Ecology

5/1/12

• Objective: To examine foundations of general ecology

• Do Now: – In your notes, define deciduous and coniferous trees

• Do Later:– Ch. 31.1-4– General ecology crossword and niche activity

Ecology

• Study of the relationships between organisms and the environment– Biotic Factors - Living organisms– Abiotic Factors – Nonliving components• Temperature• Forms of energy• Water• Nutrients

Levels of Organization• Organisms – Simplest level of study– Observing a single organism and its interaction

with its environment

Levels of Organization

• Population– A group of individuals of the same species living in

a geographic area.

Levels of Organization

• Community– The collection of all populations in a geographic

area

Levels of Organization• Ecosystem– The collection of biotic and abiotic factors in a

geographic area

Review time!

• Classify each of these images as an organism, population, community or ecosystem.

Ecological Niche

• Niche – The role an organism plays in its environment– Where it lives

• Habitat• Geographic distribution

– How it lives• Nocturnal, diurnal• Daily habits and behaviors• Reproduction

– What it uses• Food, resources

– What it returns• Products, wastes• Predators

What is the niche of a honeybee?

Ecological Niche

• Example: Koala bear– Geographic distribution: • Eastern Australia• Forest dweller

– Food/shelter• Live in and eat eucalyptus trees• Poisonous to most other species

– Predators• Foxes, pythons, birds of prey (owls, eagles, etc.)

Reflection

• In your notes: – Describe the niche of humans in our environment– How has our niche changed over time?

5/2/12

• Objective: To examine food webs and biomes

• Do Now: – Turn in homework activities– In your notes: describe your niche in Hyde School

• Do Later: Ch. 34.8-17

Food Chains and Webs

• Food chains – Flow of energy from plants to top level predators– Interconnected to form food webs

Trophic Levels

• Trophic level – An organism’s position in the food chain

flow of energy

Trophic Levels

• Producers– Green plants and algae

– Use the sun’s energy to make sugars by photosynthesis

– All energy on earth comes from the sun

Trophic Levels

• Primary consumers– Consumers of plants– a.k.a. Herbivores

Trophic Levels

• Secondary consumers– Consumers of

herbivores– First level carnivores

Trophic Levels

• Tertiary consumers– Consumers of

secondary consumers– Second level carnivores

Challenge Time

• Where do humans fall in a food pyramid?

Trophic levels

• Omnivores are consumers of:– Plants (producers)– Animals (consumers)

Trophic Levels

• Decomposers derive energy from decomposing dead organic matter

Practice time

• In your notes: – Construct a food chain, and label the trophic level

of each individual.

– When you’re done, you can expand your food chain into a food web.

Biomes

• Biome – a collection of ecosystems grouped together based on similar characteristics

Tundra

Deciduous forest

Desert

Biomes of the World

Biomes

• The type of biome found in an area is determined by:– Predominant vegetation– Temperature– Precipitation (rain/snow)

Challenge question

• Why do you think the type of biome in an area is determined by its primary vegetation?

Challenge question

• Why do you think the type of biome in an area is determined by its temperature and precipitation?

Biomes of the World

What type of biome do we live in?

Temperate Deciduous Forest

• Primary vegetation: Deciduous trees• Temperatures: Cold winters to hot summers• Precipitation: Moderate to high (30-60 in./year)

Adaptation Time

• Why do deciduous trees have broad, flat leaves? – Flat leaves increase surface area exposed to

sunlight – maximum photosynthesis

Temperate Deciduous Forest

• Why do deciduous trees lose their leaves? – In winter, precipitation is frozen and does not

penetrate into the ground

– Trees shed their leaves to decrease surface area and minimize water loss

Coniferous Forest

• Primary vegetation: Coniferous (evergreen) trees• Temperatures: Long, cold winters. Short, wet

summers. • Precipitation: Mostly snow. Heavy melt in

summer.

Challenge Time!

• Why do you think coniferous trees have needles instead of leaves? – Coniferous forests have low ground water– Northern latitudes little sunlight

5/7/12

• Objective: Old and new business

• Do Now: Put together your tree book – Binder– 7 protector sheets– Make a cover with paper and markers

• Do Later– Finish Hare-Lynx activity– Tree hunting!

Tree Book

• Final project:– Find 10/15 trees marked with a hidden ribbon– Trees are located on the main campus– Collect/press/identify leaves or needles– At least 10 entries in final tree book

Carrying Capacity

• Last class: – Plant life is the base of the food chain

Carrying Capacity

• Carrying capacity: – The maximum number of organisms that an area

can sustain indefinitely

– Limited by the amount of food and resources in an area

Carrying capacity

• Which trophic level do you think has the greatest impact on the carrying capacity of an area?

Carrying Capacity

• Carrying capacity tends to decrease in higher trophic levels– Energy is lost at each step of the food chain– Less higher-order consumers can find food

Population Dynamics

• Study of changes in the size and composition of populations

Models of Population growth

• Logistic Growth– Population increases rapidly until it approaches

carrying capacity

Models of Population Growth

• Exceeding the carrying capacity leads to population crash

Models of Population Growth

• Where is the human population on our logistic growth curve?

Models of Population Growth

• UN estimate of population growth:

Models of Population Growth

• Central questions of human ecology– How are humans going to approach our carrying

capacity?

– Have we already exceeded it?