the evolutionary history of biodiversity

What is phylogeny?
The evolutionary history of a species or group of related species.
What is systematics?
A discipline that focuses on classifying organisms and their evolutionary relationships. (fossils, morphology, genes, molecular evidence)
What is taxonomy?
An ordered division of organisms into categories based on a set of characteristics assessing similarities and differences.
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binomial nomenclature
two-part naming system including genus and species
List the levels of classification. what is each category called?
domain, kingdom, phylum, class, order, family, genus, species- a taxon
What are homologous structures?
similarities due to shared ancestry
What is convergent evolution
when organisms develop similarities as they adapted to similar environmental challenges (analogous)
what is a clade?
a group of species that includes ancestral species and all its descendants
What are the three domains of life?
Bacteria, Archaea, Eukarya
Bacteria has:
no nuclear envelope, no membrane-enclosed organelles, no introns, no histone proteins assoc. with dna, a circular chromosome
Archaea has:
no nuclear envelope, no membrane-enclosed organelles, introns, histone proteins assoc. with dna, a circular chromosome
Eukarya has:
a nuclear envelope, membrane-enclosed organelles, introns, histone proteins assoc. with dna, no circular chromosome
Compare prokaryotes and eukaryotes with respect to genome, membrane-bound organelles, size, reproduction
Prokaryotes: rods/spheres/helices shaped, 1-5 micrometers in size, no true nuclei or internal compartmentalization, simple small genome, contain plasmids, reproduce through binary fission
Eukaryotes: bigger than prokaryote, simple small genome
Three ways bacteria can transfer genetic material include:
transformation, conjugation, transduction
What is transformation?
prokaryote takes up dna from environment
What is conjugation?
genes are directly transferred from one prokaryote to another (bridge/sex pilus)
What is transduction?
genes transferred through viruses
What is the major source of genetic variation in prokaryotes?
Describe photoautotrophs:
use sunlight to convert co2 into organic compounds
describe chemoautotrophs:
use co2 as source of carbon, but get energy from oxidizing inorganic substances
describe photoheterotrophs
use light to make atp but most obtain carbon from outside source fixed in organic compounds
describe chemoheterotrophs:
get both carbon and energy from organic compounds
What are extremophiles?
first prokaryotes classified in domain Archaea that live in extreme environments
What are extreme halophiles?
live in saline environments
what are extreme thermophiles?
live in very hot environments
Why are protists no longer considered a kingdom?
-they are paraphyletic
-they are eukaryotes that are neither plants, animals, nor fungi
Describe monophyletic group:
a group/clade consisting of an ancestral species and all of its descendants
describe paraphyletic:
consists of an ancestral species and some of but not all of its descendants (one may be missing)
describe polyphyletic:
includes descendants of two or more common ancestors
list two important characteristics of protists:
1. most are unicellular
2. most use aerobic metabolism and have mitochondria
How did mitochondria and chloroplasts evolve through endosymbiosis?
-originally unicellular organisms (eukaryote) one engulfed by the other- grew together/endosymbiotic relationship formed w/ a prokaryote
Why are protists some of the most important organisms?
1/4 of the worlds oxygen is produced by photosynthetic protists
What are 5 pieces of evidence that land plants have evolved from green algae?
1. produce cellulose for cell walls in same fashion
2. the peroxisomes of these 2 groups have enzymes that reduce the effects of photorespiration
3. similar sperm structure
4. produce cell plates in same way during cell division
5. genetic evidence including analysis of nuclear and chloroplast genes shows they are closely related
what are advantages of plants life on land?
increased sunlight unfiltered by water, more co2 in atmosphere than the water, nutrient rich soil, fewer predators
what are the disadvantages?
lack of water, desiccation, lack of structural support against gravity
Plants have a life cycle consisting of 2 multicellular stages which is called:
alternation of generations
what are these two stages?
gametophyte stage (plant cells are haploid) and sporophyte stage (plant cells are diploid)
what happens in these stages?
-gametes are produced
-during fertilization, egg and sperm fuse to form diploid zygote (sporophyte) which divides mitotically
-sporophyte produces spores by meiosis
-zygote develops within the tissue of female parent (referred to as embryophytes)
Bryophytes include what 3 main phyla?
mosses, liverworts, hornworts
Why are bryophytes considered nonvascular?
they have no xylem or phloem tissue
Unlike vascular plants, what are the dominant stages of the bryophyte life cycle?
Bryophytes require water for what?
for sperm to swim to the egg during fertilization
the seedless vascular plant life cycle is dominated by what stage?
sporophyte stage
Nonvascular plant is:
seedless vascular plant is:
List some characteristics of fungi:
-multicellular heterotrophs that obtain nutrients by absorption
-fungi reproduce by spores
-modes of nutrition include decomposers, parasites, mutualists
Describe mycorrhizal fungi:
-found in association with plant roots
-helps deliver minerals to plants, white then being supplied with nutrients (mutualism)
Describe lichens:
-hardy organisms that are pioneers on rock and soil surfaces
-symbiotic associations of photosynthetic microorganisms (algae) embedded in a network of fungal hyphae
what do megaspores produce?
female gametophytes which produce the eggs
what do microspores produce?
male gametophytes which contain sperm nuclei
list some characteristics of gynosperms:
-exposed seeds
-do not have fruits
list some characteristics of angiosperms:
-flowering plants
-seeds enclosed in fruits
-seed plants that produce reproductive structures called flowers and fruits
what is the function of the stamen? (anther+filament)
male reproductive structure- produces microspores in anthers (ends) that develop into pollen grains
what is the function of carpels? (stigma, style, ovary)
female reproductive structure- produces megaspores and female gametophytes with eggs
what are FRUITS?
-mature ovaries of the plant
-as seeds develop from ovules after fertilization, the wall of ovary thickens to become the fruit

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