Evolution and Taxonomy Flashcards
4 Purposes of Classification
- Identify and compare based on recognized characteristics
- Organized global system
- Compare organisms to predict evolutionary links
- Systematic collection and classification of information
4 Characteristics for Classification
Physical appeareance, behavior, biochemical characteristics, physiological characteristics
Phylogenetic Classification
Classifying organisms based on their differences and similarities on a genetic level
Hierarchy of Classification
Domaine, kingdom, phylum, class, order, family, genus, species
7 Phyla of Animal Kingdom
Porifera, cnidarian, platyhelminthes, annelida, mollusca, arthropoda and chordata
Phylum of Animal Kingdom: Porifera
Sack liked body with onelarge opening at the top, many tiny pores, no distinct tissues, live attached to the bottom of the sea floor
Phylum of Animal Kingdom: Cnidarian
Soft, sack like with one opening, opening surrounded by tentacles containing stinging cells (cnidae)
- Medusa form: tentacles hang down
- Polyp form: tentacles face up
Phylum of Animal Kingdom: Platyhelminthes
Flatworms: flattened dorsoventrally, bilateral symmetry, ring like divisions instead of segments, incomplete digestive system (mouth is anus)
Phylum of Animal Kingdom: Annelida
Segmented worms, cylindrical or slightly flattened, setate (tiny hair projections) for locomotion, bilateral symmetry, complete digestive system
Phylum of Animal Kingdom: Mollusca
Soft and slimy body, muscular foor for locomotion, partial shell or hinged shell that opens
Phylum of Animal Kingdom: Arthropoda
Insects.
- Jointed legs
- Tough chitin exoskeleton
- Shell that doesn’t open
- Head with well developed mouth and jaw
- Bilateral symmetry
Phylum of Animal Kingdom: Chordata
Bilateral symmetry, notochord present, head with developed mouth and jaw, visible eyespots
5 Classes of Phylum Chordata
Fish, amphibian, reptile, bird and mammal
Tetrapod
4 limbs
Class of Phylum Chordata: Fish
Scales, obtains oxygen dissovled in water through gills, external fertilization, only one type of teeth, no pentadactyl limbs (fins), ectothermic (body temperature depends on the environment)
Class of Phylum Chordata: Amphibian
Moist and highly permeable skin that conducts gas exchange alongside gills and/or lungs, either external or internal fertilization, vomerine teeth (only upper front jaw), four pentadactyl limbs, ectothermic
Class of Phylum Chordata: Reptile
Thick, scaly skin, shed periodically, lungs, internal fertilization, amniotic leather shelled egg, one type of teeth, tetrapod, ectothermic
Class of Phylum Chordata: Birds
Feathered, lungs, internal fertilization with a calcium carbonate shell, no teeth: bills, tetrapod (2 wings), endothermic
Class of Phylum Chordata: Mammal
Hairs on skin, lungs, internal fertilization, tetrapod, endothermic
4 Phyla of Plantae Kingdom
Bryophytes, filicinophytes, coniferophytes, angiospermophytes
3 common characteristics of all members of the plantae kingdom
Multicellular, have a cellulose cell wall, mostly autotrophs
Bryophyte Phylum of Plantae Kingdom
No vascular tissue (xylem or phloem), short in height, no flower or seeds covered by fruit, sperm cells swim towards the egg to fertilize, spores.
Have no roots, only rhizoids. Simple leaves or thalli. Must live in moist habitats, as substances are moved through osmosis and diffusion from surface moisture and sperm swims towards egg.
Rhizoid
Hair like projections that grow directly out of the photosynthetic tissue of bryophytes.
Thallus (thalli)
Plant bodies not distinguished into stem, leaf or root
Spore
Haploid cells that undergo mitosis to develop into new organisms
Vascular Plants
- Have roots, stems and leaves
- Have vascular tissues: xylem and phloem
- Have xylem vessels with the stiffening agent lignin to grow taller
- Include seedless plants (filicinophytes) and seed plants (coniferophytes and angiospermophtes)
Filicinophyte Phylum of Plantae Kingdom
- Leaves are often pinnate
- Must live in moist habitats since the sperm cells have to swim through water to fertilize the egg
- Have haploid spores, visible in clusters called sori on the underside of leaves
Pinnate
Fronds with leaflets on each side of a common axis
Seed Plants
Coniferophytes and angiospermophytes. Produce pollen and seeds, dispersed by wind or pollinators. Eliminate the need for sperm to swim to the egg: don’t need moist environment, can grow high. Seeds are diploid cells, protected by a seed coat and nourishes the plant before it can undergo photosynthesis.
Coniferophytes
- Have roots, stems and leaves
- Leaves usually evergreen, don’t drop seasonally
- Leaves are needle shaped and have waxy cuticle to limit water loss
- Have vascular tissue: can grow tall
- Have woody stems and produce seeds in cones
Angiospermophytes
- Have roots, stems and leaves
- Flowering
- Have vascular tissue
- Reproduce seeds produced from ovules within flowers
- Produce seeds in fruits
Cladogram
A tree diagram representing the most probable sequence of divergence within a group that shares characteristics
Challenges of Cladogram Creation
Mostly based on sequences analysis of either DNA bases or AAs from proteins. However, DNA cannot be extracted from fossils. The orders are interpreted using incomplete information.
Cladogram vs Phylogenetic Tree
Cladogram doesn’t have a timeline; phylogenetic trees do.
Cladogram Interpretation
- A clade includes a common ancestor and all of its descendants
- Each line represents a separate species
- A line shorter than the others represents an extinct species
- At least one derived characteristic is needed to separate each branch from the others
- The more nodes there are between species, the more distance their relationship
- Length of branches within a cladogram aren’t proportional to the time since divergence
Errors in Classificaction: Figwort Classification
Originally classified based on shared morphological features, changed by DNA sequence analysis.