Biology 25.1 What is an Animal?
Roughly how many phyla are invertebrates classified into, and what are some examples of invertebrates?
33 phyla, including animals like sea stars, jellyfishes, and insects
What do vertebrates develop that invertebrates don't?
A backbone, or vertebral column
What four characteristics are exhibited by chordates at some point in their development?
A dorsal, hollow nerve cord; a notochord; a tail that extends beyond the anus; and pharyngeal pouches
What is a notochord?
A supporting rod that runs through the body just below the nerve cord
What are the 4 characteristics of all animals?
All animals are multicellular, heterotrophic, and eukaryotic, and lack a cell wall
Most chordates have a large number of nerve cells concentrated into a...?
Brain
What two categories are animals classified into?
Chordates and invertebrates
What process allows some aquatic animals to "breathe" through their skin?
Diffusion
Collecting and eliminating metabolic wastes is a function performed by what 3 systems?
Digestive, circulatory, and excretory systems
In complex animals, which three body systems work together to obtain and distribute oxygen and nutrients?
Digestive, respiratory, and circulatory
How is feedback inhibition similar to a furnace in a house?
Feedback inhibition will cause you to sweat if you're too hot and shiver if you're too cold to help maintain homeostasis, similar to how a furnace controls temperature in a house in that it constantly changes what it's doing to keep a consistent temperature
What 5 groups of animals are vertebrates?
Fishes, amphibians, reptiles, birds, mammals
How do the skeletons of insects and vertebrates differ?
Insects have external skeletons; vertebrates have internal skeleton
Why do invertebrates not form a clade?
Invertebrates are defined by the lack of a backbone, but clades aren't defined by a lack of a characteristics
What is an advantage of asexual reproduction?
It produces large numbers of offspring rapidly
How does muscle tissue generate force?
It shortens
What structure performs a function most similar to that of gills?
Lungs
What percent of all animal species are invertebrates?
More than 95% of all animal species
What system gathers information through receptors for sound, light, chemicals, and other stimuli?
Nervous system
Are all chordates vertebrates?
No, because some chordates don't develop a backbone
In complex animals, what system collects metabolic wastes and delivers them to the respiratory and excretory systems?
The circulatory system
How does an animal's nervous and musculoskeletal systems work together to allow it to escape a predator?
The nervous system gathers information, processes it, and then sends the processed information to the musculoskeletal system, which then physically responds by working with the nervous system to move muscles
What different wastes do the respiratory and excretory eliminate?
The respiratory system eliminates carbon dioxide, while the excretory system eliminates ammonia
What are pharyngeal pouches?
They are paired structures in the throat region
What do invertebrates not have?
They don't have a backbone, or vertebral column
What three things do animals do to maintain homeostasis?
They gather and respond to information; obtain and distribute oxygen and nutrients; collect and eliminate carbon dioxide and other wastes
What is one way that animals maintain homeostasis, and what is a different name for it?
They maintain homeostasis by feedback inhibition, or negative feed-back
