Eukaryotic Diversity Midterm Study Guide

Introduction to Eukaryotic Diversity

• Impacts of biodiversity on humans

  • Biodiversity hotspots

  • Ecosystem services

    1. Provisioning Services = Food, water, natural gas

    2. Regulating Services = Waste management, pest regulation

    3. Supporting Services = Nutrient cycling, pollination

    4. Cultural Services = Recreation, religion, heritage

• Human impacts on biodiversity

  • Bioprospecting = the exploration of natural resources for commercially valuable products

  • Most medicines from plants & algaes

  • Some organisms have a small proportion of species identified.

  • Overharvesting & Habitat Loss are threats

• Importance of museums, herbaria, and citizen science in documenting biodiversity

  • Museums hold all life forms and herbariums hold plants

  • “Citizen Science Projects” = Crowd-sourced blogs with information

Unit 1 Lesson 1: Organizing Biodiversity

• Address the idea of “evolution as progress”

  • Meaning there’s a linear organization of living things

  • Less to more complex

  • Selection only acts on existing variation

• Compare classifications of organisms throughout history & describe how classifications change with growing understanding

  • Aristotle: “Ladder of Nature”

  • Carl Linnaeus: Divine creation, introduced binomial nomenclature, nested hierarchy

  • Charles Darwin: Natural selection, descent with modification (not a line, but rather a changing tree)

  • Ernst Haeckel: Established Protista as 3rd kingdom

  • Robert Whittaker: Proposed five-kingdom classification

  • Carl Woese: Proposed three-domain classification of life and split prokaryotes into two groups

• Distinguish between the five kingdom and three domain schemes & identify shortcomings of the five-kingdom approach

  • The five-kingdom model fails to account for genetic and evolutionary relationships in microorganisms.

  • The three-domain model addresses these shortcomings by grouping organisms based on genetic material and evolutionary history

• Describe how animal phylogeny has improved/confirmed by molecular data.

  • Many genes are present across a wide range of species

  • Large amount of data

• Relate taxonomic classification to phylogeny

  • “Phylogenetic classification” is when the nested hierarchical classification also reflects the branching evolutionary relationships among organisms

  • Phylogeny: a visualization of the evolutionary history of a group of organisms

• Compare homologous and analogous structures

  • Homologous: Organisms share similar traits due to common ancestry

  • Analogous: Organisms have similar traits due to convergent evolution

• Interpret phylogenetic trees:

  • Identify nodes and describe their meaning

  • Trace ancestry backwards from living taxa

  • Interpret the mapping of traits (in terms of homology)

Unit 1 Lesson 2: Origin of Eukaryotic Life and Endosymbiosis

• Key Dates:

  • Origin of Earth: ~4.6 billion years ago

  • Origin of Prokaryotes: ~3.5 billion years ago

  • Origin of Unicellular Eukaryotes: ~2.1 billion years ago

  • Origin of Multicellular Eukaryotes: ~1.5 billion years ago

• Fossil record's impact on understanding animal evolution

  • Cambrian period = a rapid increase in biodiversity and the emergence of many major groups of animals.

  • Oxygen in the atmosphere rose before the Cambrian explosion, which allowed the organisms to get bigger and more active

• Explain primary endosymbiotic event and its importance for eukaryote evolution.

  • Explains the origin of chloroplasts and mitochondria in eukaryotic cells

• Distinguish between primary and secondary endosymbiosis in chloroplasts and photosynthesis.

  • Endosymbiosis = a relationship between two species in which one organism lives inside the cells of another organism

  • Primary endosymbiosis = Larger host cell directly engulfs a prokaryote, leading to a eukaryotic cell with mitochondria

  • Secondary endosymbiosis = Ancestral cell engulfs cell produced from primary endosymbiosis

• Name the five Eukaryotic supergroups.

