Option G: Ecology & Conservation

(22 hours)

G1: Community Ecology

(5 hours)

G.1.1 Outline the (abiotic) factors that affect the distribution of plant species--

• Example: sand dune community • Temperature (xref- photosynthesis- 3.8.8) & Water

– Foredune—very hot in summer, little water• Grass adapted to conditions• Long roots find water; leaves can curl to save

water and resist heat

– Mature dune—much cooler, more moist• More species diversity• Example – @ “forest” floor--ferns (low light,

moist conditions)

G.1.1 Outline the (abiotic) factors that affect the distribution of plant species--

• Light (xref- photosynthesis- 3.8.8)

– Grasses in high light• Thin leaves reduce water loss, withstand heat

– Ferns – low light• Wide leaves capture the small amt light / shade

• Soil pH (xref- pH on enzymes- 3.6.3)

– pH varies among dune regions– Yellow dune- soil pH 7.5 (grass here too, thrives @

pH)– Grey dune-decomposition of lots grasses, soil more

rich, more acidic (acid-loving heathers here)

G.1.1 Outline the (abiotic) factors that affect the distribution of plant species--

• Salinity– Foredunes get salt spray

• Grasses can tolerate it

– Grey dune less salty• Small shrubs, mosses, lichen

• Mineral nutrients– Grey dune – diversity of plants, older region,

has mineral content to support shrubs, etc.– Mature dune – way inland, lots of nutrient-rich

soil, oldest region (soil building up 100s yrs), can support large trees (ash, birch, oak)

G.1.2 Explain the factors that affect the distribution of ANIMAL species, including• Example: Indiana Dunes, Lake Michigan• Temperature

– Animals adapted for hot/cold temps– Sand wolf spider: foredune dweller, extreme high

temps—lives in deep burrow (behavioral adaptation)

– Woodland spider: live in trees (shade, cooler)-mature dune

• Water– Water for eggs, aquatic animals for food– Heron-catches fish/frogs, lives near water– Woodpecker-eats insects in trees, lives in mature

dune

G.1.2 Explain the factors that affect the distribution of ANIMAL species, including• Breeding sites

– Nesting sites– Protection from sun, wind; mature dune, wetlands– Habitat loss!

• Food supply – Generalists, specialists– Raccoons, skunks, foxes-move to where food is

located; nocturnal– Rabbits-burrows in foredune, near grass (food)

• Territory– Packs of coyotes, scent to mark space– May or may not overlap

G.1.3 Describe one method of random sampling, based on quadrat methods, that is used to compare the population size of two plant or two animal species.

• Statistics- Topic 1!!!Statistics- Topic 1!!!• Easier than counting every individualEasier than counting every individual• RandomRandom = each organism has equal chance of being selected = each organism has equal chance of being selected

for the countfor the count• QuadratQuadrat: square (certain size, dep. on organism): square (certain size, dep. on organism)

– Map the whole areaMap the whole area– Determine quadrat size Determine quadrat size – Use a #d grid over the mapUse a #d grid over the map– Random # table Random # table to decide which squares (quadrats) to to decide which squares (quadrats) to

samplesample– CountCount # of xxxx and # of yyyy within sample quadrats # of xxxx and # of yyyy within sample quadrats– CalculateCalculate avg # xxxx and avg # yyyy in each avg # xxxx and avg # yyyy in each– Multiply avg (for xxxx, for yyyy) x total # quadrats in whole Multiply avg (for xxxx, for yyyy) x total # quadrats in whole

area to area to estimate populationestimate population of xxxx and yyyy of xxxx and yyyy

G.1.4 Outline the use of a transect to correlate the distribution of plant or animal species with an abiotic variable.

• Common for studying distribution of plants/animals in ecosystem, abiotic factors affecting it

• Use a tape/line through the area• Every 10-20 m along tape, mark a quadrat (use consistent

size for all)• Identify, count plant/animal species of interest in quadrats• Measure abiotic feature in each quadrat (temp, light, soil pH,

water, mineral nutrients)• Determine pattern of distrib of species correlation w/abiotic

factor??

Hmmm...quadrat or transect??

Depends on if habitat’s fairly uniform –or-

if you see a progression along an environmental gradient

G.1.5 Explain what is meant by the niche concept, including an organism’s spatial habitat, its feeding activities its interactions with other species.

