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79 Cards in this Set
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Evolution
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-Genetic change in a lineage over time (generations)
-change in allele frequencies = evolution has occured -first convincing case put forth by Charles Darwin ("father of evolution" |
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Natural Selection
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survival of the fittest
-"fit"= the ability to survive AND reproduce ie: goddamn British Peppered Moth (industrial melanism) |
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Artificial Selection
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evolution due to an unnatural factor
ie: breeding of dogs -cross breeding of plants to produce superior offspring |
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Vestigial Structures
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structures (ie:bones) that have no funtionality
-supports the idea that all living organisms evolved from another structurally diff. ancestor ie: whales have bones thought to be leftover leg bones |
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Charles Darwin
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-Naturalist, sailed on HMS Beagle in 1831
-Galapagos Islands -his book, Origin of Species, published 1859 |
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Origin of Species
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-written by Charles Darwin in 1859
-argued two main points: 1. Evolution explains the unity & diversity of life... descent w/modification 2. Natural Selection is the main cause of evolution (survival of the fittest) *differential reproductive success leads to adaptation |
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Microevolution
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evolution on a small scale
-a population is the smallest unit that can evolve *individuals do not evolve |
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Speciation
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the creation of a new species
-a new species is created with the evolution of reproductive barriers |
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Reproductive Barriers
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any barrier that impedes two individuals from producing fertile hybrids
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What are the two categories of Reproductive Barriers?
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*prezygotic (zygote will not form)
*postzygotic (zygote forms, but does not survive) |
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Types of Speciation
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1. Allopatric Speciation
2. Sympatric Speciation |
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Allopatric Speciation
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a speciation event in which the initial block of gene flow is caused by a geographic barrier that physically isolates the populations
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Sympatric Speciation
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formation of a new species within the rage of the parental population
-no physical geographic barrier -much less common than allopatric speciation |
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Macroevolution
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Origin of taxonomic groups higher than the species level
-evolutionary change substantial enough to view its products as new genera, families or phyla *Has a random component |
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What do Macroevolutionary Biologists study?
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-major evolutionary changes
ie: bird feathers, insect wings when did these features evolve? -evolutionary trends (why certain changes came about over time in a specific species) ie: extinctions and radiations |
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Pace of evolution
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the rate at which evolution occurs...
consists of two theories 1. gradualism 2. punctuated equilibrium |
theories
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Gradualism
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one of the theories of the pace of evolution
-change that slowly accumulates over time |
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Punctuated Equilibrium
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one of the theories of the pace of evolution
- change consisting of periods of stasis, followed by periods of rapid change |
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Radiations
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a period of time where many species evolve
-an increase in biodiversity over a relatively short period of time -usually occurs after extinction |
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Ecology
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the study of how organisms interact with each other and with their environment
-ecology drives evolution |
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Levels of Ecological Organization
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-populations
-communities -ecosystems |
general... basic levels
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Populations
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groups of individuals of the same species living together in one area
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Communities
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populations of different species living together in one area
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Ecosystems
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communities and the non-living parts of the environment with which they interact
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Population Structure
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Key aspects:
Population Size Population Density Population Dispersion |
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Population Size
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a count of the total number of individuals that exist
-Affects populations ability to survive -small populations - more likely to go extinct |
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Population Density
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Number of individuals per unit area
-low density can be a problem for that population (harder to come in contact w/each other in order to mate) |
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Population Dispersion
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Spacing of individuals within the population
*Random, uniform or clumped |
3 types
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Clumped Dispersion
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Clumped dispersion is when individuals aggregate in patches.
ie: schools of fish |
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Uniform Dispersion
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uniform dispersion is when individuals are evenly spaced.
- usually due to territoriality |
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Random Dispersion
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In random dispersion, the position of each individual is independent of the others.
Overall, dispersion depends on resource distribution. |
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Survivorship Curves
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Graphical representation of the survivorship (opposite of mortality) at each age
Type I, Type II & Type III |
definition and 3 types
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Type I Survivorship Curve
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increased risk of dying when old
ie: humans |
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Type II Survivorship Curve
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equal chance of dying at all ages
ie: hydra |
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Type III Survivorship Curve
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increased chance of dying when young
ie: shellfish (oysters, clams, etc.) -due to lack of parental care |
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Biotic Potential
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the rate a population would grow at with no limits
*represented by "r" an intrinstic rate of increase |
has to do with population growth
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Two Models of Population Growth
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1. Exponential Growth ( J-curve)
2. Logistic Growth (S-curve) -growth rate slows as carrying capacity is reached |
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Carrying Capacity
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populations eventually reach a limit to their growth
*number of individuals that the environment can support (represented by the letter "k") |
has to do with population growth
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Limits to Population Growth
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-resource limitation (not enough food, etc)
-predation (get eaten, ha.) |
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Community Ecology
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interactions among populations
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Niche
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-a species/population's place in the ecosystem
-total of all the ways an organism uses resources in its environment -food consumption, space utilization, temp range, etc... |
Community Ecology
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Habitat
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physical location of a species
-the environment in which it resides |
Community Ecology
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Definition of Competition
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the struggle between organisms to utilize the same resource when the resource is limited
-niches overlap and resources are limited |
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Types of Competition & their definitions
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1. Interference Competition
-"fighting" physical interaction between individuals 2. Exploitive Competition - consuming shared resources (no physical interaction, one community uses up all the food, the other dies) |
2 types
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Interspecific competition
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between individuals from different species
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Intraspecific competition
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between individuals from same species
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Competitive exclusion
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-no two species can occupy the same niche indefinitely
-one species will be outcompeted and may be driven to extinction locally |
Interspecific competition
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What can niche overlap lead to?
