Ch 26 Sponges, Cnidarians, and unsegmented worms Flashcards
1
Q
what is an animal
A
- heterotrophic
- multi-cellular
- eukaryotic
- lack cell walls
2
Q
what is cell specialization and division of labour within animals
A
- animals have different cell types that do certain tasks
- division of labour is a phenomena in multicellular organisms where certain cells have specialities or task
- necessary for animals to function
3
Q
what are different types of animal feeding
A
- herbivores eat plants
- Carnivores eat animals
- omnivores eat a variety of animals and plants
- Parasites feed on living animals and plants in units less than 1
- Filter feeders take tiny organisms from the water
- Detritus feeders eat tiny bits of dead animals and plants
4
Q
how do animals respirate
A
- All cells need oxygen and give off CO2
- Animals need ways to supply O2 to cells and move Co2 away
- Some use absorption
- Others use various organs
5
Q
how do animals accomplish internal transport
A
- not necessary In small aquatic animals
- contain O2, nutrients, and waste, which they move to/from cells
- Example: the human circulatory system
6
Q
how do animals excrete waste
A
- Wastes like ammonia must be eliminated
- small aquatic animals diffuse it out
- Larger animals need a system to remove their poisonous waste products
7
Q
how do animals respond to stimuli
A
- Animals need to react to stimuli
- Most develop a system of neurons (special cells) called a nervous system to react to stimuli
- some have what we call brains, but there is a lot of variety
8
Q
how do animals move
A
- most animals move
- tissue called muscles generate force on solid structures (mostly)
- Exoskeletoms
- Endoskeletons
form the muscle-skeletal system
9
Q
how do animals reproduce
A
- Many ways to reproduce
- sexual, asexual, sometimes both
- eggs, live birth, other methods
- all young develop, though some have larval forms that metamorphosis into adults
10
Q
what are some trends in animal evolution
A
- all phyla have a complex family tree of relation
- levels of organization become higher as animals become more complex in form (cells to organ systems)
- many simple animals have radial symmetry, complex ones have bilateral symmetry
- for bilateral animals the front = anterior, back = posterior, top = dorsal, bottom = ventral
- many complex animals concentrate sense organs near the anterior end (head) region, along with nerve cells. This is called cephalisation
- clusters of nerve cells can make decisions and react to stimuli, these are called ganglia and even bigger structures are called brains
11
Q
what are sponges
A
- The most ancient animals
- appeared 580 million years ago
- live mostly in salt water, some live in fresh
- live in most oceans
- phylum porifera
- don’t move, once thought to be plants
- no mouth or gut
- no specialized tissues or organ systems
- biologists think sponges were an early split that produced no other animals, possible split before they were animals
12
Q
what do sponges look like
A
- very simple
- a wall formed around an internal cavity
- the wall is very porous and certain cells called collar cells use flagella to pump water into it
- the water exits through a hole called the osculum
- the flow of water delivers food and O2, and moves waste, gametes, and larva out
- Tiny spines called spicules form a skeleton
- cells called amebocytes build spicules from CaCO3 or SiO2
- The softer sponge skeletons are made of fibers called spongins
13
Q
how do sponges reproduce
A
- sponges filter feed and cells use endocytosis to digest inter cellularly
- sponges pump a large amount of water through its body each day
14
Q
how do sponges reproduce
A
- sponges release sperm into the water which can eventually reach a sponge where the amebocytes transport it to eggs, eventually the larva are released into the water
- Some freshwater sponges release gemmules, collections of amebocytes surrounded by a layer of spicules which act as spores
- most sponges can also bud to reproduce
- sponges can also reassemble or regenerate when destroyed
15
Q
how do sponges fit into our world
A
- they are the most common forms of life in dark aquatic places
- other marine animals live on, in, and around them
- they form symbiotic relations with non animal organisms
- a type of sponge called the boring sponge tunnels through old shells and coral, and so help clean up the ocean
- Sponges are used by humans for various things, cleaning, certain chemicals are used, etc
- they produce antibiotic foundations (or antivirals)
16
Q
what is within phylum Cnidaria
A
- Phylum Cnidaria
- Contain jelly fish, anemones, and others
17
Q
what do Cnidarians look like
A
- soft bodied organisms with stinging tentacles around a mouth
- most have a two stage lifestyle, with a sessile flowerlike polyp becoming a mobile bell shaped medusa
- their body wall surrounds a gastrovascular cavity where digestion is performed
- the body wall has three layers, the epidermis, mesoglea, and gastroderm
- The Mesoglea is a non-cellular membrane that varies in thickness, many contain amebocytes
18
Q
how do Cnidarians perform their functions
A
- have stinging structures called nematocysts which catch food
- each nematocyst is a venom filled sac containing a spring loaded dart
- the food item is poisoned, pushed into the cavity, broken down, and diffused into the cells (before being pushed out the mouth/anus opening)
- Cnidarians are heterotrophic but may have symbiotic relationships with photosynthetic lifeforms
