Intro to Ecology and Symbiotic Relationships Ecology How

Intro to Ecology and Symbiotic Relationships

Ecology: How individual organisms interact with each other and with their environment

Levels of Organization • Ecologists organize the world into different biological levels: – Individual – a single member of a species – Populations – group of individuals of the same species living in the same place – Communities – interacting populations of different species – Ecosystems – interacting populations + abiotic factors – Biomes - group of ecosystems (same climate, etc. ) – Biosphere – the part of Earth that can support life

Abiotic vs. Biotic factors • Abiotic factors: the nonliving parts of the environment – Ex. air, temperature, moisture, light, soil – These often determine which species survive in a particular environment • Biotic factors: the living parts of the environment

Ecosystem Interactions • The place where an organism lives (including both abiotic and biotic factors) is called its habitat

Ecosystem Interactions • If an organism’s habitat is its address, its niche is its occupation. • A niche is the role that the organism plays in its habitat; how does it fit in?

Ecosystem Interactions • A fundamental rule in ecology is the competitive exclusion principle, which states that no two species can occupy the same niche in the same habitat at the same time. • Why?

Ecosystem Interactions • A fundamental rule in ecology is the competitive exclusion principle, which states that no two species can occupy the same niche in the same habitat at the same time. • Why? • When organisms share habitats, it creates competition – therefore each organism must find its own niche in order to have enough resources to survive

Community Interactions • Most species survive because of their relationships with other species • Species benefit from one another, harm one another, and are dependent on one another

Community Relationships • Symbiosis – any relationship in which two species live closely together – Competition – Predation – Mutualism – Parasitism

Community Interactions • Competition – organisms fight for resources that they need to survive (food, water, mates)

Community Interactions • Predation – when one organism (a predator) captures/feeds on another (prey)

Community Interactions • Q: How do predator-prey relationships maintain stability in an ecosystem?

Mutualism – both organisms benefit from the relationship

Mutualism examples: - plants + pollinators (birds/ bees) - sea anemones and clown fish - algae and fungi (lichens) - plants and fungi (mycorrhizae)

Parasitism only one organism benefits from the relationship Filarial worms (causes Elephantitis)

Parasitism one organism lives on/inside another and harms it (one helped, one harmed) Filarial worms (causes Elephantitis)

Parasitism examples: - athlete’s foot (fungi on human feet) - mosquitos and animals - cuckoos and cowbirds - tapeworms and dogs

What kind of community interaction is described here? • • A mountain lion pounces and attacks a hare for dinner A tapeworm lives and feeds in the intestine of a dog A bee feeds on the nectar of a honeysuckle flower E. coli live in the human gut and aid in digestion

What kind of community interaction is described here? • A mountain lion pounces and attacks a hare for dinner PREDATION • A tapeworm lives and feeds in the intestine of a dog PARASITISM • A bee feeds on the nectar of a honeysuckle flower MUTUALISM • E. coli live in the human gut and aid in digestion MUTUALISM