Animals : Unit 2

Animals are

• Multicellar, heterophs

• Collagen protein in cells due to a lack of a cell wall that plants and fungi usually have

Animal cells also differ because they have 3 junctions

• tight junction : seals space between cells

• Desmosomes : anchors between adjacent cells

• Gap junction: open channels between cells so they can share things/ communicate back and forth

Animals are also unique because of these specialized cells…what are they ?

Nervous tissue and muscle tissue

Animal reproduction and Development

1. Diploid zygote

2. Zygote goes through cleavage

3. Then mitotic cell divisions without the cell growth between divisions leading to a morula ( a solid ball of cells abt 8-32 cells)

4. As the divisions grows: goes to blastula ( a hollow ball of cells)

5. Gastrulation is layers of etoderm, indodem embryonic tissue, that cell cluster is now called a gastrula

Animal reproduction and development pt.2

Some animals develop as mini versions of the adult versions

Example: humans, elephants, etc

Some animals will have a larval stage then metamorphosize into the mature version of the animal

Example: caterpillar to a butterfly or a tadpole to a frog

The caterpillar is the larva( different form and function, different food sources and different habitats)

Hox Gene

• unique to animals : plants, protist, fungi don’t have this

• Helps with the diversity of animals

• Important for the development of the animal embryos, also controls hundreds of other genes 🧬 ( the morphological features of the animal , cell division, differentiation: unspecialized cells become specialized )

Neoproterozoic Era

When animals evolved and showed up

Paleozoic Era —Cambrian explosion

Where the diversity of animals accelerated

Why was there such a rapid explosion of diversity in the Cambrian period?

1. New predators prey relationship drove diversity through natural selection

2. There was a lot of oxygen back then— higher metabolic rates and larger body sizes

3. The Hox Gene evolved during this time leasing to variations in morphology

Mesozoic Era

• time of the dinosaurs

• Small mammals, large coral reefs emerging

Cenozoic Era ( still in this era)

• time of the mammals: most importantly humans

  characterized by mass extinction of terrestrial and marine animals

Body Plan

• a group of animals that share similar levels or organizations are grouped at grades

• The morphological and developmental traits that determine the grade are referred to as body plans

• body plans include: symmetry, body cavities, level of development

Asymmetry

one side of the body doesn’t match the other side no matter how you cut them : typically only found in sponges

Radial symmetry

• you was to cut through the organism, you would get at least 2 sides that match up ( some sponges and cnidarians: jellyfish etc )

Bilateral symmetry

Only one cut can create that mirror image ( left to right

example: lobster 🦞humans, cats, dogs

Most animals that are bilateral symmetry will have a head, which is known as

Cephalization

Tissues

• groups of specialized cells isolated from other tissues by membranous layers

• Sponges are the only animal that lack true tissue ( b/c they have a cells working together but no membrane separating their specialized cells)

The 3 different germ layers

Ectoderm: outside layer : outside organs like skin,nervous system

Endoderm: inside layer: inside organs like digestive tract, liver etc

The 3rd layer some organisms like humans have: Mesoderm —> located between ectoderm and endoderm: produces muscles, bones, connective tissues, circulatory systems

If an animal has just the ectoderm + endoderm they are called

Diplomatic

Example of diplomatic organisms: comb jellies, jelly fish, corrals

Animals that also have a mesoderm are called

Triploblastic

Example : cockroach, cuttlefish, oysters

Inorder to classify an animal as having a coelom/body cavity the must be

Triploblastic: Mesoderm+ Endoderm+Ectoderm

Coelomates/Eucoometes

Animals with a true body cavity, they have the Mesoderm( in the mesoderm, there is a hollow space, that space is the coelom) Endoderm+Ectoderm

Pseudoceolomates

Animals that have an ectoderm, endoderm and mesoderm but and there is a large space because the mesoderm is not on both sides

Acoelomate

Animals with no coelom, they have ectoderm and endoderm no mesoderm

Protostome or deuterostome only applies to animals who are

Triploblastic, with true body cavity:Acelomates only

When trying to identity whether an animal is a Protostome or a Deuterostome we are evaluating the

Cleavage, coelom formation, the fate of the blastopore

Cleavage: Protostome

• the cells on the top are in line with the circle in the bottom( spiral cleavage)

Protostomes always have determinate cleavage: develop into a specific tissue type, one cell can’t make a whole new embryo

Cleavage: Deuterostome

Cells on the top line up with the cells on the bottom ( radial cleavage)

****Deuterostomes are only going to be Indeterminate cleavage, each one of the cells can turn into a different tissue in the body : can grow a whole new embryo with just one of the cells***

Fate of the Blastopore: Protostome ( first mouth) 👄

1. The intention formed during gastrulation becomes the mouth, then comes the anus

Fate of the Blastopore: Deuterostome(second mouth)

1. The indention formed during gastrulation becomes the anus, next comes the mouth

Fun Fact 🤩 humans are deuterostomes !!!