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resource partitioning (results in species coexisting, territories for feeding)
-character displacement (species develop diff. traits to allow them to use diff resources, ie: galapagos finches) |
there are two diff results
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Predation
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Predator uses prey for food
-prey evolves defenses, predator evolves adaptations to overcome (coevolution)…arms race |
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Plant defenses against herbivores:
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morphological (physical structures) -thorns, spines, plant hairs
chemicals - secondary compounds |
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Animal defenses against predators:
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-Behavioral defenses include fleeing, hiding, self-defense, noises, and mobbing.
-Camouflage includes cryptic coloration, deceptive markings. Mechanical defenses include spines & shells. Chemical defenses include odors and toxins – may get them from the plants they eat (ex: monarch butterfly & milkweed) |
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Aposematic coloration
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is indicated by warning colors, and is sometimes associated with other defenses (toxins).
ie: poison dart frogs |
Animal defenses against predators:
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Batesian mimicry
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is when a harmless species mimics a harmful one.
ie: certain species of caterpillar mimics a snake (behaviorally & physically) |
Animal defenses against predators:
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Müllerian mimicry
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is where two or more unpalatable species resemble each other.
ie: yellow jackets, wasps, etc. all look similar, predators know not to eat anything that looks like them |
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Keystone species
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-a species that regulates other species in a community
ie: sea stars pick off mussels in rocky intertidal zones, allow less dominant species to thrive there as well *a community structure is greatly affected if keystone species are removed ie: kelp- sea urchins-sea otters-orcha |
predation
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Coevolution
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refers to reciprocal evolutionary adaptations of two interacting species.
-When one species evolves, it exerts selective pressure on the other to evolve to continue the interaction. |
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Systematics
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The study of biological diversity in an evolutionary context
-encompasses both taxonomy and phylogeny |
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Taxonomy
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The science of the classification of organisms into species
-also to classify species into higher taxonomic levels *Species that appear to be closely related are grouped into the same genus. |
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Taxonomic System
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-classification system
Domain Eukarya Kingdom Animalia Phylum Chordata Class Mammalia Order Primates Family Hominidae Genus Homo species sapiens |
did King Philip....
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Phylogeny
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Evolutionary history of a group
represented graphically in phylogenetic trees *time goes from the bottom up read from bottom up, NOT LEFT TO RIGHT branch “length” = the number of changes |
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Monophyletic Group
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- a single ancestor gave rise to all species in a particular taxon
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phylogeny
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Homology
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= likeness due to common ancestry
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Analogy
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= likeness due to convergent evolution
ie: flippers on whales and penguins |
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Evidence used to reconstruct phylogenies on a molecular level
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-Protein comparisons (since protein codes for DNA)
-DNA comparisons DNA-DNA hybridization, restriction mapping, DNA sequencing |
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The rule of Parsimony
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used when mapping phylogenies
-"simplest is best" |
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Cladistics
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a school of taxonomy
-uses shared derived characteristics to classify organisms concerned with branching order, not with morphological similarities |
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Kingdoms of Life
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Archaebacteria
Eubacteria Protista Plantae Fungi Animalia |
there are 6
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Domains
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(above kingdoms)
Domain Bacteria (Bacteria) Domain Archaea (Archaebacteria) Domain Eukarya (Eukaryotes) |
there are 3
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Kindom Archaebacteria
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-one of the branches of Monera
-prokaryotic -live in extreme enviroments (ie: hot springs, extreme cold, salty) as well as typical environments -considered to be molecularly more similar to the eukaryotes -very abundant -important decomposers and symbionts |
all characteristics
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Kingdom Protista
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-eukaryotic
-very diverse and controversial kingdom -origianlly consisted of all unicellular eukaryotes -now split into as many as 20 kingdoms -characteristics used to classify protists: mode of locomotion, nutrition, overall body form, pigments etc. ie: seaweed |
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Kingdom Plantae
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-eukaryotic
-multicellular -autotrophic -cell walls present |
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Kingdom Fungi
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-eukaryotic
-mostly multicellular (exception: yeast) -heterotrophic (nonphotosynthetic) -cell walls present -decomposers, some cause disease -acquire nutrients through absorption (digest outside the body) |
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Kingdom Animalia
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-eukaryotic
-multicellular -heterotrophic -no cell walls |
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Kingdom Eubacteria
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-one of the branches of Monera
-prokaryotic -very abundant - cell walls made of peptidoglycan (molecule) -genome in nucleoid region -single major chromosome (one double stranded DNA molecule forms ring) -plasmids present |
characteristics
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Common shapes of Prokaryotes
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cocci- round
bacilli- rod-shaped helical- spiral shaped |
3 distinct shapes
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Endosymbiotic Theory
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-theory that mitochondria & chloroplasts were once free living cells, taken in to form eukaryotic cells
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Hyphae
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-thin threads of tubular walls surrounding cell membranes & cytoplasm
-form an interwoven net called the mycelium |
fungi body form
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Mycelium
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-an interwoven net of hyphae
-part of the fungi body |
fungi body form
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Fungi Reproduction
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-spores are produced either sexually or asexually
-hyphae and spore nuclei are haploid *except for a brief diploid stage that occurs during sexual reproduction (opposite of human reproduction) |
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