NERDS 2012 Pre-Session #1

Content Lecture: Terrestrial and Aquatic Ecology

Dr. Jennifer HollanderDr. 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

8

Ecosystems in the Sierra Nevada – affected by elevation and precipitation

Lodgepole forest

Whitebark pine/ white fir

Jeffrey pine

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

SquirrelsSciuridae (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

Diatoms

Crysophytes

Dinoflagelates

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

• Sponges– Simplest – Evolutionarily oldest– Lack symmetry– Lack true tissues

Ancestral colonialchoanoflagellate

Eumetazoa

Bilateria

Deuterostomia

Porif

era

Cnid

aria

Oth

er b

ilate

rians

(inc

ludi

ngN

emat

oda,

Art

hrop

oda,

Mol

lusc

a, a

nd A

nnel

ida)

Echi

node

rmat

a

Chor

data

Porifera Anatomy

Phylum Cnidaria

• Corals, anemones, hydroids, jellyfish– Eumetazoa– Radial symetry– True tissues– Diploblastic

Ancestral colonialchoanoflagellate

Eumetazoa

Bilateria

Deuterostomia

Porif

era

Cnid

aria

Oth

er b

ilate

rians

(inc

ludi

ngN

emat

oda,

Art

hrop

oda,

Mol

lusc

a, a

nd A

nnel

ida)

Echi

node

rmat

a

Chor

data

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

Ancestral colonialchoanoflagellate

Eumetazoa

Bilateria

Deuterostomia

Porif

era

Cnid

aria

Oth

er b

ilate

rians

(inc

ludi

ngN

emat

oda,

Art

hrop

oda,

Mol

lusc

a, a

nd A

nnel

ida)

Echi

node

rmat

a

Chor

data

• Invertebrate Phyla– Platyhelminthes– Mollusca– Annelida– Nematoda– Arthropoda

Phylum Platyhelminthes

• “Flat worms”– Acoelomates– Mostly free-living– Mostly marine– Some freshwater– Some parasitic

A freshwater turbellarian

• 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)

Phylum Mollusca

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 NymphStonefly Nymph

Caddisfly larva Caddisfly Adult

Chironomid Larva

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 SizesMeiofauna Macrofauna Megafauna

0.063 mm – 0.5 mmLive on surface or within sediment, smallenough to live between sand grains

0.5 mm – 5 cm Live on surface or burrow within sediment (most are lessone centimeter).

5 cm, easily see with naked eye

• A theoretical phylogeny of chordates

Vertebrates

• Amphibians• Reptiles• Fish• Birds