Animals contain specialized cells

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1

2 What is an Animal?

3 Kingdom Animalia Main Characteristics Members of the Animal Kingdom are: Eukaryotic Multicellular Heterotrophic Have cells with membranes BUT NO cell wall Animals contain specialized cells (This is called division of labour as certain cells or groups of cells have specific functions) In order to survive animals must perform essential functions: Feeding Respiration Internal Transport Excretion Response to Stimuli Movement Reproduction

4 Feeding (Digestive Systems) Animals ingest food (feed) in a number of different manners: Herbivores - eat only plants Carnivores - eat only meat Omnivores - eat both plants and meat Parasites - live on or in another animal doing harm Filter feeders - strain from water Detritus feeder - feed on decaying material The level of Digestive System Complexity depends on the method of feeding of that type of animal

5 Feeding Simple Diffusion - Food that is small enough to pass through the cell membrane is absorbed and used by the cell Intracellular Digestion - Food is ingested into the cell and then is broken down One Opening Incomplete/Sac Digestive System - Mouth and Anus are the same opening No Specialized Structures Complex Extracellular Digestion - Food is broken down outside of the cell and then absorbed - This allows for consumption of food that is larger than a cell Two Openings Tube in Tube Digestive System - Mouth and Anus are at opposite ends of the digestive system Specialized Structures

6 Feeding Mouth/anus Gastrovascular cavity Annelid Intestine Gizzard Crop Pharynx Mouth Gastrovascular cavity Cnidarian Pharynx Crop Arthropod Anus Pharynx Mouth/anus Flatworm Mouth Stomach and digestive glands Intestine Rectum

7 Respiration All animals need to take in oxygen for cellular respiration (all Animals are Obligate Aerobes) This produces carbon dioxide as a waste product C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O In basic animal life this can be done by Diffusion More complex animal life requires some type of respiratory system All respiration systems have two features: A way to maximize surface area for more gas exchange A way to keep the membrane moist Aquatic animals = no problems, have gills Terrestrial animals = air dries the respiratory surface, so have mucus membrane or water layer Some that live in wet soil respire through the skin (cnidarians and flatworms)

8 Section 29-2 Respiration Gill Siphons Tracheal tubes Mollusk Movement of water Insect Spiracles Airflow Spider Book lung

9 Internal Transport In addition to oxygen, all cells of a multicellular organisms need to be supplied with nutrients and have waste products removed Simple Organisms material and waste are transported via diffusion Complex Organisms material and waste are transported by a circulatory system Pumps (hearts), fluid (blood), and tubes (blood vessels)

10 Circulatory Systems Two types: open and closed Open: blood is not completely contained in blood vessels and comes in direct contact with tissues This type of system is commonly found in animals with smaller bodies and less complex body systems Closed: blood is completely contained within blood vessels Closed systems are more efficient at directing blood at various parts of the body These types of systems are typically found in larger bodied animals and/or animals with more complex body systems

11 Section 29-2Internal Transport Hearts Heartlike structure Small vessels in tissues Blood vessels Heart Sinuses and organs Insect: Open Circulatory System Heartlike structures Annelid: Closed Circulatory System Blood vessels

12 Excretion All multicellular animals must balance water levels and remove nitrogen waste products (NH 3 ammonia, from the breakdown of amino acids during metabolism) NH 3 is highly toxic Basic aquatic animals NH 3 diffuses into water More complex animals will have some sort of cell, gland or structure that removes nitrogen waste Even more complex terrestrial animals converted to urea which is less toxic, excreted as urine. This allows for waste removal while conserving water

13 Section 29-2 Excretion Excretory tubules Nephrostome Flame cells Flatworm Excretory pore Flame cell Excretory tubule Nephridia Digestive tract Annelid Arthropod Malpighian tubules

14 Responsiveness (Nervous System) Animals need to be aware of their surroundings Need to find food, detect predators, and find their own kind For this they need specialized cells to detect stimuli such as light, chemicals and temperature They also need cells to process and respond to the stimuli

15 Nervous System Simple Nerve Nets are the most basic nervous system individual nerve cells form a net-like arrangement in the body Common in basic animals that do not require coordination or high levels of responsiveness. Three trends in evolution of the nervous system: centralization, cephalization and specialization Centralization nerve cells are concentrated, allow for quick responses Cephalization concentration of nerve cells (ganglia) in head area Specialization in more complex organisms, are specialized sense organs

16 Section 29-2 Nervous System Arthropod Brain Ganglia Ganglia Brain Nerve Cells Flatworm Cnidarian Mollusk

17 Movement Some animals are sessile (spend their entire life in one spot) Others are motile (can move around) Muscles work with a skeleton Endoskeleton: skeleton on the inside with muscles outside of it Example: bone structure, skeletal systems Exoskeleton: skeleton on the outside with muscles inside Example: shells, external cartilage

18 Hydrostatic Skeleton Do not contain hard structures Muscles surround and are supported by a fluid filled cavity

19 Reproduction There are many different methods of reproduction - Asexual vs. sexual - external vs. internal fertilization - Larval stages, egg laying, live births, etc - As well as different levels of parental care Asexual Reproduction Simple invertebrates = asexually through fragmentation or budding Fragmentation each piece regenerates into a new individual Budding new individuals are produced from outgrowths of the parent s body wall More complex also use asexual reproduction through unfertilized eggs Advantage - Allows for one individual to produce offspring quickly Disadvantage no genetic diversity

20 Asexual Reproduction Example: Hydra

21 Sexual Reproduction Advantage increases genetic diversity Most species have male and female sexes Some are hermaphrodites produce both sperm and eggs - any time two sexually mature individuals meet they can mate - all mating result in two batches of offspring

22 Fertilization External Fertilization - less complex animals (jellyfish, clams, sea urchins) - Adults release sperm and eggs into water - many disadvantages Can only work under water Animals must release large numbers of gametes to increase chances of fertilization Internal Fertilization More complex animals Specialized organs for both male and female Egg is fertilized inside the females body Common in terrestrial animals

23 Parental Care With many species of invertebrates young are ignored as soon as eggs are laid What other option does coral have? Some take care of their young

24 Be thankful you aren t a mite! In some species of mite the eggs hatch within the mother s body cavity. The larvae begin to devour the mother from the inside out. Within two days the mites mature in the nearly empty exoskeleton of the mother, mate and then eat their way out. The males die within a few hours and the females seek out prey to eat while their offspring begin to hatch and eat away at their insides.