Transcript Figure 18.3A - cloudfront.net

Biology I
Chapter 32
Introduction to Animals
Do Now
• What are the two organ systems that
animals have that nothing else has?
Review
• Photosynthesis:
• H2O + CO2 + Sunlight C6H12O6 + O2
• Cellular Respiration:
• C6H12O6 + O2H2O + CO2
• What is missing?
• ATP
• Why is cellular respiration necessary for
animals?
• Cellular respiration provides the energy cells
need to support life activities
Definitions
• Animal-multicellular heterotrophic
organisms that lack cell walls
• Vertebrate-have a backbone
• Invertebrate-do not have a backbone
Multicellularity
• Specialization-the evolutionary
adaptation of a cell for a particular
function
• Tissue-group of similar cells that
perform a common function
• Organ-body structures that are
composed of more than one type of
tissue and that are specialized for a
certain function
Heterotrophy
• Ingestion-an animal takes in organic
material or food, usually in the form of
other living things.
Figure 18.1A
Sexual Reproduction
• Gamete-haploid cell
• Zygote-diploid cell
• Differentiation-cells become
specialized and therefore
different from each other.
Movement
• Two types of tissues found only in
animals:
• Nervous tissue
• Muscle tissue
Movement
• Nervous tissue-allows an animal to
detect stimuli in its environment and
within its own body
• Neurons-cells of nervous tissue that
conduce electrical signals through an
animals body
Neuron
• Dendrite-moves impulses toward the
neuron
• Axon-moves impulses away from the
neuron
Evolution
• Animals evolved from heterotrophic protists.
• Modern organisms that are thought to
resemble the earliest animals are colonial
protists
Origin and Classification
• Protostome-one digestive opening;
“two-way traffic”
• Has mouth only
• Deuterostome-two digestive openings;
“one-way traffic”
• Has mouth and anus
Sponges
Cnidarians
Flatworms
Chordates
Molluscs
Annelids
Echinoderms
Deuterostomes
Protostomes
Bilaterians
Radial symmetry
Bilateral symmetry
Eumetazoans
No true tissues
Figure 18.4
True tissues
Ancestral
colonial protist
Arthropods
Nematodes
Invertebrates
• Invertebrates-do not have a backbone
• Make up the greatest number of
animal species
Chordates-4 Characteristics
• Notochord-firm, flexible rod of tissues
located in the dorsal part of the body;
becomes the vertebrae
• Dorsal nerve cord-hollow tube containing
nerves; becomes the spinal cord
Chordates
• Pharyngeal pouches-small, outpockets
of the digestive tract; becomes the gills
or lungs
• Post Anal Tail-consists of muscle
tissue and lies behind the posterior
opening of the digestive tract;
becomes the tailbone or tail.
Body Plan
• Body Plan-describes an animal’s
shape, symmetry, and internal
organization
• Symmetry-a body arrangement
• Asymmetrical-do not display symmetry
• Ex. Sponges
• Radial Symmetry- body plan in which
the parts are organized in a circle
around an axis
• Ex. Cnidarians
Body Plan
• Bilateral symmetry-two similar halves
on either side of a central plane
Top
Dorsal surface
Anterior
end
Posterior
end
Ventral surface
Figure 18.3A
Bottom
Body Plan
• Cephalization-characterized by the
concentration of sensory and brain
structures in the anterior end.
Body Plan
•
•
•
•
Dorsal-back
Ventral-front
Anterior-toward the head
Posterior-toward the tail
Germ layers
• Germ Layers-tissue layers in the
embryos of all animals except sponges
• Coelom-fluid-filled hollow space found
in higher animals
Embryonic Development
• Endoderm-Digestive system
• Mesoderm-Skeletal system
• Ectoderm-Nervous system
Body Cavity
• The body cavity aids movement by
providing a firm, fluid-filled structure
against which muscles can contract.
Anatomy
• Comparative anatomy-the study of the
structure of animal bodies
Invertebrate Characteristics
• Most are radial, but the motile ones
are bilateral.
• Segmentation-a body composed of a
series of repeating similar units
• Exoskeleton-rigid outer covering that
protects the soft tissues of many
animals
Respiration and Circulation
• Gills-organs specialized for gas
exchange in water.
• Open circulatory system-circulatory
fluid is pumped by the heart through
vessels and into the body cavity and is
then returned to the vessels.
Invertebrate Reproduction
• Hermaphrodites-produce both male and
female gametes.
• Indirect development-have an intermediate
larval stage
• Larva-a free-living, immature form of an
organism that is different from the adult.
• Direct development-the young animal is born or
hatched with the same appearance and way of
life it will have as an adult; no larval stage occurs
Vertebrate Characteristics
• Endoskeleton-an internal skeleton
made of bone and cartilage
• Integument-the outer covering of an
animal
• Lung-organ for gas exchange
Vertebrate Characteristics
• Kidneys-filter wastes from the blood
while regulating water levels in the
body
• Vertebrates are not the first to have a
brain, but are the first to have highly
organized brains
Vertebrate Reproduction
• A major difference between the
development of invertebrates and that
of vertebrates is that most
invertebrates undergo
indirect development,
while most vertebrates
undergo direct
development.
Embryonic Development
•Embryonic developmental evidence
suggests that echinoderms are closely
related to chordates.
•Crash Course