Relationships, Biomes & Population Growth

Unit 10

Relationships

What is Ecology?

Ecology: Scientific study of interactions among organisms and between organisms and their environment.

To understand relationships within the biosphere, ecologists ask questions about events and organisms that range in complexity from a single organism to the entire biosphere.

What are the levels of organization?

What are the levels of organization?

Species: Group of similar organisms that can breed and reproduce fertile offspring.

One

Zebra

What are the levels of organization?

Populations: Group of individuals of the same species that live in the same area.

Herd of zebra

What are the levels of organization?

Communities: Assemblage of different populations that live together in a defined area.

Herd of animals on

the Serengeti

What are the levels of organization?

Ecosystem: A biological community and all of the abiotic factors that affect it.

What are the levels of organization?

Biome: Group of ecosystems that have the same climate and similar dominate communities.

Rainforest Desert

What are the levels of organization?

Biosphere: Part of Earth in which life exists including land, water, and air or atmosphere.

• Ecosystems are influenced by biological and physical factors.

• The biological influences on organisms within an ecosystem are called biotic factors.

• Includes; all biological creatures which an organism may interact or, it’s community. Mushrooms, birds, trees, bacteria

What are ecosystems composed of?

• Physical, or non-living factors that shape ecosystems are

called abiotic factors.

• Includes; the climate like—temperature, precipitation,

humidity, wind, nutrient type, soil type, sunlight etc.

What are ecosystems composed of?

Abiotic Factors

ECOSYSTEM

Biotic Factors

Living ONLY

Non-Living ONLY

Living & Non-Living Together

Trees, bird, grass, rabbit, & moose

Mountain, clouds, water &

rocks

What is an ecosystem composed of?

What is a habitat?

Habitat: An area where organisms live

Provides: * Food * Water * Space * Shelter

What is a niche?• Is the organisms occupation...Its job...What it does.

• A niche is the full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions.

What is symbiosis and what are the different types?

• Any relationship in which two species live closely together is called symbiosis or “living together”

• Examples: mutualism, commensalism, parasitism

What is symbiosis and what are the different types?

Mutualism: Both species benefit.

(Ex.: Bee and flower & Cleaner fish/other fish)

Mutualism Video

What is symbiosis and what are the different types?

Commensalism: One member benefits and the other is neither helped nor harmed.

(Example: bird nest in a tree, barnacle on a whale)

What is symbiosis and what are the different types?

Parasitism: One organism lives on or inside another organism and harms it.

• A host is the organism in which a parasite obtains its nutritional needs.

The cuckoo bird is a parasite!

The cuckoo lays eggs in other species of bird’s

nests. It hatches first and pushes out the other bird’s eggs. Then the mother bird

raises the cuckoo rather than her own babies!

Cuckoo Egg!

Parasite Example

Parasite Example • This is a tapeworm. If your dog/cat ingests a flea, and the flea has a tapeworm egg in it, this is born in the animals intestinal tract and feeds off of the animals food.

What is the difference between weather & climate?

Weather is the day to day condition of Earth’s atmosphere at a particular time and place.

Climate refers to the average year after year conditions of temperature and precipitation in a particular region.

What is a climatogram?

A Climatogram is a diagram that summarizes a region’s climate, including temperature and precipitation.

• The major biomes are defined by a unique set of abiotic factors• Each has a characteristic ecological community and each is

defined by its climate (temperature & precipitation)

• It has nothing to do with countries!

The Major Biomes

Types of Biomes

Tropical Rainforest

Hot, wet biome with year-round humidity

Contains Earth’s MOST diverse species of plants and animals

TundraA biome that is treeless with a layer of permanently

frozen soil below the surface called permafrost

* Very little precipitation!

Taiga/Boreal Forest* South of the tundra

* Summers are warmer and longer than the tundra.

* Lacks permafrost layer

Temperate Grassland

* Mostly grasses and very few trees

* Fertile soil

* Many grazing animals like buffalo & horses

* Also called prairies in the US

Temperate Grasslands

* These grasses contain oils that make them flammable

* Grass fires help the biome’s grasses grow healthier after the fire

Tropical Savanna

* Grasses with scattered trees

Desert

* Annual rate of evaporation exceeds the rate of precipitation

* Very little rain

* Can have a little variety of animals

Populations

What affects a population?

1. Predation- Predators: as the number of prey increase, the number of

predators will too

2. Disease - Outbreaks occurs when population density is high

- Disease is transmitted easier

3. Parasites- Similar to disease, when population density

is high, parasites are

transmitted easier

4. Competition- Individuals compete for:

Food, water, shelter, & space

What is Population Growth Rate?• Population Growth Rate: Explains how fast a given

population grows

– If death rates decrease and births increase, the population with increase OR decrease?

• Emigration: Used to describe the number of individuals who move away from a population.

• Immigration: Used to describe the number of individuals who move into a population.

Types of GrowthPredator/Prey Model:

As the number of lynx increase, the number of hare also increase.

As then number of hare decrease, the number of lynx decrease.

Population Limiting Factors

• Density-dependent– Deaths occur more quickly in a crowded

population– Ex: resources, predation, disease

• Density-independent– A certain proportion dies regardless of

population density– Ex: severe weather, natural disaster

Types of GrowthExponential Growth Model:

Bacteria in a Petri dish

• Food is placed into a Petri dish, and bacteria is introduced to the food.

• The first 2 hours is the “lag phase”, followed with exponential growth.

• During the 2nd hour, bacteria begin to reproduce because there is

plenty of food available.

• The bacteria will grow exponentially until there is no more food, and then

they will all die.

Exponential Growth

Often referred to as

“J-Shaped Growth”

Lag Phase

Video

Rate of Reproduction Video

Types of GrowthLogistic Growth Model:

• Notice the S-shape in this graph…

the population levels off (stabilizes)

• Carrying Capacity: The maximum number of individuals in a species that an environment can support for a long period of time.

Carrying Capacity Video

The End