D. Shell, SMHS

Eventually, all the giraffes

that survive will be tall if

isolated from short ones or

the environment remains

favorable for tall giraffes.

The species has EVOLVED

(changed).

Five Kingdoms of Life (Earth’s Biodiversity)

Bacteria Protists Fungus Plants Animals

prokaryotic eukaryotic eukaryotic eukaryotic eukaryotic

single cell single cell

(A few multi-)

multi-cell

(yeast single) multi-cell multi-cell

heterotroph consumer

(decomposer)

or autotroph producer

heterotroph

consumer or

autotroph producer

heterotroph consumer

(decomposer)

autotroph producer

heterotroph consumer

(herbi, carni,

omni, detritus

eaters) most important

decomposer

ciliates, ameoba mushrooms, mold,

yeast are

decomposers

mosses, ferns,

bushes, shrubs,

trees

Invertebrate

(insects #1)

Vertebrates

(people, etc.)

Some bad

Streptococcus &

Salmonella

algae, protozoans

(malaria),

dinoflagellates

(Pfiesteria)

some molds,

mildews kill

plants

we grow too many

annuals & not

enough perennials

Evolution = genetic change in population over time. The Big Picture

Darwin’s Theory of Natural Selection

Drives evolution & means “nature selects who lives, who dies ” (based on their

adaptations)

nature selects the smartest, fastest, and best camouflaged to live. (these good things

that help animal to survive are called Adaptations)

Medium-sized giraffe

has mostly medium

babies, but there is

genetic variability

Good mutation

causes one to be

much taller

medium babies

If environment changes

(taller trees more common),

then the tall giraffe will be

selected by nature to live &

have babies

D. Shell, SMHS

whichever animals have the best adaptations will live and have babies (most babies

will inherit good adaptations)

4 observations of natural selection

1. Overproduction- organisms have more offspring than will survive to

maturity to ensure some can pass on genes

2. Variation- individuals in a population exhibit inherited variation

3. Limiting Factors limit population- it’s a struggle to survive (competition)

4. Differential Reproductive Success- best adapted breed the most & pass

on traits & new potential variation

Natural Selection can choose certain genes to be successful over others in 3 ways

1. Stabilizing Natural Selection

nature selects those with average traits to survive, extremes die

2. Directional Natural Selection

nature selects those with one extreme variation in trait to survive, average trait &

other extreme creatures die

3. Diversifying Natural Selection

nature selects those with both extremes (big & small) to survive, those with

average traits die

small large average

Size of spiders

Normal variation of

spiders w/ no predators

Variation of spiders w/

selection for average size

(birds eat large, small

can’t get food)

)

)

white color brown color tan

Color of shellfish

Normal variation of

shellfish w/ no predators

Variation of shellfish color

w/ selection for extreme

colors (birds eat average

color on light rocks & on

dark rocks)

Normal variation of

woodpecker beaks w/ no

natural selection

Variation of beak size w/

nature selecting for ability

to get food (long beaks can

get more food in bark)

small large average

Size of beak

D. Shell, SMHS

The Green Anole is from Florida. (green niche) When the brown Anole was

introduced from Cuba it first overlapped the niche of the Green Anole. But

according to Competitive Exclusion, the larger Brown Anole overtook part of

the Green’s niche.

Habitat: where an organism actually lives

Niche: what the organism’s job is in that area

How does one species evolve into two species (Macroevolution)?

Isolation & Change in Environment leads to…speciation Ecological Niche -the role or “job” of an organism in an environment

-range of conditions & resources within which the

organism can live (real niche never as big as it could be

due to competition)

Types of Species in an Environment

1. Native species that normally thrive in that ecosystem

2. Nonnative migrate into or accidentally or intentionally introduced

(exotic) by humans

3. Indicator sensitive species that provide early warning of ecosystem

problems (their #’s go down before other species)

4. Keystone species plays vital role to ecosystem (ex. pollinators)

3 Basic Types of Species Interaction

1. Interspecific Competition

competition between members of two

or more different species for food, space, or any other limiting resource

Competitive Exclusion

similar species cannot occupy the same niche indefinitely, one species

eliminates the other through competition for limited resources

How do species reduce competition?

Resource Partitioning

D. Shell, SMHS

dividing up resources by using at different times, different ways, different places. ex. Owls & hawks -similar prey but hawks feed/day and owls feed/night

Lions & leopards -similar prey, but lions/larger prey & leopards/smaller prey

2. Predation

one species (predator) feed directly on living organism of another species

by pursuit or ambush (removes weakest of prey from population)

since predators must assess prey during pursuit or stalking, their brains

are usually larger than prey animals

Ways to avoid predation

camouflage

chemical warfare

travel in schools or

herds

warning coloration of

poison

deceptive looks & behaviors

shells, speed, flight, smell

3. Symbiosis

relationship in which species live together in an intimate association

a. Parasitism parasite benefits & host harmed similar to predation but parasite is usually smaller

than host, gradually weakens host, & rarely kills host

b. Commensalisms

one species benefits & host doesn’t care

c. Mutualism

both species benefit

ex. nutritional mutualism

Orchid + tree

Lamprey + fish

D. Shell, SMHS

a. Bare rock is exposed.

b. Since there is no soil, LICHENS are first

to appear since they can live on rocks

c. Lichens SLOWLY dissolve rock into sand

d. Plants die & become humus & allow

rooted plants to grow

e. Small plants first, then big ones take over

lichens (fungus + blue-green cyanbacteria)

legume root nodules (N2-fixing bacteria+ plant root)

Succession natural changes & species replacement in an ecosystem over time

1. Primary (1o) Succession (100s-1000s of years)

succession that describes the order of plant & animal species “take-

over” on new land that starts as rock (slowly weathered into soil)

ex.

4. Secondary (2o) Succession (40-200 years)

succession that describes the order in which animals & plants will grow

on existing land that is destroyed by natural disaster, or farming, etc.

MUCH FASTER than 1o succession because environment does NOT

start with bare rock (there is already soil there)

Ex. Yellowstone burns down 1988 (abandoned farms another example)

a. Flowers take over first b. Shrubs and bushes second

Clownfish + sea anemone

Pioneer

Species

D. Shell, SMHS

c. Pine saplings return

d. park returns to climax community

of tall pines & hardwoods

Species Richness = the # of species in a community

varies from one habitat to another (coral reefs & rain forest = high richness)

usually greatest at ecotone ecosystems (transition zone between 2 zones)

isolated islands & mountaintops have least richness – too few niches

the richer the community = more stable (loss of one organism doesn’t affect

whole community) & provide more ecosystem services

Ecosystem services