Ch.32 - Animal Diversity Flashcards
Ch.32 Goals
- Defining characteristics of animals; describe general stages of embryonic dev.
- Identify closest Protist ancestor, key fossil finds, and timing of major events
- Recognize diff types of symmetry and groups incl
- Interpret relationships depicted in phylogenies of animals
Ch.32 Goals
- Defining characteristics of animals; describe general stages of embryonic dev.
- Identify closest Protist ancestor, key fossil finds, and timing of major events
- Recognize diff types of symmetry and groups incl
- Interpret relationships depicted in phylogenies of animals
What is an animal?
Eukaryotic
Multicellular; cells lack cell walls
Heterotrophic; obtain nutrients by ingestion
Have tissues that dev fr embryonic layers
- Tissues: groups of similar cells that act as a functional unit
Animal cells lack cell walls. How are they held t/g?
Structural proteins
- Collagen - most common; only found in animals.
Name two types of specialized cells
Muscle
Nerve
T/F: animal reprod is exclusively sexual.
False
Some asexual reprod too
What are the basic stages of embryonic dev?
Fertilization
Cleavage (mitotic div w/o cell growth) → Blastula
Gastrulation
_______ are sexually immature and morphologically distinct from adult; specialized for eating and growth.
Larva are sexually immature and morphologically distinct from adult; specialized for eating and growth.
Metamorphosis is the developmental transformation from larva to ______.
Metamorphosis is the developmental transformation from larva to juvenile.
______ genes det morphology of organisms by laying out the location of the axis
Hox genes det morphology of organisms by laying out the location of the axis
- Found in ALL animals, but not in any other orgs
- Highly conserved, but prod wide variety of body plans.
Estimated that animals split from fungi about ________ years ago
Estimated that animals split from fungi about 1 billion years ago
- Choanoflagellates: protists; closest to animals
__________ are the closest protist relative to animals
Choanoflagellates are the closest protist relative to animals
Early members of the Neoproterozoic Era (1 bil-542 mya) included _______ biota
Early members of the Neoproterozoic Era (1 bil-542 mya) included Ediacaran biota
The Cambrian Explosion occurred ____ to ___ MYA, during the ________ Era.
The Cambrian Explosion occurred 542 to 251 MYA, during the Paleozoic Era.
- Marked earliest fossil appearance of many major groups of living animals.
Most fossils fr Cambrian explosion are bilaterians, orgs w which traits?
Bilaterally symmetric form
Complete, one-way digestive tract
Which era followed the paleozoic era, and featured the origin and diversification of dinosaurs?
Mesozoic (251 - 65.5 MYA)
Diversification of mammals occurred in which era?
Cenozoic (0-65.5 MYA)
Animal diversity continued to increase through the Paleozoic, but was punctuated by ___________
Animal diversity continued to increase through the Paleozoic, but was punctuated by mass extinctions
Animals began to make an impact on land by ____ MYA.
Vertebrates made the transition to land around ____ MYA.
First mammals emerged during the ________ Era.
Animals began to make an impact on land by 450 MYA.
Vertebrates made the transition to land around 365MYA.
First mammals emerged during the Mesozoic Era (251–65.5 MYA).
A ________ is a set of morphological and developmental traits
A body plan is a set of morphological and developmental traits
Differentiate symmetry of body plans in sponges, cnidaria/ctenophora, and everything else.
Sponges (porifera): asymmetric
Cnidaria and Ctenophora: radial
Everything else: bilateral
Describe radial symmetry
Top/bottom, but NOT L/R or front/back.
