FW Lecture #2

Species:

A biological classification that denotes a group of organisms capable of interbreeding and producing fertile offspring, distinguishing them from other groups.

Population

A specific collection of individuals belonging to the same species, sharing a common geographic area and interacting within a particular time frame.

Modern Synthesis Definition of Evolution

An integrated theory of evolution that explains how the genetic composition of populations changes over time through mechanisms such as natural selection and genetic drift, highlighting shifts in allele frequencies within populations.

Variation

Differences in physical traits or genetics among individuals in a population, which can be inherited and play a crucial role in the process of evolution.

Artificial Selection

A type of selective breeding process undertaken by humans, in which individuals with desirable traits are chosen for reproduction to enhance those traits in future generations.

Natural Selection

A natural process by which organisms with advantageous traits are more likely to thrive, reproduce, and pass on those favorable traits to their offspring, leading to evolutionary change.

Phylogeny

The study of the evolutionary history and relationships among species, tracing their lineage and common ancestry over time.

Systematics

The field of scientific study focused on the classification, naming, and understanding the evolutionary relationships among organisms.

Taxonomy

The science that involves the naming, description, and classification of living organisms into hierarchical categories, such as domain, kingdom, phylum, class, order, family, genus, and species.

Phylogenetic Tree

A branching diagram that represents the evolutionary relationships among species, where each branch point signifies a divergence event, illustrating how species are related through common ancestry.

Cladogram

A diagram showcasing the evolutionary relationships among taxa based on shared characteristics, which serves as a foundation for creating phylogenetic trees; it depicts clades formed by common ancestry.

Clade

A specific group of organisms that includes a common ancestor and all its descendants, representing a monophyletic lineage.

Monophyletic

A valid clade in taxonomy that encompasses an ancestor species and all its descendants, signifying a complete lineage.

Radial Symmetry

A body plan in which the organism’s body parts are arranged symmetrically around a central axis, allowing for multiple planes of symmetry, as seen in jellyfish and sea anemones.

Bilateral Symmetry

A body plan in which the left and right sides of the organism are mirror images of each other, allowing symmetrical division along a single plane, characteristic of most animals including humans.

Porifera

A phylum that consists of approximately 150 species of freshwater sponges, primarily found in clear, shallow waters such as ponds and streams.

Polyp

A life stage in certain cnidarians such as hydras and corals, characterized by a cylindrical body form with a mouth at one end surrounded by tentacles, usually fixed to a surface.

Medusa

A life stage of certain cnidarians, such as jellyfish, characterized by an umbrella-shaped bell with hanging tentacles that allows for free-swimming in marine environments.

Cnidarians

A phylum representing diverse aquatic animals known for their stinging cells (cnidocytes), including freshwater species; they are predators feeding on zooplankton.

Hydra

A genus of freshwater cnidarians known for their regenerative abilities, existing in multiple species across North America.

Phylum Platyhelminthes

A phylum of flatworms, particularly those within class Turbellaria, which includes around 200 species found in shallow freshwater regions of lakes and streams.

Rotifera

A phylum comprising approximately 2000 species of microscopic animals found in various freshwater habitats, playing a significant role in aquatic ecosystems.

Ectoprocta (Bryozoans)

A phylum, represented by about 25 freshwater species in North America, that consists of colonial aquatic animals.

Class Gastropoda

A class within the phylum Mollusca characterized by a coiled body with a distinct head, foot, and visceral mass; it includes approximately 500 freshwater species in North America.

Class Bivalvia

A class of Mollusca containing around 270 freshwater species in North America with two hinged shells, commonly known as clams.

Class Oligochaeta

A class within the phylum Annelida, which includes around 170 freshwater species such as earthworms.

Class Hirudinea

A class of annelids that comprises approximately 69 species of leeches found in North America.

Tardigrata (water bears):

Microbiota commonly found in mosses and lichens, known for their resilience; over 200 species are documented in North America.

Nematoda:

A phylum containing about 360 species of freshwater nematodes, primarily microscopic and found in sediments.

Human Parasitic Diseases Related to Freshwater Animals:

Diseases caused by parasites from freshwater species, including schistosomiasis (from trematodes affecting snails), river blindness (from blackfly nematodes), and guinea worm disease (from Cladocera nematodes).

Subphylum Crustacea:

A subphylum of arthropods representing approximately 1000 freshwater species in North America, characterized by segmented bodies, exoskeletons, jointed legs, and gills.

Subphylum Unirama (Hexapoda) → Class Insecta:

A classification grouping insects with three body segments (head, thorax, abdomen), jointed legs, and one pair of antennae, characterized typically by six legs and compound eyes.

Osteichthyes:

A class of fish known as bony fishes, characterized by a skeleton made of bone tissue.

Class Amphibia:

A class of terrestrial and aquatic animals that includes frogs, characterized by their dual life stages ranging from aquatic larvae to terrestrial adults.

Protista:

A diverse, polyphyletic group of simple eukaryotic organisms, classified based on DNA similarities, endosymbiotic events, and flagella morphology; includes photosynthetic algae.

Protozoa:

A sub-group within Protista comprising heterotrophic, motile organisms without a cell wall, with at least one stage of locomotion

Class Branchiopoda:

A class within the phylum Arthropoda, corresponding to water-fleas, which includes approximately 500 species worldwide.

Order Cladocera (waterfleas):

A group within the class Branchiopoda, representing around 500 species found in freshwater environments.

Subclass Copepoda:

A subclass of small crustaceans containing around 2800 freshwater species, essential to aquatic food webs.

Points for a Quantitative Sampling Program:

Guidelines for conducting effective quantitative sampling in ecological studies; these include formulating a specific research question, consulting statistical expertise, taking preliminary samples, ensuring replicate samples, selecting random sample sites, calculating total area, and establishing control treatments for experimentation.

Holometabolous life cycle:

A life cycle involving four distinct stages: egg, larva, pupa, and adult, with metamorphosis occurring between each stage

Hemimetabolous life cycle:

A life cycle comprising three stages: egg, nymph (immature, wingless form), and adult, without a distinct pupal stage.

Paurometabolous life cycle:

A life cycle characterized by gradual development through multiple nymphal stages, transitioning to adulthood.

Coleoptera:

An order of insects known as beetles, with over 500,000 species characterized by two pairs of wings and diverse feeding modes, including biting, chewing, and suction.

Diptera:

An order of insects comprising around 120,000 species, including flies and mosquitoes, characterized by a single pair of wings and varied mouthparts

Hemiptera:

An order of insects known as true bugs, characterized by two pairs of wings (one leathery and one membranous) and piercing or sucking mouthparts.

Trichoptera:

An order of insects known as caddisflies, characterized by two pairs of hairy wings and aquatic larvae that construct silk cases

Ephemeroptera (mayflies):

An order of insects with incomplete metamorphosis, featuring aquatic nymphs and short-lived adult stages, consisting of about 21 families and 676 species in North America.

Plecoptera (stoneflies):

An order of insects with aquatic nymphs, featuring a distinct two-winged adult form, consisting of 9 families and 626 species in North America.

Megaloptera (hellgrammites):

An order of insects that includes species such as hellgrammites, known for their aquatic larvae stages, consisting of 2 families and 46 species in North America