Animals
What is an Animal? • We take it for granted that animals are things that are fuzzy, furry and we can pet • However to really understand what animals are, we have to have a broad definition of animals and an open mind • Not all animals fit the 3rd grade idea of an animal
What is an Animal? • Animals are… • Multicellular • Heterotrophs • Eukaryotic • Obtain nutrients through ingestion • Multicellular – Many Cells • Heterotrophic – Other Feeding • Eukaryotic – True Nut • Ingestion – Process of Eating
What is an Animal? • Also animals have a few other fun features • Distinctive cell organelles • No cell walls • Held together by collagen • All of these factors are things that make animals unique
Animal Development • The process of reproduction is similar to most animals as well • Adults produce the gametes eggs or sperm through meiosis • Eggs and sperm combine to create a zygote • A zygote is a single cell created from the fusion of egg and sperm
Animal Development • The zygote starts to undergo mitosis • This happens rapidly and the number of cells starts to grow • The cells then form a blastula • A blastula is a ball of cells that is typically hollow
Animal Development • Once the blastula has formed one of the sides starts to fold into itself • When this happens the group of cells is called a gastrula • The inner folds are called the endoderm • They will form the digestive tract
Animal Development • The cells that remain on the outer layer are called the endoderm • They will eventually form the outer coverings of the animal • They can also form some nervous organs
Animal Development • The cells that are trapped in between the two layers are called the mesoderm • These will form most of the internal organs of the animal
Animal Development • After the gastrula stage, many animals develop to adults • However not all animals are the same • Some animals develop into a larval stage • These animals will have to undergo metamorphosis later in life to reach an adult form
Body Plans • Animals can be characterized by their body plans • This means the makeup and location of their major parts, organs and brain • Based on how organisms are laid out, we can tell a large amount about their history
Body Plans • Symmetry plays a portent role in describing body plans • Symmetry is a mathematical patterned self similarity • Types of symmetry are important to understanding body plans
Body Plans • Radial symmetry is when an organism is symmetric on a central body part • All parts would be symmetrical if you used a pizza cutter • Bilateral symmetry is when an organism’s halves are symmetrical • All parts would be symmetrical if you used a buzzsaw
Body Plans • To define symmetry we have to define the surfaces of an organism • Anterior – Refers to an organisms head • Posterior – Refers to an organisms tail (end) • Dorsal– Refers to an organisms back • Ventral – Refers to an organisms bottom (stomach)
Space – The Biological Frontier • Take your hand and poke your partner’s (or your own if they object) belly • What do you feel? • Is there a strong muscle that goes from ventral to dorsal? • What makes up that area?
Space – The Biological Frontier • Organisms can have a body cavity… or not • A body cavity is a fluid filled space between the outer digestive tract and the body wall • Not every organism has a body cavity
Space – The Biological Frontier • If there is a fluid filled space between the body wall and the inner digestive tract it is called a hydrostatic skeleton • This enables a greater range of movement for the organism and cushions and protects the inner organs
Taxonomy • Once you understand how organisms are built and develop we can define which ones are related • Remember, a biological family tree is called a phylogenetic tree
Taxonomy • Today we will be studying the different groupings of invertebrates • Invertebrates lack a spinal column • This does not limit their complex nature or their role in the environment
Sponges • Sponges are organisms that have a simple porous body • Considered the most simple organisms • Contain no muscles or nerves • Some are radially symmetric, however most have no major body plan
Sponges • https://www.youtube.com/watch?v=BW05vMziy2o
Cnidarians • One of the oldest invertebrates • Includes hydras, sea anemones, corals and jellies (aka jellyfish) • They have radial symmetry • They are all carnivores • They use complex nematocyststhat sting prey
Cnidarians • They have two major body types • A polyp is fixed on one end with extending tentacles • A medusa is a free moving form of the cnidarian that can move with or against the tide
Cnidarians • http://shapeoflife.org/video/behavior/cnidarians-anemone-catches-goby
Platyhelminthes • This consists of the flatworms • They are worms… that are flat • Have a gastrointestinal system with only one opening • Due to their nature they need to be in water or damp envrionments
Platyhelminthes • Free-living Flatworms live under rocks and have light sensitive eyecups • Flukes live as parasites and can utilize multiple hosts • Tapeworms are intestinal parasites that have no digestive tract
http://videos.howstuffworks.com/discovery/42160-monsters-inside-me-japanese-lung-fluke-video.htmhttp://videos.howstuffworks.com/discovery/42160-monsters-inside-me-japanese-lung-fluke-video.htm • http://www.mirror.co.uk/tv/tv-news/infected-video-bbc-presenter-infected-3094743
Nematodes • Nematodes are also called roundworms • This is because they are round… and worms • They have bilateral symmetry and they have a false body cavity • They have a mouth at the blunt end of the body • They also have a tough outer coat called a cuticle
Nematodes • Nematodes are the first organisms that have a one way digestive tract • Many nematodes have a function as detritus feeders • Some nematodes are parasites and can be dangerous
Video • A real life heartworm extraction • Warning (Not for everyone) • https://www.youtube.com/watch?v=phCod-0tfkE
Annelids • Annelids are segmented worms • This means they are worms … that have segments • Its body is segmented into a region of repeating parts • Each part is designed to function and move on its own • Greatly increases the flexibility and speed of the organism
Annelids • Has a true body cavity • They have an opencirculatory system • This means that organs are bathed directly in blood • Their body has one small brain with nerve clusters in each segment • Their body has a large pumping organ in front and behind the body
Annelids • Earthworms are the most commonly found in damp soils • The polychaetes are mostly marine and they are distinct for their “hairy” and feathery appearance • Leeches are carnivores or parasites that are mostly in freshwater, salt water or live in trees
