New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

Ecology, Week 3

by: Rheanna Gimple

Ecology, Week 3 LIFE 320

Rheanna Gimple

Preview These Notes for FREE

Get a free preview of these Notes, just enter your email below.

Unlock Preview
Unlock Preview

Preview these materials now for free

Why put in your email? Get access to more of this material and other relevant free materials for your school

View Preview

About this Document

Biomes and Natural Selection
Dale R Lockwood
Class Notes
Ecology, Genetics, biomes, Biology, evolution, animal, Science
25 ?




Popular in Ecology

Popular in Biology

This 6 page Class Notes was uploaded by Rheanna Gimple on Monday September 19, 2016. The Class Notes belongs to LIFE 320 at Colorado State University taught by Dale R Lockwood in Fall 2016. Since its upload, it has received 7 views. For similar materials see Ecology in Biology at Colorado State University.


Reviews for Ecology, Week 3


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 09/19/16
Biomes  Facet of Ecology: Natural History o Fundamentally descriptive o Study how organisms influenced by climate, soils, predator, competitors, and evolutionary history o Another example of natural history is most of genomics:  Natural history of genome  Describing genetic patterns  Species range o Species have range of conditions over which they can survive  Edaphic factors: properties of soils (i.e. moisture, geologic origin, etc.) that influence plants o Species perceive quality of conditions from optimum to poor  I.e. sugar maple found around great lakes due to weather and soil conditions o Species independently distributed  Drier to wetter environments have species overlap but not clustered together  Biomes: major vegetation divisions o Influenced by physical properties of the environment o Simplify to generalize, but no two ecosystems are exactly alike  Goal is to capture  Explain similarities and differences among  Convergence o Organisms evolve similar traits in response to common environmental conditions:  Organisms may be unrelated, or related  But evolutionary response is independent o Similar adaptive responses emerge in response to particular selective conditions  I.e. mangroves - thick, leather leaves, root projections, viviparity  Condition/place not plant  Convergent evolution  Can be different families genetically w/ diff. evolutionary pathways, but are similar due to similar environments  Biome concept o Character of natural of natural communities is determined by climate, topography and soil: physical factors o Because of convergence, similar dominant plant forms occur under similar conditions o Biomes are categories that group communities by dominant plant forms o Life is not so simple  Interactions of many kinds, chance, history also critical in determining the distribution/abundance of organisms o Annual precipitation and average temperature are basic factors for biomes  When temp changes and rain comes is also important  Tundra o Cold and dark much of year o Arctic tundra encircles earth just south of ice-covered polar seas in N Hemisphere  Covers about 20% earth's land surface o Arctic tundra has extremely long, cold, and harsh, short summers (6/8 weeks) o B/c rainfall amounts to only about 20 cm a year, tundra could possibly be considered desert  Coniferous forests - dominated by gymnosperms o Coniferous forests are found in 3 locations  Taiga  Near mountaintops  Along pacific coast of N America  Temperate deciduous forests have abundant life o Temperate deciduous forests  Found S of Taiga in E. N. America, E. Asia, and much of Europe  Seasons well defined, and growing season ranges between 140 and 300 days  Temperate grasslands have extreme seasons o Temperate grasslands  Include Russian steppes. S. American pampas, and N. America prairies  Bitterly cold winters and hot dry summers  Savannas - grasslands in tropics o Savannas - in regions where a cool dry season is followed by hot rainy season  Largest savannas in Central and S. Africa  Others in Australia, SE Asia, and S America  Deserts o Deserts usually found at latitude of about 30 degrees in both N and S hemispheres  Winds that descend in these regions lack moisture, and the annual rainfall is less than 25 cm  Days are hot because of lack of cloud cover - allows sun to penetrate easily  Night cold because heat escapes easily into atmosphere  Tropical rainforests are warm with abundant rainfall o Tropical rainforests of S America, Africa, and Indo-Malayan  Temperature always warm (20-25)  Lots of rain (min 190 cm/yr.) o May be richest ecosystem  Diversity of species is enormous  Topography and other effects also influence climate o Topography: surface of land  Mountains are topographic features that affect climate, and distribution of ecosystems  Difference between the windward side and the leeward side can be dramatic  Ex: Hawaiian Islands  Windward receives more than 750 cm of rain a year Leeward side, which is in a rain shadow, gets on the  average only 50 cm of rain and is generally sunny  Going up in altitude very similar to going north o Nearby bodies of water  Ocean Temperature is more stable than landmasses  Ocean water gains or loses heat more slowly than terrestrial environments  Monsoon climate - wet ocean winds blow onshore for almost half the year o Important trivia  What is land surface area of the earth: 150 million km2  What biomes occupy most land area  Moisture gradient: mesophytic forest -> oak-hickory forest -> oak woodland -> prairie -> dry grasslands -> desert  Temperature gradient: tropical forest -> subtropical -> temperate deciduous ->temperate mixed-boreal forest -> tundra  Aquatic ecosystems o Aquatic ecosystems vary in size, physical properties, and biological systems o Key components to consider:  Light  Depth: less light penetrates the farther down you go  Temperature  