Biology 1B - Ecology

Key sections to look for in scientific papers

1. Title

2. Abstract

3. Introduction

4. Methods

5. Results

6. Discussion

7. References

8. Acknowledgments

CREATES Method

Consider the introduction

Read and annotate the methods and results

Elucidate the hypothesis

Analyze and interpret the data

Think of the next Experiment

Synthesize

What is the purpose of a scientific paper?

Communicate results to scientific community to be evaluated, researched, build upon, and replicated.

What is the main goal of the Introduction section of a scientific paper?

Provides background information, define research question and hypothesis.

Stream ecology

Study of interactions between aquatic organisms and their abiotic environment.

Riparian zone

Area along the banks of a stream or river

Healthy creeks

• Runs, riffles, and pools with diverse communities

• Vegetation

• Riparian buffer zone

• Clear, flowing water

• Lots of bends

• Woody debris

Unhealthy creeks

• No flow

• No curves

Why is a diverse creek structure important for stream health?

Diverse structure supports different habitats which supports biodiversity.

What are two types of pollution that negatively impact creek ecosystems?

Organic and inorganic pollution

2 methods to test water quality

• Chemical sampling (abiotic)

• Bioindicator (organisms) sampling (biotic)

Bioindicators advantages

• Reflect long term conditions

• Sensitive to discrete events

• Wide range of tolerances to pollution

• Numerous, high diversity

%EPT

Found in unpolluted streams

Family Biotic Index (FBI)

Represents organism’s tolerance to pollution

Taxon richness

• # of unique taxa in a sample of bioindicators

• Alpha diversity: Taxon richness at one location

• Beta diversity: Difference of taxon richness between two sites

Shannon Diversity Index

• Relative abundance of the different taxa present in a community

• Combines taxon richness and evenness

• Greater evenness = greater water quality

6 major biome types

• Freshwater

• Marine

• Desert

• Forest

• Grassland

• Tundra

3 freshwater types

• Ponds + lakes

• Streams + rivers

• Wetlands

Freshwater biome

• <1% salt concentration

Ponds and lakes (freshwater biome)

• Limited species diversity

• 3 zones

  • Littoral zone: Algae, insects, fish

  • Limnetic zone: Plankton

  • Profundal zone: Heterotrophs

Streams and rivers (freshwater biome)

• Flows in one direction

• Source: Cooler than mouth, clearer water, higher oxygen levels, trout + heterotrophs

• Middle region: Increased width → Increased species diversity, plants + algae

• Mouth: Unclear water from sediments, less light → Less flora diversity, lower oxygen levels, catfish + carp

Wetlands (freshwater biome)

• Water on surface (Marshes, swamps, bogs)

• Highest species diversity of all ecosystems

• Plants adapted to humid conditions: Hydrophytes

• Not all are freshwater bc of high salt concentration

3 marine types

• Oceans

• Coral Reefs

• Estuaries

Oceans (marine biome)

• Largest ecosystem

• 4 zones

  • Intertidal: Ocean meets land

  • Pelagic: Open ocean, generally cold

  • Benthic: Below pelagic, depth increase → Temperature decrease

  • Abyssal: Deep ocean, very cold, high pressure, high oxygen

Coral reefs (marine biome)

• In warm shallow waters

• Corals get nutrients from algae

Estuaries (marine biome)

• Where freshwater merge with ocean

• Diverse species

Desert biome

• Rainfall < 50cm/year

• Nonmammalian vertebrates (ex. reptiles) are most common

4 desert types

• Hot and dry

• Semiarid

• Coastal

• Cold

Hot and dry (desert biome)

• Mean annual temp 20-25°C

• Atmosphere has little humidity → Extreme temperatures

• Course, shallow, rocky soil w/ good drainage

Semiarid (desert biome)

• Summer temps 21-27°C

• Does not go above 38°C

• Evening temps 10°C

• Sandy, fine or loose rock or gravel soil

• Low salt concentration

• Spiny plants provide shade → Reduce transpiration

• Plants have glossy leaves → Reflect energy

Coastal (desert biome)

• Moderately cool → Warm

• Avg summer temp 13-24°C

• Winter temps <5°C

• Fine soil that is porous + good drainage

• Moderate salt content

• Plants have extensive root systems

• Plants have thick leaves to store water

Cold (desert biome)

• Cold winter w/ snowfall and high rainfall

• Heavy + salty soil that is porous + drainage

3 forest types

• Tropical

• Temperate

• Boreal (taiga)

Tropical forest

• Greatest diversity of species

• No winters, only rainy or dry

• Avg temp 20-25°C

• Nutrient-poor + acidic soil

• Multiple layers of canopy

4 types of tropical forests

• Evergreen: No dry

• Seasonal: Short dry period

• Semievergreen: Longer dry season

• Moist/Dry Deciduous (Monsoon): Rainfall decreases → Longer dry season

Temperate forest

• Distinct winter, moderate climate

• Fertile soil

• Moderate dense canopy

5 types of temperate forests

• Moist conifer and evergreen broad-leaved: Wet winters + dry summers

• Dry conifer forests: Higher elevation zones, low precipitation

• Mediterranean: High precipitation in winter

• Temperate coniferous: Mild winters, high annual precipitation

• Temperate broad-leaved; Mild winters, high precipitation

Boreal/taiga forest

• Largest terrestrial biome

• 50-60°N

• Very low temps

• Thin, nutrient-poor, acidic soil

• Low-light penetration

2 types of grasslands

• Savanna

• Temperate grasslands

Savana (grassland biome)

• Scattered trees

• Hot climates

• Concentrated rainfall → Drought

• Climatic savannas, edaphic savannas, derived savanna

• Porous soil with rapid drainage

• Fires often

Temperate grassland

• Grassy

• Hot summers, cold winters

• Moderate rainfall

• Dark soil w/ fertile upper layers

• Few shrubs and trees

Praries

Grasslands w/ tall grasses

Steppes

Grasslands w/ short grasses

Tundra

• Coldest, little precipitation, poor nutrients

• 2 major nutrients: nitrogen + phosphorus

• Low biotic diversity

2 types of tundra

• Arctic

• Alpine

Arctic tundra

• Desert-like

• Soil forms slowly

• Permafrost: Layer of frozen soil

• Plants group together to resist cold

• Plants reprove by budding + division

Alpine tundra

• At high altitude, no trees