1407_Exam_3_Review Question & Answer

A set of question-and-answer flashcards covering producers, plant biology, animal diversity, reproduction, and related key terms for Exam 3 preparation.

What is meant by a biological “producer,” and what are two common examples?

An organism that makes its own organic food (autotroph); examples: green plants and cyanobacteria.

Which trophic strategy uses light to fix carbon, and what is one group that does this?

Photoautotrophy; practiced by plants, algae and cyanobacteria.

Which trophic strategy uses chemical energy from inorganic compounds to fix carbon?

Chemoautotrophy.

What are phytoplankton?

Microscopic, photosynthetic organisms (mostly algae and cyanobacteria) that drift near the surface of aquatic environments and form the base of most ocean food webs.

What is a red tide and what causes it?

A harmful algal bloom (often of dinoflagellates) that discolors water and may release toxins; triggered by nutrient enrichment and warm, calm waters.

Name two major microbial producer phyla and one key trait of each.

Diatoms – silica cell walls; Dinoflagellates – two flagella & cellulose plates.

Give two examples of algal symbiosis discussed in class.

(1) Zooxanthellae living inside coral tissue; (2) Green algae (or cyanobacteria) partnered with fungi in lichens.

How are algal blooms related to coastal dead zones?

______ fueled by nutrient runoff eventually die and decompose, a process that depletes dissolved O₂ and creates hypoxic ‘dead zones.’

What are the two broad categories of early land plants covered, and one feature of each?

Bryophytes – non-vascular, need water for sperm to swim; Seedless vascular plants – have xylem/phloem but reproduce with spores, not seeds.

Define peat and state its ecological importance.

Partially decayed plant matter (mainly sphagnum) in bogs; stores vast carbon and is harvested as fuel.

Differentiate heterosporous vs. homosporous plants.

_________ make separate male (micro) and female (mega) spores; __________ produce one spore type that can become bisexual gametophytes.

What is xylem?

Vascular tissue that transports water and minerals from roots upward; composed of tracheids and vessel elements.

What is phloem?

Vascular tissue that distributes sugars, amino acids and hormones throughout the plant; composed of sieve-tube elements and companion cells.

What are meristems?

Regions of undifferentiated, actively dividing cells that give rise to new plant tissues.

Explain ‘alternation of generations.’

A plant life cycle that alternates between multicellular haploid gametophyte and multicellular diploid sporophyte phases.

Give two root modifications and their functions.

Prop roots – support (e.g., mangroves); Storage roots – store starch (e.g., sweet potato).

Give two stem modifications and their functions.

Rhizomes – horizontal underground stems for spreading; Tubers – swollen stems for starch storage (e.g., potato).

Give two leaf modifications and their roles.

Tendrils – climbing support; Spines – defense and reduced water loss (cacti).

What does an apical bud do?

Located at shoot tip, it drives primary (length) growth and produces most leaves/flowers.

What does an axillary bud do?

Found in leaf axils; can form lateral branches, flowers or leaves when released from apical dominance.

Contrast primary growth with secondary growth and name the meristems involved.

_________ lengthens roots/shoots via apical meristems; _______ growth increases girth via lateral meristems (vascular & cork cambia).

How do parasitic plants differ from carnivorous plants?

______ plants tap into other plants for nutrients; ______ plants photosynthesize but trap animals to obtain nitrogen/minerals.

What is crop rotation and why is it beneficial?

Sequentially planting different crops on the same field; reduces soil nutrient depletion, interrupts pest cycles, and can add nitrogen (with legumes).

Define carnivore, herbivore, and omnivore.

_______ eats animals; _______ eats plants/algae; ______ eats both plants and animals.

Name four invertebrate phyla covered and one hallmark of each.

Porifera – porous bodies, no true tissues; Cnidaria – stinging nematocysts; Mollusca – muscular foot & mantle; Arthropoda – exoskeleton & jointed appendages.

What is bilateral symmetry?

Body plan with a single plane producing left/right mirror images, associated with cephalization.

What is radial symmetry?

Body parts arranged around a central axis; many body planes yield identical halves (e.g., jellyfish).

Define a body cavity (coelom) and its significance.

Fluid-filled space between digestive tract and body wall; cushions organs, allows independent organ movement, and can serve as hydrostatic skeleton.

Give two parasitic animal examples discussed.

Tapeworms (Platyhelminthes) and hookworms (Nematoda).

List the major vertebrate groups in order of appearance and one trait for each.

Fish – gills & fins; Amphibians – moist skin, metamorphosis; Reptiles – scales, amniotic egg; Birds – feathers & hollow bones; Mammals – hair & mammary glands.

Define oviparous reproduction.

Eggs laid outside the mother’s body; embryo nourished by yolk (e.g., birds).

Define ovoviviparous reproduction.

Eggs retained in mother; hatch internally; embryo nourished by yolk, not placenta (e.g., some sharks).

Define viviparous reproduction.

Young develop inside mother and receive nutrients directly from her (placenta); born live (e.g., most mammals).

What is an amniote?

Tetrapod whose embryo is protected by an amniotic egg (reptiles, birds, mammals).

Contrast endotherms and ectotherms.

______ generate internal heat to maintain constant body temperature (birds, mammals); _______ rely largely on environmental heat (reptiles, amphibians, fish).

Name four extra-embryonic membranes of an amniotic egg and their primary functions.

Amnion – cushions embryo in fluid; Chorion – gas exchange; Allantois – waste storage & respiration; Yolk sac – nutrient supply.

What is the role of the eggshell and albumen?

protects and limits water loss while allowing gas exchange; (egg white) provides water and additional protein to the developing embryo.