FW Lecture #2
Species- A group of organisms that can interbreed and produce fertile offspring.
Population- A group of individuals of the same species at the same place and time.
Modern Synthesis Definition of Evolution: The process by which the genetic composition of a population of organisms (a gene pool) changes over time. A change in the frequency of alleles for genes.
Main Points of Evolution
•There is variation among individuals in a population (which can be inherited)
•More individuals are born than can survive
•Individuals compete for resources that enable them to survive
•Some individuals have traits which make them better competitors, and they are more likely to survive and pass those traits on to their offspring
Biological Taxonomic Naming System: Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species
Variation: This needs a definition, if the ai should scan this within quotes it should make a flashcard with a definition for “Variation” in the context of evolution
Artificial Selection: This needs a definition, if the ai should scan this within quotes it should make a flashcard with a definition for Artificial Selection” in the context of evolution
Natural Selection: This needs a definition, if the ai should scan this within quotes it should make a flashcard with a definition for “Variation” in the context of evolution
Phylogeny and Systematics
Phylogeny- the evolutionary history of a species or group of related species
Systematics- The study of the diversity and relationships among organisms
Taxonomy-Naming and classifying the diverse forms or organisms
Phylogenetic Tree: Each branch point represents the divergence of two species and “Deeper” branch points represent progressively greater amounts of divergence
Cladogram: a depiction of patterns of shared characteristics among taxa IF these shared traits are due to a common ancestor then a cladogram is the basis for a phylogenic tree.
A clade within a cladogram: defined as a group of species that includes an ancestral species and all its descendants
A valid clade is monophyletic: Signifying that it consists of the ancestor species and all its descendants
3 Domains: Bacteria, Archaea and Eukarya
4 Kingdoms in Domain Eukarya: Protists (multiple kingdoms), Kingdom plantae, Kingdom Fungi and Kingdom Animalia
Radial Symmetry: A body plan in which the body is arranged around a central axis, allowing for multiple planes of symmetry, commonly seen in organisms like jellyfish and sea anemones.
Bilateral Symmetry: A body plan where the body can be divided into two identical halves along a single plane, which is characteristic of organisms such as humans and most other animals.
Porifera: Approximately 150 species of freshwater sponges in the US. Usually found in clear, shallow waters of ponds, lakes, and stream backwaters.
Polyp: A life stage of certain cnidarians, such as hydras and corals, characterized by a tubular body and a mouth surrounded by tentacles, typically attached to a substrate.
Medusa: A life stage of certain cnidarians, such as jellyfish, characterized by a bell-shaped body and tentacles that hang downwards, allowing for free-swimming movement in the water.
Cnidarians: A couple of FW species worldwide. Not native to US. Lakes and quarries. Predators of zooplankton 5-25 mm diameter
Hydra All FW about 30 sp
Phylum Platyhelmenthes: Class Tubellaria –flatworm 200 spp. in North America: mostly inhabit shallow regions of both lakes and streams.
Rotifera: ca 2000 sp - all FW species found in various freshwater habitats, ranging from ponds to streams, playing a crucial role in the aquatic food web.
Ectoprocta (Bryozoans): About 25 FW in North America
Mollusca
Class Gastropoda: The body has a head, a foot and a visceral mass. 15 Freshwater families and 500 species in North America
Class Bivalvia: About 10 fw families 270 species in NA Some introduced.
Annelida
Class Oligochaeta, about 170 fw species in NA
Class Hirudinea (leech) About 69 fw spp. in NA
Tardigrata (water bears): Commonly found in mosses, lichens, leaf litter, and freshwater. Over 200 species of water bear are known to occur in North America
Nematoda: 360 species of North American freshwater nematodes < 1 mm long. Common in sediment.
Parasitic Human Diseases Rated to Freshwater Animals
•Platyhelminthes (trematodes)- Schistomiasis parasite, snails are an intermediate host (207 million)
•Blackflies (nematode parasite) - River Blindness (18 million)
•Cladocera (nematode parasite) -Guinea Worm Disease
Arthropoda
Subphylum Crustacea: 13 orders 1000 fw species in NA, a segmented body with a hard exterior (known as exoskeleton), jointed limbs each with two branches (termed biramous),two pairs of anternnae and have gills.
Subphylum Unirama (Hexapoda) → Class Insecta: Three body segments: head, abdomen, and thorax. Jointed legs are attached to the thorax. Hexapoda (have 6 legs). One pair of antennae. 2 compound eyes. 0-3 simple eyes called ocelli.
Osteoichytes: Bony fishes
Class Amphibia: frogs
Protista- A polyphyletic group of simple eukaryotic organisms. Classification based on DNA, endosymbiotic events, and structure of flagella. Some photosynthetic-algae!
Protoza- A polyphyletic group within the protists: heterotrophic, no cell wall, at least 1 motile stage.
Class Branchiopoda
Order Cladocera (waterfleas) : around 500 spp. worldwide
Subclass Copepoda: About 2800 freshwater species (10,000 marine spp) Calanoid, Cyclopoid, Harpacticoid and Nauplii (mostly benthic orders)
Points for a quantitative sampling program
•Have a definite question
•Consult with someone who knows statistics
•Take preliminary samples
•Need to have REPLICATE samples for each site and time
•Sample sites must be chosen randomly within a location
•Need to know total area of locations
•If testing for an effect (an experiment) need to have a CONTROL treatment.
Holometabolous life cycle: egg mass → larva → pupal sieve plate + case → pupa → adult
Hemimetabolis life cycle: aggs → early instars (Nymphs or nyaids) → last instar → adult
Paurometabolous life cycle: eggs → multiple instars → adult
Coleoptera: 500,000 spp., Two pairs of wings sucking, piercing or lapping mouthparts and incomplete metamorphosis. ; biting and chewing mouth parts and complete metamorphosis. Beetles. About 1000 spp in 20 families that are aquatic and are in North America.
Diptera: 120,000 spp., One pair of wings and halteres (balancing organs); sucking, piercing, or lapping mouth parts and undergo complete metamorphosis (ex. flies, mosquitos). About 3500 aquatic species in 29 families in North America.
Hemiptera: 55,000 spp., Two pairs of wings (one pair leathery, one pair membranous); piercing or sucking mouthparts; incomplete metamorphosis. (Ex. True bugs, assassin bug, bedbug or chinch bug) About 400 aquatic species in 15 families in North America.
Trichoptera: 7,000 spp., two pairs of hairy wings, chewing or lapping mouthparts; complete metamorphosis; aquatic larvae build silken nets or cases (of sand, gravel, and wood) bound together by silk. (ex. caddisflies). 21 families with 1400 spp. in North America.
Ephemeroptera -mayflies: 21 Families 676 species in NA
Plecoptera -stoneflies: 9 families 626 species in NA
Megaloptera -hellgrammites: 2 families, 46 species in NA