Ch 32 An Overview of Animal Diversity Flashcards
1
Q
What are key characteristics of animals?
A
- Eukaryotic, heterotrophic (obtaining nutrients from outside) and multicellular
- History spans more than half a billion years
- Can be characterized by “body plans”
- New views of animal phylogeny (evolution of a genetically related group of organisms via the study of protein or gene evolution by involving the comparison of homologous sequences) continue to be shaped by new molecular data
- Scientists have identified 1.3 million living species of animals, out of an estimated total of approximately 10 million.
2
Q
Heterotroph
A
- cannot construct organic molecules on their own
- Obtain organic molecules from food ingested within their body
3
Q
Describe what happens to fertilized egg
A
- zygote + cleavage
- Eight-cell stage + cleavage
- Blastula
- Gastrulation
= endoderm, ectoderm blastopore
4
Q
Larva
def
A
sexually immature
morphologically distinct from adult
eventually undergoes metamorphosis to become a juvenile
5
Q
Juvenile
def
A
resembles adult
not sexually mature
6
Q
Hox gene
A
only animals
most animals have them
lay out the basic body form
set-up head to tail organization
highly conserved, but can produce a huge diversity or animal morphology
7
Q
Common ancestor or all living animals
characteristics
A
lived 700-770 million years ago
resembled modern choanoflagellates (protist, closest living relative of animals)
Life on earth: 3.5 billion years
8
Q
Radial vs bilateral symmetry
A
- Radial: no front or back, no left or right sides (sea star)
- Bilateral symmetry: dorsal and ventral side, right and left sides, anterior (front) and posterior end. Many have sensory equipment at anterior end. Development of head = cephalization
9
Q
Tissues
def
A
Collection of specialized cells isolated from other tissues by membranous layer
During development, 3 germ layers turn into tissues and organs
10
Q
Ectoderm
vs
Endoderm
A
- Ectoderm: surface
- Endoderm: innermost layer, lines digestive tube (archenteron)
11
Q
Diploblastic individuals
A
- ectoderm and endoderm (cnidarians etc)
- Triploblastic: also have mesoderm (all bilaterians). Mesoderm creates body cavity (coelom)
12
Q
Coelom
A
Body cavity
Made from the mesoderm
13
Q
Protostome
vs
Deuterostome
A
- Protostome: cleavage spiral and determinate (molluscs, annelids)
- Deuterostome: cleavage radial and indeterminate (each cell retains the capacity to develop into a complete embryo) (echinoderms, chordates)
14
Q
5 important points about relationships among living animals reflected in phyla
A
- All animals have common ancestor
- Sponges are basal animals (radial symmetry, simple, diploblast)
- Eumetazoa (true animals): animals with true tissues
- Most phyla are bilaterians
- 3 major clades of bilaterian animals
15
Q
3 clades of bilatarians
A
- Deuterostomia (hemichordates, echinoderms, chordates) (radial cleavage, anus forms from blastopore). DNA similarities
- Ecdysozoa (invertebrates that shed exoskeletons = ecdysis) (nematodes and arthropods)
- Lophotrochozoa (weird feeding structure called lophophore, or they have a developmental stage called trochophore larva) (flatworms, molluscs, annelids, rotifers (small multicellular marine animals))
16
Q
Important Eras
A
- Origin of Earth: 4.5 Billion years
- 3.5 billion: prokariotic cells
- 2 billion: eukaryotic cells
- 26 million years: genus HOMO: quatenary part of the cenozoic
17
Q
Which clade has the widest range of animal body forms?
A
Lophotrochozoans
18
Q
What is an ancient phylum of eumetazoans?
A
Cnidarians
19
Q
What is the most species-rich animal group?