• Niche = role in ecosystem• Spatial habitat: where it lives

– Presence of organism changes the habitat (frogs burrow in mud @ pond bank)

• Feeding activities: keep prey pop in check– Frog eats larvae of mosquitoes, flies, etc.

• Interactions w/other species: competition, herbivory, predation, parasitism, mutualism– Heron is predator for frog– Frog is host to parasite

Who Cares?!?!?!?• We Do! • Ecologists study niches to measure impacts on

populations• Danger of extinction need to understand as

much as possible about species– Habitat Loss = biggest threat

G.1.6 Outline the following interactions between species, giving two examples of each:

• Competition (2 sp compete for same resource)– Coyote (grassland) & red fox (edges of forests &

meadows): both eat small rodents, birds; more farmland reduces forest fox overlapping w/coyote, compete for food

– Natterjack toad & common toad: disturbance in coastal dunes in UK, limiting habitat for both

• Herbivory (primary consumer feeds on producer: growth of producer critical to primary consumer’s survival)– Rabbits eat grass in sand dune ecosystem– Monarch b’fly larvae eat leaves of milkweed

G.1.6 Outline the following interactions between species, giving two examples of each:• Predation (consumer-pred. eats consumer-prey; # prey affects #

pred, vice versa)– Canadian lynx and arctic hare: lynx pop changes followed by

hare pop changes– Blue heron pred. for frogs in sand dune ponds

• Parasitism (lives in/on host, depends on host, host is harmed)– Plasmodium (malaria in humans) reproduces in human liver

and RBCs; part of life cycle in Anopheles mosquito (vector, transmits from human to human)

– Leeches—hosts are humans/mammals, puncture skin & secrete enzyme to prevent clotting

• Mutualism (2 sp live together, both benefit)– Lichen= algae + fungi (photosynthesis, make food; absorb

minerals algae need)– Rhizobium = N-fixing bacteria in legume roots (fixes N for

plant; plant makes carbs for bacteria)– Clownfish & anemone (fish has mucusto protect it, fish lures

other fish to anemone...food for anemone...clownfish eats leftovers

G.1.7 Explain the principle of competitive exclusion.

• No two species in same community can occupy same niche: one will be excluded– 1934, Gause: Paramecium expts– Interspecific competition

• Red fox & coyote– If they do inhabit same

area, same niche...– 1 will die out, other will

survive Fig. 19.1. Competitive exclusion of one species of the ciliate protozoan Paramecium by another.

Data from Gause (Gause, G.F. 1934. The Struggle for Existence. Williams and Wilkins, Baltimore, MD.).

G.1.8 Distinguish between fundamental niche & realized niche.• fundamental niche of a species

– potential mode of existence, given the adaptations of the species

– Complete range of biological and physical conditions within which it can live

– (red fox used to live @ forest edge & meadows)• realized niche of a species

– actual mode of existence, narrower range– results from its adaptations and competition with other

species– (now red fox habitat shrunk, competing w/coyote, in the

realized niche)

G.1.9 Define biomass.

• Total mass of organic matter• Carbs, lipids, proteins• DRY the matter 1st to remove water content• g m-2 yr -1

G.1.10 Describe one method for the measurement of biomass of different trophic levels in an ecosystem.• Aim 8: Ethical issues of returning the species and

destructive techniques should be considered. • Tables/charts to get biomass of animal vs size/weight ,

small plants too • Biomass of ecosystem of terrestrial community:

– Measure total area of forest– Divide into small area (grids, plots)– Sample one plot– Measure size of each plant species, including trees

(height, diameter) & low-growing.– Cut down ALL the trees and vegetation on that ONE

plot

G.1.10 Describe one method for the measurement of biomass of different trophic levels in an ecosystem.

• Dry all plant samples (circulating drying oven)• Math. Model: relationship b/w weight and height of

each plant species and its biomass• Sample other plots for height and size only—no need

to cut down/dry/killlllll....use the model!• ANIMALS: set traps in the plot, weigh, measure & use

tables to get biomass• Avg data for all species per plot• Multiply x # plots in ecosystem biomass for whole

ecosystem• Seasonal/yearly sampling to track changes over time