Animal Diversity
HOW ARE ANIMALS DIFFERENT? Science
MODE OF NUTRITION
Heterotrophic: takes in organic compounds as food
Animals ingest food, while other heterotrophs (for example: fungi) absorb their food.
STRUCTURE
Multicellular Eukaryote: more than one cell with membrane bound nucleus
No Cell Walls: structural support comes from proteins (for example: collagen)
Tissues: cells with similar structure
Muscle cells vs Nerve Cells
REPRODUCTION
1. Sperm fertilizes egg
2. Cleavage: mitotic cell division
3. Blastula: becomes multicellular, forms hollow ball
4. Gastrula: undergo gastrulation: making of embryonic tissue which becomes body parts
HOW ARE ANIMALS DIFFERENT? Science
MODE OF NUTRITION
Heterotrophic: takes in organic compounds as food
Animals ingest food, while other heterotrophs (for example: fungi) absorb their food.
STRUCTURE
Multicellular Eukaryote: more than one cell with membrane bound nucleus
No Cell Walls: structural support comes from proteins (for example: collagen)
Tissues: cells with similar structure
Muscle cells vs Nerve Cells
REPRODUCTION
1. Sperm fertilizes egg
2. Cleavage: mitotic cell division
3. Blastula: becomes multicellular, forms hollow ball
4. Gastrula: undergo gastrulation: making of embryonic tissue which becomes body parts
GROWTH
Larva: sexually immature
Metamorphosis: major physical change larva undergoes before becoming an adult
sometimes they even have different homes and eat different food
(for example: caterpillars are actually prepubescent butterflies)
(another example: Munchlax pokémon evolve into Snorlax after they level up with high friendship)
Larva: sexually immature
Metamorphosis: major physical change larva undergoes before becoming an adult
sometimes they even have different homes and eat different food
(for example: caterpillars are actually prepubescent butterflies)
(another example: Munchlax pokémon evolve into Snorlax after they level up with high friendship)
Homeobox Gene Sequences: regulatory genes
Hox Genes: develop animal embryos
HOW DID IT HAPPEN? History
Diversity increased during the Cambrian Explosion (535-525 million years ago)
continue to diversify during next three periods
Lowered diversity of Ediacaran life forms
Increased diversity of animals
Ordovician, Silurian, and Devonian: diversity increases with periodic mass extinction
HYPOTHESIS I:
-Predators adapt to capture more prey (for example: locomotion)
-Prey adapt to defend themselves (for example: shells)
Adaptations strengthened predator-prey relationships
Natural Selection begins to take control, eradicating some animal groups
HYPOTHESIS II:
-Cambrian Explosion increases atmospheric oxygen
Larger animals with high metabolism thrive
HYPOTHESIS III:
-Hox gene (transcription factor gene that identifies body parts) and other gene changes are formed
Developmental genes are regulated differently
New animal body forms evolve
History of Animals on the Planet
NEOPROTEROZOIC ERA: 1 billion- 542 million years ago
Ediacaranbiota: soft bodied multicellular eukaryotes discovered in the Ediacara Hills of Australia and other continents
FOSSILS: sponges, may be related to present day cnidarians
others do not appear to be related to any living organisms
some are embryos: we do not know whether these are animals are other animals
PALEOZOIC ERA: 542-251 million years ago
Cambrian Explosion: animal diversification (See "Animal Diversity")
FOSSILS: oldest animals with hard skeleton structure: extinct animal phyla or relatives
Ordovician Period, Silurian Period, Devonian Period
365 million years ago: Vertebrates transition to land
amphibians and amniotes
MESOZOIC ERA: 251-65.5 million years ago
Animal phyla spreads to new habitats
Dinosaurs
Plants and insects undergo dramatic diversification
CENOZOIC ERA: 65.5 million years ago
Mass extinctions
Body Plans: set of traits in development and morphology of living animal
used to compare and contrast features
