Chapter 6

Biome

One of the globes’s major ecosystem types, classified according to the predominant vegetation (for terrestrial) and the physical environment (for aquatic) present

• are also characterized by the adaptations of organisms to that particular environment

Climate

The long-term, major weather conditions in an area

• has major influence on the distribution of terrestrial biomes

Climate abiotic factors

1) temperature

2) Precipitation

3) Sunlight

4) Wind

Climograph

Plots the annual mean temperature and precipitation for a particular region

Tropical forests

• Near equator

• High temps with low seasonality

• High rainfall

• Broadleaf evergreen or deciduous trees

• Highest animal diversity

Savannas

1) Near equator

2) High temps with more seasonality

3) Low rainfall

4) Scattered trees, grasses, forbs

5) Fire adapted

Chaparral

1) Midlatitude coasts

2) Cold temps with hot summers

3) Low rainfall with high seasonality

4) Small trees

5) Fire adapted shrubs

Tundra

1) The Arctic and very high mountaintops

2) Very low temps

3) Low to moderate precipitation

4) mosses, grasses, forbs, lichens

Temperate broadleaf forests

1) Midlatitudes

2) Cold winters and hot, humid summers

3) Moderate precipitation all year

4) Deciduous trees in North America

Temperate grasslands, deserts, and Northern coniferous forests (taiga)

Are three terrestrial biomes common in New Mexico

Ecotone

An area of integration between biomes

Oceans

The largest biome, covering 75% of Earth surface

Photic zone

Sufficient light for photosysthesis

Aphotic zone

Little light can penetrate

Pelagic zone

Open water colum

Benthic zone

On the bottom, including organic and inorganic sediments and the benthos

Benthos

Community of organisms

Littoral zone

Near shore

Limnetic zone

Away from shore

Estuary

The transition zone between rivers and the ocean

Thermocline

A narrow layer of abrupt temperature change that separates warm, upper layer from cold, deep water

Oligotrophic lakes

Nutrient poor and oxygen rich

Eutrophic lakes

Are nutrient rich and oxygen poor

Microbiome

The collection of microorganisms living in and on the body

• can differ based on diet, disease, age, host environment, host phylogeny and body region

Biodiversity

Describe the total variety and variability of life on Earth

• considered at three levels

  • Genetic diversity

  • Species diversity

  • Ecosystem diversity

Genetic diversity

Comprises variation within individuals within populations, and between populations

• the variation necessary for adaptive evolution

Species Diversity

Includes the total number of species an their relative abundances in an ecosystem and across the biosphere

• endangered species

• Threatened species

The total variety of different organisms present

• species richness

• Relative abundance

Endangered species

Are in danger of extinction throughout all or much of their ranges

Threatened species

Likely to become endangered in the future

Ecosystem diversity

The variety of ecosystems on earth, including the interactions between organisms and their environment

Species richness

The number of different species in a community

Relative abundance

The proportion of individuals in the community represented by each species

Species area curve

The pattern that the larger the geographic area of a community, the more species it has

Dispersal

Mobility of species can limit diversity in come areas

Biogeography

The study of the geographical distributions of species and cosystems across geographic space and geological time

Cosmopolitan

Wide ranging

They may be habitat or diet generalists, or parasites that are host generalists

Endemic species

Are found in one are and nowhere else in the world

Enderism

Mountains and islands then ti restrict ranges and promote

Community science (citizen science)

Scientific research conducted by members of the public

iNaturalists

(Started in 2008) allows anyone with a smart phone to upload photos or audio of species observed in nature

Global Biodiversity Information Facility

Aggregators that museums send specimens data

Primary Producers

(Autotrophs) ultimately support all other tropic levels

Detritus

Nonliving organic material such as dead organisms and leaves

Detritivores or decomposers

Digest the dead materials and nutrients can be cycled back to producers and consumers

Net Primary Production

The gross primary production minus the energy used by the autotrophs for their own cellular respiration

NPP= GPP - Ra

Net Ecosystem Production

The gross primary production minus the total respiration of all organisms, including autotrophs and heterotrophs in the system

NEP = GPP - Rt

Biophilla

Hypothesis says humans have a sense of connection to nature and all forms of life

Biomass

G

Introduced species

K

Ecosystem services

Include all processes through which natural ecosystems help sustain human life

List the ecosystem services

1) purify air and water

2) detoxify and decompose wastes

3) reduce impacts of flooding

4) control pests

5) create and pressure soils

6) pollinate crops

Bioremediation

Involves using organisms such as prokaryotes, fungi, or plants to detoxify polluted ecosystems by removing harmful substances

Biological augmentation

Uses organisms to add essential materials to be degraded ecosystems

Law of conservation of mass

States that matter cannot be created or destroyed

Biogeochemical cycle

Describes the path an element takes as it moves between abiotic and biotic components

Decomposers

growth is controlled by temperature, moisture, and nutrients

Reservoirs

Where chemical elements are found in and move between

Major: ocean (97%)

glaciers and polar ice caps (2%)

lakes, rivers, groundwater (1%)

Include: fossil fuels, soils, oceans, organisms, atmosphere, and sedimentary rock

Atmosphere: N2 gas (80%)

