Chapter 32 Flashcards
What are animals
multicellular, heterotrophic, mobile organisms, with tissues that develop from embryonic layers
Animal attributes
- Multicellularity
- Mobile
- Consumers (heterotrophic)
- Usually produce sexually and develop
What is the difference between plant/fungus cells and animal cells?
Animal cells lack a cell wall for support.
What supports animal cells and connects them to one another?
structural proteins
What is the most abundant structural protein in animals that is not in plants/fungi
collagen
Both animal cells and plant and fungal cells are organized into tissues, but what is unique to animals?
muscle and nervous tissues
Autotrophs
generate own energy through photosynethsis or chemosythesis - “self-feeding”
Heterotrophs
consume other living things or nonliving organic material (animals and fungi) - “other feeding”
How do we distinguish animals and fungi if both are heterotrophic?
Animals ingest their food and digest it internally via enzymatic activity; fungi secrete digestive enzymes to breakdown food and then absorb it
WHat usually dominates the life cycle of animals?
the diploid stage
Zygote
diploid cell produced by the union of haploid gametes during fertilization; a fertilized egg
Cleavage
succession of rapid cell divisions (mitosis) without growth during early embryonic development that converts the zygote into a ball of cells (blastula)
Blastula
a hollow ball of cells that marks the end of the cleavage stage during ebryonic development
Gastrulation
series of cell and tissue movements in which the blastula-stage embryo folds inward, producing a three-layered embryo (gastrula)
Gastrula
embryonic stage in animal development encompassing the formation of three layers: ectoderm, mesoderm, and endoderm
Larvae
free-living, sexually immature form in some animal life cycles that may different from the adult animal in morpholog nutrition, and habitat
Metamorphosis
developmental transformation that turns an animal larva into either an adult or an adult-like stage that is not yet sexually mature
Juvenile
post-larval stage that is not yet reproductively mature
Adult
reproductively mature stage
Stages of reproduction and development
- Sperm fertilizes egg to form diploid zygote
- Zygote undergoes cleavage to form blastula
- Blastula undergoes gastrulation forming gastrula
Homeobox genes (Hox genes)
Regulatory genes found in most animals and only animals (not sponges). Regulate development of body form (anterior-posterior axis)
A mutation of the HoxD13 gene
Synpolydactyly
When did the common ancestor of all living animals likely live?
about 770 mya
A group of protists that are likely the closest living relatives to animals
choanoflagellates
HOw many living animal species are there to date?
1.3 million - for more are estimated to exist
What evidence shows that the common ancestor of all animals may have resembled modern choanoflagellates?
- the origin of multicellularity requires the evoltion of new ways for cells to attach and communicate to each other
- Choanoflagellates and animals have sequence similarities in genes involved in adherence and attachment
What specific gene coding for a group of proteins do both choanoflagellates and animals have?
cadherins
What do a nimals have that choanoflagellates don’t?
the CCD domain (novel cadherin protein domain)
Neoproterozoic Era
(1bya - 542 mya)
- ediacaran biota
- evidence of predation
Ediacaran biota
soft bodied multicellular eukaryotes
soft bodied multicellular eukaryotes
Ediacaran biota
First generally accepted macroscopic fossils of animals
Ediacaran biota
Palezoic Era
(542-251 mya)
- cambrian explosion
- animal diversity continues to increase
Cambrian explosion
marks the earliest fossil appearance of many major groups of living animals
Most fossils from the Cambrian explosion are…
bilaterians
- bilaterally smmetric
- complete digestive tract
- one-way digestive system
What caused the Cambrian Explosion?
- new predatory-prey relationships
- rise in atmospheric oxygen (enabled animals with higher metabolic rates and larger body sizes to thrive)
- evoltuion of Hox gene
New predatory-prey relationships that caused the Cambrian Explosion
- Predators evolved novel traits for catching prey
- Prey evolved new defenses (protective shells)
- (decline in soft bodied Ediacaran biota)
How does animal diversit continue to increase through Paleozoic
- Arthropods are first animals to transition to land
2. vertebrates colonize land
Mesozoic Era
(251-65.5 mya)
- coral reefs emerged
- ancestors of plesiosaurs were reptiles that returned to the water
- dinosaurs
- first mammals
- angiosperm radiation
Cenozoic Era
(65. 5 mya - present)
- rise of mammals
- first primates appear in Africa
The beginning of cenozoic era followed…
mass extinctions of terrestrial and marine animals
What is considered when categorizing animals?
- Symmetry (or lack thereof)
- Tissues
- Body Cavity
- Embronic Development
Symmetry
- asymmetrical
- radial symmetry
- bilateral symmetry
Radial animals
often sessile or planktonic (drifting or weakly swimming)
What is bilateral symmetry accompanied by?
cephalization
cephalization
concentration of sense organs and nervous control at the anterior end of the body (head and brain/ganglia)
