ANIMAL PHYLA, DEVELOPMENT Flashcards
What is the common ancestor to fungi and animals?
Choanoflagellates
What 3 lines of evidence indicate that choanoflagellates are closely related to animals?
- Similarity of choanoflagellate cells and collar cells of sponges
- No such cell in other protists, or in fungi and plants
- DNA sequences common only to animals and choanoflagellates
How do fungi feed?
Fungi are heterotrophs which feed through absorption
How do fungi produce spores?
Asexual life cycles
What are hyphae?
Hyphae form interwoven masses called mycelium, which maximize surface-to-volume ratios, this increasing feeding efficiency
What features are unique to animals?
- Eukatyote
- Multicellular
- Heterotrophic
- Cells without cell walls
- Collagen is the main structure protein
- Hox genes
Why would gene duplication events, such as those seen in the Hox gene complex, set the stage for adaptive radiation?
One copy of the gene can perform the original function while other copies are available to take on new functions
How did the Cambrian Explosion increase animal diversity?
- Evolving predator-prey relationship
- Accumulation of O2 in the atmosphere
- Allowed for aerobic metabolism
- Hox gene complex duplication
- Hox complex - family of genes controlling development form
What are the different types of symmetry?
- Bilateral symmetry
- Radial symmetry
What are the characteristics of bilateral symmetry?
- Divided into symmetrical halves
- 3 germ layers
- Cephalization
- CNS development - sensory equipment concentrated at anterior end
- Move actively
What are the characteristics of radial symmetry?
- Symmetry around central axis
- 2 germ layers
- Sessile or planktonic (free floating)
What are the 3 germ layers?
- Ectoderm - outermost layer which covers surface of embryo
- Mesoderm - middle layer which develops into muscle and other organs
- Endoderm - innermost layer which gives rise to digestive tract lining (liver, lungs)
What are the different types of body cavities?
- Coelomate
- Pseudocoelomate
- Acoelomate
What is a coelomate?
A coelomate is an organism with a “true” coelom derived from the mesoderm
What is a pseudocoelomate?
A pseudocoelomate is an organism with a body cavity derived form the mesoderm and endoderm
What is an acoelomate?
An acoelomate is an organism that lacks a body cavity
What are the 7 main phyla of the animal kingdom?
- Proifera
- Cnidaria
- Platyhelminithes
- Mollusca
- Annelida
- Chordata
What are the advantages to sexual reproduction?
- Greater fitness
- Can survive and reproduce in unpredictable, changing environments
What are the disadvantages to sexual reproduction?
- Must maintain the 2 sexes
- Fewer offspring production
- Only females produce offspring
What are the advantages to asexual reproduction?
- More effective in stable environment
- Offspring are clones of parents
- Large numbers can be produced quickly
What are the disadvantages to asexual reproduction?
- Disadvantageous in unstable environments
- Decrease in diversity
Types of asexual production?
- Fission
- Budding
- Fragmentation
- Parthenogenesis
What is fission?
Fission occurs when an organism splits into 2 parts and, if necessary, regenerates the missing parts of each new organism
What is budding?
Budding occurs when part of the body “buds” or separates from the original organism, producing 2 individuals, 1 smaller than the other
What is fragmentation?
Fragmentation is the breaking of individual parts followed by regeneration
What is parthogenesis?
Parthogenesis occurs when an egg develops without fertilzation
What are the types of sexual reproduction?
- Hermaphroditism
- External fertilization
- Internal fertilization
What is spawning?
Spawning is when individuals clustered in the same area release their gametes into the water at the same time
What are the types of internal fertilization?
- Oviparous - fertilized egg layed outside of body
- Ovoviviparous - fertilized egg hatches inside mother, who gives birth to live offspring
- Viviparous - young is born alive
What are the 4 steps of food processing?
- Ingesting
- Digestion
- Absorption
- Excretion
What are the 4 basic types of ingestion?
- Filter feeders
- Substrate feeders
- Fluid feeders
- Bulk feeders
What are the 2 types of digestion?
- Mechanical digestion - increases surface area of food
- Chemical digestion - cleaves larger molecules into smaller components
What digestive components prevent self-digestion?