  • Excavata

  • Chromalveolata

  • Rhizaria

  • Archaeplastida

  • Unikonta

Unit 1 Lesson 3: Supergroup Phylogeny Part I

• Excavata

  • Unicellular protists

  • Some are photosynthetic due to secondary endosymbiosis

  • Some lack mitochondria as endoparasites

• Chromalveolata

  • Alveolates (diverse unicellular organisms)

    • Dinoflagellates (unicellular marine plankton, some photosynthetic)

    • Apicomplexans (important parasites)

    • Ciliates (unicellular heterotrophs)

  • Stramenopiles (mostly photosynthetic algae)

    • Diatoms (Silica walls, unicellular photosynthetic marine)

    • Brown algae (multicellular, photosynthetic seaweed)

    • Oomycetes (decomposers or parasites)

• Rhizaria

  • Amoeba-like with threadlike pseudopodia to move and eat

  • Pseudopodia extend through shell

  • Forams = Pseudopodia extend through a porous CaCO3 shell

  • Radiolarians = Pseudopodia radiate from silica shell

• Archaeplastida

  • First to evolve chloroplasts and all perform photosynthesis

  • Green algae: mostly aquatic but also tree trunks

  • Red algae: marine, multicellular, grows deep in waters

  • Chlorophytes

  • Charophytes: Sister taxon to land plants

• Embryophyte phyla categorization:

  • Non-vascular, seedless vascular, or seeded vascular

• Phylogenetic relationships of bryophytes, lycophytes, and pterophytes to other land plants.

  • Bryophytes: non-vascular land plants that are tethered to water for reproduction

  • Lycophytes: small seedless vascular plants with microphyll that require water for reproduction

  • Pterophytes: large seedless vascular plants with megaphyll that require water for reproduction

• Identify angiosperms and gymnosperms on a phylogeny depicting embryophytes

  • Angiosperms are seeds enclosed in ovaries (fruits)

  • Gymnosperms are known as “naked” seeds (no fruits)

• Describe the four phyla of gymnosperms:

  • Conifers: Largest gymnosperm phylum, thin needle like leaves to reduce water loss

  • Cycads: Dioecious and second largest gymnosperm group

  • Ginkgos: One species in China that is dioecious

  • Gnetophytes: Includes some plants used in medicine

Unit 1 Lesson 4: Supergroup Phylogeny Part II

• Major groups of Angiosperms: description and examples

  • Monocots (Orchidaceae)

  • Eudicots (Asteraceae)

  • Basal lineages (water lillies, star anise, magnoliids)

• Compare Amoebozoans to other organisms with pseudopodia

  • Amoebozoans: Slime molds and amoebas with lobe/tube shaped pseudopodia to move and engulf via phagocytosis

• Evolutionary relationships of fungi to nucleariid amoebas and animals

  • Fungi are most closely related to nucleariids

  • Animals are most closely related to choanoflagellates

  • Multicellularity arose independently in fungi and animals

• General characteristics and representative members of fungi groups

  • Chytrids: Aquatic, flagellated spores

  • Zygomycetes: Fast-growing bread mold

  • Glomeromycetes: Soil mycorrhizae

  • Ascomycetes: Yeasts, truffles, Penicillium mold

  • Basidiomycetes: Common mushrooms, puffballs, some produce “fairy rings”

• Broadly explain animal diversity:

  • Arthropods are most diverse, particularly insects

• Identify where animals in the overall phylogeny of eukaryotes & sister taxon to animals

• Describe why Porifera are different from other animal phyla

• Why are sponges animals

  • Many sponges are similar to choanoflagellates

• Four classes of sponges

• Compare major groups of Cnidaria

Unit 1 Lesson 5: Supergroup Phylogeny Part III

• Five major classes in phylum Platyhelminthes:

  • How parasitism evolved in this group

• Key characteristics of Gastropoda, Bivalvia, and Cephalopoda.

• Two major clades of Annelida.

• Basic characteristics of Rotifera and Nematoda.

• Diversity of Arthropods and why they are so “successful.”

