Biology: Sponges and Cnidarians Overview

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Questions and Answers

What is the primary function of choanocytes in sponges?

To produce eggs and transport nutrients

To form the external layer of the sponge

To circulate water and facilitate feeding (correct)

To capture and digests food particles

What distinguishes cnidarians from other animal groups?

They have a true coelom

They exhibit bilateral symmetry

They lack a gastrovascular cavity

They possess cnidocytes for prey capture (correct)

What major life stage is dominant in the medusozoa clade under Cnidaria?

Polyp stage

Asexual budding stage

Diploid stage (correct)

Larval stage

Which of the following is NOT a characteristic of lophotrochozoans?

Radial symmetry Signup and view all the answers

Flatworms are classified as:

Acoelomates with a gastrovascular cavity Signup and view all the answers

What is the primary role of the ciliated crown in rotifers?

To draw food particles into the mouth Signup and view all the answers

What feature do all lophotrochozoans share?

Triploblastic development Signup and view all the answers

Which of the following phyla is NOT included in the lophotrochozoans?

Arthropods Signup and view all the answers

What is the primary function of a lophophore in ectoprocts and brachiopods?

Feeding Signup and view all the answers

What is the significance of molting in arthropods?

To increase size Signup and view all the answers

Which of the following describes lobe-finned fishes?

Have modified fins evolved from lobes Signup and view all the answers

What key trait distinguishes mammals from other vertebrates?

Mammary glands Signup and view all the answers

Which clade of amphibians is characterized by a lack of limbs?

Caecilians Signup and view all the answers

What adaptation allows amphibians to live both in water and on land?

Lungs and gills Signup and view all the answers

What is the primary function of the amnion in amniotes?

Embryo protection Signup and view all the answers

What defines the diapsid lineage among reptiles?

Presence of two temporal openings in the skull Signup and view all the answers

What unique feature do birds exhibit to facilitate flight?

Honeycombed bone structure Signup and view all the answers

Who are considered the early relatives of modern mammals?

Synapsids Signup and view all the answers

Which group of mammals is known for giving birth to underdeveloped young?

Marsupials Signup and view all the answers

What trait distinguishes early hominins such as Sahelanthropus?

Bipedalism Signup and view all the answers

What feature is characteristic of Neanderthals?

Extensive tool-making skills Signup and view all the answers

How do birds differ from reptiles in terms of reproduction?

Birds lack urinary bladders Signup and view all the answers

What are the characteristics of ectoprocts or bryozoans?

They are colonial animals with a lophophore and U-shaped alimentary canal. Signup and view all the answers

Which feature is unique to brachiopods compared to clams?

They possess a stalk that attaches them to the sea floor. Signup and view all the answers

What is the primary function of the radula in molluscs?

Scraping food from surfaces. Signup and view all the answers

Which of the following statements about annelids is true?

They have a true coelom and segmented body structure. Signup and view all the answers

What role do Hox genes play in arthropod evolution?

They regulate the fusion of segments into specialized body regions. Signup and view all the answers

What is a key feature of the arthropod exoskeleton?

It provides muscle attachment points and protection. Signup and view all the answers

Which group of arthropods are characterized by having clawlike feeding appendages?

Chelicerates Signup and view all the answers

What distinguishes echinoderms from other animal groups?

They have an endoskeleton and a water vascular system. Signup and view all the answers

Which characteristic is present in all chordates at some developmental stage?

A notochord and dorsal hollow nerve cord. Signup and view all the answers

What significant evolutionary development is associated with gnathostomes?

Evolution of jaws for more efficient feeding. Signup and view all the answers

How do ray-finned fishes differ from lobe-finned fishes?

Ray-finned fishes form the majority of fish species. Signup and view all the answers

Which statement accurately reflects the development of insects?

Insects exhibit both complete and incomplete metamorphosis. Signup and view all the answers

Which statement accurately describes natural selection?

It favors individuals with beneficial traits that enhance survival and reproduction. Signup and view all the answers

What characterizes a desert biome?

Extreme temperatures and low precipitation. Signup and view all the answers

Which of these factors does NOT influence species distribution?

Cosmic radiation levels. Signup and view all the answers

What is a fundamental niche?

The potential range of environments an organism can occupy. Signup and view all the answers

Which scenario exemplifies a keystone species?

A predator that maintains population levels of other species. Signup and view all the answers

What is one effect of habitat loss?

Extinction of species that are unable to adapt. Signup and view all the answers

Which of the following is a method to combat biodiversity loss?