- few complicated systems
- have a nerve net instead of a brain
- some have simple sense organs
- no muscles, but they can contract their epidermis
- polyps can bud asexually while medusas have “sex”, produce offspring which become medusas
19
Q
what are hydras and their relatives
A
- Class Hydrozoa
- Spend majority of their life as polyps
- grow in branching colonies
- specialized polyps do certain functions like feeding or defense
- Hydras are common in fresh water
- they are solitary and lack medusa stages of life
- asexual or sexual
- both separate sexes and hermaphrodite
- are one example of an unusual hydrozoan is the Portuguese man-o-war
20
Q
what are jellyfish
A
- class Scyphozoa, true jellyfish
- Polyp = larval stage
- Vary a lot, only some are harmful
21
Q
what are sea anemones and corals
A
- class Anthozoa
- only polyps
- bud or release eggs/sperm into water
- some have symbiotes
- corals produce a CaCO3 skeleton
- Bud to reproduce
- form coral reefs
22
Q
how do cnidarians fit into our world
A
- lots of symbiosis
- coral reefs form habitats and are very important for marine life
- some have medical implications of their chemicals
- lots of research to be done
23
Q
what are unsegmented worms
A
- bodies not fully divided into segments
- 2 phyla: Flatworms (Platyhelminthes) and Round worms (Nematoda)
24
Q
what are flatworms
A
- Platyhelminthes
- Simplest animals with bilateral symmetry
- some have cephalization
- very thin, though can be long or wide
- more developed organ systems than sponges and Cnidarians
25
what are the two forms of flatworms
- 2 very different lifestyles
- Free living, aquatic, flatworms
- Carnivores, predators, or scavengers
- an opening at the end of a tube is called the pharynx and sucks in food
- cavity forms long intestines which break down food
- food is diffused and waste expelled through mouth
- Parasitic flatworms
- drink blood, or inhabit host
- ex: tapeworms
- many don’t have stomachs and just absorb pre-digested food from the host
26
what is the form and functions of flatworms
- Flatworms have no circulatory or respiratory systems
- some fresh water flatworms have cells called flame cells that get rid of excess water
- free living flatworms have developed nervous systems, simple brains, nerve cords, and light sensitive ocelli (or eyespots) that can see shadows
- Parasitic Flatworms have less nerves
- Free living flatworms use cilia on epidermal cells or have muscle cells that allow twisting
- Free living flatworms reproduce with both hermaphroditic sex or asexually via fission
- parasitic reproduce sexually in complex lifecycles
27
what are planarias
- class turbellaria
- free living flat worms
- vary a lot, the biggest are 60 cm long
28
what are flukes
- class Trematoda
- parasites
- live in and on hosts, lost of damage
- many infect humans
29
what are blood flukes
- Blood flukes are found in SE Asia, N Africa, and other tropical regions
- they live in blood
- the genus Schistosoma use humans as hosts
- many flukes reproduce as hermaphrodites (with individuals producing eggs + sperm)
- Schistosoma have separate sexes, they release many eggs into blood vessels, which burst and leak into the intestines, pooped out, and sometimes go into water where they hatch into larva, the larva then enter a snail, grow, and eventually find a new human host
- Human flukes can be very dangerous
- non human flukes can infect humans, but only cause swimmers itch
30
what are tapeworms
- class Cestoda
- simple parasites
- have a head with hooks called a scolex
- they attach to the intestine and absorb food
- can be over 15 m long
- usually don’t kill, but eat a lot
- behind the scolex is a neck part that divides to make proglottids or sections that extend the body and contain reproductive eggs in the later sections
- eggs fertilize and drop off with the back proglottids
- tapeworms can inhabit muscles of intermedial hosts and form a cyst
31
what are round worms
- phylum Nematoda
- Simplest animals to have 2 digestive openings, a mouth and an anus
- vary in length up to 10 meters
- many around us at all times, 90 000+ in a rotting apple
32
where can round worms be found
- mostly free living
- found all across earth
- some parasites, in nearly every kind of plant and animal
33
how do round worms perform life functions
- long tube shaped digestive tract
- free living are carnivores for the most part
- some have other diets
- parasitic damage to lots of crops
- excrete waste through body walls
- simple nervous system, less than flatworms, no brain, only ganglia
- muscles strips allow movement
- all ways reproduce sexually, internal fertilization
- some parasitic roundworms have 2-3 hosts, others spend time in multiple different organs
34
what is ascaris
Ascaris affects humans, they live in the intestines where the produce eggs, when the eggs are consumed larva hatch, burrow into blood vessels of small intestines, entre the blood stream, go to lungs, climb to throat, get swallowed and end up in the intestine once again
35
how do unsegmented worms fit into our world
- little effect on humans aside from some parasites
- hook worms, found in the USA, are similar to ascaris
- Trichinosis is caused by worms called trichinella which burrow into organs to cause pain
- Filarial worms are found in the tropics of Asia and cause Elephantiasis
- Eye worms burrow below the skin and can be seen crossing the eye on occasion
