Stuff you need to know…

TERMS TO KNOW!! EVOLUTION: the process by which

modern organisms have descended from ancient organisms.

(“CHANGE OVER TIME”)

  FITNESS: refers to traits and behaviors of organisms that enable them to survive and reproduce

 ADAPTATION: any inherited characteristic that enhances an organism’s ability to survive and reproduce

~based on variations randomly inherited

Charles Darwin’s Explanation on Evolution

(six major ideas of Darwin)Overproduction occurs in nature

Variation occurs in all populations

Not all organisms can survive

Variations are inherited

Populations as a whole become FIT = evolved!

Organisms with favorable variations survive and reproduce

Insecticide applied

Genetic DriftChanges in the gene pool of a small population due to chance

Examples:

-Bottleneck Effect: results from drastic decrease in population size

-Founder Effect: few individuals in a population colonize a new habitat

Bottleneck Effect

SpeciationThe origin of new species (the appearance of new species is the source of biological diversity)

• Reproductive Isolation: barriers that prevent members of two species from producing viable, fertile hybrids

• Geographic Isolation: Gene flow between gene pools is interrupted when a population is divided into two geographically isolated subpopulations– Ex: the water level in a lake decreases– Ex: a river splits a population into two

Ecology

1) Life is ORGANIZED on many structural levels:

AtomsBiological Molecules

Subcellular organellesCells

TissuesOrgans

Organ SystemsComplex Organism

Levels beyond the individual organism:

PopulationCommunityEcosystem

BiomesBiosphere

Biodiversity

• Definition: the number and variety of organisms found within a specified geographic region – affected by alterations

of habitats.

• fluctuations in population size in an ecosystem are determined by the relative rates of birth, immigration, emigration, and death. – Change in pop size = [B + I] – [D + E]

Review• Autotrophs—capture energy from

sunlight or chemicals and use that energy to produce food– AKA producers

• Photosynthesis– Plants

• Chemosynthesis– Bacteria

• Heterotrophs (Consumers)– Herbivores– Carnivores– Omnivores– Detritivores

• Feed on plant and animal remains (have a mouth; ingest food)

– Mites, earthworms, snails

– Decomposers• Break down organic matter

– Bacteria and fungi

Flow of EnergyEnergy flows through an ecosystem (a section of the

biosphere) from the sun, to producers, to consumers

IN ONE DIRECTION!!!

Food Chains

• Food Chain—transfer of energy by eating and being eaten

Food Webs

• Food Web—describes complex relationships of organisms in an ecosystem– A food web links

together all the food chains in an ecosystem

• each step of an organism eating another organism is called a trophic level (trophe means food in Greek)

• Shows the relative amounts of energy contained within each trophic level in a food chain or food web

• Only part of the energy that is stored in one trophic level is passed on…(10%)

Tertiary Consumers

Producers

Energy PyramidPrimary Consumers

• Approximately 10% of the energy at one trophic level can be used by animals at the next trophic level – ex: 90% of

produced/consumed energy is used in that organisms cellular respiration

– Only 10% incorporated into tissues

• More energy efficient to eat producers

• Although energy moves in a one-way direction through an ecosystem, nutrients are recycled

Succession• series of changes in an ecological community that

occur over time after a disturbance

Fossils- Any preserved evidence of life from a past geological age (ex: impressions & remains of organisms embedded in stratified

rocks; mineralized remains of an animal or plant

Fossils include shells, imprints, burrows, and organically-produced chemicals. The oldest fossils are of bacteria (prokarytotes) & they are 3.8 billion years old.

Bacteria vs.Virus BACTERIA VIRUS

*Alive (1 celled organism) take ANTIBIOTICS to slow growth

*Not alive, therefore no antibiotics

*Viruses “hijack” cells & use the cells’ machinery in order to reproduce (use cells’ ribosomes. ATP, amino acids, etc.)

* 2 types: 1. hijacker (cold) 2. hijacker & infiltrator (HIV)

*VACCINES prepare your immune in case you are exposed to that virus later (difficult due to high # of mutations)