Lecture 14 Animal Kingdom Flashcards
1
Q
Different domains
A
slide 2
2
Q
Three domains
A
slide 3
3
Q
Key characteristics of Eukaryotes (that distinguish from porkaryotes)
A
- eukaryotic group is very diverse,
- three main characteristics distinguishing them from prokaryotes:
1. Compartmentalization
2. Multicellularity in many, but not all, eukaryotes
3. Sexual reproduction
4
Q
LEARNING OUTCOMES
A
slide 5
5
Q
General Features of Animals
A
- Nutritional Mode
– Heterotrophy - obtain energy/ organic molecules by ingestion of food
– animals ingest food and then digest it internally - Cell Structure and Specialization
– Multicellularity - Many have complex bodies
– Tissues - organized into structural and functional units
– No cell walls – NO rigid cell walls and are usually flexible - Active movement - Move more rapidly and in more complex ways
- Diversity of form - Vary greatly in form, ranging in size from organisms too small to see with the unaided eye to enormous
- Reproduction and Development
– Sexual reproduction - Animal eggs, which are nonmobile.
– Embryonic development - Zygote, cleavage, blastula, gastrula - Larval stage possible with metamorphosis
6
Q
Key Evolutionary Innovations of Animals
A
Five key transitions can be noted in animal evolution
– Tissues
– Symmetry
– Body cavity
– Patterns of Development
– Segmentation
7
Q
Evolution of symmetry
A
There are two main types of symmetry:
Radial symmetry
– Body parts arranged around central axis
– Can be bisected into two equal halves in any 2-D plane
Bilateral symmetry
– Body has right and left halves that are mirror images
– Only the sagittal plane bisects the animal into two equal halves
Advantages
1. Cephalization - Evolution of a definite brain area
2. Greater mobility
slide 9 and 10
8
Q
Evolution of tissues
A
Diploblastic - animals (cnidarians), have only ectoderm and endoderm
Triploblastic - animals, all bilaterally symmetrical animals produce three germ layers (Eumetazoa)
– Outer ectoderm (body coverings and nervous system)
– Middle mesoderm (skeleton and muscles)
– Inner endoderm (digestive organs and intestine
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9
Q
3 germ layers
A
Ectoderm-forms the exoskeleton
Mesoderm-develops into organs
Endoderm- forms the inner lining of organs
10
Q
Evolution of body cavities
A
Body cavity = Space surrounded by
mesoderm tissue that is
– Acoelomates = No body cavity
– Pseudocoelomates = cavity between
mesoderm and endoderm
Called the pseudocoelom
– Coelomates = Body cavity entirely within
the mesoderm
Called the coelom
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11
Q
Bilaterians can be divided into two groups:
A
- Protostomes - develop mouth
first from or near the
blastopore
– Anus (if present) develops
either from blastopore or
another region of embryo - Deuterostomes - develop
the anus first from the
blastopore
– Mouth develops later from
another region of the
embryo
slide 13
12
Q
Deuterostomes vs. protostomes
A
- Cleavage pattern of embryonic cells
–Protostomes = Spiral cleavage
–Deuterostomes = Radial cleavage - Developmental fate of cells
–Protostomes = Determinate development
–Deuterostomes = Indeterminate development - Formation of the coelom
–Protostomes = cells split off
–Deuterostomes = cells pouch off
13
Q
Evolution of segmentation
A
Two advantages
1. Redundant organ system in adults
such as occurs in the annelids
2. Efficient and flexible movement
-segments can move independently
slide 15
14
Q
Animal Phylogeny and diversification
A
Several data sources are used to infer evolutionary relationships among the three dozen extant animal phyla
–Whole genomes
–Morphological traits
–Ribosomal RNA (rRNA) genes
–Hox genes
–Protein-coding nuclear genes
–Mitochondrial genes
15
Q
Animal Phylogeny and diversification
A
Five important points about the relationships among living animals are reflected in their phylogeny
- All animals share a common ancestor
- Sponges are the sister group to all other animals
- Eumetazoa is a clade of animals with tissues
- All animals except for sponges and a few others
belong to the eumetazoans (“true animals”) - Most animal phyla belong to the clade Bilateria
- There are three major clades of bilaterian animals
– Most bilaterians are invertebrates, animals that lack a backbone
– Chordata is the only phylum that also includes vertebrates, animals
with a backbone
16