Movement (currents, tides) Oxygen content (determined by latter two)   Productivity  Amount of photosynthesis  Dissolved salts o Streams  Pools  Tend to have more life than places with strong currents  Riffles o Lakes  Basins that collect water  Physical features:  Stratified (layered) with respect to  Light penetration  Temperature  Temperate lakes cold water sits on bottom w/ sharp divide b/t warm water on top  Oxygen  biological activity is also stratified in water o Lakes Ponds and Oceans  Littoral zone:  In lakes: shallow area at edge with rooted vegetation  In oceans: region between high and low tides Limnetic zone: open water, gets enough light for photosynthesis   Benthic: sediments and subsurface layers below limnetic o Oceans  Littoral zones: shallow area at edge = intertidal  Neritic zone: beyond low tide zone out above continental shelf  Oceanic: past continental shelf  Photic: with light for photosynthesis  Aphotic: insufficient light, depends on nutrient rain  Pelagic zone: region of ocean not near shore on the bottom  Demersal zone: region of water near and influenced by benthos (benthic zone)  Intertidal zone:  Rocky intertidal has more complexity than typical intertidal  Tide pools  Coral reefs  Similar to biodiversity of rainforests  Vertical structures  Different light levels  Pelagic zone  Very stratified- not really nutrient upwelling  A lot of animals move through zone to get calories  Move great distances  Demersal zone  Mostly invertebrates  Streams and rivers  Key features:  Move  High oxygen  Depend on movement, temperature, pollution  Dissolved nutrients and sediments come from land  Light varies  River continuum  Organic matter and nutrients come from headwaters  Streams are primarily allochthonous - production dominated from outside material  Nutrients 'spiral' downstream to rivers  Rivers primarily autochthonous - algae dominate production (fed by nutrients)  Water warmer and slower  Estuaries at mouths of rivers  Brackish waters (part salt part fresh)  One of most productive habitats on earth  Nursery for many fisheries from crabs to fishes  Antarctica only continent with no river systems  Australia has 1 Evolution  evolution: change in allele frequency in a population from one generation to the next  macroevolution: large-scale changes that lead to speciation or higher level diversification o Large scale patterns in nature  microevolution: small-scale changes within populations over time o Underlying processes and mechanisms  Gene: Sequence of DNA that species cell structure, including proteins and several types of RNA o Genes do not always produce the same phenotype: gene regulation and modification is important  Allele: an instantiation of a gene  4 mechanisms of evolution o Selection o Genetic drift  Random changes in allele frequencies from one generation to the next Larger impact on small populations   All alleles either go to fixation or loss eventually  If operating only under drift  Reduces genetic diversity o Mutation  Basic source of novel variation  Increases genetic diversity o Migration  Increases diversity as gene flow enters a population  Natural selection o Evolution by natural selection described by Darwin and Wallace o Mechanism eluded them  Mendel's paper was forgotten for years o 4 postulates of evolution by natural selection  Individuals within a population show variation in a trait  Some of the variation is inherited by offspring (heritable)  Individuals have differential reproductive and survival success  Survival and reproduction are not random with respect to the trait: individuals that survive and reproduce have the most favorable variations o Selection  directional selection (incomplete dominance)  One allele is favored  Allele is driven to fixation with the loss of other alleles  Favors one extreme  balancing selection (over dominance)  Heterozygote is more fit than either homozygote  Ex: sickle cell anemia  Both alleles are maintained in population  Favors average traits  disruptive selection (under dominance)  Heterozygote is less fit than homozygote  Don’t see very often  Favors both extremes  Properties of populations o Population is a group of organisms of the same species that share a specific area o Populations evolve in response to natural selection o Study of natural selection will provide foundation for studying population ecology  Ex: finches on Galapagos islands  Bigger beaked birds eat bigger seeds, smaller beak depth smaller seeds  Population correlates with seed abundance  Harder seeds select for bigger beak size  Wetter season lots of small seeds produced  As environment changes so does selection  Natural Selection o Genotype: the genetic makeup of an individual o Evolution: changes in genetic makeup of a population o Natural Selection: if well suited to environment organism tends to have more offspring  Can help drive adaptations in an environment  Phenotypic plasticity: modifies organisms over time based on phenotype  Genetics and environments go hand in hand


Buy Material

Are you sure you want to buy this material for

25 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Bentley McCaw University of Florida

"I was shooting for a perfect 4.0 GPA this semester. Having StudySoup as a study aid was critical to helping me achieve my goal...and I nailed it!"

Amaris Trozzo George Washington University

"I made $350 in just two days after posting my first study guide."

Bentley McCaw University of Florida

"I was shooting for a perfect 4.0 GPA this semester. Having StudySoup as a study aid was critical to helping me achieve my goal...and I nailed it!"

Parker Thompson 500 Startups

"It's a great way for students to improve their educational experience and it seemed like a product that everybody wants, so all the people participating are winning."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.