Biodiversity Lecture - Summary Campbell Biology PDF

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Chapter 22- DEscent with modification ●

Evolution ○

Descent with modification ■

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Darwin

Aristotle (384-322 BCE) ○

Believed that organisms were unchanged or fixed in nature

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Developed the scala naturae (scale of nature) which was like a ladder that classified organisms by increasing complexity

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Carolus Linnaeus (1707-1778) ○

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Fossil ○

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Remains or traces of organisms from the past

Strata ○

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Developed the two part of binomial way of naming species that is still used today

When new layers of sediment cover older ones and compress it

Paleontology ○

The study of fossils ■

Developed by georges Cuvier (1769-1832) ●

He noted that in the strata older fossils were more dissimilar from current life forms

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Also while from layer to layer, some new species appeared and others disappeared

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James Hutton (1726-1797) ○

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Each layer is due to a catastrophic event

Earth's features are due to gradual mechanisms of nature

Charles Lyell (1797-1875) ○

Used hutton's theory but expanded on it by saying that these same gradual mechanisms are still happening today

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Lamarck (1744-1829) ○

Noticed lines of descent

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Use and disuse ■

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Giraffe stretches its neck and it becomes longer and stronger

Inheritance of acquired characteristics ■

This more complex neck is now passed on to its offspring

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Adaptations ○

During his trip to the galapagos darwin noticed many organisms have inherited characteristics that enhance their chance of survival and reproductions

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Natural selection ○

Individuals that possess certain traits have a better chance of survival and reproduction over organisms without these specific traits

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Artificial selection ○

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Homology ○

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The selecting and breeding of desired traits

Due to common ancestry there are similarities between species

Homologous structures ○

Underlying structures in the skeletons of the arms, forelegs, flippers and wings of different mammals

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Vestigial structures ○

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“Leftover” structures that served a function in an organism's ancestor

Convergent Evolution ○

The independent evolution of similar traits in different lineages due  to similar  environments

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In species because they share these characteristics due to convergent evolution, their resemblance is said to be analogous and homologous

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Biogeography ○

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The scientific study of the geographic distributions of species

Pangea ○

The supercontinent which was a combination of all the continents around 200 million years ago

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Often times islands have species that are endemic, or not found anywhere else in the world

Chapter 23-The Evolution of Populations ●

Microevolution ○

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Evolution of a population, the smallest scale of evolution

Genetic Variation ○

Differences in individuals in the composition of their genes or other DNA sequences

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Only the genetically determined part of a phenotype variation can have evolutionary consequences

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New alleles can arise through mutation ○

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Neutral Variation ○

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A change in the nucleotide sequence of an organism's DNA

Differences in the DNA sequence that do not offer an advantage or disadvantage

Population ○

Group of an individual species that live in the same area and interbreed

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Different populations of a species may be isolated, exchanging genetic material rarely

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Gene Pool ○

All copies of every type of allele at every locus in all members of the population ■

If only one allele exists for a particular locus in a population then that allele is said to be fixed, a  nd all individuals are homozygous for that allele

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p-q=1

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Hardy weinberg equilibrium

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Allele and genotype frequencies are constant from generation to generation

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The generation is not evolving ■

P2 + 2pq + q2 = 1

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Homozygous Dominant + heterozygous + Homozygous Recessive

Conditions for Hardy Weinberg Equilibrium 1. No mutations 2. Random mating 3. No natural selection 4. Extremely large population size 5. No gene flow

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Adaptive evolution ○

By consistently favoring alleles over others, this can happen which leads to traits enhancing the chance of survival or reproduction increasingly in frequency over time

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Genetic drift ○

Chance events can cause allele frequencies to shift from one generation to the next

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Especially in small populations

Founder effect ○

A few individuals become isolated from a larger population, this smaller group establishes a population, it may establish a gene pool different than the larger population

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Bottleneck effect ○

Due to a sudden change in the environment, the population is drastically reduced ■

Due to chance alone, certain alleles may be overrepresented, underrepresented or absent in the survivors

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Effects of genetic drift: a summary

1. Genetic drift is significant in small populations a. Chance events can cause an allele to be disproportionately over or under represented in the next generation. Chance vents occur in all population sizes but they tend to alter the allele frequencies substantially in only small populations 2. Genetic drift can cause allele frequencies to change at random a. An allele can increase in frequency one year and then decrease the next, the change is not predictable 3. Genetic drift can lead to a loss of genetic variation within populations a. It can cause allele frequencies to fluctuate over time randomly so there is a chance that an allele can be eliminated from a population. Because evolution depends on genetic variation, such losses can affect how effectively a population can adapt to a change in the environment 4. Genetic drift can cause harmful alleles to become fixed a. Alleles that are neither harmful nor beneficial can be lost or become fixed (reach a frequency of 100%) by chance through genetic drift ●