- intracellular digestion - hydrolysis of food engulfed by vacuoles by phagocytosis or liquid by pinocytosis
- Extracellular digestion - breakdown of the food in compartments that are continuous with the outside of the body
- Simple body plan - gastrovascular cavity (1 opening)
- Complex body plan - alimentary canal (2 openings)
What are the 3 accessory glands and what do they do to aid in digestion?
- Pancreas produces enzymes which digest proteins and starch
- Liver produced bile, breaks up fats, and emulsifies lipids
- Fluid is alkaline for pH correction
- Gallbladder stores bile
What are the components of saliva and what are their functions?
- Mucus is a viscous mixture of water, salts, cells, and glycoproteins whcih luricates food for easier swallowing
- Amylase which breaks down starch into glucose
- Buffers which neutralize acids to prevent tooth decay
- Anti-bacterial chemicals which suppress bacteria
What kind of movements push food into the stomach?
Peristasis pushes food along via alternating waves of smooth muscle contraction and relaxation
Explain the process behind the production of gastric juices?
- Pepsinogen (inactive) is secreted by chief cells into the stomach
- HCl is secreted by parietal cells into the lumen of the stomach
- HCl converts pepsinogen into pepsin
- Pepsin then activates ore pepsinogen starting a chain rxn
What is the function of pepsin?
Pepsin breaks down proteins into amino acids
What is the pH of HCl?
HCl has a pH of 2, making it highly acidic
What is the function of the small intestine in digestion?
The SI is where most enzymatic hydrolysisof macromolecules occurs
What occurs in the duodenum?
The duodenum is the main location for chemical digestion in the SI
What acts as a buffer to chemical digestion in the. duodenum?
Bicarbonate, which is secreated by the pancreas in response to secretin
What occurs in the jejunum and the ilium?
The jejunum and the ilium are the main components for nutrient absorption in the SI
What is the function of the large intestine in digestion?
The LI reabsorbed water, and vitamins K and B
What is the result of too much water absorption in the LI?
Constipation
What is the result of too little water absorption in the LI?
Diahrrea
What are photoreceptors?
Photoreceptrs are sensory cells within the eye which contain light-absorbing pigment molecules
What are compound eyes?
Compound eyes consist of several thousand light-detectors caled ommatidia, which are very effective at detecting movement and have excellent color vision
What are single-lens eyes?
Single-lens eyes work somewhat like a camera - the change in iris diameter controls how much light enters the eye
What is the connective tissue within the eye?
Sclera
What is the thin, pigmented layer within the eye?
Choroid
What part of the eye refracts light?
Cornea
What part of the eye expands and contracts, changing pupil diameter?
Iris
What part of the eye does light enter through?
Pupil
What part of the eye consists of neurons and photoreceptors?
Retina
What divides the eye into 2 cavities and is a transparent disc of protein?
Lens
Which humor of the eye is water-like?
Aqueous humor
Which humor of the eye is jelly-like?
Vitreous humor
What are the 2 types of photoreceptors in the retina?
- Rods - light sensitivity
- Cones - color vision
What part of the eye lacks photoreceptors?
The optic disc, thus forming a blind spot in the back of the eye
What is another name for the visual pigment of the eye?
Rhodopsin
What is rhodopsin composed of?
- Retinal - light-absorbing pigment bound to opsin
- Opsin - membrane protein
What is phototransduction?
Phototransduction is the process by which light is converted into electrical signals in the rods, cones, and photosensitive ganglion cells in the retina of the eye
What is innate immunity?
Innate immunity is the recognition of traits share by broad ranges of pathogens, using a small set of receptors to produce a rapid response
What are the 2 types of defenses in innate immunity?
- Barrier defenses
- Internal defenses
What are examples of barrier defenses in innate immunity?
- Skin
- Mucus membrane
- Secretions
What are examples of internal defenses in innate immunity?
- Phagocytic cells
- Natural killer cells
- Antimicrobial proteins
- Antimicrobial peptides which disrupt the plasma membrane of bacteria and fungi
- Inflammatory response
What is adaptive immunity?
Adaptive immunity is the recognition of traits specific to particular pathogens, using a vast array of receptors which produces a slower response
What are the 2 types of responses in adaptive immunity?
- Humoral responses
- Cell-mediated responses
What are examples of humoral responses?
Antibodies which defend against infection in body fluids
What are examples of cell-mediated responses?
Cytotoxin cells whic defend against infection in body cells