A
Ecdysozoans
20
Q
Name two phyla of deuterostomes
A
Echinoderms and chordates
21
Q
Locate the common ancestor of all animals
A
it’s at the branch between porifera and eumetazoa
22
Q
How do sponges eat
A
In their oscolum (cavity), they have choanocyte cells with a collar and a flagella that has mucus that traps food particles
23
Q
Eumetazoa
description
A
- All animals except sponges and a few other groups belong to clade Eumetazoa
- Animals with true tissues
- Cnidaria is one of the oldest groups in this clade
24
Q
Cnidaria
characteristics
A
- Part of eumetazoa clade
- sessile or motile
- simple, diploblastic radial body plan
- basic body plan is a sac with a gastrovascular cavity
25
Bilateria
characteristics
* Clade contains: deuterostomia, ecdysozoa, lophotrochozoa
* triploblastic development
* most have coelom and digestive tract with 2 openings
26
Protostome vs deuterostome
CLEAVAGE
At 8 cell stage:
Protostome: spiral and determinate
Deuterostome: radial and inteterminate
27
Protostome vs deuterostome
COELOM FORMATION
Protostome: solid masses of mesoderm split and form coelom
Deuterostome: Folds of archenteron form the coelom
28
Protostome vs deuterostome
FATE OF THE BLASTOPORE
Protostome: mouth develops from the blastopore
Deuterostome: anus develops from the blastopore
29
Chordates
characteristics
* deuterostomia clade
* all have a set of derived characteristics, though some only have them during embryonic development (notochord, dorsal hollow nerve cord, pharyngeal slits, post-anal tail)
* 2 subphyla: invertebrates and vertebrates
* bilateral symmetry
* coelom
* segmented body
* did NOT evolve from echinoderms
* notochord and dorsal hollow nerve cord
30
vertebrates
def
chordates that have a backbone
52,000 species
31
gnathostome
def
* vertebrates that have jaws
* genome duplication (incl hox genes)
* enlarged forebrain (enhanced vision and smell)
* in aquatic gnathostomes: lateral line system is sensitive to vibrations
32
tetrapods
def
gnathostomes that have limbs
33
aminotes
def
tetrapods that have a terrestrially adapted egg
34
notochord
def
longitudinal, flexible rod
between digestive tube and nerve cord
provides skeletal support
in most vertebrates, a jointed skeleton forms and the adult retains only remnants of the embryonic notochord
35
Dorsal hollow nerve cord
characteristics
Develops from a plate of ectoderm that rolls into a tube dorsal to the notochord
develops the central nervous system (brain and spinal cord
36
Why are tunicates chordates
They resemble them as larva
adult tunicates draw water in to filter food particles
37
Vertebrates
characteristics
* have 2 or more sets of hox genes
* lancets and tunicates only have one set
* derived characteristics: vertebrae enclosing a spinal cord and an elaborate skull
38
Chondrichthyans
def
* type of vertebrate
* skeleton composed of cartilage
* sharks, rays
39
Osteichthyes
* vast majority of vertebrates gnathostomes
* bony endoskeleton
* include bony fish and tetrapods
40
Tetrapods
def
* gnathostomes with limbs
* limbs evolved from fins
* 4 limbs
* feet with digits
* neck which allows separate movement of head
* pelvic girdle fused with backbone
* no gills (except some aquatic species)
* ears
41
Amniotes
def
* tetrapods that have a terrestrially adapted egg
* amniotic egg was a key adaptation to life on land
* terrestrial adaptations include impermeable skin and rib cage to ventilate lungs
42
Reptiles
characteristics
* ectothermic: absorb external heat
* regulate body temperature through behaviour adaptations
* birds, however, are endothermic
* birds are dinosaurs (reptiles), but reptilian anatomy has undergone modification for flight
43
Bird
Flight Adaptations
* wings with keratin feathers
* lack of urinary bladder
* females have only one ovary
* small gonads in both sexes
* no teeth
44
Mammals
Derived characteristics
* Mammary glands
* Hair
* High metabolic rate due to endothermy
* Larger brain than other vertebrates of same size
* Differentiated teeth
1. Monotremes: egg laying mammals
45
Primates
Characteristics
* Large brain
* Short jaws
* Forward-looking eyes, close together on face (depth perception)
* Complexe social behaviour and parental care
* Opposable thumb
* Homo sapiens: 200,000 years old
* human and chimpanzee: 99% identical genome
46
Anatomy
vs
Physiology
anatomy: form
physiology: function
47
Evolutionary convergence
Reflects different species' adaptations to a similar environmental challenge