Gene flow ○

Transfer of alleles in or out of a population due to the movement of fertile individuals or their gametes ■

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Relative fitness ○

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Reduces the genetic differences between populations

The contribution an individual makes to the gene pool of the next generation

Directional selection

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When conditions favor individuals exhibiting one extreme of a phenotypic range (white mice vs black mice, black mice are favorable) ■

Shifts the populations frequency curve for the phenotypic character in one direction or the other

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Disruptive selection ○

Occurs when conditions favor both extremes of a phenotypic range over those of intermediate phenotypes (3 mice: white, grey, black. This would favor the white mice and the black mice)

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Stabilizing selection ○

Acts against both extreme phenotypes and favors the intermediate variants (3 mice: white, grey, black. The grey mice are favorable)

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Sexual selection ○

Individuals with certain inherited characteristics are more likely than others of the same sex to obtain mates

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Sexual dimorphism ○

Difference in secondary sexual characteristics between males and females of the same species (male peacocks-colorful and vibrant, female peacocks-dulls colors)

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Intrasexual selection ○

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Individuals of one sex compete directly for mates of the opposite sex

Intersexual selection ○

Individuals of one sex (ususally the females) are choosy in selecting their mates from the other sex

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Frequency dependent selection ○

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The fitness of a phenotype depends on how common it is in the population

Heterozygote advantage ○

Individuals who are heterozygous at a particular locus have greater fitness than do both kinds of homozygotes

Chapter 24 ●

Allopatric speciation ○

Gene flow is interrupted when populations are split into geographically isolated subpopulations

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Speciation ○

When one species splits into two or more species

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Sympatric speciation ○

Speciation that occurs in populations in the same geographic area ■

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Polyploidy ○

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Occurs because of polyploidy and sexual selection

Species may originate from an accident in cell division

Autopolyploid ○

An individual that has two or more chromosomal sets derived from a single species

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Allopolyploid ○

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Fertile polyploid

Punctuated equilibria ○

Periods of apparent stasis punctuated by sudden changes ■

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Prezygotic barrier ○

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May contribute to reproductive isolation after the hybrid zygote is formed

Hybrid zone ○

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Prevents fertilization from occuring

Postzygotic barriers ○

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Change and then equilibrium

A region in which members of a different species meet and mate

Reinforcement\ ○

When natural selection strengthens prezygotic barriers

Chapter 25 ●

Macroevolution ○

Evolution of a population or the broad pattern of evolution above the species level

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Hydrothermal vents ○

Areas on the seafloor where heated water and minerals gushed from earth's interior

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Alkaline vents ○

Released water with a high ph and was warm (not hot) making it better suited for the origin of life

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RNA ○

Likely the first genetic material

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Ribozymes ○

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RNA catalyst

Geologic record ○

Standard time scale that divides Earth's history into four eons and further subdivisions

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Stromatolites ○

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Layered rocks that form when prokaryotes bind thin films of sediment together

Endosymbiosis ○

The prokaryotic cell would engulf another cell that would then evolve into an organelle found in all eukaryotes, the mitochondria

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Serial endosymbiosis ○

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Mitochondria evolved before plastids through several endosymbiosis events

Cambrian explosion ○

Many present day animal phyla suddenly appeared about 535-525 mya according to the fossil record

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Pangea ○

Supercontinent from 250 mya

Chapter 26 ●

Phylogeny ○

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Evolutionary history of a species or group of species

Dear K  ing P  hillip Came Over For Good Soup ○

Domain ■

Phyla ●

Class ○

Order ■

Family ●

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Taxon ○

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The named taxonomy unit at any level of the hierarchy

Branch point ○

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Species

Common ancestor

Homology ○

Shared ancestry

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Analogy ○

Convergent evolution ■

Similar characteristics between species that evolved due to environment

Chapter 27: Bacteria and Archaea ●

Prokaryotes can tolerate extreme conditions well ○

Most are unicellular

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Cell wall ■

Helps it maintain shape, protects it and prevents it from bursting in hypotonic environment

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Peptidoglycan ○

Is in most bacterial cell walls-Polymer composed of modified sugars cross-linked by short polypeptides ■

Encloses the entire bacterium and anchors other molecules that extend from its surface

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Gram Stain Technique ○

Stained with crystal violet dye and iodine ■

Rinsed in alcohol ●

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Gram positive Bacteria ○

Simple walls composed of a thick layer of peptidoglycan

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Appear Violet after Gram Stain

