic acids. The packaging of these molecules into "protocells," membrane-enclosed droplets that maintained an internal chemistry different from that of their surroundings. The origin of self-replicating molecules that eventually made inheritance possible.

Explain how volcanoes and earthquakes result from plate tectonics.

The boundaries of plates are hotspots of volcanic and earthquake activity when they rub by each other

Explain the differences between a deuterostomes and protostomes.

The fate of the opening formed during gastrulation leads to the developing digestive tract. In protostomes, this opening becomes the mouth, and, in deuterostomes, it becomes the anus. Other differences between the two include the pattern of early cell divisions and the way the coelom forms. The difference in embryonic development between them represent an evolutionary split such that any features that are shared between the two groups beyond being bi-lateral are homologous.

Describe the conditions on the surface of the early Earth. Describe the evidence that life on Earth existed at least 3.5 billion years ago.

The first atmosphere was probably thick with water vapor and various compounds released by volcanic eruptions, including nitrogen and its oxides, carbon dioxide, methane, ammonia, hydrogen, and hydrogen sulfide. Lightning, volcanic activity, and ultraviolet radiation were much more intense than today. Evidence because of the fossils in the stromatolites,

Define zygote

The initial cell formed when two gamete cells are joined by means of sexual reproduction.

In what ways are amphibians not completely adapted for terrestrial life?

Their eggs are not well protected against dehydration; many species have an aquatic larval form; their skin is not waterproof and must remain moist to permit gas exchange.

Describe the evidence that suggests that hominids didn't evolve in a straight line leading directly to our species.

There were many different branches in the human family tree. All hominids evolved in Africa. Each branch followed its own evolutionary path such that each developed a mosaic of characteristics some appearing more or less humanlike. It's difficult to know which were in the direct human line too because they coexisted and continued to exist after more modern hominids appeared. There is no "missing link as would be predicted by a gradualism pace of evolution where all features evolved at the same time, and so a halfway point fossil would need to be found. Nothing halfway between. The bottom evolved first before the top, which remained almost completely ape.

Describe the evidence that suggests when upright posture and large brains first evolved in humans.

To be a hominid, a mammal must be bipedal as evidence by a magnum foramen located beneath the skull. Also typically has reduced canine teeth which in other primates are used for intimidating others and so indicates a more cooperative social structure. Early hominid skeletons had pelvis shapes that were more similar to modern humans than to chimps but still had brains the same size as chimps. Bi=pedal walking evolved to get to more dispersed food patches because it is a very efficient form of locomotion.

Describe the nutritional diversity of prokaryotes and explain the significance of biofilms.

They are highly organized colonies that attach to surfaces; They form on most any support, including rocks, soil, organic material, or the surface of stagnant water; Biofilm formation begins when prokaryotes secrete signaling molecules that attract nearby cells into a cluster. Once the cluster becomes sufficiently large, the cells produce a gooey coating that glues them to the support and to each other, making the biofilm extremely difficult to dislodge.

Describe the characteristics of lancelets.

They have all structures to be a chordate. They also have a notochord that goes the length of body and thus don't have a distinct head segment even though they have brains.

Name and describe the transitional species that occupy the range between fishes and amphibians in evolutionary history.

Tiktaalik was a transitional species between fish and amphibians. It had eyes on top, fins with three sets of bones, one long bone, two skinny bones, lots of little bones. lobed fin fish like paddle fish similar to common ancestor with tiktaalik. lung fish are lobed fin fish and use swim bladder like a lung. The fossil record for the transition from fish to tetrapod demonstrates that many of the tetrapod features evolved prior to becoming terrestrial organisms.

Describe the Cambrian "explosion" of animal diversity and two hypotheses that have been advanced to explain its occurrence.

