BIOL 3120 Ryan Stork Environmental Science Ch 4-6

Evolution

Change over time

Given as the explanation for why there are so many different kinds of organisms.

Biological evolution

The scientific process of heritable, genetic changes within a population over successive generations, driven by natural selection, mutation, and drift

A change in gene frequencies in a population over time

Who came up with evolution by natural selection?

Charles Darwin and Alfred Russel Wallace both came up with it indpendently of each other in 1858, and Darwin detailed it further in his book "On the Origin of Species".

Natural Selection

Organisms become better adapted to their environment; those that adapt are more likely to survive and reproduce

Adaptation

The process by which an organism becomes better fit to its environment; This includes concepts like the longer term selection of natural gene process and is a product of evolution.

Theories that must be accepted for the hypothesis of evolution to be true

The answers to these questions must be yes, or the hypothesis is rejected

Is there variation in the feature of interest?

Is at least some part of that variation heritable?

Does that heritable trait influence fitness? Can the organism survive and then pass on the gene

Is there a conflict between science and religion?

There is a conflict between the interpretations of both

Methodological naturalism

Natural explanations are required for natural observations

Teleological / Absolute Naturalism

Only things in the physical world are real

(Science requires methodological, but does not require teleological)

Abiotic Factor

Abiotic factors are the non-living parts of an organism's habitat. Things like light, temperature, pH, nutrients.

Biotic Factors

living elements of an organism, including predation, competition, consumption, parasitism, disease, etc.

Stochastic Factor

Can be either biotic or abiotic, and is randomly determined. An example would be an organism being struck by lightning.

Critical Limits

A limiting or critical factor is in the shortest supply relative to the demand. Has minimum and maximum tolerance limits.

Optimum / Optimum Range

The range of optimal values of a variable in which an organism is able to thrive

This varies for different developmental stages of an organism.

Zone of Physiological Stress

Outside of the optimal zone, but not quite in the fatal zone. The organism is able to survive, but in a stressed state.

Indicator species

a species that has narrow tolerance limits and shows that there is an issue before other species in an ecosystem begin to suffer.

Habitat

the place where the organism currently exists

Ecological niche

The theoretical space that predicts where organisms will survive

Generalist

has a wide ecological niche

Specialist

very small ecological niche, can tend to be an indicator species

Can two species occupy the same ecological niche?

No two species can occupy the exact same ecological niche at the exact same time, which means that they will end up in competiton with each other.

Competitive exclusion

When one species removes another to occupy the ecological niche

Resource partitioning

The division of limited resources by species to help avoid competition in an ecological niche

Speciation

The development of a new species

Allpatric speciation

Where there is geographic isolation, adaptation can follow because of the physical separation

Sympatric speciation

When a new species evolves in the same geographic location, driven by things like reproductive isolation or niche differentiation

Directional Selection

Where ONE extreme can become more abundant in the next generation

Stabilizing Selection

Selective pressures that opt towards the moderate option, does not introduce much variation into the population

Disruptive selection

Two extremes are focused on at the same time, and the moderate form is left behind.

Taxonomy

The subdivision of biology focused on classifying and naming organisms or species

Taxon

any particular group within a taxonomic system

Dear King Philip Came Over For Good Soup

Do Kind People Care Only For Good Snacks

Dumb Kids Prefer Chocolate Over Fresh Green Salad

Life

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

Subdivisions?

T or F

Every Taxon above the species is based on hypothesized connection of similarity

True

In addition, things above the species can be potentially moved around if a greater similarity is found or discovered

Taxonomy basics

Binomial nomenclature

Genus is capitalized

Specific epithet is lower case

Both italicized or underlined

Latinized

Who was the creator of the taxonomy system?

Carolus Linnaeus - 1707 to 1778

Swedish botanist

Known as the father of taxonomy

Systema Naturae was the book that he wrote detailing the classification system

Ecology

the study of interactions of individuals with things around them

Population

A group of individuals of the same species in a given time and space

Can potentially interbreed with each other - gene flow

Share common resources

Exposed to similar environmental conditions

Community

A group of all the populations in the same time and place

Ecosystem

A biological community of interacting organisms and their physical environment.

Biome

A group of ecosystems that share similar climates and typical organisms

Biosphere

Consists of all life on Earth and all parts of the Earth in which life exists, including land, water, and the atmosphere.