Gram Negative ○

Less peptidoglycan, more complex

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Outer membrane that contains lipopolysaccharides ■

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Carbohydrates bonded to lipids

Appear Pink or red after Gram Stain

Capsule ○

Layer of sticky polysaccharide or protein ■

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Stained with a red dye that enters the cell and binds to its DNA

Allow cells to adhere to other cells in a colony

Endospores ○

Resistant cells bacteria develop when they lack water or essential nutrients

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Original cell produces a copy of its chromosome and surrounds that copy with a multilayered structure, forming the endospore ○

Original cell then lyses, releasing the endospore ■

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Fimbriae ○

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Hairlike appendages some bacteria stick to their substrate

Flagella ○

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Most endospores are extremely durable

Help the cell move

Prokaryotic cells lack complex compartmentalization associated with the membrane bound organelles of eukaryotes

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Nucleoid ○

Region of the cytoplasm that is not enclosed by a membrane where the chromosomes are located

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Plasmids ○

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BInary Fission ○

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Single prokaryotic cell divides into two cells, then four, then 8, then 16 and so on

Genetic Recombination ○

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Dna molecule that is independently self replicated and only carries a few genes

Combining of dna from two sources

Transformation, transduction, and conjugation can bring together DNA from different individuals (cells) ○

This movement of genes from one organism to another is called Horizontal Gene Transfer

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Transformation ○

Genotype and possibly phenotype are altered by the uptake of foreign DNA from its surroundings ■

ex.) harmless strain of Streptococcus pneumoniae c an be transformed into pneumonia causing cells if the cells are exposed to DNA from a pathogenic strain

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Transduction ○

Phages (from “bacteriophages,” the viruses that infect bacteria) carry prokaryotic genes from one host to another

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Conjugation

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R plasmids ○

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Must us O2 for cellular respiration and cannot grow without it

Obligate Anaerobes ○

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Often carry resistance genes

Obligate Aerobes ○

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DNA is transferred between two prokaryotic cells that are temporarily joined

Are poisoned by O2

Anaerobic Respiration ○

Other substances than O2 such as NO3- or SO42-  accept electrons at the downhill end of electron support chains

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Facultative Anaerobes ○

Use O2 if its present but also carry out fermentation or anaerobic respiration when needed in that environment

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Nitrogen fixation ○

Some cyanobacteria and some methanogens (a group of archaea) convert atmospheric nitrogen (N2) into ammonia (NH3) ■

They then incorporate this fixed nitrogen into amino acids and other organic molecules

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Heterocysts ○

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Specialized cell that only focuses on nitrogen fixation

Biofilms ○

Where metabolic cooperation between different prokaryotic species often occurs in surface coating colonies

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Extremophiles ○

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Extreme Halophiles ○

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High saline environments

Extreme thermophiles ○

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Certain archaea that “love” extreme conditions

Very hot environments

Methanogen ○

Archaea that live in a more moderate environment and release methane as a byproduct of their unique way of obtaining energy ■

Use CO2 to oxidize O2

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Decomposer ○

Chemoautotroph that breaks down dead organisms ■

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Unlock supplies of carbon, nitrogen and other components

Symbiosis ○

Ecological relationship in which two organisms live in close contact with each other

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Host ○

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Symbiont ○

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Larger organism in symbiotic relationship

Smaller organisms in symbiotic relationship

Mutualism ○

Both species benefit ■

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Common involving prokaryotes

Commensalism ○

One organism benefits while the other is not harmed or helped in any significant way

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Parasitism ○

Ecological relationship in which a parasite eats the cell contents, tissue or body fluids of its host

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Pathogens ○

Diseases that parasites cause ■

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Exotoxin ○

Proteins secreted by certain bacteria and other organisms ■

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Many pathogens are prokaryotic

Exotoxin is a poison

Endotoxin ○

Lipopolysaccharide components of the outer membrane or gram negative bacteria ■

Released only when bacteria die and their cell walls break down

Chapter 28: Protists ●

Protists ○

Mostly unicellular groups of eukaryotes ■

Have nucleus and membrane enclosed organelles

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Mixotrophs ○

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Such as mitochondria and Golgi apparatus

Combine photosynthesis and heterotrophic nutrition

There are 4 supergroups of protists

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Excavata ○

Excavated groove on one side of cell body

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Two major clades (parabasalids and diplomonads) have highly reduced mitochondria

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Euglenozoans have flagella that differ in structure from the other organisms

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Include many predatory and photosynthetic species

SAR ○

Three large and diverse clades ■