Invertebrates facts

• come in different shapes and sizes

• The occupy almost every habitat on Earth ( glaciers, freshwater etc everything)

• Out of all the known animal species invertebrates make up 95%

• All but just one of the total 35 animal phyla’s are invertebrates

What is one thing all invertebrates have in common?

They lack a vertebrate column/ spine

What are some animals that are invertebrates?

• insects

• Jelly fish

• Starfish

• Snails and clams

What are some facts about the phylum Porifera ?

• Pylum for sponges ( both marine and freshwater)

• Known as suspension feeders because they take food particels out of the water as it passes through their body then expel the water out

• Sponges have specialized cells, however, aren’t tissues because they are not divided by anything

What are poroytes

One of the pores, they allow water into the sponge

Choanocytes structures and purpose

1. Flagella: moves and as it moves creates a water current and draws water into the sponge

2. Collar: lined with mucus, any particles in the water get stuck on it: filterization

3. Pass the practices into the Amoebocyte: digest some practicles and use some of it for nutrients for themselves , also crawls around and feed all the other cells in the sponge

What are spicules and let are the 3 types of spicules and what do they create?

To support the cells in the sponge, give the cells something to hold on to

1. Calcium carbonate : chalk sponges

2. Silica : glass sponges

3. Spongin / proteinaceous sponges: they are proteins based

Sponges sex and reproduction ?

Hermaphrodites: both male and female ,producing both sperm and eggs

Neighboring sponges are able to take up sperm , fertilizing the eggs

• The zygote develops a flagelllum and swims off as larvae, once it finds a place to settle begins to develop into the sessile adult version( sponges never move locations, they stay there forever)

What are some benefits to sponges?

They produce many antibiotics like

1. Cribrostatin can kill penicillin-resistant Streptococcus( bracteria)

2. Other compounds are being studied for anti-cancer agents 😊

Why sponges are important for our ecosystem?

• amazing filters for the environment, clean up aquatic systems

• We can use sponges to cure disease and illness due to the chemicals they produce

Cnidarians facts

1. the animals: corals, jelly fishes, hydra

2. diploblastic organisms : the have the entoderm and the endoderm: have true tissue

3. Radial body plan

4. They have a gastrovascular cavity , a sac with one opening ( the mouth and the anus is the same opening)

5. Cnidarians are carnivorous, they feed with their tentacles

6. Their tentacles are lined with specialized cells called cnidocytes, the tentacle structure helps them with both self defense and capturing prey

7. Some Cnidarians contain long sticky threads that are used to capture prey, other contain nematocysts, which are stinging capsules

What are the two forms Cindarians can take and describe them in grave detail.

1. Polyps : gastrovascular cavity: attached to substrate by their aboral ends, then mouth/anus on top: oral or tentacles waiting up for prey

2. Medusa: tentacles and mouth facing downward, be able to move by floating on the current and contraction of its belly shaped body

Different types of Condarians, identify them

A)The one in the far left is hydrozoa ( looks like bushes

B) The next one is a jellyfish

C) is a seawasp

D) sea anemones

What is this structure?

Living corals

Platyhelminthes facts

• flat worms that occupy marine, freshwater and moist terrestrial habitats

• Bilateral symmetry

• Triploblastic development

• Can be freeliving or parastitic

• They are acoelomates

• These animals have a gastrovascular cavity with one opening

What Platyhelminthes is that? Some facts?

That image is of a marine flatworm, they are free living

What type of Platyhelminthes is the image? Some facts?

Flatworm called planaria, live in unpolluted ponds and streams

Types of parasitic flatworms

Blood flukes: spend part of their life cycle in snails and part in humans, releases molecules that influence the immune system to tolerate it’s existence

Tapeworms: have a scolex which contains suckers and hooks to allow it to attach and hold to the intentions wall, proglottids: reproductive factories that release thousands of eggs: humans become infected by eating food that has tapeworm larval form encrusts into the muscle of pigs and cattle

What is Rotifera

• microscopic organisms

• Occur in marine, freshwater and some soil habitats

• Have a alimentary canal, a digestive tube with two openings

• The are pseudocelomates because mesoderm doesn’t completely line their body cavity

Explain Rotifer reproduction

Some reproduce by parthenogenesis : the females develop eggs that never have to be fertilized( they produce clones of themselves)

There’re zygote can survive long periods of drought as unstable conditions, they will wait until they are in the right conditions to begin developing and reproducing again

Explain the Nemertea group

• often referred to as ribbon worms or proboscis

• They are acoelomates

• They have a specialized openings where they can push fluid through them but they are still acoelomates