Supporting native species through conservation. Signup and view all the answers

In the experiment between Balanus and Chthamalus barnacles, what does the realized niche refer to?

The habitat where Chthamalus barnacles are found due to competition. Signup and view all the answers

What impact does climate change have on ecosystems?

It leads to ecosystem disruption and habitat loss. Signup and view all the answers

Which type of biodiversity refers to the variety of habitats within a given area?

Ecosystem diversity. Signup and view all the answers

What are learned behaviors characterized by?

Dependence on experience and neural connections Signup and view all the answers

What does imprinting refer to in behavioral terms?

A form of learning during a sensitive period early in life Signup and view all the answers

What differentiates marsupials from eutherians?

Marsupials have shorter gestation periods and longer lactation periods. Signup and view all the answers

Which statement best describes foraging behavior?

Optimizing the balance between energy gain and expenditure Signup and view all the answers

What is a primary function of agonistic behavior?

To compete for resources like food or mates Signup and view all the answers

Which of the following characteristics is NOT typical of primates?

Walking on four legs Signup and view all the answers

Where do Old World monkeys primarily reside?

Africa and Asia Signup and view all the answers

Why is altruistic behavior considered beneficial for species survival?

It aids the survival of relatives or ensures future assistance Signup and view all the answers

Which ecological system focuses specifically on interactions between different species?

Community ecology Signup and view all the answers

Which hominin is known to be the earliest, existing around 6.5 million years ago?

Sahelanthropus tchadensis Signup and view all the answers

Which of the following statements about Neanderthals is true?

They shared a common ancestor with humans. Signup and view all the answers

How does energy flow in an ecosystem?

It moves from producers to consumers and loses energy at each level Signup and view all the answers

What role do abiotic factors play in an ecosystem?

They refer to the physical and chemical elements of the environment Signup and view all the answers

What is the function of the amnion during embryonic development?

It surrounds and protects the embryo. Signup and view all the answers

What are the two main adaptations that primates developed for arboreal life?

Opposable thumbs and front-facing eyes Signup and view all the answers

What is true about sexual dimorphism in humans?

Males have wider shoulders and more muscle mass. Signup and view all the answers

What is a potential outcome of ecological disturbances?

Transition to alternate stable states Signup and view all the answers

What defines antagonistic pleiotropy?

A mutation beneficial for early life but harmful later. Signup and view all the answers

Which group of vertebrates is characterized by having jaws?

Gnathostomes Signup and view all the answers

What factor greatly influences climate according to landscape features?

Geological formations like mountains Signup and view all the answers

What is landscape ecology focused on?

Spatial patterns and processes across multiple ecosystems Signup and view all the answers

What is considered a proximate cause of animal behavior?

Physiological changes that lead to a specific behavior. Signup and view all the answers

What mechanism is primarily responsible for bird migration?

Instinctive responses to changes in daylight and temperature Signup and view all the answers

Which feature is typical of robust australopiths like Paranthropus boisei?

Sturdy skulls and powerful jaws. Signup and view all the answers

Which human capability is specifically highlighted as evolved in Homo sapiens?

Capacity for symbolic thought. Signup and view all the answers

What defines the biosphere?

The complete range of ecosystems on Earth Signup and view all the answers

What common misconception about human evolution is corrected by stating that species coexisted and interbred?

Human evolution is a strict linear progression. Signup and view all the answers

Study Notes

Filter Feeders

Capture particles in water passing through their bodies.

Sponges (Porifera)

Water enters a central cavity (spongocoel) and exits through the osculum.
Choanocytes, flagellated cells with collars, circulate water, bringing food into cells via phagocytosis.
Amoebocytes digest food, transport it, produce eggs, and form spicules (skeleton).
Body has two cell layers separated by mesohyl (gelatinous region).

Cnidarians

Radially symmetrical, diploblastic animals with a gastrovascular cavity.
Examples: corals, jellies, sea anemones, hydras.
Basic body plan: sac with a central digestive compartment (gastrovascular cavity); single opening acts as mouth and anus.
Cnidocytes (cells) with nematocysts (stinging organelles) for defense and prey capture.

Medusozoa

Clade within Cnidaria.
Life cycle dominated by the diploid stage, alternating between polyp and medusa forms.
Reproduce sexually (medusae production) and asexually (budding from polyps).

Lophotrochozoans

Bilaterian animals with triploblastic development.
Characterized by a lophophore (feeding tentacles) or a trochophore larval stage (though some lack both).

