Introduction to Animal Evolution

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					Nutrient cycling is strongly regulated by vegetation. When plants are
not present, nutrients are lost from the system.




 Fig. 54.21




pages 1213-1214
                              Ohio reservoir




Gizzard shad




               Ecologists are recognizing the need
               of understanding how landscapes
               (comprise different ecosystems) and
               food webs interact.
                                       Bioscience 2005
Ecosystem. All the organisms living in a community AND the abiotic
factors with which they interact.

Ecosystem Dynamics
1- Energy flow
   Primary production
       gross and net
       aquatic (light and nutrients).
       terrestrial (climate and nutrients).
    Secondary production
       gross and net
       production and trophic efficiencies
       biomass and number pyramids
       green world hypothesis.
2- Matter (chemical) cycling
    Biogeochemical model.
    Water, carbon, nitrogen.
    Role of decomposers.
    Vegetation regulation.
                SOME questions from February 24th

1- Is the final cumulative? Can we have some sort of study guide?

2- What happens to the rest of the light energy if only 1% is used?


3- How would omnivores be classified in consumer nomenclature?

4- If organic and inorganic materials are only recycled, where are
they from?
5- Is there any way to artificially produce photosynthesis to limit
CO2?
6- If we need 2,000 calories per day and maybe half go out as
feces, does that mean that we use only 10 calories for growth per
day?
World population 'to rise
by 40%'
 The world's population
 continues to grow but at a
 slower pace. The world's
 population is expected to rise
 from the current 6.5 billion to
 9.1 billion by 2050, the UN
 says.
Introduction to Animal
      Evolution
What is an animal?
• How would you know?
• What are the challenges that all
   animals must deal with?
• Are there some fundamental similarities in
the ways that animals solve these problems
(similar adaptations) ?
                               Major Themes -->
         Growth & Development
• form and function are related
  Compare the means of support for animal and plant bodies.
• differentiation and specialization into tissues
  – tissues, organs, and organ systems
  – body plan, size, and symmetry
  How is it possible that cells of the same animal can have a
    different structure and function?
• reproduction
  – sexual and asexual
  – developmental stages
  What is significant about the fact that
  larval forms are “sexually immature”?
  Sensing and Responding to the
          Environment
• sensory systems
  Describe what is meant by “environment”
  in this context. Provide some examples of
  conditions that are monitored.
• motor systems (locomotion)
  What special tissue(s) enable this kind of
  movement?
• feeding and digestive functions
 Describe some examples of how body
 structure is related to feeding style.
           Internal Regulation
• energy balance
  What factors may influence an animal’s “energy
   budget”?
• transport
  – water
  – nutrients and wastes
  – gas exchange
  How do animals cope with abiotic stresses?
• intercellular communication
  – local
                       Provide one example of each type of
  – long distance      intercellular communication.
Proposed evolution of the
        animals
                            Fig 28.8
     Early embryonic development can help
      organize the diversity of animal life
         What type of cell division occurs during cleavage?




When does the body form take on a “tube within a tube” appearance?
      Patterns in Animal Evolution
  • Simple to more complex body form
  • Hypothesized colonial flagellated protist ancestor
  • Cell aggregates, to a gastrula-like (or tissue-grade)
    “protoanimal” to




                                     Fig. 32.3

Which stages demonstrate cell differentiation? … morphogenesis?
                                         “pore-bearers”
  The Parazoa - Phylum Porifera




                               Describe at least two functions
                               of amoebocytes.

