What is the Eukaryotic domain characterized by?
- Multicellular
- Lack cell walls
- Heterotrophic
Heterotrophy means unable to synthesize own food, requiring external food sources.
Define Heterotrophy.
Unable to synthesize own food; must acquire externally from food source
This characteristic classifies them as consumers.
What is a Monophyletic group?
A clade consisting of an ancestor and all its descendants
It represents a complete branch tree of life with shared derived traits.
What is a Polyphyletic group?
Do not share a common ancestor; similarities arise from convergent evolution or analogous traits
This contrasts with monophyletic groups.
What are the two types of digestion in animals?
- Intracellular: phagocytosis
- Extracellular: digestive enzymes secreted into gut cavity
Intracellular digestion involves specialized cells, while extracellular digestion breaks down food in the gut.
What are the two types of guts in animals?
- Complete: two openings
- Incomplete: one opening for ingesting food and eliminating waste
The type of gut affects the digestive process.
Define Body symmetry.
- Asymmetrical: no axis of symmetry
- Radial: many axes
- Bilateral: one axis, both halves mirror each other
Most animals exhibit bilateral symmetry, which is associated with cephalization.
What is cephalization?
Development of head-like structures with concentration of sense organs and nerve cells at the front end
It enhances control, coordination, and response to surroundings.
What are the two types of circulatory systems in animals?
- Closed: blood stays inside vessels
- Open: blood flows freely within body cavity
Closed systems are more efficient for nutrient transport.
List the nine animal phyla mentioned.
- Porifera
- Cnidaria
- Platyhelminthes
- Nematoda
- Annelida
- Mollusca
- Arthropoda
- Echinodermata
- Chordata
Each phylum has distinct characteristics and examples.
What is the simplest animal phylum?
Porifera
Sponges are asymmetrical, lack true guts, and rely on diffusion.
What are cnidocytes and their function?
Stinging cells in Cnidaria used for defense and capturing prey
They release a toxic substance.
What is the role of the madreporite?
Allows entry of seawater into the vascular system for movement, respiration, and feeding
It is crucial for echinoderms.
What are the four characteristics all animals in the Phylum Chordata share at one point in their life?
- Dorsal hollow nerve cord
- Pharyngeal slits
- Notochord
- Post-anal tail
These traits are essential for classification within Chordata.
Are all chordates vertebrates?
No
Invertebrates in this phylum include lancelets and tunicates.
What is the primary distinction between terrestrial and aquatic species within the Arthropoda phylum regarding respiratory adaptations?
- Aquatic species use gills
- Terrestrial species use a tracheal system
This adaptation is crucial for gas exchange.
What is the function of spiracles in a grasshopper?
Allow air to enter and leave the insect’s body
They are essential for respiration.
What are the three characteristics that all arthropods share?
- Hard exoskeleton made of chitin
- Segmented bodies
- Jointed appendages
These features contribute to their adaptability.
What is cephalothorax in crayfish?
The fused head and thorax region
It is one of the two main body parts of crayfish.
What is the mantle in mollusks?
Muscular structure that houses internal organs
It also secretes the shell.
What is the clitellum in earthworms?
Produces mucus for mating and is responsible for the cocoon
It facilitates reproduction in segmented worms.
What are the two adaptations of squid for locomotion?
- Tentacles
- Siphon
The siphon expels water for jet propulsion.