Lophotrochozoan Phyla

Includes: flatworms, rotifers, acantocephalans, ectoprocts, brachiopods, mollusks, and annelids.

Flatworms (Platyhelminthes)

Dorsoventrally flattened, acoelomate animals in marine, freshwater, and terrestrial habitats.
Many are parasitic (flukes, tapeworms).
Gastrovascular cavity branches throughout the body.
Ventral nerve cord and ganglia; mouth and pharynx for digestion.

Rotifers

Tiny, multicellular animals in freshwater, marine, and damp soil.
Specialized organ systems.
Smaller than many protists.
Ciliated crown draws water and food into mouth; mouth and anus present.

Ectoprocts/Bryozoans

Sessile, colonial animals with a lophophore and a U-shaped alimentary canal.
Lack a distinct head; have a coelom; often encased in hard exoskeleton.
Lophophore extends through pores for feeding.

Brachiopods

Resemble clams but with dorsal and ventral shells, not lateral.
Lophophore for feeding; attach to sea floor with a stalk.
Entirely marine.

Mollusks

Soft bodies, often with calcium carbonate shells.
Slugs, squids, octopuses have reduced or internal shells for quick movement.
Body plan: muscular foot, visceral mass (internal organs), mantle (tissue forming the shell), radula (scraping organ).
Diverse locomotion methods.

Annelids

Segmented worms in marine, freshwater, and damp soil.
True coelom, digestive system, and circulatory system with ventral nerve cord.
Segmented body plan is unique to lophotrochozoans.

Ecdysozoans

Bilaterians with a tough external cuticle (exoskeleton) made of chitin and protein.
Shed exoskeleton (molting) during ecdysis.
Diverse group, including arthropods (largest phylum).

Arthropods

Most diverse animal group (over a million species).
Body plan: segmented body, hard exoskeleton, jointed appendages.
Appear in almost all habitats.
Includes butterflies, cockroaches, spiders.
Evolved during the Cambrian explosion (535-525 mya).

Arthropod Exoskeleton

Cuticle (exoskeleton) of chitin and polysaccharides.
Provides protection, muscle attachment points.
Enabled land colonization due to protection from desiccation.

Arthropod Advancements

Sensory systems: eyes, olfactory receptors, antennae (touch and smell).
Open circulatory system with hemolymph (circulatory fluid) pumped by a heart into hemocoel (body cavity).
Three subphyla: Chelicerates, Myriapods, Pancrustaceans.

Vertebrates

Chordates with a backbone.

Neural Crest

Unique to vertebrates; forms teeth, bones, cartilage, neurons, sensory organs.

Lampreys

Primitive jawless fish with notochord and cartilage skeleton.
Reduced vertebrae.

Gnathostomes

Vertebrates with jaws; prey capture and consumption improved.
Jaws evolved from skeletal rods supporting gill slits.
Paired fins, tail, efficient gills.

Gnathostome Lineages

Chondrichthyans (cartilaginous skeletons), ray-finned fishes, lobe-finned fishes.

Chondrichthyans

Cartilaginous skeletons with some bone in teeth and scales.
Sharks, rays, ratfish.

Ray-Finned and Lobe-Finned Fishes

Ray-finned (Actinopterygii): bony skeleton - most fish species.
Lobe-finned (Sarcopterygii): thick, muscle-surrounded bones in fins; gave rise to tetrapods.

Fish Innovations

Gills protected by operculum (covering); water drawn over gills.
Swim bladder maintains buoyancy.

Lophotrochozoa

Ectoprocts and Brachiopods have lophophores.

Molting (Arthropods)

Exoskeletons must be shed to grow.

Lobe-Finned Fish Lineages

Coelacanths (Actinistia), Lungfish (Dipnoi), and Tetrapods.

Lungfish

Live in stagnant waters.
Breathe air (lung) or gills.

Tetrapods

Evolved from lobe-finned fish; developed limbs and feet for land.
Key differences include four limbs, neck, altered sensory organs.

Amphibians

First vertebrates to live on land.
Three clades: Salamanders (Urodela), Frogs (Anura), Caecilians (Apoda).
Larval stage (often aquatic); adult stage (often terrestrial).
Metamorphosis from aquatic to land adaptations (e.g., gills to lungs).

Amphibian Eggs

Lack shells; require moist environments.
External fertilization is common.
Some provide parental care.

Amniotes

Tetrapods with land-adapted eggs with four protective membranes (amniotic egg).
Reduced dependence on water for reproduction.