Limiting nutrient

In plants nitrogen is essential for amino acids, proteins, and nucleic acids

Nitrogen fixations

2 is converted to biologically usable forms by fungi and bacteria

Nitrification

The conversion of ammonia to nitrite and nitrate

Denitrification

The conversion of nitrite and nitrate into N2

Eutrophication

A process in which nutrient concentrations increase and cause increased growth of algae and Cyanobacteria

Fossil

The preserved remains of a once-living organism, often formed when minerals fill the spaces within organic material and create a cast

Trace fossils

Preserve the evidence of life, but not the organism itself (footprints, burrows)

Strata

The position of fossils within sedimentary rock layers that provides a relative age

Radiometric dating

Used to determine the age of rocks and fossils by measuring the abundance of radioactive isotopes within them

Half life

Time require for 50% of the isotope to decay

Geological record

A standard time scale dividing Earth’s history into four eons and further subdivisions

Precambrian

The first three eons that lasted approximately 4 billion years

1) Hadean Eon

2) Archaean Eon

3) Proterozoic Eon

Phanerozoic Eon

the fourth and current eon that includes the last 541 million years

Split into three eras ( which are split into periods then epochs)

1) Paleozoic era

2) Mesozoic era

3) Cenozoic era

Paleozoic Era

541 to 252 MYA

• Starts with the Cambrian Explosion

• major radiations of fungi, arthropods, mollusks, fishes, early tetrapods, conifers

• Colonization of land by fungi, plants, giant arthropods, tetrapods

• Formation of ecosystems including coral reefs, soils, forests, coal beds

Cambrian Explosion

A sudden increase in diversity of lifeforms, including the first appearance of all modern animal phyla

Tetrapods

Four limbed vertebrates

The Great Dying

Mass extinction in the Permian period and the largest recorded extinction event

Permian extinction

Claimed 96% of marine animal species, drastically altered ocean life, and wiped out a substantial number of insect groups

Mesozoic era

252 to 66 MYA

• “The age of the reptiles”

• Begins with a period of recovery and major faunal shifts

• Appearance of major modern groups including angiosperms, insects, mammals, birds

Major radiations of chordates including dinosaurs, crocodiles, turtles, synapsids (ancestors of mammals), and pterosaurs (first with powered flight)

Cretaceous extinction

Wiped out >50% of marine species and major terrestrial animals including dinosaurs (except birds)

Cenozoic Era

66 MYA to present

• “age of mammals”

• Begins with a period of recovery ad major faunal shifts

• Diversification of grasses, mammals, birds, and evolution o modern genera and species

• The Great American Interchange occurred 2.7 million years ago when the isthmus of Panama arose and Nearctic and Neotropical fauna mixed

Cenozoic era

Ends with quaternary period, including two epochs

1) Pleistocene

2) Holocene

Pleistocene epoch

2.6M to 11,700

• glacial-interglacial cycling: alternating periods of the planet cooling (ice ages) and warming

• Anatomically modern humans spread around the globe

• Megafaunal extinctions around the globe, debated whether caused by climate change, human hunting, or both

Holocene Epoch

11,000 ya to present

• all of written human history

• Industrialization and human population increase in last ~200 years

Hadean Eon

4.6 to 4 billion years ago

• water brought from asteroids and comets begins to accumulate

• Surface solidifies into plates sitting on top of magma, moving around via currents

• Organic compounds are interpreted as the first evidence of life on earth

Archaean Eon

4 to 2.5 billion years ago

• first fossil evidence of life

• Oxygen producing bacteria are present and atmospheric oxygen begins to increase

Stromatolites

Layered rocks formed by prokaryotes

Proterozoic Eon

2.5 billion to 541 million years ago

• oxygenation of the atmospheric leads to a shift from anaerobic to aerobic lifeforms

• Eukaryotic life (cells and nuclei) originates 1.8 billion years ago and becomes dominant

• multi cellular eukaryotes emerge 1.3 billion years ago

Precambrian

By the end, fund consisted of soft-bodied organisms with tissues that do not resemble most of modern lifeforms

Speciation rate

Number of species produces in a period of time, also called origination)

Extinction rate

Number of species lost in a period of time

Plate tectonics

How continents are part of large fragments of earths crust, floating on hot mantle below

Continental drift

Currents in the mantle cause plates to move over time

Pangaea

Supercontinent at the end of Paleozoic era

Laurasia

Northern landmass by mid-Mesozoic era

Gondwana

Southern landmass

Mass extinction

When large numbers of species become extinct worldwide at a rate exceeding the typical average rate

Adaptive radiations

The loss of species in ecological roles in which a group diversifies to fill empty niches

Anthropocene

Been proposed as a new geological epoch that highlights the significant impacts humans are having on earth

Threats to biodiversity

1) Habitat loss

2) Over harvesting

3) Global change

Habitat loss

By far the greatest threat to biodiversity is habitat loss, fragmentation, and alteration

Reasons: agriculture, forestry, mining, urban development, pollution, dams and reservoirs, ocean trawling, climate change

Effects: extinction, deceases in population size, genetic diversity

Possible solutions: shift towards plant-based diet, protected lands, restoration, land using planning

Overharvesting