Presentation on theme: " All multicellular & eukaryotic Cells lack cell walls and come in a variety of shapes. Ingestive heterotrophs (take in food and internally digest."— Presentation transcript:
All multicellular & eukaryotic Cells lack cell walls and come in a variety of shapes. Ingestive heterotrophs (take in food and internally digest it).
Have some type of skeletal support Exoskeletons found in arthropods cover the outside of the body but limit size. Endoskeletons found in all vertebrates are found inside the body and are made of cartilage and/or bone.
Worms have fluid-filled internal cavities giving them skeletal support. Sponges have the simplest skeleton. May be sessile (attached and non-moving) or motile (able to move around).
Muscular tissue provides energy for movement. Reproduces sexually. Shows levels of organization including cell, tissue, organ, and system.
Most show division of labor among cells. Cells are specialized for particular functions. Cell junctions hold individual cells in a tissue together. They link neighboring cells. Most vertebrates have a backbone or spine made of repeating bones called vertebrae that protect the spinal cord. Some show cephalization (have a head with sensory organs concentrated there).
Simplest animals Contains the greatest number of animal species Most found in water Do not have a backbone Includes sponges, cnidarians, flatworms, roundworms, annelids (segmented worms), mollusks, arthropods, and echinoderms.
More complex animals Most have a backbone Includes fish, amphibians, reptiles, birds, and mammals.
Dorsal is the back or upper surface Ventral is the belly or lower surface Anterior head or front end Posterior is the tail or hind end opposite the head Oral surface in echinoderms is where the mouth is located (underside) Aboral surface in echinoderms is the surface opposite the mouth
DORSAL VENTRAL ANTERIOR POSTERIOR
Also called asymmetrical
Symmetry is the arrangement of body parts around a central plane or axis Asymmetry occurs when the body can’t be divided into similar sections (sponges)
Radial symmetry occurs when body parts are arranged around a central point like spokes on a wheel (echinoderms) Most animals with radial symmetry are sessile (attached) or sedentary (move very little)
Bilateral symmetry occurs when animals can be divided into equal halves along a single plane Organisms will have right and left sides that are mirror images of each other More complex type of symmetry
Animals with bilateral symmetry are usually motile Animals have an anterior and posterior ends Show cephalization (concentration of sensory organs on the head or anterior end)
Occurs whenever animal bodies are divided into repeating units or segments Found in more complex animals Earthworms show external segmentation, while humans show internal segmentation (vertebrae of the backbone) Segments may be fused together such as cephalothorax covering chest & head of a crayfish
All animals reproduce sexually, but some also reproduce asexually (sponges bud & flatworms fragment) Zygote is the fertilized egg all animals form from Zygote undergoes rapid cell divisions known as cleavage to become hollow ball of cells called blastula Blastocoel is the central cavity of the blastula
Blastula folds inward at one point to form an opening & two cell or germ layers; process called gastrulation New cup-shaped structure with 2 cell layers is called the gastrula Archenteron is the deep cavity of the gastrula that forms the primitive gut Blastula
Inner germ layer called endoderm & outer germ layer called ectoderm Opening may become the mouth or the anus Protostomes (mollusks, arthropods, & annelids) develop mouth from blastopore, while deuterostomes (echinoderms & vertebrates) develop an anus from blastopore
Some animals form a third germ layer in the middle called mesoderm Cells differentiation during development changing their shapes to fit their function ( neurons or nerve cells become long to conduct messages)
Form tissues, organs, & systems NOT present in sponges Ectoderm (outer) – forms skin, nerves, sense organs Endoderm (inner) – forms liver and lungs Mesoderm (middle) – forms muscles & other systems
Sponges have NO tissues or organs, only specialized cells Cnidarians like jellyfish & coral have only two body layers & one body opening (mouth/anus) into gastrovascular cavity Cnidarians have outer epidermis & inner gastrodermis with jelly-like mesoglea between the layers