Like how a penguin and a fish have a totally different shape, but both are adapted to swimming well despite the viscosity of water
48
Exchange with the environment
* Wastes, gases, nutrients must be exchanged with the environment
* Rate of exchange is proportional to the cell's surface area
* Amount of exchange is proportional to a cell's volume
* In flat animals, like tapeworms, most cells are in direct contact with the outside. For those who are not flat, adaptations like branched or folded structures allow exchange with environment
* In vertebrates, space between cells is filled with interstitial fluid which allows for the movement in and out of cells
49
Regulator
vs
Conformer
Regulators: Use internal control mechanisms to moderate internal change in the face of environmental fluctuations (homeostasis)
Conformers: allow their internal conditions to vary with certain environmental changes
some animals can do both
50
Homeostasis
* keeps steady state regardless of environment
* body temperature, blood ph, glucose concentration are maintained at a constant level
* fluctuations below or above a certain point act as a stimulus detected by a sensor that triggers a response
* when you reached the right point, it stops = negative feedback
* homeostasis relies heavily on negative feedback (positive feedback doesn't contribute to homeostasis)
51
Endothermic
vs
Ectothermic
Endothermic: create their heat by metabolism. More energetically expensive than ectothermy
Ectothermic: absorb heat from their environment. Ectotherms can tolerate a greater variation in internal temperature. They have a much lower metabolic rate
52
Heat regulation
In mammals, involves integumentary system (hair, nails, skin
Adaptations that help with thermoregulation:
1. insulation (skin, blubber, feathers reduce heat flow)
2. circulatory adaptation: vasodilation: blood flow to skin increases. vasoconstriction: blood flow decreases to skin. countercurrent exchange allows heat flow between fluids flowing in opposite directions to reduce heat loss
3. cooling by evaporative heat loss
4. behavioural response
5. adjusting metabolic heat production (thermogenesis). Increased by moving or by hormones increasing mitochondria activity
53
Bioenergetics
* Overall flow and transformation of energy in an animal
* Determines how much food and O2 and animal needs
* Related to animal's size, environment and activity levels
54
Autotroph
vs
Heterotroph
Autotroph: harness energy from light to build energy-rich molecules
Heterotroph: harvest chemical energy from food
55
Energy allocation and use
process
* Energy-rich molecules from food are used to make ATP to power the cell
* This is used to stay alive, grow, repair, synthesis of fat, gamete production
56
Metabolic Rate
* How much energy used per unit of time
* Calculated from heat loss, oxygen consumed, CO2 produced
* Calories consumed and lost in waste products
* Proportional to mass by a power of 3/4: m3/4
* Smaller animals have higher metabolic rate per gram than larger animals
* Basal BMR: for endotherms
* Standard SMR: for ectotherms
* both those rates assume at rest, not growing, not stressed, fasting
* Average daily rate is around 2-4 times BMR or SMR
57
Torpor
vs
Hibernation
* Torpor: State in which activity is low and metabolism decreases. Enables animal to save energy.
* Hibernation: long term torpor. Adaptation for cold or food scarcity.
58
Main stages of Food Processing
1. Ingestion: eating
2. Digestion: breaking down food into absorbable molecules. Mechanical (increases surface area of food) and chemical (splits food into small molecules that can pass through membranes
3. Absorption: uptake of nutrients by body cells
4. Elimination: undigested food exits digestive system
59
Essential Nutrients
process
* Carbon and nitrogen are used to synthesize
* Essential nutrients are obtained from the diet
* 4 classes:
1. amino acids (20 needed, 10 synthesized 10 eaten directly) meat, eggs, cheese. complete proteins
2. fatty acids (must be obtained from diet) unsaturated = double bonds
3. vitamins: required in small amounts. 13 needed.
4. minerals: small amounts, inorganic. large amounts upset homeostatic balance
60
Suspension Feeders
* Aquatic animals that sift small food particles from water
61
Substrate Feeders
Animals that live on or inside their food source
ex: caterpillar that burrows into a leaf
62
Fluid Feeders
Suck nutrient-rich fluid from a living host
63
Bulk Feeders
Eat relatively large pieces of food
ex: snake that eats a whole animal
64
Why do animals have digestive compartments?