Competition

-/-

Negative / Negative interaction where two individuals are competing for the same resources

Resource

some substance that can be used up and made unavailable

Intraspecific competition

When a bunch of individuals of the SAME species are competing for the same resources

Interspecific competition

Competition between two different species for the same resources

Predation

+/-

When one animal kills and eats and consumes all or one part of another

Evolutionary arms race

When two species adapt back and forth to develop traits that allow them to hunt or to escape being hunted

Coevolution

When two species influence each other's evolution over time.

Does not have to be an arms race; it can be cooperative or competitive as well.

An Arms Race is always a form of coevolution

Batesian mimicry

a harmful species with a specific physical appearance (like coloration) is copied by a nonharmful species

Mullerian mimicry

Both species evolve to look the same, and they are both toxic

Top-down regulation of a community

Effects of a predator change the community composition

Bottom-up regulation of a community

Prey control the predator populations

Symbiosis

A close relationship between two species that benefits at least one of the species.

Has three forms: Mutualism, commensalism, and parasitism

Mutualism

+/+

Both species benefit in some way

Commensalism

+/0

One benefits, but the other is essentially unaffected by the relationship

Parsitism

+/-

Another form of predation, but the creature does not eat the other

Keystone species

One that has a greater influence on its community than its numbers would suggest

Ecosystem engineers

species that create or maintain habitat for other species

Species abundance

The number of individuals of each species

Species richness

the number of different species in a community

Eveness

distribution of individuals among the different species

Diversity

balance and measure of richness and evenness

Spans multiple levels: molecular, species, ecosystem

Greater diversity often leads to greater stability

Ecological Structure

the physical arrangement of individuals within a community

Random Distribution

distribution in which the location of members in a population is totally random, location of each individual is determined by chance

Uniform Distribution

every individual is equally spaced from other individuals, gives a tendency towards territorialism or competition

Complexity

The number of trophic levels. Not to be confused with ecological structure

Community properties

characteristics of a community that influence how that community functions and how it affects the surrounding ecosystem

Primary productivity

The rate at which producers convert sunlight into chemical energy through photosynthesis

Net Primary Productivity (NPP)

Total amount minus the cost of living

The amount of energy plants store as biomass after they use some for their own respiration, which in practice ends up being the energy available to the rest of the food web.

(Tropical rainforests and coral reefs have the highest productivity)

Secondary productivity

When the NPP is consumed

Biomass

physical mass of the organism

Ecological succession

Changing structure over time

Primary succession happens through:

Pioneer species - the very first species that moves in. Can be a relatively simple species but it will modify the environment it is moving into.

Pioneer community - the first group of organisms that can live in the virgin area

Eventually gets replaced by a more competitive community, which is an ongoing process until the best fit for that habitat is the one that is left

Secondary succession

when disturbances clear a spot, new organisms move in

Climax community

the winner, best fit, cannot be outcompeted or pushed out

Rarely exists in the real world, requires that there is a stable environment which is not common. More of a theoretical community

Disturbance

Disrupts established patterns of communities

Resilience

The ability to recover after a disturbance

(Greater diversity generally leads to a more resilient community)

Intermediate disturbance hypothesis:

If you have very few disturbances, then you are closer to reaching a climax community, which usually does not have very much diversity

Terrestrial biomes

Share similar climate, topographic, and soil conditions, and biology

Temperature and precipitation are the two most abiotic factors that determine what biome you are looking at

Biogeography

Subdivision of biology and ecology that focuses on where things live and why they live where they live

Tropical Rainforest

Humid regions in the tropics; complex and biologically rich

>80 inches of rainfall per year

Warm to Hot; Fairly constant - 27.5 C Ave. Temperature

Thin, acidic, and nutrient poor soils

Water washes away everything that is not tied down, nutrients in the soil and the soil itself can get washed away

90% of the nutrients are tied up in the biomass/living organisms

½ to ⅔ of terrestrial plant and animal species are found in the tropical rainforests

Similar to cloud forests where fog and mist keep vegetation wet

Temperatures and biodiversity in cloud forests tend to be much lower, and are similar to temperate areas. Because of the abundant moisture and that they are secluded up in the clouds, you often find animals that you cannot find anywhere else.

Tropical Seasonal Forests

Tropical regions with wet and dry seasons and constant hot temperatures

Brown and dormant until rainy season

Drought deciduous plants - meaning that they drop leaves during certain environmental seasons, like when it is dry.

