BIOL 172 - EXAM 1 (short)

What are the main characteristics of eukaryotes?

Nucleus + membrane-bound organelles

What is primary endosymbiosis?

Eukaryote engulfs a cyanobacterium → primary plastid

What is secondary endosymbiosis?

Eukaryote engulfs a photosynthetic eukaryote → secondary plastid

What protist group resulted from secondary endosymbiosis of red algae?

Parts of SAR

What is a mixotroph?

Both autotrophic + heterotrophic

What is a classic mixotroph example?

Euglena

What defines Excavata?

Cytoskeleton often has a feeding groove

What defines SAR?

Stramenopiles + Alveolates + Rhizarians

What defines Archaeplastida?

Red algae + green algae + land plants

What defines Unikonta?

Amoebozoans + Opisthokonts

What are Euglenozoans?

Excavata

What are Stramenopiles?

Diatoms + brown algae

What are Alveolates?

Membrane sacs called alveoli

What are Rhizarians?

Thread-like pseudopodia

What are red algae?

Archaeplastids

What are green algae?

Archaeplastids

What are Amoebozoans?

Amoebas with lobe-shaped pseudopodia

What are the three Archaeplastida groups?

Red algae, green algae, land plants

What are the two major Unikonta groups?

Amoebozoans + Opisthokonts

How are protists important as producers?

Base of many aquatic food webs

How do protists help ecosystems?

Food webs + nutrient cycling

What are the main characteristics of fungi?

Eukaryotic + absorptive heterotrophs

How do fungi “eat”?

Secrete enzymes → absorb nutrients

Why are fungal infections harder to treat than bacterial infections?

Fungi are eukaryotic like humans

What are hyphae?

Filamentous fungal structures

What are septate hyphae?

Hyphae divided by septa

What are coenocytic hyphae?

Hyphae without septa

What is plasmogamy?

Cytoplasm fusion

What is karyogamy?

Nuclear fusion

What is the heterokaryontic stage?

Different nuclei in one cytoplasm

What are Ascomycetes?

Sac fungi

What is an ascus?

Saclike spore-producing structure

What is an ascocarp?

Ascomycete fruiting body

What are examples of Ascomycetes?

Yeasts, cup fungi, morels

What are Basidiomycetes?

Club fungi

What is a basidium?

Club-shaped cell where karyogamy + meiosis occur

What is a basidiocarp?

Mushroom/fruiting body

What are examples of Basidiomycetes?

Mushrooms

What are Mucoromycetes?

Molds

What is a mycorrhiza?

Fungus + plant root mutualism

What percentage of plant species have arbuscular mycorrhizae?

~85%

What is a lichen?

Fungus + green algae/cyanobacteria

How can fungi benefit insects?

Fungi living in plants can produce insect-toxic compounds

What are major ecosystem roles of fungi?

Decomposers + pathogens + symbionts

Why are fungi economically important?

Food + medicine + agriculture + fermentation

What are the main characteristics of animals?

Heterotrophic + multicellular + internal digestion

What supports animal cells instead of cell walls?

Structural proteins, especially collagen

What tissues do most animals have?

Muscle + nervous tissue

What type of life cycle do animals have?

Diplontic

What is a diplontic life cycle?

Multicellular stage is diploid

What are Hox genes?

Developmental genes regulating other genes

What do Hox genes control?

Body segments + appendage placement + head-tail direction

What is cephalization?

Concentration of sensory/nervous structures at the head

What symmetry is associated with cephalization?

Bilateral symmetry

What is diploblastic?

2 embryonic tissue layers

What layers are in diploblastic animals?

Ectoderm + endoderm

What is missing in diploblastic animals?

Mesoderm

What is triploblastic?

3 embryonic tissue layers

What are the three germ layers?

Ectoderm + mesoderm + endoderm

What is an acoelomate?

No body cavity

What is a pseudocoelomate?

Partially mesoderm-lined cavity

What is a coelomate?

Completely mesoderm-lined cavity

What is the blastopore in protostomes?

Becomes mouth

What is the blastopore in deuterostomes?

Becomes anus

What is the Cambrian explosion?

Rapid animal diversification ~535–525 mya

Why is the Cambrian explosion important?

Many modern animal phyla appeared

What are the main characteristics of Porifera(sponge)?

No true tissues + no symmetry + no gut

What cells create water currents in sponges?

Choanocytes

What do choanocytes do?

Create currents + capture food

Why do choanocytes suggest a relationship with choanoflagellates?

Similar structure/function

What is the sponge water-flow pathway?

Pores → spongocoel → osculum

What are amoebocytes?

Cells that move through mesohyl

What can amoebocytes do?

Differentiate into other cell types

What animals are in Cnidaria?

Jellies, hydras, corals, sea anemones

What is the cnidarian body plan?

Sac with gastrovascular cavity

Are cnidarians diploblastic or triploblastic?

Diploblastic

How many openings does the cnidarian digestive cavity have?

One

What are cnidocytes?

Specialized stinging cells

What are nematocysts?

Stinging structures for defense/prey capture

What are the two cnidarian body forms?

Polyp + medusa

What is a polyp?

Sessile/Fixed in place

What is a medusa?

Free-swimming

What are Medusozoans?

Have a medusa stage

What are Anthozoans?

Polyp-only life cycle

Do cnidarians have a brain?

No

What are the three shared mollusc body parts?

Foot + visceral mass + mantle

What is a radula?

Straplike scraping organ

What are the three major mollusc groups?

Gastropods + Bivalves + Cephalopods

What are gastropods?

Snails + slugs

What are bivalves?

Clams + oysters + mussels

What are key bivalve traits?

No head + filter feeders + no radula

What are cephalopods?

Squid + octopus + nautilus + cuttlefish

What are key cephalopod traits?

Complex brains/eyes + reduced/absent shell

What are the defining traits of annelids?

Segmented + complete gut + closed circulation

What are the two annelid groups?

Errantia + Sedentaria

What are Errantia?

More mobile

What do parapodia do?

Locomotion + gills

What are Sedentaria?

Less mobile

What defines Ecdysozoa?

Molting

What is ecdysis?

Shedding the cuticle