Amniote Egg Membranes

Amnion: protects embryo.
Yolk sac: nutrients.
Allantois: waste.
Chorion: gas exchange (with allantois).

Early Amniotes

Small, lizard-like predators.
Evolved from warm, moist environments into diverse habitats.

Reptiles

Amniotes with keratinized scales to prevent desiccation.
Most lay shelled eggs on land; internal fertilization.

Reptile Lineages (Diapsids)

Turtles, Lepidosaurs (lizards, snakes, tuataras), Archosaurs (crocodiles, birds, pterosaurs, dinosaurs).

Turtles

Lack skull holes typical of diapsids.
Shells formed by fused shields and vertebrae, clavicles, and ribs.

Snakes

Descended from lizards with legs; sometimes have vestigial limbs.
Move by lateral bending; belly scales for grip.

Birds

Evolved from theropod dinosaurs; lightweight, beaks, one ovary, small gonads, honeycombed bones.

Birds' Origins

Derived from theropod dinosaurs, specifically feathered ones.
Archaeopteryx is an early bird with both bird and reptilian features.

Mammals

Derived characters: mammary glands, hair, endothermy, large brains, specialized teeth.
Early mammals (Synapsids): unique jaw bones that evolved into earbones (incus and malleus).

Mammal Lineages

Monotremes (egg-laying), marsupials (pouch-bearing), eutherians (placental).

Monotremes

Egg-laying mammals (echidnas, platypus) in Australia/New Guinea.
Lack nipples; secrete milk from skin glands.

Marsupials

Short gestation, long lactation.
Placenta present but short gestation.
Include opossums in North America.

Eutherians

Longer gestation, equal gestation/lactation periods.
Placental mammals.

Primates

Adapted to arboreal (tree-dwelling) life.
Grasping hands, opposable thumbs, forward-facing eyes.
Complex social behavior.

Primate Groups

Lemurs (Madagascar), Lorises, Bush babies, Tarsiers, Anthropoids (monkeys, apes).

Old World Monkeys

Africa/Asia (macaques).

Apes

Old World monkeys; have larger brains, no tails, flexible shoulders.
Gibbons, orangutans, gorillas, chimpanzees, bonobos, humans.

Orangutans

Indonesia/Malaysia.
Solitary (except females with young).
Fully arboreal; fruit-eaters; pronounced sexual dimorphism.

Gorillas

Largest primates (up to 400 pounds).
Mostly terrestrial; knuckle-walkers.
Herbivores (stems, leaves, fruits); live in groups led by silverback male.

Chimpanzees/Bonobos

Knuckle-walkers; omnivorous; tool users; moderate sexual dimorphism.
Bonobos: Democratic Republic of Congo.
Share 98-99% DNA with humans.

Derived Human Traits

Upright posture, bipedal locomotion, large brain, tool use, reduced jawbones.
Short digestive tract, sparse hair (except head), omnivorous.

Sexual Dimorphism (Humans)

Males 15% larger; wider shoulders, more muscle, facial hair, larger larynx.
Females: wider hips, more fat, enlarged breasts after puberty.

Fertilization and Early Growth

Meeting of egg and sperm (ovaries, testes).
Zygote formation.
Morula to blastocyst; implantation in the uterus.

Embryo to Fetus

Amnion surrounds embryo.
Placenta forms from chorion; umbilical cord connects.
Fetus forms; limbs/organs in place.
Birth (nine months).

Hominins

Extinct species more closely related to humans than to chimpanzees.

Earliest Known Hominin

Sahelanthropus tchadensis (6.5 mya); features like upright posture, reduced canine teeth, flat face.

Early Hominins

Smaller brains; larger teeth; protruding jaws.
Ardipithecus ramidus (4.4 mya); 1.2 m tall.

Misconceptions About Human Evolution

Early hominins were chimpanzees, or evolved from them.
Human evolution is a linear progression.

Australopiths

Hominins (4-2 mya).
Australopithecus anamensis (4.2-3.9 mya).
Bipedal; human-like hands and teeth.
Footprints confirm bipedalism.

Robust Australopiths

Paranthropus boisei: sturdy skulls, powerful jaws, large teeth.

Gracile Species

Australopithecus afarensis, afiricanus : Lighter feeding structures for softer foods.

Homo habilis

Homo habilis (2.4-1.6 mya).
Larger brains; shorter jaws.
Associated with tool use.