• There fluid sacs are jmpprtant because they create a hydraulically operating system which enables the worms to shoot out a proboscis which delivers toxins to its prey

• Most Nemertea are marine, some live in freshwater or damp soils

• They have a full closes circulatory system,( pumps through vessels which makes it closed) which pumps their blood around their body, they have no heart

Describe Mollusca

• They have a foot

• They have a visceral mass( organs)

They have a mantle: a fold of tissue that covers their organs, which makes a shell ( the mantle may or may not make a shell)

For example: slugs, octopus 🐙 don’t have shells

• Some Mollusca have a mantle cavity, which is when the mantle forms a water filled chamber that contains the gills, anus, and excretory pores

• Some mantles have a radula, which is used to scrape food

Major classes of Mollusca to know for exam:

1. Polyplacophora : (chitons) : shells made of 8 plates

Gastropoda: snails and slugs, abalone and limpets : 🐌 : when the develop they go through a process called torsion their visceral mass rotates 180 degrees causing the anus and mantle cavity to be over its head

3. Bivalves: clams, oysters, mussels and scallops; their shells are divided into two halves and are hinged with a powerful adductor muscle

4. Cephalopoda: octopus, squids, cuttlefishfish, nautilus: have a closed circulatory system, well developed sensory organs and a complex brain, they have a visceral mass and a mantle, in squid’s and cuttlefish their mantle creates a shell and is very reduced, octopus have no shell at all and the nautilus

Annelida

Segmented worms : found in marine, freshwater or terrestrial ( relating to earth) habitats

Oligochaete’s: are the earthworms : important for soil to mix it, they eat through the soil and the undigested material and mucus is expelled their bodies to, earthworm are hermaphordites meaning they have both sec organs, they cross feterilze the male part of one earthworm mates with the female part of that earthworm, they can lay twice as many eggs

Polychaeta: variety of different worms: tube worms, christmas tree worms, clam worms etc

Hirdinea: leeches: not all leeches feed on blood, they produce hirudin, a chemical that prevents blood from clotting and where they usually attach is unknown because they produce an anesthetic : they are used for medical purposes to drain blood that accumulates due to an injury or surgery

Nematodes

Roundworms : pseudocelmates,

found all over the place,

they have an outside covering called the cuticle which is for protection,

important decomposures

Some are parasitic to animals and plants

Ex: humans can host 50 diff species of nematodes such as trichinrlla spirals in muscle tissue which causes trichinosis and infects humans when they eat uncooked pork

Arthropoda

• most diverse and abundant

• Found in all types of environment

• Segmented bodies, jointed appendages and exo skeleton : made up of proteins and polysaccharide (Clinton)

• The segmentation allows for division of labor

• The appendages: designed for a different purpose: feeding or reproduction , walking or defense

• Exoskeleton: good for protection in and out of water, where muscles contract to move body around, prevent organism from drying out

Disadvange of an exoskeleton: makes it difficult for the organism yo gro, as they get bigger they have to slit out of old exoskeleton ( shedding/molten) the organism is vulnerable to pretetors

• Open circulatory system

Class/Subphlyum of Arthropoda

Chelicerforms: tics, mites, scorpions, spiders, horseshoe crabs

Myriads:

centipedes & millipedes: the centipedes have speaciized fangs for injecting

One pair of walking legs per segment

Millipedes:

Two pairs of legs per segments

Can produce chrmicsls that act as irritants if they feel threatened, but they don’t use it for hunting

Hexopoda: part of Arthropoda

Insects

Some can fly:escape pretenders, find new habitats , Find mates easier, find new food sources

Incomplete metamorphosis :

The nymphs look like mini versions of adult version but just different body proportions and lack wings, each time it molts it gets closer to the adult size : last molt is where they develop wings : don’t change dramatically, which is why it’s an jncomple metaphorous

Complete Metamorphorus

; egg hatchfblatchs into larval stage (maggimk

Looks entirely difffeent from adult

Never

Crustaceans ( part of Anthropoda)

Typ( seafood/ crabs, barnacles, maxiapoda, shrimp

Echinoderms

Organisms with spines skin : starfish, sea cucumbers

All evhinoderms have radial symmetry

• spines skin

Water vascular system : tube that run throughout body where they pump water through for circulation moving and gas exchange

Males have sperm

Females have eggs

Mix in the water, then go through ferritin, the zygote and develop into larvae stage, develop into adults and eventually have radial symmetry

The classes of Enchioderms

1. Asteroidea : starfish

2. Ophiuroidea:brittle star, basket star

3. Echinoidea: Sand Dollar, Sea Urchin

4. Crinoidea: feather stars

5. Holothuroidea: sea Cucumbers

6. Conentrochrodea: sea daisies