Transcript Introduction to Animal Evolution

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
– long distance
Provide one example of each type of
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)
to bodies with a “true”
body cavity
What normally fills the pseudocoelom?
coelom
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
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.
X
X
X XX
Plylum Cnidaria
“cnidarians”
• extracellular digestion by
gastrodermis allows food
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
– Gastrovascular
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:
clams, etc.
Gastropods:
snails, slugs
Fig 33.18
Fig 33.20
Polyplacophora:
chitons
Cephalopods:
squid, etc.
Fig 33.17
Fig 33.22b
Mollusk
anatomy
• Important consumers:
– Filter feeders
– Grazers
– Carnivores
• 3 Main body parts:
– Foot
• movement
– Viscera mass
• internal organs
– Mantle
• secretes shell;
gas exchange
Most use a strap like
rasping organ called
a radula to scrape
food; cephalopods
have a beak