                               How would you describe the
                               feeding strategy?
• No gastrulation occurs during development; no true tissues
  If sponges have no muscle or nerve tissues, how do they
      accomplish movement of water into the spongocoel?
Patterns in Animal Evolution (continued)

       tissues organized into organs and organ systems (a
         “tube w/in a tube” body plan, with 3 embryonic
         germ layers)
                                   Discuss the concept of “stem cells” in
                                   the context of animal embryology.
  Mesoderm (although, not in all animals)
                                                Fig. 32.1
                                                Characteristics of the body
                                                plan (anatomy) and
                                                embryonic development are
                                                key to understanding the
                                                relationships between
                                                different animal groups.
  Patterns in Animal Evolution (continued)
               • Bodies with no symmetry to bodies
                 with symmetry
                 – Branch Radiata
                      • 2 germ layers: ectoderm &
                        endoderm
Fig. 32.5         – Branch Bilateria
                      • 3 germ layers
               Which body form demonstrates
                 cephalization?
               Describe at least one example of an animal
                 with a high degree of cephalization. What
                 other characteristics are associated with
                 cephalization?
  Patterns in Animal Evolution (continued)
What do the colored layers represent?       Fig. 32.6
  Bodies with no body cavity
  (e.g. flatworms)
                                        pseudocoelom

   to bodies with a “false”
       body cavity
   (e.g. rotifers and round worms)

                                         coelom
   to bodies with a “true”
       body cavity
What normally fills the pseudocoelom?
                              Fig. 32.7


     Coelomates
•    Differences include:
•    Cleavage
•    Fate of blastopore
•    Process of coelom
     formation
    Name one organism
    representative of the
    animal groups listed at
    the top of the figure.
How is structure
related to function at
major stages in the
life cycle of a sea
star?

What can early
embryonic
development tell us
about phylogentic
relationships in
animals?

What is
metamorphosis, and
how is it different
from morphogenesis?
Traditional
Animal
Phylogentic
Tree
Which animals have a
body cavity?

What are the possible
functions of a body cavity
in animals?
Animal Phylogeny – Modern
                      • Based on sequences in
                        ribosomal RNA
                        (molecular systematics)
                      • Acoelomate flatworms
                        lost their coelom
                      • Coelom development
                        happened early

                      • Combine phyla with
                        lophophore and
                        trocophore larvae


                      • Combine phyla that molt
                        (ecdysis)
           Fig 32.8
                     X   X   X   X XX
Tissues allow for
different cells to
take different
roles:
cnidocytes,
unique in the
animal kingdom,
and extracellular
digestion by
gastrodermis
allow food larger
than individual
cells.
Plylum Cnidaria   • extracellular digestion by
                    gastrodermis allows food
  “cnidarians”      larger than individual cells
                  • Radial symmetry - detect and
                    respond to stimuli from any
                    direction
                  • Muscles and simple nerve net

                                 Fig 33.6
                     Polyp vs. medusa
• 2 cell layers
   – Skin
   – Gastro-
     vascular
     cavity lining
• 2 body forms
   – polyp
   – medusa


Hydra eating
Swimming jelly
  fish
                                        Fig 33.4
 Phylum Platyhelminthes – “flat worms”
• Bilateral symmetry with some cephalization;
  gastrovascular cavity
• A thin body between dorsal and ventral surfaces
• NO coelom (acoelomate)
• Flatworms, trematodes, tapeworms



      Fig 33.12
   Phylum Nemertea - “ribbon worms”
•Actually acoelomate, but some similarities to the protostomes
•Complete digestive tract; closed circulatory system
                                                       What are the
                                                       advantages of a
                                                       complete digestive
                                                       tract?
                                                       …of a closed
                                                       circulatory system?




Photo from: http://www.seaslugforum.net/factsheet.cfm?base=nemertea
      Phylum mollusca – “mollusks”
• Over 150,000 spp; mostly marine
• Soft body protected in most by a hard shell made of
  calcium carbonate
               Bivalves:                       Gastropods:
               clams, etc.                     snails, slugs




                             Fig 33.20                         Fig 33.18


        Polyplacophora:                        Cephalopods:
                 chitons                       squid, etc.




                             Fig 33.17                         Fig 33.22b
    Mollusk
    anatomy
• Important consumers:
   – Filter feeders
   – Grazers
   – Carnivores
• 3 Main body parts:
   – Foot
      • movement          Most use a strap like
   – Viscera mass         rasping organ called
                          a radula to scrape
      • internal organs   food; cephalopods
   – Mantle               have a beak
      • secretes shell;
         gas exchange

				
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posted:11/24/2011
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