Toolbox genes like Hox genes got acted upon by natural selection. The explosion represented the culmination of millions of years of evolution during which all the genes evolved to create the body plans, and when the correct selective pressure was placed on the organisms, it was simply a matter of mutations in switches or duplication and modification of existing genes that resulted in the diversity of body forms. Two hypotheses: increasingly complex predator prey relationships drove a diversity of body forms. increased levels of oxygen may have also played a role in enabling later animals with greater metabolic needs.

Explain what we have learned about the evolution of life from the study of velvet worms.

Velvet worms confirm that changes in body form occurred because of changes in gene expression due to gene duplication and modification of switches rather than evolution of new genes. Velvet worms are evolutionarily ancient organisms. *** The same box genes that are present more modern organisms. Only the pattern of gene expression is different, reinforcing the ideas of the cambrian explosion. All genes were in place very early on. evolution rarely invents something new, just modifies an existing structure.

Describe the goals of systematics. List the progressively broader categories of classification used in systematics in order, from most specific to most general.

a discipline of biology that focuses on classifying organisms and determining their evolutionary relationships. domain, kingdom, phylum,class, order, family, genus, species

Describe the causes, frequency, and consequences of mass extinctions over the last 500 million years.

affect biological diversity profoundly, takes a long time to recover (if ever)

Describe the characteristics of reptiles.

amniotic eggs enable internal fertilization and so reptiles aren't dependent on water for reproduction

Describe the structures and functions of the diverse features of prokaryotes and explain how these features have contributed to their success.

are able to live in diverse habitats, help maintain all the chemical cycles on Earth, and are the reason eukaryotes exist. Divided in to Archae and Bacteria; flagella help them move,fimbrae stick them to other surfaces, multiply quickly,

Describe the characteristics of amphibians.

became tetrapods (vertebrates with two sets of limbs), still tied to water because they have to fertilize externally

Describe the defining characteristics of animals.

bodies composed of multiple eukaryotic cells; ingestion of food (heterotrophic nutrition); absence of cell walls; unique cell junctions; nerve and muscle cells (generally); sexual reproduction and life cycles with unique embryonic stages; unique developmental genes; gametes alone representing the haploid stage of the life cycle

How can paleoanthropologists conclude that a species was bipedal based on only a fossil skull?

by the location of the opening where the spinal chord exits the skull

Define the terms clade, monophyletic groups, shared derived characters, shared ancestral characters, ingroup, outgroup, phylogenetic trees, and parsimony.

clade= organisms are grouped in to monophyletic groups=an ancestral species and all of its descendants. shared derived characters= unique evolutionary novelties. shared ancestral characters= , characters that originated in an ancestor. Ingroup=the taxa whose phylogeny is being investigated outgroup= a taxon that diverged before the lineage leading to the members of the ingroup phylogenic trees= parsimony= looking for the simplest explanation for observed phenomena

Describe the characteristics of Chordata.

deuterostome, dorsal hollow nerve chord and ventral gut, pharyngeal slits, post anal tail, notochord

Describe the characteristics of Echinodermata.

deuterostomes, embryos are bilateral, see stuff on starfish

Describe the steps of Koch's postulates and explain why they are used.

establish a causative relationship between a microbe and a disease.

What types of evidence indicate that Homo sapiens originated in Africa?

fossils and analyses of mitochondrial DNA and chromosomal DNA

Explain how geologic processes can fragment populations and lead to speciation

geographically separated = gene pool separated Isolated populations will no longer share changes in allele frequencies caused by natural selection, genetic drift, and/or mutation.

