Biology: Animals Reproduction and Development

• The presentation is about animals and their biological functions.

Objectives

• The goal is to compare and contrast biological processes in plants and animals.
• These processes include reproduction, development, nutrition, gas exchange, transport/circulation
• Also include, regulation of body fluids, chemical and nervous control, immune systems
• Lastly, include sensory and motor mechanisms.

Symmetry

• Asymmetry: No symmetry
• Radial symmetry: Body parts are arranged around a central axis and bisected into two equal halves in any 2-D plane.
• Bilateral Symmetry: Right and left halves are mirror images, with only the sagittal plane bisecting the animal into two equal halves.

Animal Kingdom Classification

• Invertebrates have no backbone.
• Vertebrates have a backbone.
• Examples of invertebrates: sponges, jellyfish, flatworms, roundworms, segmented worms, mollusks, arthropods, and sea stars.
• Examples of vertebrates: fish, birds, mammals, reptiles, and amphibians.

Animal Kingdom Phyla & Classes

• Phyla include Annelida (segmented worms), Nematoda (round worms), Arthropoda, Platyhelminthes (flat worms), Chordata, Porifera (sponges), Echinodermata (starfish, sea urchins), Cnidaria (coral, jellyfish), and Mollusca (snails, clams, octopi).
• Subphyla include Chelicerates, Crustaceans, and Labiatae.
• Invertebrate classes include spiders, scorpions, crabs, lobsters, barnacles, insects, centipedes, and millipedes.
• Vertebrate classes include amphibians, reptiles, birds, mammals, bony fish, cartilaginous fish, lampreys, and hagfish.

Nourishment and Digestive Systems

• Herbivorous animals eat plants (e.g., cows, hippos).
• Carnivorous animals eat meat (e.g., lions, crocodiles).
• Omnivorous animals eat plants and meat (e.g., lemurs, jackals).
• Scavengers eat dead animals.
• Types of animals based on food include herbivores, carnivores, omnivores, and detritivores that eat detritus/dead organic matter.

Feeding Mechanisms

• Filter Feeding: Nutrients are obtained from particles suspended in the water.
• Fluid feeding: Nutrients are is obtained by consuming other organisms' fluids.
• Deposit Feeding: Nutrients are obtained from particles suspended in the soil
• Bulk Feeding: Nutrients are obtained by eating the whole of an organism

Animal Digestive Systems

• Avian Digestive System: includes a crop, gizzard, proventriculus, and other organs.
• The Crop is a pouch in the esophagus used to temporarily store food.
• The Gizzard is a muscular organ that mechanically grinds and mixes food.
• Monogastric Digestive System: stomach only contains one chamber to digest food while the cecum absorbs the fluids and salts that remain after digestion.
• Ruminant Digestive System: Contains four compartments
• The Rumen has Microbes that produce fatty acids, vitamin B, K & amino acids.
• The Reticulum collects smaller digesta particles and move them into the omasum, while the larger particles remain in the rumen for further digestion.
• The Omasum absorbs water and other substances from digestive contents.
• The Abomasum is the only compartment with glands that produces digestive enzymes & hydrochloric acids.

Ruminant Digestion and Methane Emission

• Methane-forming microbes combine the hydrogen and carbon dioxide molecules in the rumen to form enteric methane (CH4).
• Cows and other ruminant animals expel the methane via belching, at which point it enters the atmosphere and begins adding heat.
• Pseudo-Ruminant Digestive System: The stomach has three-chambers.
• The cecum is large and is the site where the roughage is fermented and digested.
• Examples include horses, camels, alpacas, hippopotamus, rabbits, guinea pigs, and hamsters.

Comparison of Ruminant and Pseudo-Ruminant Systems

• Ruminant digestive systems have three compartments in the stomach and are found in horses, camels, alpacas, hippopotamus, rabbits, guinea pigs, and hamsters.
• Pseudo Ruminant system are a digestive system that has four compartments in the stomach, has a rumen and are found in goats, cows, sheep, etc.

Animal Locomotion

• Motile: Animals that can move and demonstrate complex movement (e.g., bird).
• Sedentary: Animals that can move when needed (e.g., clam).
• Sessile: Animals are rooted in one spot (e.g., coral).

Thermal Regulation

• Cold Blooded (Ectothermic): Body temperature changes with the environment (e.g., fish, reptile, amphibian).
• Warm Blooded (Endothermic): Body temperature is stable even in an extreme hot/cold environment.
• This is achieved through sweating, panting, or changing position (e.g., birds, mammals).

Animal Circulatory Systems

• Open Circulatory System: Common in mollusks & arthropods; multiple hearts and smaller bodies pump blood into the hemocoel, and it diffuses back to blood vessels (no true blood, i.e., hemolymph).
• Closed Circulatory System: Common in vertebrates with one heart where blood is pumped through blood vessels (examples: birds, mammals, amphibians, reptiles).

Circulation

• In closed circulation, blood does not bathe the cells but flows in vessels.
• In open circulation, blood directly bathes the cells and flows in haemocoel.
• Closed circulation includes a muscular heart; open circulation does not have a muscular heat, but uses nodes as a simple heart.
• The blood pressure is higher in closed circulation, but blood includes hemoglobin.
• The blood pressure is lower in open circulation, and does not have hemoglobin.
• Closed circulation - earthworms, fish, frog, humans, etc.
• Open circulation - insects, arachnids, etc.