  • Identify related taxa to this group

Unit 1 Lesson 6: Supergroup Phylogeny Part IV

• Extinct subphylum of Arthropoda

• Distinguish between class Merostomata and class Arachnida in subphylum Chelicerata

• Distinguish between class Diplopoda and class Chilopoda in subphylum Myriapoda

• Key differences in body plan between classes of Subphylum Crustacea

• Reasons why Hexapoda is arguably the most successful group of animals:

  • Describe the order of insects with the greatest diversity and most species.

• Organize groups of insects based on presence of wings and mode of development.

Unit 1 Lesson 7: Supergroup Phylogeny Part V

• Identify protostomes and deuterostomes on a phylogenetic tree:

  • List two differences between these groups

• Differentiate between members of the five echinoderm classes

• Four characteristics that define members of Chordata

• Details of the three subphyla of Chordata

• Jawlessness as a possible example of convergent evolution:

  • Distinguish between jawed and jawless vertebrates

• Actinopterygii details:

  • Note it is the most diverse group of living vertebrates

• Key players involved in the transition of tetrapods onto land.

• Define “amniote” and explain what this means:

  • Adaptations of amniotes for life on land

• Distinguish between the major clades of amniotes

• List the three main types of dinosaurs and the three main types of birds:

  • How birds are related to dinosaurs

• Origins of mammals and the evolution of the three main mammalian groups

• Differences between the three mammalian subclasses:

  • Examples of convergent evolution through mammalian history

Unit 2 Lesson 1: SA:V Ratio/Form & Function

• Surface area: volume ratios change with size:

  • Relevance of SA:V ratio for the evolution of body shapes

• Small organisms live in a different “world” relative to large organisms:

  • Consider diffusion, support, terminal velocity, and Reynold’s numbers.

• Three ways eukaryotes obtain energy and nutrients.

• Examples of common functions animals perform:

  • How SA:V ratio impacts these functions

• How physical constraints affect internal structure in animals.

• How functional constraints affect food processing in animals.

• SA:V relates to the flattened body structure of flat worms

• Major orientations of an organism (anterior, medial, etc):

  • Also the major planes

Unit 2 Lesson 2: Evolutionary Innovations

• Distinguish between true multicellularity and colonial organisms.

• Derived traits unique to land plants (embryophytes)

• Two types of vascular tissue and their function.

• How vascular tissue allows plants to grow much taller

• Physiological consequences of vascular tissue

• Evolutionary advantages of seed plants.

• Advantages of bilateral symmetry:

  • How it relates to cephalization and axis development

• Consequences of an elongated segmentation on body function

• Define tagmosis:

  • Implications for specialization of body regions

  • Describe how different arthropod groups exhibit different patterns of tagmosis

• Challenges that tetrapods faced on land:

  • Solutions to these issues

• Benefits and costs of flight:

  • Avian and insect adaptations for flight

Unit 2 Lesson 3: Plant Anatomy and Physiology

• Function of plant roots and shoots:

  • Including their components (root hairs, apical meristems, nodes, axillary buds, etc)

• Identify and describe the functions of major components of the leaf.

• Map the evolution of microphyll and megaphyll leaves to the evolution of plants.

• Distinguish between compound, doubly compound, and single leaves.

• Leaf adaptations to specialized ways of life.

• Examples and significance of specialized roots, stems and leaves as described in class.

• Label and describe the basic structure of the angiosperm flower.

• Organization of flowers into inflorescences:

  • Organization of ovaries and ovules into fruits

Unit 2 Lesson 4: Fungi & Animal Anatomy and Physiology

• Characteristics of fungi bodies:

  • Chitin cell wall, hyphae, mycelium etc.

• How the organization of the fungal body allows the mycelium to expand in size without changing surface area: volume ratios.

• Compare types of support and locomotion among different animal taxa, with examples.

Unit 2 Lesson 5: Animal Anatomy and Physiology II

• Compare types of sensory structures among different animal taxa, with examples.

• Compare types of circulation/transport and osmoregulation/excretory processes and structures among different animal taxa, with examples.

Unit 2 Lesson 6: Animal Anatomy and Physiology III

• Compare types of respiration and feeding mechanisms among different animal taxa, with examples.