Few remain - people have removed them during the dry seasons because they did not understand that they were not dead in the dry seasons

Soil more productive than tropical rain forests

Tropical Savannas and Grasslands

Grassland with few trees

Rainfall amounts don't suppress forests

Dry season is prone to fire

Plants with deep, long lived roots

Survive drought, heat, and fire

Migratory grazers common

Desert

Defined by very low water variability

Dry hot days and cold nights

<10 in (25 cm) of rain/yr

Soil is thin and porous

Feedback loop of not having plants and not holding water, wind blows away nutrients when it is dry for a very long time

Widely scattered thorny bushes and shrubs; Cacti

Too valuable to lose the accumulated nutrients and biomass

Rodents, lizards, snakes, insects, owls, hawks and small birds

All very specifically adapted animals that allow them to deal with the challenges

Found in N & SW Africa; Middle East; Asia; SW North America

Temperate Grassland

Seasonal Rainfall 10-60 in (25-152cm)/yr

Fires are frequent because there may be dry seasons

While there is sufficient rainfall for trees, fires eliminate these trees. Additionally, these areas being full of grazers prevents the trees from growing as well.

Soils are rich and deep

Grasses; scattered shrubs and trees

Large grazing mammals; prairie dogs; coyotes; lions; termites important

Central NA; Central Asia; Subequatorial Africa and SA; S India; N Australia

Temperate (Mediterranean) Shrubland

Warm, dry, and cool, moist winters

Evergreen shrubs, scrub oaks, and pines

Fires a major factor in plant succession

There can be seasonal and long term succession

Also referred to as chaparral

High number of unique species

Mediterranean Coast, SW Australia, Central Chile, And S America

Temperate Deciduous Forest

Seasonal; below freezing winter and warm summer

30-80 in (76-200cm)/yr

Broad leafed deciduous trees; some conifers; shrubby undergrowth; ferns; mosses

W & C Europe; E Asia; E N America

E Half of N America was covered; settlers cut much of it down

Some areas have regrown but with different dominant species

Temperate Rainforest

Cool, rainy forests often foggy

Condensation in canopy major precipitation in understory

Mild temperature year round and abundant rain >200cm/yr

Coniferous forests of Pacific Northwest and Redwoods in California

Very heavily covered in mosses and ferns that thrive in the wet environment

Boreal Forest

Northern Coniferous forests

Between 50 and 60 N Latitude

Pines, hemlock, spruce, cedar, and fir with some deciduous mixed in

Taiga, Northern edge of boreal forest, essentially has nothing but conifers in it

Extreme cold and short summer limit growth rate of trees, also has lower light

Many animals are migratory in this region, and are adapted to the cold low light areas

Tunda

If you continue North of the boreal forests, you enter into the Tunda

Treeless landscape at high latitudes and high altitudes

Short growing season because of the low light and cold temperatures

Frost any month

No trees

Water is frozen and unavailable most of the year

Permafrost located here doesn't mean that all of the soil is frozen. Soil on the very top may not be frozen, but further below the surface is where the permafrost might be located

Marine Ecosystems

Oceans cover 75% of earth's surface

Algae and phytoplankton main primary producers

Greatest productivity near coasts - nutrients wash into ocean

Dead organisms fall to floor and used by deep ocean ecosystems

The marine snow is enough organic material to support life in the deep sea

Upwelling currents circulate nutrients

Vertical stratification a key feature - different strata of the ocean have very different characteristics

Light and temperature decrease with depth

Cold water holds more oxygen than warm water - productivity often high in cold water

Benthic Region

bottom of the ocean, sediment layer

Pelagic Region

The water column above the bottom

Littoral or Intertidal Zone

Near the shores, next to land

Epipelagic or Euphotic Zone

(Inside the Pelagic zone)

The uppermost layer of the ocean where there is sunlight and goes about 200 m deep. Is supported by algae and other things that require photosynthesis

Mesopelagic Zone (Twilight Zone)

(Inside the Pelagic zone)

only about 1% of sunlight is able to reach this zone, photosynthesis is not much of a player here, although animals will migrate up to take advantage of the the plants there

Bathypelagic or Bathyl Zone

dark, cold, high pressures

Abyssal Zone

between 4000 and 6000 meters below the surface

Hadal zone

6000-11000 meters below the surface, typically found in deep trenches

Coastal Zones and Coral Reefs

Vary with depth, light, temperature, and nutrient concentration

Coral reefs

Calcium skeletons of coral polyps build up reef

Symbiotic relationship between coral and zooxanthellae

Shallow water - light must penetrate

Biodiverse and economically important

Coral bleaching a problem

Mangroves / Mangrove Swamps

Mangrove trees grown in saltwater along tropical coastlines

Helps to stabilize shoreline and prevents erosion

Nurseries for fish and other animals

Can be cut for timber