Introduction to Ecology

1
Introduction to Ecology
Reading Ch. 50 (1125-8 1133-4 1142-46 skim
1128-39) Introduction, today Ch. 52
Population ecology, today and M Ch. 54
Ecosystem ecology, WF

• Outline of Lecture
• 1. Levels of ecology
• 2. Biomes
• Climate - temperature and water
• Dominant species
• Terrestrial and aquatic
• 3. Factors affecting species distributions

2
What is ecology?

• Ecology is the study of how organisms interact
  with their environment
• What factors control the distribution and
  abundance of organisms?
• Eco from Oiko home

3
1. Types of Ecology

• Organismal (physiological and behavioral)
• Population
• Community
• Ecosystem
• Global

4
Organismal ecology

• Questions center on how organisms respond to
  biotic and abiotic factors in their environment
• Physiology, morphology, and behavior

5
Population ecology

• a population is a group of organisms of the same
  species living in the same place at the same
  time.
• questions are related to factors that affect the
  number of individuals living in a habitat
• size, distribution of population?
• - birth and death rates?
• - population growth rate?

6
Community ecology

• a community consists of the organisms that live
  in an area and interact
• questions focus on
• the interactions between organisms (who competes
  with who, who eats who, who helps who)
• how those interactions affect community structure
  (number of species in a community, relative
  abundances of species in a community)

7
Mutualism
Competition
Species Interactions
Predators and parasites
8
Community structure

• What factors affect community structure?
• Factors abiotic (e.g., climate, dist.) and
  biotic (species interactions)
• Community structure species composition, number,
  abundance

California serpentine grassland and adjacent oak
savannah
9
Ecosystem ecology

• an ecosystem consists of the biotic (living)
  community and the abiotic (nonliving) factors
  that affect it.
• abiotic factors are things such as soil,
  atmosphere, water, nutrients, energy, temperature
• questions emphasize energy flow and cycling of
  nutrients

10
Soil nitrogen cycle
litter
decomp.
Bacteria and fungi
uptake
NO3-
mineralization
NH4
nitrification
11
Global ecology
Atmospheric CO2 and Temp.

• Controls and patterns of worldwide circulation of
  energy and nutrients

CR Fig. 54.26
12
2. Biomes

• Aquatic environments
• - Freshwater lakes, wetlands, streams
• - Saltwater ocean
• - Mixed estuaries
• Terrestrial environments
• 14 biomes
• - temperature moisture averages and seasonal
  variability

13
Terrestrial Biomes
Determined by climate latitudinal patterns
local effects. Based on dominant vegetation type
Characteristic life forms. Gradation in
boundaries ecotone.
Fig. 50.9
14
Biomes

• Regions of the earth that are similar in organism
  type although the particular species differ
• Driven largely by climate temp., water,
  seasonality
• Other factors soil, topography

Fig. 50.10 Biomes of North America
15
3. What factors affect the distribution of
organisms?

• species dispersal
• biotic factors other organisms such as
  predators, competitors, or facilitators
• abiotic factors such as nutrient availability,
  water, temperature, and disturbance regime.

16
For Chapter 50 (see also the rest of this
powerpoint)

• Focus on
• What are the differences between different levels
  of ecology?
• What are the two main factors affecting types of
  aquatic habitats? How do they influence light
  and oxygen availability? What areas are the
  tropical forests (e.g., very productive) and
  deserts of aquatic habitats? Why?
• For the six terrestrial biomes described,
  understand how temp and moisture interact to
  determine the dominant species types and levels
  of productivity, but you dont need to know all
  the details of each biome.
• What is the difference between biomass and
  productivity?
• How do history (dispersal), species interactions,
  and the abiotic environment affect the
  biogeographic patterns of species? What is an
  invasive species?

17
Note

• The following figures are mostly from Chapman and
  Reese 7th Ed., but your book has many similar
  figures. You should be able to understand the
  processes illustrated independent of the specific
  illustration.

18
What affects the distribution of organisms?
Fig. 50.5
19
Species dispersal
Species may not inhabit an area because of
biogeographical boundaries.
Fig. 50.6
20
Example Arctic Treeline
Farthest north spruce
Fig. 54.17 - C cycle feedback
21
- breakdown in dispersal barriers- most do not
cause problems- some do- problems can be large,
expensive, and difficult or impossible to
reverseSee cheatgrass example in the Freeman
textbook.
Application Invasive species
Fig. 50.8 Zebra mussel
22
Behavior and habitat selection

• organisms do not always occupy all available,
  suitable habitat
• may be specific in reproduction needs
• larval needs may be different from adult needs

23
Biotic factors

• interactions with other organisms
• Negative predation or competition
• Positive facilitation (e.g., pollinators

Fig. 50.9
urchin barrens
24
Biotic and abiotic factors adaptations
Tolerate
Avoid
Predation - Aposematic coloration
Predation Cryptic coloration
Dry conditions - cacti
Dry conditions spring annuals
25
Abiotic factors

• temperature
• high temperature cause cell membranes to leak and
  enzymes to stop working
• low temperature causes freezing
• some animals have antifreezes that allow them to
  survive below freezing temperatures.

Fig. 27.1 thermophilic bacteria, Nevada
Cool arctic fish (spp.?)
26
Abiotic factors

• water availability
• too little water (desiccation)
• Deserts, saltwater
• too much water (anaerobic)

Mangroves
Organ pipe cacti, desert shrubs
27
Abiotic factors Water availability

• All terrestrial organisms

Insects tolerate, cuticle
Leaves, stomata
Worms avoid, behavior
28
Abiotic factors Water availability
And aquatic organisms too!
Freshwater
Saltwater
29
Abiotic factors

• Sunlight
• Competition, shade tolerance for plants
• Photic zone, different wavelengths for aquatic
  organisms

Fig. 50.23
Fig. 50.18
30
Abiotic factors

• Wind
• exacerbates the effects of temperature and water
  loss
• also exerts forces on organisms (waves act in the
  same manner)

krummholz
31
Abiotic factors

• rocks and soil
• substratum type
• nutrient availability
• pH

32
Combinations of factors

• barnacle distribution in the intertidal-predation
  from below, desiccation from above