Respiration

• Human Lungs: inhale by moving the diaphragm to lower the air pressure in the chest cavity and pull air into the lungs.
• Bird Lungs: air flows one way through bird lungs, allowing birds to take in oxygen even during exhalation.
• Grasshopper Trachea: Grasshoppers transport air directly to tissue cells using tracheal tubes.

Animal Respiration

• Mammals are terrestrial and use lungs for breathing
• Birds use their lungs for breathing.
• Exchange of oxygen and carbon dioxide in the lungs takes place in millions of tiny air sacs.
• These air sacs are called alveoli in mammals and atria in birds.
• Insects have tracheal respiration, where air is drawn in and out of the body through openings called spiracles.
• Their Spiracles take the air to tube-like structures called the trachea in the abdominal cavity, then moves into smaller tubes called tracheoles present throughout the body.

Respiration in Specific Animals

• Bird Respiration: first breath, air moves into the air sac, then air sac sends air into lungs on first breath out. Then on second breath in air moves into front air sac and second breath out air leaves the body.
• Fish Respiration: the fish opens its mouth, water runs over the feathery filaments of the gills. The blood in the capillaries picks up oxygen that's dissolved in the water
• Amoeba Respiration: gas exchange occurs by diffusion across the cell membrane.
• Earthworm Respiration: skin serves as the organ of respiration (cutaneous respiration.)
• They take in the atmospheric oxygen and expel carbon dioxide through their moist skin
• Oxygen diffuses through the earthworm's body surface and spreads across the body via a network of capillaries.
• Frog Respiration: frogs have lungs, but a great deal of their respiration takes place through their skin (cutaneous respiration).
• This skin is permeable and frogs in the larval stage (tadpole) use gills for breathing.

Animal Reproduction

• Sexual Reproduction: Requires 2 gametes, resulting to a haploid cell (e.g. fishes spawning)
• Asexual: Requires 1 parent, forming an identical offspring (e.g., budding of the hydra).

Asexual Reproduction

• Binary Fission: Organism splits itself into two parts and regenerates missing parts.
• Budding: Outgrowth of a part of the body leads to a separation of the "bud" from the original organism and to formation of two individuals. one is smaller than the other.
• Fragmentation: breaking of an individual into parts followed by regeneration
• Pathogenesis: egg develops into an individual without being fertilized

Hermaphroditism

• One individual has both male and female reproductive systems
• This allows them to self-fertilize or mate with another of their species so that they fertilize each other.
• Both producing offspring (e.g., snails, hamlets, cuttlefish).

Sexual Reproduction

• It includes Meiosis, egg and sperm.
• It includes Fertilization and creating a Zygote and Growth. Advantages of asexual reproduction - no need for a mate, less time and energy, reliable, produces offspring quickly and can better adapt in stable environments quickly.
• Disadvantages - Very little genetic variation, harmful mutations can pass on to all offspring and entire populations an go extinct.
• • Advantages- Each offspring is unique, more genetic variation, increased diversity makes the population better able to evolve
• Disadvantages- Requires more time and energy to find a mate and requires more parental care, and usually results fewer offspring.

Fertilization Types

• External Fertilization: Aquatic environments where both eggs and sperm are released (spawning). (e.g. frog, fish, crab, shrimp, oyster, squid, sea urchin, sea cucumber).
• Internal Fertilization:
• Takes place internally but embryo developement takes place inside the egg where the yolk provides nourishment (birds & reptiles) and the animals lay eggs: (Oviparous)
• Animals develop and hatch inside the eggs of the mother's body (Ovoviviparous); hatchlings are born live (basking shark, rattle snake).
• Animals give birth to live offspring (Viviparous).
• Matrotrophy occurs; the embryo obtains the nutrients directly from the mother through the placenta (most mammals).

Nervous System

• The nervous system contains nerves that allow the feeling of pain, and or other sensory information.
• The Somatic Nervous System controls skeletal muscle as well as external sensory organs.
• The Autonomic Nervous System controls involuntary muscles, such as smooth and cardiac muscle, including the Sympathetic (fight-or-flight) and Parasympathetic (rest-and-digest) parts.

Nervous System Types

• Aves (Bird): It has CNS & PNS, a well-developed cerebellum, vision & a weak sense of smell
• Reptiles: Has a brain, nerves & spinal cord, but less intelligent than mammals & birds.
• Porifera(Sponges): Has no brains and no neurons, organs or even tissues
• Echinoderms (Starfish): Has no brains. It consists of a Nerve ring and radial nerve, which are responsible for sensory information.
• Cnidarians (Sea Anemone): no brains nor CNS but have independent nerve nets to sense odor & motor neurons that contract muscles.
• Platyhelminthes (Flatworm): Has a pair of ganglia in the anterior end & have ladder-shaped nerve cords
• Mollusks (Octopus): molluscan nervous system consists of a pair of ganglia and nerve cords, with statocysts (balance organs) and eyes as major sense organs. Most mollusks have a head with eyes, and all have sensor-containing tentacles.