Q
Animal Phylogeny and diversification
A
slide 18
17
Q
Summary of key concepts: key steps in animal evolution
A
slide 19
18
Q
INVERTEBRATES
A
Classifying invertebrate species into groups based on evolutionary relationships helps us to understand their great diversity
slide 21
19
Q
- Basis of the classification of animals
A
- Level of organization - multicellular
2.Type of symmetry – distribution around the main central axis
* Bilateral –median plane
* Radial – radiate from central axis
* Asymmetrical – no symmetry
3.Type of skeleton
* Endoskeleton –internal (bone or cartilage)
* Exoskeleton – external (calcium carbonate shells, chitin, silica)
- Nature of digestive tract
* Absent
* Incomplete – one opening (mouth for input and output)
* Complete – two openings (mouth and anus)
slide 22
20
Q
Protosomes
A
- Phylum Porifera
- Phylum Cnidaria
- Phylum Ctenophora
- Phylum Platyhelminthes
- Phylum Mollusca
- Phylum Annelida
- Phylum Nematoda
- Phylum Arthropoda
21
Q
Summary of key concepts: key steps in animal evolution
A
slide 24
22
Q
Phylum Porifera
A
- Sponges
- Asymmetry
- Endoskeleton with spicules
- Various growth forms
– Larval sponges free-swimming
– Adults remain attached – sessile - Cell types
– Truly multicellular
– 3 functional layers in “vase” - Stationary
- Asexual or sexual reproduction
- Choanocytes
– Flagellated – contributes to water circulation
– Engulf and digest food from passing water
slide 25
23
Q
Summary of key concepts: key steps in animal evolution
A
slide 26
24
Q
Phylum Cnidaria
A
- radially symmetrical, diploblastic
- Carnivores - Tentacles for stinging prey, and defense
– First muscles and nerves - Extracellular digestion – one opening
– Digestion takes place partly in gastrovascular cavity
– Cells then engulf fragments by phagocytosis - Two body forms possible
– Medusae- free-floating “jelly-fish”
– Polyps- attached,
corals, sea anemones, Hydra
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Phylum Ctenophora
* Diploblastic, radial symmetry
* Resemble Cnidarian with their gelatinous, medusa-like form
* eight “combs” of cilia to propel them through water
* Comb jelly
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26
Summary of key concepts: key steps in animal evolution
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27
Phylum Platyhelminthes
* Most prominent group is the flatworms
– NO circulatory,
– NO respiratory systems - Diffusion for gas transport
– NO digestive system - absorb food directly through body walls – one opening
– planarians and parasitic flukes and tapeworms
* Simple Bilateral symmetry, no coelom
* No coelom, Flatworms are ciliated, soft-bodied animals
* Parasitic or free-living - Marine, freshwater, moist terrestrial
* Cephalization - sensory equipment in the head
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28
Phylum Mollusca
* Second in diversity only to arthropods
* Soft bodied unsegmented animals
* Bilateral symmetry
* Exoskeleton - Protected by shells
* Include snails, slugs, clams, octopuses and others
* Reproduction - gonochoric
– A few are hermaphroditic
– Asexual reproduction
* Major Classes
– Class Gastropoda – snails
– Class Cephalopoda –squids
– Class Bivalvia –clams
– Class Polyplacophora -chitons
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29
Phylum Annelida
* Segmented worms – earthworm, sandworm
– Body built of repeated units - Allows for specialization
– Head has well-developed cerebral ganglion
* Bilateral symmetry
* Move by contracting their segments (filled with fluid)
– Longitudinal and circular muscles
* Closed circulatory system
* Ventral nerve cord
* Complete digestive tract (two openings)
– Tube within a tube
* Active burrowing affects climate change
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Summary of key concepts: key steps in animal evolution
slide 33
31
Phylum Nematoda
* Vinegar eels, eelworms, and other roundworms
* Found everywhere – abundant and diverse
* Marine, freshwater, parasites, free-living
* Bilaterally symmetrical and unsegmented
* Covered by a flexible, thick cuticle that is molted as they grow
* Digestive system well developed
– Stylets – piercing organs near mouth
– Pharynx – creates sucking action
– Anus
* Sexual life cycle
* C. elegans - model organism
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32
Nematode-caused diseases
* Trichonosis, Trichinella
– Rare in U.S.
