Animal Classifications Flashcards
What are the general characteristics of animals?
- Multicellular with specialized cells that form tissues and organs.
- Possesses nervous and muscular tissues that allow for mobility (locomotion).
- Have a life cycle in which the adult is typically diploid.
- Usually undergo sexual reproduction and produce an embryo that goes through developmental stages.
- Heterotrophs that acquire food by ingestion, followed by digestion.
The animal kingdom is currently divided into ___ groups or phyla.
30
The animal kingdom is currently divided into 30 groups or phyla where the majority of these animals are ___.
invertebrates
___ lack an internal skeleton, or endoskeleton, of bone or cartilage. They evolved first, and they far outnumber the vertebrates (animals with an endoskeleton).
Invertebrates
This tree represents the relationships among different animal groups or phyla. It shows different species that evolved from a common ancestors over time. Provides insight to the diversity of life
Evolutionary tree
___ have played a major role in establishing evolutionary relationships, because the more closely related two organisms are, the more their DNA sequences will have in common
Molecular comparisons
It is characterized based on body structures or morphology.
Phylum/Phyla
In eumetazoans, multicellularity led to the formation of ___ (ectoderm, mesoderm, endoderm).
germ layers
___ preceded bilateral symmetry.
Radial symmetry
Bilateral symmetry led to __, or the formation of a head containing a brain and sensory receptors.
cephalization
Bilaterally symmetrical animals undergo either ___ development or ___ development.
protostome, deuterostome
In protostomes, the __ embryonic opening becomes the mouth. They are also characterized by spiral cell division.
first
In deuterostomes, the __ embryonic opening becomes the mouth while the first opening is the ___. They are also characterized by radial cell division.
second, anus
Animals may be further identified as ___, ___, or ___, depending on the structure of their body cavity.
coelomates, pseudocoelomates, acoelomates
Some ___ animals exhibit segmentation or repetition of parts of the body.
coelomate
What are the evolutionary trends?
- Germ layers
- Animal symmetry
- Animal development
- Animal body cavities
- Animal segmentation
How many germs layers does a diploblast have?
2
How many germs layers does a triploblast have?
3
What are the three germ layers?
- Ectoderm
- Mesoderm
- Endoderm
This germ layer forms many external and neural structures including the epidermis (skin), hair, nails, formation of exoskeleton (not all animals have exoskeletons), etc. Serves as outer covering
Ectoderm
This germ layer develops into organs.
Mesoderm
This germ layer forms the inner lining of organs in digestion and respiration systems.
Endoderm
What germ layer does a diploblast don’t contain?
Mesoderm
With __, two mirror images are obtained no matter how the animal is sliced longitudinally. This is common in animals that live underwater or those who are sessile (animals that don’t move that much). Top - oral side (mouth is located), aboral - opposite of the oral side.
radial symmetry
With __, mirror images are obtained only if the animal is sliced down the middle. This is common in animals who are locomotive.
bilateral symmetry
This kind of animals has no body cavity. Their body are filled with mesenchyme, a solid tissue where the organs are embedded; Flatworms
Acoelomate
This kind of animals has body cavity.; Dirtworms
Coelomate
This kind of animals’s body cavity is incompletely lined by mesoderm. ;Nematodes, roundworms
Pseudocoelomate
This is the repetition of the body units along the length of the body of animals.
Segmentation
What are the early animals?
Sponges (porifera) and cnidarians
__ have saclike bodies perforated by many pores called ostia. They are multicellular (lack tissues) and some have various symmetries or no symmetries at all.
Sponges (porifera)
__ have two tissue layers, are radially symmetrical, have a saclike digestive cavity (with only one opening), and possess nematocytes are specialized cells that contain nematocysts, which are the organelles that deliver a sting.
Cnidarians
___ are characterized by feeding structure and larval development. They increase their body mass gradually without molting.
Lophotrochozoans
What are the
lophotrochozoans?
Flatworms, Mollusks, and Annelids