Chapter 32 Flashcards
Nutritional modes of plants, fungi, and animals
Plants- autotrophic eukaryotes
Fungi- heterotrophs
Animals- ingesting organic material
How do animal and fungi differ in nutritional modes?
Animals ingest then secrete enzymes, opposite of fungi
What are 4 characteristics of animal cells?
Eukaryotic
Lack cell walls
External proteins in the cell membrane provides structure
Ex- collagen
Orgnaized into tissues
What is the reproduction method of animals, and what stage is dominant?
Sexually
Dominant diploid stage
What occurs during the haploid stage of animals? (3)
meiotic division to produce eggs and sperm
Small, flagellated sperm
Larger, nonmotile egg
What is cleavage, and what does it lead to?
mitotic cell division without cell growth done by zygote
leads to a blastula
What is a blastula, and what does it lead to?
multicellular stage which the zygote takes a form of a ball
gastrulation
What is gastrulation?
process where embryonic tissues form that wild evelop into adult body parts
What is a larva, and three ways it differs from an adult?
sexually immature form of an animal
Morphologically distinct from the adult
Usually feeds on different food
Can inhibit different habitats
What is metamorphosis, and what is the result?
developmental transformation of a larvae that turns it into a juvenile
Juvenile looks like the adult but is not sexually mature
What trait is shared amongst a broad taxa?
Genes that control development
What do development genes do, and what do they contain?
Regulate expression of other genes
Contains homeoboxes- sets of DNA sequences
What are hox genes, what do they contain, 3 roles, and how did they arise?
unique homeobox shared by most animals
Contains family of genes
Aids in development of animal embryo
Controls expression of genes influencing morphology
Regulates formation of anterior-posterior axis
Arose through duplication of homeobox genes
What species lack hox genes, but what do they possess?
sponges
other homeoboxes that influence shape
When did animals arise?
710 million years ago
How do we know when animals arose (3)?
From fossil steroids that produced sponges
Molecular clock estimates sponges originated 700 million years ago
Common ancestor of all extant animal species lived about 770 million years ago
How did we find the origins of multicellular animals?
identify protists groups closely related to animals
What are multicellular animals closest living relatives?
choanoflagellates
How do we know that multicellular animals adn choanoflagellates are closely related? (4)
Common ancestor of animals and choanoflagellates may have been suspension feeders
Choanoflagellate cells and collor cells of sponges are morphologically indistinguishable
Collar cells in flatworms and other animals are also similar to choanoflagellate cells
DNA sequence indicate choanoflagellates and animals are sister groups
What do choanoflagellates and animals share?
Same signal genes and adhesion proteins
Ex- cadherins- adhesion proteins
How does multicellularity arise?
only if cells can adhere and signal to each other
How did cadherin proteins arise?
Cadherin domain in choanoflagellate underwent rearrangement and incorporation of other novel domains to form animal cadherin domains
When was the Neoproterozoic Era, and what 2 things were found?
1 billion to 542 million yeats ago
First accepted animal fossil dates 560 million years ago
Also contains fossils of animal embryos
Still debated whether they are animal embryos
What was the first accepted animal fossil, and what was it thought to be?
ossil of ediacaran biota- Soft-bodied multicellular eukaryote
THOUGHT TO BE MOLLUSCS, SPONGES, AND CNIDARIANS
When was the Ediacaran period, and what was found?
635-542 million years ago
Evidence of predation
What was the first evidence of predation?
Cloudina- animal whose body was protected by a shell shows signs of attack
When was the Paleozoic era?
542-251 million years ago
When was the Cambrian period, and what occured?
535-525
Cambrian explosion- findings of the oldest fossils of about half of alle xtant animal phyla
What was found in the Cambrian explosion?
Includes arthropods, chordates, and echinoderms
Includes first large animal
Most are bilaterians- clade have two-sided or bilaterally symmetric form
What do bilaterians possess (2), and what do they include?
Possess complete digestive tract
Efficient digestive system with mouth at one end and anus at the other
Includes molluscs, arthropods, chordates
What increased in the Cambrian period, and what did it lead to?
diversity of the Cambrian period increases, Ediacaran life-forms decline
Why did soft-bodied Ediacarian species decline? (3)
Predator-prey relationships emerged, and led to the decline of soft-bodied ediacaran species
Increase of atmospheric oxygen led to the decline
Genetic changes affecting development, like Hox genes and microRNAs facilitated formation of new forms
WHat followed the Cambrian period? (2)
increase in diversity
episodes of mass extinction
What were the first terrestrial species, and what two evidences point to this?
Arthropods were the first terrestrial species
Through fossils of millipedes, centipedes, and spiders
Emergence of fern galls- fern openings where insects resided
When did vertebrates colonize lands, and what were the first ones?
365 million years ago
Tetrapods- Amphibians and amniotes (reptiles) survived
When was the Mesozoic Era?
251 to 65.5 million years ago
What occured during the Mesozoic Era? (7)
Animals began spreading to new habitats
Coral reef formed
Some reptiles returned to water
Tetrapods developed wings and other flight equipment
Dinosaurs arose
First mammals- tiny nocturnal insect eaters emerged
Angiosperms and insects underwent dramatic diversification
What occured during the Cenozoic era (3)?