– Eating undercooked pork or bear
transmits the worms
* Pinworms, Enterobius vermicularis
– Infects 30% of children in U.S.
– Causes itching of the anus
* Serious tropical nematode disease
– Filariasis
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33
Phylum Arthropoda
* By far the most successful animals
– The most species (80% of all arthropods are insects)
* Segmented body enclosed in exoskeleton of chitin
* First to live in air
* Bilateral symmetry/segmentation
* Jointed appendages on either side of the body
* Complete digestive tract (two openings)
* Divided into four extant classes (some books use subphylum)
– Chelicerata – spiders, mites, scorpions
– Crustacea – lobster, crabs, shrimps
– Hexapoda - insects
– Myriapoda – centi- millipedes
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34
Summary of key concepts: key steps in animal evolution
slide 37
35
Deuterostomes
* Deuterostomes are composed of echinoderms and chordates
* Consist of fewer phyla and species than protostomes
* Are more uniform in many ways, despite great differences in
appearance
❖ Phylum Echinodermata
❖ Phylum Chordata
36
Phylum Echinodermata
Exclusively marine (ocean)
* Deuterostomes with an endoskeleton
* Pentaradial symmetry
* Complete digestive tract (2 openings)
* Sea stars
* brittle stars,
* sea urchins,
* sand dollars,
* sea cucumbers
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37
Features of echinoderms
* Symmetry
– Pentaradial as adult, bilateral as larva
– Oral surface defines mouth
– All systems organized with branches radiating from center
– Nervous system is nerve ring with branches
* Endoskeleton
– Epidermis covers endoskeleton
– Composed of calcium carbonate ossicles
– May be tightly or loosely joined
* Water-vascular system - network of hydraulic canals branching
into extensions called tube feet (locomotion and feeding)
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38
Phylum Chordata (vertebrates)
* Chordates are deuterostome coelomates
* Most advanced animal group (more DNA)
* Nearest relatives are echinoderms (the only other deuterostomes)
* Four Characteristics of chordates
1. Nerve cord - develops in CNS
2. Notochord
* May be replaced by vertebral column
3. Pharyngeal slits
* gas exchange, feeding structures
4. Postanal tail
* propelling force in many aquatic species
* Fishes
* amphibians
* reptiles
* birds
* mammals
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Phylum Chordata
* Chordates are deuterostome coelomates
* Nonvertebrate forms – subphyla urochordata, cephalochordata
– Do not form bone
* Vertebrate forms
– Fishes, amphibians, reptiles, birds, and mammals
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Phylogeny of living Chordates
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41
KEY Characteristics of vertebrate evolution
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Non Vertebrates
A. Urochordata
* Tunicates are marine animals
* Larvae are tadpole-like and have notochord and nerve cord
– Are free-swimming but do not feed
* Adults typically lose the tail and notochord
– Are immobile filter-feeders
– Many secrete a tunic (cellulose sac) that surrounds the animal
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Non Vertebrates pt 2
B. Cephalochordata
* Lancelets are scaleless chordates
* Notochord persists throughout animal’s life
* Spend most of their time partly buried
* Have no distinguishable head
* Feed on plankton using cilia-generated currents
* Closest relatives to vertebrates
44
Vertebrata
* Chordates with a spinal column - Almost all chordates are vertebrates
* Distinguished from nonvertebrates by
– Vertebral column – Encloses and protects the dorsal nerve cord
– Head – Distinct and well-differentiated possessing sensory organs
* Neural crest – unique group of embryonic cells that forms
many vertebrate structures (teeth, neurons, some bones)
* Internal organs – liver, kidneys, endocrine glands, heart, and
closed circulatory system
* Endoskeleton – made of cartilage or bone
– Makes great size possible and extraordinary powers of movement
45
1. Fishes - Earliest and most diverse vertebrate group
* Over half of all vertebrates
* Provided the evolutionary base for invasion of land by amphibians