To reduce the risk of digesting your own cells and tissues
65
Intracellular Digestion
* Particles are engulfed by phagocytosis
* Food vacuoles, containing food, fuse with lysosomes containing hydrolytic enzymes
* Sponges digest entirely this way
66
Extracellular Digestion
* Break down of food particles OUTSIDE the cell
* Animals with simple body plans have a gastrovascular cavity that digests and distributes nutrients
* Complexe animals have a digestive tube with 2 openings (complete digestive tract or alimentary canal)
67
Mammalian Digestive System
parts and movement
* Alimentary canal + glands (salivary, pancreas, liver, gallbladder)
* Food pushed by peristalsis
* Valves called sphincters regulate movement of material between compartments
68
Digestion in the Oral Cavity
1. Mechanical: oral cavity. teeth chew to break down
2. Salivary glands lubricate food (mucus). Salivary amylase starts to break down glucose
3. Food goes into Pharynx then oesophagus
69
Digestion in stomach
* Stomach stores food and begins digestion of proteins
* Stomach secretes gastric (HCl and pepsin) juices which converts food to chyme
* Low PH (2) which kills bacteria and denatures proteins
* Pepsin is a protease (protein digesting enzyme) that cuts proteins into smaller peptides
* Mucus protects stomach lining from gastric juice
70
Digestion and absorption in Small Intestine
* Most enzymatic hydrolysis of macromolecules happens here
* First portion of small intestine is called DUODENDUM where chyme from stomach mixes with digestive juices from pancreas, liver, gallbladder and the small intestine itself
* Absorption facilitated due to large surface area (due to villi and microvilli)
* Transport across epithelial cells can be passive or active, depending on the nutrient
* Hepatic portal vein carries nutrient-rich blood from villi capillaries to liver
* Liver regulates nutrient distribution, detoxes some organic molecules
* Epithelial cells absorb fatty acids and monoglicerides and recombine them into triglicerides
71
Pancreatic Secretions
* Protease called trypsin and chymotrypsin that are activated in the lumen of the duodendum
* Solution is alkaline and neutralizes acidic chyme
72
Liver Secretion
* Bile aids to digest and absorb fats
* Bile is made in the liver and stored in gallbladder
* Bile destroys nonfunctional red blood cells
73
Absorption in large intestine
* Colon is connected to small intestine
* Cecum (extension = appendix - for immunity) aids in fermentation of plant material
* Colon recovers water
* Houses bacteria that live off unabsorvbed material
74
Carnivore
vs
Herbivore
vs
Omnivore
* Carnivores have large expandable stomach
* Herbivores and omnivores have longer alimentary canals (longer time to digest vegetation)
75
Mutualistic adaptations for nutrition
* mutualistic symbiosis: microbiome (innate immune system)
* Herbivores have fermentation chambers where mutualistic microorganisms digest cellulose (ruminants)
76
Feedback circuits and digestion
* Nervous system helps regulate digestive process
* Endocrine System regulates digestion through hormones
* Ghrelin (hormone secreted by stomach) triggers feeling hungry
* Insulin and PYY (secreted by small intestine) suppress apetite
* Leptin (produced by adipose tissue) suppresses apetite and regulates body fat levels
77
Energy Storage
* In humans, energy stored in liver and muslces in the polymer glycogen
* Excess energy stored in adipose tissue
* When fewer calories eaten, body expands liver glycogen, then muscle, then fat
78
Neurons
* Nerve cells that transfer information within the body
* Transfer electric signals (long-distance) and chemical signals (short-distance)
* Organelles are in cell body
* Dendrites: highly branched extensions that receive signals from other neurons
* Axon: longer extension that transmits signals to other cells at synapses
* Synaptic terminal of one axon passes info across the synapse as chemical messengers (neurotransmitters)
* Synapse: junction between axon and another cell
* Info goes from presynaptic cell (neuron) towards postsynaptic cell (neuron, muscle, gland cell)
* Neurons are nourished and insulated by cells called glia
79
Processing of information
location
* Ganglia: simple cluster of neurons
* Brain: complexe organization of neurons
* 3 steps:
1. sensory input: sensors detect external stimuli and internal conditions and transmit info via sensory neurons
2. integration: info sent to brain or ganglia where interneurons integrate the info
3. motor output: leaves brain or ganglia via motor neurons which trigger muscle or gland
* giant ring axon in jellyfish coordinate movement of bell and tentacles
80
Central Nervous System
CNS
* Integration takes place
* Brain and nerve cord
81
Peripheral Nervous System
PNS
* Carries info into and out of CNS
* Bundled neurons of PNS form nerves
