NERDS XII Pre

Report
NERDS 2012 Pre-Session #1
Content Lecture:
Terrestrial and Aquatic Ecology
Dr. Jennifer Hollander
Dr. Jeffrey Baguley
Outline
• Climate and Life Zones of the Sierra Nevada
• Plants
– Gymnosperms
– Angiosperms
• Animals
• Plant-Animal Interactions
• Aquatic Organisms
Basic physics of the atmosphere
• Rule #1 – Warm air holds more water
• Rule #2 – Warm air rises, cold air falls
• Regional climates are determined
by a combination of factors, most
of which are influenced by these
rules.
Hadley cells
Subtropical high: arid
Ecosystems in the Sierra Nevada – affected by elevation
and precipitation
Whitebark pine/
white fir
Lodgepole forest
Jeffrey pine
8
Plants
Gymnosperm Characteristics
• “Naked seed” – seeds mature in cones
• Found primarily in the Northern Hemisphere
• Conifers (largest
Gymnosperm
group) and Ephedra
have modified leaf
structures and can
carry on
photosynthesis in
the winter (no
leaves to drop)
Angiosperm Characteristics
• Flowers!
– The function of the flower is to ensure fertilization
of the ovule and development of fruit
– Angiosperms are often classified based on their
flowers (shape, number of petals, etc.)
• Fruit
– Ovary which encases the seeds
– May serve to attract dispersers
Two major types of angiosperms
• We will talk about specific species of animals
during the second pre-session
• Today we are focusing on the bigger picture,
and groups of animals that are involved in
dispersing seeds of forest plants
Order Rodentia
• 40% of all mammal species
• Characterized by two continuously growing
incisors in upper and lower jaw
– Kept short by gnawing
Squirrels
Sciuridae (Spermophilus or Ammospermophilus)
• Small to medium sized rodents found
worldwide
• Live in almost every habitat
• Mostly eat seeds, however some squirrels are
known to be omnivorous at times
Chipmunks
Sciuridae (Tamias or Eutamias)
• Small, striped mammals in squirrel family
• All species (except one) are found in N. America
• Omnivorous, but collect and store seeds for
winter us
Other Rodents
Community Ecology
• In ecology, a community is a group of two or
more populations of a different species
• Community ecology study the interactions
between species in a community
• There are many different types of species
interaction, including some that involve
multiple species
Some types of species interactions
• Competition – species may compete with each
other for finite resources
• Predation – using another species for food
(not always “hunting” them)
• Mutualism – an interaction between species
in which both species benefit
• Parasitism – one organism benefits (the
parasite) at the expense of the other (the
host)
Plant-Animal Interactions
• Pollination
• Seed dispersal
Frugivory
• Frugivorous animals (primarily birds) disperse seeds by
eating fruits and then defecating the seeds in a
microsite conducive to germination and emergence
Seed Caching
Larderhoard
Scatterhoard
Seed caching resulting in dispersal
Seed caching animals disperse
seeds by storing them for
winter, and then “forgetting”
to retrieve them. The seeds
must be placed in a microsite
conducive to germination and
emergence.
Watersheds
• The entire land mass
that drains into a
given stream or river
system.
• The Feather River
watershed includes
catchments for the
various tributaries of
the Feather and Yuba
Rivers.
Terrestrial/Aquatic Commonalities
• Every living organism needs to eat something.
– Photosynthesis fuels the food webs
• Every living organism needs to reproduce.
• Organisms will interact with each other in multiple
ways.
– Competition, predation, symbiosis, etc.
• While some organisms are exclusively aquatic or
terrestrial, others depend on both habitats.
Bacteria & Cyanobacteria
• Unicellular prokaryotic organisms
• Bacteria are important decomposers and
recyclers of organic and inorganic wastes
• Cyanobacteria may be important for
photosynthesis, but blooms may also be an
indication of poor ecosystem health.
Protists
• Unicellular (and some multicellular)
eukaryotes
• Some are photosynthetic
• Some are heterotrophic
• Some mixotrophic
Phytoplankton and Benthic Microalgae
Euglena
Dinoflagelates
Crysophytes
Diatoms
Plants & Macroalgae
• “Macrophytes”
• There are several types of freshwater aquatic
plants that are an important source of
photosynthesis and also habitat in aquatic
ecosystems.