***Describe the characteristics of lobe-finned fishes.

have bones in limbs that match the box expression of tetrapod limbs, swim bladder

Explain how prokaryotes help clean up the environment.

have great nutritional diversity, are quickly adaptable, and can form biofilms; help to remove pollutants from soil, air, and water; decompose organic matter so then the sludge can be placed in a landfill; can remove organic materials from waste

Describe the characteristics of chondrichthyans.

have skeletons made out of cartilage (developmentally cartilage becomes bone, ancestors likely had bone and lost it later in evolution), sharks and rays. They have a hinged jaw that evolved from the anterior most pharyngeal slits which were originally used for filtering food. In humans, the jaw bones make up the inner ear. slits used for gas exchange

***Describe the characteristics of ray-finned fishes.

have swim bladders which is used for holding air so that the fish can remain buoyant (that is homologous with tetrapod lungs), skeleton made of bone

Explain how primary endosymbiosis and secondary endosymbiosis led to further cellular diversity.

primary- eukaryote englufs prokaryote secondary- eukaryote engulfs eukaryote creation of the mitochondia and other organelles

Describe the key events in the history of life on Earth.

prokaryotes, oxygen forms, unicellular eukaryotes, multicellular eukaryotes, animals, colonization of land

Describe the experiments of Stanley Miller and others in understanding how life might have first evolved on Earth.

may have started in deep sea vents, meteorites

Distinguish between monotremes, marsupials, and placental mammals.

monotremes-egg laying mammal (duck-billed platypus marsupials- short gestation (kangaroo) placental mammals- long gestation (humans)

Describe the characteristics of mammals.

nurse and care for their young, hair, mammary glands that produce milk

Explain how and why adaptive radiations occur.

periods of evolutionary change in which many new species evolve from a common ancestor, often following the colonization of new, unexploited areas.

Describe how Earth's continents have changed over the past 250 million years and the consequences of these changes for life on Earth.

plate movement shapes different lands; environement, climate, and biodiversity were all shaped by plate tectonics. continental drift---marsupials only in australia

Describe the significance of protocells and ribozymes in the origin of the first cells.

protocells- membran enclosed droplets; formed when lipids mix with water ribozymes- help carry out self-replicating processes

Describe the characteristics of Arthropoda.

protostomes, have an exoskeleton, have a ventral hollow nerve chord and a dorsal digestive tract, jointed appendages, body segmentation- makes it modular meaning that one part can evolve without affecting other modules, develops independently, results in vast number of bug species

Explain how radiometric dating and the relative position of a fossil within rock strata are used to determine the age of rocks.

related to the sequences and ages of the fossils in the rock strata

Explain how molecular clocks are used to track evolutionary time.

rely on genes that have a reliable rate of change; can be used to date evolutionary episodes

Explain how populations of prokaryotes can adapt rapidly to changes in their environment.

reproduce by binary fission, can rapidly produce a new generation within hours.......great deal of genetic variation by spontaneous mutations, increasing the likelihood that some members of the population will survive changes in the environment.

Describe the life cycle of Ulva, noting each form in the alternation of generations and how each is produced.

sea lettuce, is a multicellular green alga with a complex life cycle that includes an alternation of generations that consists of a multicellular diploid (2n) form, the sporophyte, that alternates with a multicellular haploid (1n) form, the gametophyte.

From what structure might the swim bladder of ray-finned fishes have evolved?

simple lungs of an ancestral species

Explain how genes that program development function in the evolution of life. Define and describe examples of paedomorphosis.

slight genetic changes can cause great morphological changes. paedomorphosis=The retention in the adult of body structures that were juvenile features in an ancestral species and

Researchers found the velvet worms and arthropods share the same set of homeotic genes. What conclusion did they draw from this result?

the evolution of diverse arthropod body segment types wasn't the result of new genes in arthropods

Describe the diverse types of Archaea living in extreme and moderate environments.

thrive in extreme environments; have unusual proteins and other molecular adaptations that enable them to metabolize and reproduce effectively; extreme halophiles- extremely salty environments; extreme thermophiles- extremely hot environments Methanogens- live in anaerobic environments and give off methane as a waste product from the digestive tracts of cattle and deer and decomposing materials in landfills.

Explain how bacteria can be used as biological weapons.

toxic materials produced from bacteria to kill or incapacitate the host they infect

Explain how molecular biology is used as a tool in systematics.

uses DNA to look at relatedness