Characteristics
* Vertebral column
– Hagfish and lamprey exceptions
* Jaws and paired appendages
– Hagfish and lamprey exceptions
* Internal gills
* Single-loop blood circulation
* Nutritional deficiencies
– Inability has been inherited by all their vertebrate descendants
46
Evolution of the jaw – Lampreys
* The first fishes had mouths with no jaws -jawless vertebrates
– Agnatha extant as hagfish and lampreys
* Evolved from the anterior gill arches that were made of cartilage
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Lateral line development - Sharks
* Chondrichthyes – sharks and bony fish
* Cartilage skeleton “calcified” with granules of calcium carbonate -
Light, strong skeleton – sharks, skates, rays
* Sharks - first vertebrates to develop teeth
* Sharks (and bony fishes) - fully developed lateral line system
– Series of sensory organs under the skin that detects changes in pressure waves
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The Swim bladder - Bony fishes
* Heavy internal skeleton made completely of bone
* New adaptations include: – Swim bladder - Gas-filled sac
regulate their buoyant density
– Gill cover - Hard plate (operculum)
covers gills Flexing plate permits water pumping over gilTwo groups of bony fish:
* Ray-finned fishes
* Lobe-finned fishes
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49
2. Amphibians - First Terrestrial Vertebrates
Evolutionary path to land
2. Amphibians - First Terrestrial Vertebrates
* Tetrapods:First vertebrates to walk on land * Direct descendants of fishes
* Amphibians evolved from lobe-finned fish
* 3 Modern Amphibian groups
– Order Anura (“without tail”) - frogs and toads
– Order Caudata (“visible tail”) - salamanders
– Order Apoda (“without legs”) - caecilians
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50
Five distinguishing amphibian features
* Legs – adaptation to life on land
* Lungs - Ribs
* Cutaneous respiration – supplement lungs
* Pulmonary veins – separate pulmonary circuit allows higher pressure blood to tissues
* Partially divided heart – improves separation of pulmonary and
systemic circuits
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51
3. Reptiles - Adapted to Terrestrial Living
* Over 7,000 living species
Four key features
– Amniotic eggs, which are watertight, laid on land
– Dry skin, which covers body and prevents water loss
– Thoracic breathing, which increases lung capacity
– Ectothermy, they obtain heat from external sources
52
4.Birds - Flying Reptiles
Bird characteristics
* Class Aves
* Birds are the most diverse of all terrestrial vertebrates
* Success lies in unique structure – feather
* Amniotic eggs and scales on legs
* No teeth and no tails
* Two major distinguishing traits
– Feathers
– Flight skeleton
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Adaptations for flight
Adaptations birds have to cope with the energetic demands of flight
* Efficient respiration
– Air passes all the way through lungs in a single direction
* Efficient circulation
– 4-chambered heart so muscles receive fully oxygenated blood
– Rapid heartbeat
* Endothermy
– Body temperature (40–42oC) permits higher metabolic rate
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5. Class Mammalia
* Lowest number among 5 vertebrate classes
A. Mammalian traits
* Hair - Insulation, camouflage, sensory structure
* Mammary glands - secrete milk
* Endothermy depends on higher metabolic rate
– 4-chambered heart
– Respiration using diaphragm
* Placenta (most mammals) - brings fetal and maternal blood into close contact
* Special adaptations in some groups
– Specialized teeth - match particular eating habits (carnivore vs herbivore)
– Digestion of plants - break down cellulose
* Herbivorous mammals rely on mutualistic partnerships with bacteria
– Development of hooves and horns
* Flying mammals: Bats
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6. Evolution of Primates
* Gave rise to humans
* Evolved two features - success in an arboreal environment
– Grasping fingers and toes
* Opposable thumb
– Binocular vision - Eyes shifted toward the front of the face
* Lets brain judge distances precisely
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