Homo ergaster

Homo ergaster (1.9-1.5 mya).
Fully bipedal; long legs; smaller teeth than Australopiths.

Homo erectus

Migrated out of Africa (1.8 mya); reached Indonesia.

Neanderthals

Lived in Europe/Near East (350,000-40,000 years ago).
Large brains; buried dead; made tools; interbred with humans.
Not direct ancestors of Homo sapiens.

Homo sapiens

Evolved in Africa; global spread.
Symbolic thought; advanced cognition; art.
Not descended from Neanderthals directly.

Diapsids and Synapsids

Synapsids: single temporal fenestra.
Diapsids: two temporal fenestrae.

Oldest Amniote Group

Turtles.

Cellular Aging

Damage due to free radicals (ROS) in mitochondria.
Accumulated DNA mutations.
Shortened telomeres on chromosomes.

Antagonistic Pleiotropy

Mutation beneficial up to reproductive age; harmful later.

Behavior

Active response of an organism to stimuli.

Study of Wild Behavior

Ethology (ultimate causes); Behavioral ecology (subfield).

Two Causations of Behavior

Proximate: immediate cause (physiological response).
Ultimate: evolutionary or adaptive value.

Innate Behaviors

Inborn, instinctive; determined by genetics (fixed action patterns).

Learned Behaviors

Dependent on experience; result in changes in neural connections; more adaptable to situations.

Imprinting

Specialized learning (young animals imprint to objects/individuals).

Cognitive Learning

Learned through judgment, reasoning, and problem-solving.
Seen in insects as well as other animals.

Combined Innate/Learned Behavior Types

Foraging, reproductive, agonistic, altruistic behaviors.

Foraging Behavior

Optimizing energy gain vs. expenditure.
Search, chase, capture prey.

Reproductive Behaviors

Finding mates, courtship, mate competition, parental care.

Agonistic Behavior

Conflict-related behaviors within a species.
Competition for resources (mating, food).
Includes threats, aggression, submission

Altruistic Behavior

Behaviors benefiting others at a cost to the actor.
Alarm calls; kin selection; reciprocal altruism.

Human Behavior and Genetics

Influenced by both genetics and environment.
Twin studies suggest genetic components for some traits (IQ, sexuality).

Ecology

Study of organism interactions and their environment.

Abiotic/Biotic Factors

Abiotic: physical/chemical (soil, climate).
Biotic: living organisms

Environmental Science

Integrates ecology and social sciences; human impacts on environment; addressing environmental challenges.

Ecological Balance

Stable ecosystem; species coexist.
Disturbances can lead to alternate states; ecosystems usually recover.

Ecological Systems (Order)

Organismal, population, community, ecosystem, landscape, global.

Organismal Ecology

How organism structure/physiology/behavior enhance survival and adaptation.

Population Ecology

Populations of the same species; abundance, density, composition over time/space.

Community Ecology

Populations of different species interacting (predation, competition, mutualism).

Energy Flow (Ecosystem)

Through ecosystems; from producers to consumers.
Only 10% of energy moves to next trophic level.

Ecosystem Ecology

Interactions between organisms and environment; energy flow, chemical cycling.

Landscape

Array of interacting ecosystems from above.
Visible as patches (forests, deserts).

Biosphere

All ecosystems on Earth; entire inhabited portion.

Landscape Ecology

Interactions between ecosystems in a region.
Spatial patterns; ecological connections.

Global Ecology

Interactions across the biosphere.
Energy/material flows between ecosystems.

Earth's Radiation

Direct radiation at equator; more heat.
Angle at higher latitudes; cooler climates.

Uneven Heating & Weather

Uneven heating creates wind and rain patterns.
Earth’s rotation also influences wind.

Climate & Landscapes

Geological features influence weather (e.g., rain shadows).

Bird Migration

Proximal cause: environmental cues (temperature, day length).
Ultimate cause: ensures access to food, improved reproduction in warmer climates

Primate Adaptations for Arboreal Life

Opposable thumbs/grasping hands; front-facing eyes/color vision.

Governing Principles of Ecology

Physical/biological laws (energy/matter conservation); dynamic steady state.

Evolution & Ecological Systems

Evolution shapes genetic changes driving adaptions to the environment.

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Description

Explore the fascinating world of filter feeders, particularly sponges and cnidarians. Learn about their unique structures, functions, and life cycles, including the role of choanocytes and cnidocytes. This quiz covers key concepts that define these animal groups and their significance in aquatic ecosystems.