Ushered by mass extinction of terrestrial and marine mammals- Includes large, nonflyig dinosaurs and marine reptiles
Large herbivores and predators emmerged
Climate began to cool, and animals began to shift habitat
What is a body plan?
particular set of morphological and developmental traits integrated into a functional whole
What is radial symmetry?
does not have a left or right side
What does sessile mean?
attached to a substrate
What type of animals are usially radial? (2)
Sessile
planktonic
What does bilateral symmetry mean, and three things they possess?
have a left and right side
Dorsal (top), ventral (bottom), left, right, anterior, and posterior
Have sensory equipment in the anterior
active movement
What are true tissue, and an animal that do not have true tissues?
isolated from other tissues by membranous layers
Sponges lack true tissues
What occurs during gastrulation?
embryo becomes layeres
develops germ layers which form into various tissues and organs
What are the three type of germ layers?
ectoderm
endoderm
mesoderm
What is the ectoderm, and what does it give rise to?
germ layer covering surface of the embryo
Gives rise to skin and in some, the central nervous system
What is the endoderm, what does it line, and what does it give rise to?
innermost germ layer
Lines pouch form in gastrulation
Gives rise to digestive tract and liver and lungs
What does diploblastic mean, and an example organism?
animals only possessing the ectoderm and endoderm
Cnidarians
What does triploblastic mean, and example organisms?
possession of a third germ layer
All bilaterally symmetrical animals
What is the mesoderm, and what does it form?
fills space between ectoderm and endoderm
Forms the muscle and other organs
What the coelem, and what does it form from?
Fluid or air filled space between the digestive tract and outer body wall
tissues derived from mesoderms
What does the tissue surrounding the coelom do?
connects and suspends internal organs
What is a coelomate?
animals with true coeloms
What is a pseudocoelom?
cavity formed from mesoderm and endoderm
What is a pseudocoelomates?
animals with pseudocoelom
What is an acoelomate?
animals lacking a body cavity
Four functions of the body cavity
Cushions suspended organs
Prevent internal injuries
Contain noncompressible
fluids acting like a skeleton
for muscles
Ex- earthworms
Enables independent growth and movement of organs
How do protostome and deuterostome development differ? (3)
Cleavage
Coelom formation
Fate of blastopore
What kind of cleavage does protostome development undergo? (3)
spiral, determinate cleavage
Cell division are diagonal to the vertical axis of the embryo
Smaller cells centered over larger, underlying cells
what is determinate cleavage? (2)
animals with protostome development casts the fate of each cell early on
If one cell was removed, the embryo would not fully form
What kind of cleavage do deuterostome development undergo? (2)
radial, indeterminate cleavage
Cleavage planes are parallel or perpendicular to the vertical axis of the embryo
What is indeterminate cleavage?
each cell produced retains the capacity to develop into a complete embryo
What is archenteron, and what does it become?
a blind pouch formed by the digestive tube of the embryo
Becomes the gut
How does the coelom form in protostome development?
solid masses of mesoderm split and form coelom
How does the coelom form in deuterostome development?
mesoderm buds from the wall of the archenteron, coelom arising from its cavity
What is the blastopore, and what does it become?
indentation that leads to the formation of the archenteron
Blastopore and a second opening becomes the mouth and anus
What is the fate of the blastopore in protostome and deterustomes?
Prostome development- mouth develops from the blastopore
Deuterostome development- anus develops from the blastopore
How many animal phylum exists, and what is inferred from it?
3 dozen phyla of extant animals exist
Genome, morphological traits, and rRNA genes are inferred
What do all animals share, and what is the resulting clade called?
All animals share a common ancestor
\Forms a clade called Metazoa
What is the basal animal?
sponges
What is the clade Eumatozoa, and its basal species?
a clade of animals with true tissues
Basal eumetazoans include comb jellies and diploblastic, and are radial symmetric
What is the largest animal phlya, and 2 shared derived traits of the phyla>
Bilateria
Bilateral symmetry
Presence of three germ layers
What are the three major clades of bilaterian animals?
Deuterostomia, lophotrochozoa, and ecdysozoa
What does the clade deuterostomia include?
clade including hemichordates (acorn worms), echinoderms (sea stars), and chordates
What traits the hemichordates and chordates share? (3)
Gill slits
Dorsal nerve cords
Echinoderms lack these
What is a charateristic of Ecdysozoa, and what does it include?
secrete exoskeletons
Includes nematodes, arthropods
What is ecdysis?
process of molting exoskeleton
What are characteristics of Lophotrochozoa?
some develop lophophores
have a trochophore larval stage
what is the lophophore?
unique structure of a crown with ciliated tentacles to feed
What is the trhochophore larval stage?
developmental stage of molluscs and annelidsW
What is controversial about the phylogeny of sponges?
under debate if they are monophyletic
What organism is investigated to be the basal metazoan, and why is there resistance?
ctenophores (comb jellies)
They do not resemble choanoflagellates and have true tissues
What species is the basal bilaterian?
under debate
Some conclude flatworms, while others place them within Deuterstomia