• Macroalgae are multicellular protists (not
plants)
Plants and Macroalgae
Red Algae
Green Algae
Animals
• Multicellular eukaryotes
– Invertebrates
– Vertebrates
Porifera
Deuterostomia
Bilateria
Eumetazoa
Ancestral colonial
choanoflagellate
Chordata
Echinodermata
Other bilaterians (including
Nematoda, Arthropoda,
Mollusca, and Annelida)
Cnidaria
– Simplest
– Evolutionarily oldest
– Lack symmetry
– Lack true tissues
Porifera
• Sponges
Porifera Anatomy
Deuterostomia
Bilateria
Eumetazoa
Ancestral colonial
choanoflagellate
Chordata
Echinodermata
Other bilaterians (including
Nematoda, Arthropoda,
Mollusca, and Annelida)
– Eumetazoa
– Radial symetry
– True tissues
– Diploblastic
Cnidaria
• Corals, anemones,
hydroids, jellyfish
Porifera
Phylum Cnidaria
Cnidaria Form/Function
• Polyp and Medusa
– Gastrovasular cavity
• Digestion
• Water exchange
• Gas exchange
– Tentacles
• Cnidocytes with
nematocysts
• Capture prey or
detrital particles
Bilaterally Symmetrical Animals
Deuterostomia
Bilateria
Eumetazoa
Ancestral colonial
choanoflagellate
Chordata
Echinodermata
Other bilaterians (including
Nematoda, Arthropoda,
Mollusca, and Annelida)
Cnidaria
– Platyhelminthes
– Mollusca
– Annelida
– Nematoda
– Arthropoda
Porifera
• Invertebrate Phyla
Phylum Platyhelminthes
• “Flat worms”
– Acoelomates
– Mostly free-living
– Mostly marine
– Some freshwater
– Some parasitic
A freshwater turbellarian
Phylum Mollusca
• Phylum Mollusca
– Includes snails and slugs, oysters and clams, and octopi
and squids
• Most mollusks are marine
– Though some inhabit fresh water and some are
terrestrial
• In freshwater habitats you will find:
– Gastropods (snails)
– Bivalves (clams & mussels)
Gastropods
• About three-quarters of all living species of
molluscs
– Belong to class Gastropoda
Bivalves
• Molluscs of class Bivalvia
– Include many species of clams, mussels, etc.
– Have a shell divided into two halves
– Suspension (filter) & deposit feeders
Phylum Annelida
• Annelids are segmented worms
• Annelids
– Have bodies composed of a series of fused rings
Oligochaetes
• Oligochaetes (class Oligochaeta)
– Are named for their relatively
sparse setae, or bristles made of
chitin
– Include the earthworms and a
variety of freshwater and marine
species
Leeches
• Members of class Hirudinea
– Are blood-sucking parasites, such as leeches
Figure 33.25
Phylum Nematoda
• The round worms
• Ubiquitous – found everywhere
– Marine, freshwater, terrestrial, some even live in
polar ice.
– It has been said that if you eliminated all of the
structure on the earth, but left the nematodes
behind, you would see a grey shadow of that
structure.
• 1,000,000+ species estimated globally
Phylum Arthropoda
• Probably the most successful phylum of all animals
– Approximately 1018 – 1019 individuals
– 2,000,000+ species (insects and crustaceans account for
most)
• Two out of every three known species of animals are
arthropods
• Members of the phylum Arthropoda are found in all of
Earth’s habitats
General Characteristics of Arthropods
• Arthropods are segmented coelomates that have an
exoskeleton and jointed appendages
• The diversity and success of arthropods
– largely related to their segmentation, hard exoskeleton,
and jointed appendages
Insects
• Subphylum Hexapoda, insects and their
relatives
– Are more species-rich than most other forms of
life
– Live in almost every terrestrial habitat and in fresh
water
Notable Freshwater Insects
Mayfly Nymph
Caddisfly larva
Chironomid Larva
Stonefly Nymph
Caddisfly Adult
Chironomid Adult
Crustaceans
• While arachnids and insects thrive on land
– Crustaceans, for the most part, have remained in marine
and freshwater environments
• Crustaceans (subphylum Crustacea)
– Typically have branched, appendages that are extensively
specialized for feeding and locomotion
• Decapods are all relatively large crustaceans
– And include lobsters, crabs, crayfish, and shrimp
Invertebrates Come in All Sizes
Meiofauna
0.063 mm – 0.5 mm
Live on surface or
within sediment, small
enough to live between
sand grains
Macrofauna
Megafauna
5 cm, easily see with
naked eye
0.5 mm – 5 cm
Live on surface or burrow
within sediment (most are less
one centimeter).
• A theoretical phylogeny of chordates
Vertebrates
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•
•
•
Amphibians
Reptiles
Fish
Birds

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