Lecture 4 The Distribution of Life: Physical and Biological

Lecture 4 The Distribution of Life: Physical and Biological

I. The Physical Environment A. Light B. Temperature C. Moisture D. Environmental Gradients and Species Niches II. Biological Interactions A. Predation B. Competition C. Symbiosis D. Physical and Biological Controls at work

1 Lecture 4 The Distribution of Life

I. The Physical Environment A. Light Light

6CO2 + 12H2O C6H12O6 + 6H2O +6O2 Carbon Water Sugar Water Oxygen Dioxide

Lecture 4 The Distribution of Life

I. The Physical Environment A. Light

Sciophyte Heliophyte

(Adiantum aleuticum) (Salvia leucophylla)

2 Lecture 4 The Distribution of Life

I. The Physical Environment A. Light Adaptations for living in high or low light intensities.

1. Physiological

Lecture 4 The Distribution of Life

I. The Physical Environment A. Light Adaptations for living in high or low light intensities.

2. Morphological

(Arctostaphylos patula) Sciotrophic

(Yucca schidigera)

3 Lecture 4 The Distribution of Life

I. The Physical Environment A. Light Adaptations for living in high or low light intensities. 2. Life history and reproductive behavior

Ex. annuals

Lecture 4 The Distribution of Life

Distribution of Earth’s Forests

4 Lecture 4 The Distribution of Life

I. The Physical Environment B. Temperature 1. Plants (poikilotherms)

Lecture 4 The Distribution of Life

I. The Physical Environment B. Temperature 1. Plants (poikilotherms) Plant adaptations to cold temperatures: a. Deciduous leaves (maple, beech, birch, and ashes) b. Supercooling and extracellular water loss (pine, spruce, and fir trees) c. Heat re-radiation (saguaro cactus)

a. b. c.

Spruce tree Big maple (Picea sp.) (Carnegiea gigantea) (Acer macrophyllum)

5 Lecture 4 The Distribution of Life

I. The Physical Environment B. Temperature 1. Plants (poikilotherms) Plant adaptations to warm temperatures: a. Dimorphic leaves (sage scrub in southern California) b. Waxy leaves (any cactus) c. Water storage capacity (cactus, baobab tree, etc.)

Baobab Tree (Adansonia digitata)

Sagebrush (Artemesia californica)

Lecture 4 The Distribution of Life

I. The Physical Environment B. Temperature 2. Animals Poikilotherms - a.k.a.ectotherms (fish, reptiles, amphibians) Homeotherms – a.k.a. endotherms (birds and mammals)

Antarctic icefish San Joaquin Kit Fox (Trematomus borchgrevinki) (Vulpes macrotis)

Eurythermic Vs. Stenothermic

6 Lecture 4 The Distribution of Life

2. Animals Animal adaptations to warm environments: a. Differences in metabolic rate

b. Release of sweat or panting

Lecture 4 The Distribution of Life

Animal adaptations to warm environments: a. Use of microclimate (reptiles and insects)

7 Lecture 4 The Distribution of Life

2. Animals Animal adaptations to warm environments: a. Morphological adaptations

Chameleon African elephant (Chamaeleo calyptratus) (Loxodonta africana)

Lecture 4 The Distribution of Life

I. The Physical Environment B. Temperature 2. Animals Animal adaptations to cold environments: a. Hibernation, torpor, (Chordeiles acutipennis )

(Ursus arctos)

(Lasiurus spp.) (Taxidea taxus)

8 Lecture 4 The Distribution of Life

I. The Physical Environment B. Temperature 2. Animals Animal adaptations to cold environments: a. Hibernation b. Changes in with changes in air temperature

Lecture 4 The Distribution of Life

I. The Physical Environment B. Temperature 2. Animals Animal adaptations to cold environments: c. Morphology

Polar bear (Thalarctos maritimus)

9 Lecture 4 The Distribution of Life

2. Animals

Allen’s Rule: Animals that live in cold environments have shorter extremities (relative to body mass) than related forms in warm environments.

Arctic hare Jack rabbit (Lepus arcticus) (Lepus californicus)

Lecture 4 The Distribution of Life

I. The Physical Environment C. Moisture

1. 2. Hydrophyte 3. Mesophyte

10 Lecture 4 The Distribution of Life

I. The Physical Environment C. Moisture

Lecture 4 The Distribution of Life

I. The Physical Environment C. Moisture

11 Lecture 4 The Distribution of Life

I. The Physical Environment C. Water Plant adaptations to dry conditions: a. Water stress escapees b. Water stress avoiders c. Water stress tolerators

Chamise Poppies Baobab tree (Adenostoma fasciulatum) (Eschscholzia spp.) (Adensonia digitata)

Lecture 4 The Distribution of Life

I. The Physical Environment C. Water

12 Lecture 4 The Distribution of Life

I. The Physical Environment C. Water The Impact of moisture on terrestrial animals: • Most mammals can withstand a loss of about 10% of their body water • Frogs can use as much as 40% of their body water • Water is replenished by drinking from free water such as lakes, streams, springs, and dew on leaves • Water can be replenished via food for some species (Kangaroo rate)

Lecture 4 The Distribution of Life

I. The Physical Environment D. Environmental Gradients and Species Niches

• Geographic range • Density

• Carrying capacity

Fig. 3.12: The range and population density of eastern Bluebird (Sialia sialis)

13 Lecture 4 The Distribution of Life

I. The Physical Environment D. Environmental Gradients and Species Niches

• Niche • • Generalist • Specialist Soil moisture

Air temperature

Figure 3.14. The niches of hypothetical plant species as defined by two gradients.

Lecture 4 The Distribution of Life

I. Biological Interactions A. Predation

• Stenophagus • Euryphagous

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