Evo Devo: connection between evolution and development
SYMMETRY: parts of a whole are similar in shape and size
Radial Symmetry: sides are symmetric
sessile (attached to a substrate) or planktonic (drifting)
Bilateral Symmetry: two sided symmetry
active locomotion; complicated movements
Dorsal (Top) Side
Ventral (Bottom) Side
Left/Right Side
Anterior (Front) End
Posterior (ack) End
Cephalization: brain like central nervous system in the anterior end
active locomotion; complicated movements
Dorsal (Top) Side
Ventral (Bottom) Side
Left/Right Side
Anterior (Front) End
Posterior (ack) End
Cephalization: brain like central nervous system in the anterior end
TISSUES
ANIMALS: tissues: specialized, isolated cells
PLANTS: germ layers: concentric layers, gastrulation layers embryo
Endoderm: inner germ layer
is responsible for making the lining of the gastrulation pouch
Ectoderm: germ layer covering embryo surface
is responsible for making the animal's outer covering
Triploblastic: animals with three germ layers
Mesoderm: third germ layer in between endoderm and ectoderm (only in some animals)
for ex: all bilateral symmetry animals
Diploblastic: animals with only two germ layers
for ex: cnidarians
BODY CAVITIES (aka COELOM): between digestive tract and outer wall
in most Triploblastic Animals (those with ectoderm, mesoderm, and endoderm layers)
Functions:
1. Protects organs from internal injury
2. Acts as skeleton in soft bodies (for example: worms)
3. Allows internal organs to grow independently
Coelmates: Animals with true coelem (made from tissue of mesoderm)
Pseudocoelomates: animals with pseudocoelom (not from mesoderm but still works)
Acoelomates: no body cavity
helps classify species into different Grades: groups with the same biological characteristics, but not Clades: groups with descendants of an ancestral species
Development
PROTOSOME DEVELOPMENT
Spiral Cleavage: cells divide diagonally to embryo's vertical axis
Determinate Cleavage: determines fate of each cell
Archenteron: gut "pouch" developed by the digestive tube
Blastopore: becomes mouth
DUETERSOME DEVELOPMENT
Radial Cleavage: cells divide parallel/perpendicular to the embryo's vertical axis
Indeterminate Cleavage: each cell has ability to grow into a living embryo
for example: human twins
Blastopore: becomes anus
ANIMALS: tissues: specialized, isolated cells
PLANTS: germ layers: concentric layers, gastrulation layers embryo
Endoderm: inner germ layer
is responsible for making the lining of the gastrulation pouch
Ectoderm: germ layer covering embryo surface
is responsible for making the animal's outer covering
Triploblastic: animals with three germ layers
Mesoderm: third germ layer in between endoderm and ectoderm (only in some animals)
for ex: all bilateral symmetry animals
Diploblastic: animals with only two germ layers
for ex: cnidarians
BODY CAVITIES (aka COELOM): between digestive tract and outer wall
in most Triploblastic Animals (those with ectoderm, mesoderm, and endoderm layers)
Functions:
1. Protects organs from internal injury
2. Acts as skeleton in soft bodies (for example: worms)
3. Allows internal organs to grow independently
Coelmates: Animals with true coelem (made from tissue of mesoderm)
Pseudocoelomates: animals with pseudocoelom (not from mesoderm but still works)
Acoelomates: no body cavity
helps classify species into different Grades: groups with the same biological characteristics, but not Clades: groups with descendants of an ancestral species
Development
PROTOSOME DEVELOPMENT
Spiral Cleavage: cells divide diagonally to embryo's vertical axis
Determinate Cleavage: determines fate of each cell
Archenteron: gut "pouch" developed by the digestive tube
Blastopore: becomes mouth
DUETERSOME DEVELOPMENT
Radial Cleavage: cells divide parallel/perpendicular to the embryo's vertical axis
Indeterminate Cleavage: each cell has ability to grow into a living embryo
for example: human twins
Blastopore: becomes anus