Typ sessile or planktonic (drifting or weakly swimming)
Describe bilateral symmetry
Animal can only be divided by a single plane, running the length of the body
Bilaterally symmetrical animals have:
Bilaterally symmetrical animals have:
- A dorsal (top) side and a ventral (bottom) side
- A R/L side
- Anterior (front) and posterior (back) ends
Many also have sensory equip, such as a brain, concentrated in anterior end
Often move actively and have a CNS
__________ are a collection of specialized cells isolated from other tissues by membranous layers
True tissues are a collection of specialized cells isolated from other tissues by membranous layers
- Sponges and a few other groups lack tissues
Tissues are the result of the _________ that occurs in development
Tissues are the result of the gastrulation that occurs in development
________ are diff layers created w/i the embryo
Germ layers are diff layers created w/i the embryo
- Ectoderm: layer covering embryo’s surface
- Endoderm: innermost layer, lines developing digestive tube (archenteron)
-
Mesoderm: b/w ecto/endoderm.
- Only in triploblastic (bilateral) animals.
Animals w radial symmetry are diploblastic, due to the presence of which two germ layers?
Ectoderm: layer covering embryo’s surface
Endoderm: innermost layer, lines developing digestive tube (archenteron)
Which germ layer is only present in triploblastic, bilateral animals? What is its fxn?
Mesoderm: b/w ectoderm and endoderm
Forms muscles and other organs found b/w digestive tract and outer covering
A _______ is a true body cavity, derived from mesoderm
A coelom true body cavity, derived from mesoderm
- Coelomates: animals possessing a true coelom
- Most triploblastic (bilateral) animals are coelomates
Diff b/w a coelom and pseudocoelom
Pseudocoelom: body cavity derived from the mesoderm and endoderm
- Pseudocoelomates: triploblastic (bilateral) animals that possess a pseudocoelom
________ are triploblastic animals that lack a body cavity
Acoelomates are triploblastic animals that lack a body cavity
What is the purpose of the coelom/body cavity?
Fluid cushions organs
Can act as a “skeleton”
Separation from body’s surface
Coelomates and pseudocoelomates refer to _____, NOT clades
Coelomates and pseudocoelomates refer to GRADES, NOT clades
Coelomate animals can be divided into which two groups, based on events in their dev?
Protostome - spiral and determinate cleavage
Deuterostome - radial and indeterminate cleavage
Coelomate animals are divided into protostomes and deuterostomes based on which types of cleavage?
Spiral vs radial:
- Spiral: daughter cells lie b/w pairs of cells above them.
- Radial: cells aligned directly on top of ea/o.
In- vs Determinate:
- Determinate: fate of ea embryonic cell is set v early on.
- Indeterminate: ea cell produced by early divisions retains capacity to dev into a complete embryo.
•Stem cells, identical twins
Summarize protostomes vs deuterostomes
Protostomes: solid masses of mesoderm split to form the coelom
Deuterostomes: mesoderm buds from the wall of the archenteron to form the coelom
A _______ is an indention fr wh the archenteron devs during gastrulation
A blastopore is an indention fr wh the archenteron devs during gastrulation
Think: Deuterostome & Anus, bc D & A closer in alphabet
Protostome & Mouth, bc P & M closer in alphabet
In protostome dev, the blastopore becomes the ______, while in deuterostome dev, the blastopore becomes the ______.
In protostome dev, the blastopore becomes the mouth, while in deuterostome dev, the blastopore becomes the anus.
Common ancestor of all animals
Metaozoa clade
What is meant by sponges being “basal animals”
First lineage to split off
Animals w true tissues form which clade
Eumetazoa
- Diploblasts are basal (first lineage to split off) fr this clade
What are the three major clades of bilaterian animals?
Ecdysozoa
Lophotrochozoa
Deuterostomia
Ecdysozoans shed their exoskeletons through a process called ______
Ecdysis (molting)
Lophotrochozoa are defined by which structure?
Lophophore - feeding structure formed by a crown of ciliated tentacles around the mouth
T/F: Ecdysozoans have some kind of exoskeleton or hard outer covering
TRUE
Ecdysozoans have some kind of exoskeleton or hard outer covering
_______ are basal to all animals
SPONGES are basal to all animals
T/F: all deuterostomes have a pseudocoelom
TRUE
all deuterostomes have a pseudocoelom
T/F: sponges have no true tissue
TRUE
sponges have no true tissue