All worms, mollusks, arthropods, echinoderms, and vertebrates have three cell layers ◦ Ectoderm ◦ Endoderm ◦ Mesoderm
Cleavage – rapid mitosis (cell division) of zygote Radial Cleavage – cells divide parallel or perpendicular to axis to each other
Spiral Cleavage – cellular divisions occur diagonally, in a twisting pattern
Stages of Development
Animals with Indirect development go through immature (larval) forms Larva does NOT resemble adult Cnidarian (jellyfish, coral, & sea anemone) larva called Planula
Mollusk (squid & octopus) larva called trochophore Echinoderm (starfish) larva is called Dipleurula
Usually found in arthropods May be complete or incomplete Incomplete Metamorphosis: egg nymph adult Complete Metamorphosis: egg larva pupa adult
Internal body cavity fully lined with mesoderm Body organs suspended in this cavity
Acoelomate animals have solid bodies filled with cells Acoelomate animals include sponges, cnidarians, & flatworms
Pseudocoelomate animals (roundworms) have a functional body cavity NOT fully lined with mesoderm
Spongin & spicules Spongin & spicules (sponges) Limestone cases Limestone cases (corals) Exoskeletons Chitin Exoskeletons of Chitin (arthropods) Limits Limits size molted Must be shed or molted to grow vulnerable Animal vulnerable to predators during molting
Hydrostatic skeleton Hydrostatic skeleton – fluid filled body cavity (worms) Calcium plates or Test Inner Calcium plates or Test (echinoderms) Bone cartilage endoskeleton Bone and/or cartilage endoskeleton (vertebrates)
Exoskeletons Must Be Molted
Endoskeletons Grow with the Animal
All animals are ingestive heterotrophs Choanocytes (specialized cells) capture & digest food for sponges Gastrovascular cavity with one opening in cnidarians and flatworms for food to enter & leave; called two-way digestive system
Gastrovascular Cavity with Mouth Only (Cnidarians)
Animals with a one-way digestive system have a mouth and an anus Food enters the mouth, continues in one direction through the digestive tract, and wastes leave through the anus Includes annelids, arthropods, & vertebrates
Transports oxygen & nutrients to cells Carries away wastes & carbon dioxide from cells Sponges, cnidarians, & flatworms do NOT have circulatory systems
In closed circulation, blood remains inside blood vessels until it reaches cells (annelids & vertebrates) In open circulation, blood is pumped out of blood vessels to bathe tissues in the body cavity or hemocoel (arthropods & mollusks)
Open Circulation Closed Circulation
Taking in O 2 & releasing CO 2 diffuse Gases can diffuse across moist surfaces (earthworms) Gills Gills filter O 2 from water (aquatic animals) Lungs Lungs take O 2 from air (terrestrial animals)
Skin breather Lungs Gills
Coordinates the activities of the animal’s body Neurons Neurons – nerve cells that transmit electrochemical signals Nerve net - Nerve net - network of neurons, very little coordination Ganglion Ganglion – clusters of neurons; may serve as a simple brain Brain Brain – control center at anterior end
Excretion Excretion is the removal of nitrogen wastes from the body Diffusion Diffusion is used by simple aquatic animals Flame cells Flame cells remove wastes in flatworms
nephridia Coiled tubules called nephridia remove nitrogen wastes in arthropods Kidneys Terrestrial animals remove wastes with Kidneys paired ◦ May be paired (most vertebrates) single ◦ May be single as in birds
Reproduction Reproduction is the process by which organisms make more of their own kind sexual reproduction All animals reproduce by sexual reproduction (produce eggs and sperm) asexual reproduction Some animals also use asexual reproduction creating identical offspring
Regeneration Fragmentation Regeneration or Fragmentation is the breaking off of pieces and the re- growth of a new organism Sponges Flatworms Found in simple animals like Sponges and Flatworms
Budding Budding occurs in hydra whenever a growth on the parent is released clone Creates a clone
Parthenogenesis Parthenogenesis – females produce eggs that develop unfertilized into female organisms Komodo dragon Komodo dragon is an example
Hermaphrodite BOTH Hermaphrodite are animals like earthworms that produce BOTH eggs and sperm NOT Most hermaphrodites do NOT fertilize their own eggs Mate to exchange sperm
External External – sperm and eggs are released into water where they are fertilized Internal Internal – sperm and egg are fertilized inside the female animal’s body