Lecture #1 - Ecology and Evolution What do you remember about ecology or evolution? REVIEWING TOPICS FOR SUCCESS!
Reviewing Ecology vocabulary VOCABULARY: • Ecology is the study of the parts of the environment living (biotic) and nonliving (abiotic) and how they interact with each other • An Ecosystem is a particular region of the ecology to be studied. • An Ecosystem is defined by all the various plants and animals living in the region and the habitat conditions that exist. • A Biome is a set of environmental conditions – rainfall and temperature that define certain ecosystems
Defining Organism Relationships in an Ecosystem • All organisms are linked together by their feeding relationships. • If organisms are linked together (one eats another directly) their relationship is a food chain. • If organisms are linked together indirectly (where one organism is the food or the predator of other species that are linked by different food chains) by a large network, the complex pattern is a food web.
Sample Food Chain and Food Web Food Chain Food Web
Defining Trophic Levels • Trophic levels are feeding levels of a food chain or web • At each level only 10% of the energy is passed (Rest is lost!) • Producers are the bottom or starting level of a feeding chain or web. • Producers make their own food by using chemicals or sunlight supplied in the environment • Consumers are organisms that consume producers or other consumers in a food chain. • Primary consumers consume producers. • Secondary consumers eat primary consumers • Tertiary consumers eat secondary consumers (etc.) • Decomposers are organisms that consume the organic mater of producers and consumers when they are dead or dying. • Decomposers consume all trophic levels to recycle organic materials
Trophic Levels in a Food Web Trophic Levels Tertiary consumer (4) Decomposer (5) (0.1% original energy passed) (4) (3) (worm) Secondary consumer (3) (4) (1 % of original energy passed) Primary consumers(2) (10% of orginal energy passed) (2) (2) Producer (1) (100% of original energy) (1)
Defining Niche and Organisms Relationships • A Niche is the function an organism serves in the environment • Example: a worm’s job is to decompose dead organism NOTE: ONLY ONE SPECIES CAN SURVIVE ONE HABITAT OCCUPYING ONE NICHE (competition will select one species and others will die off!) • APredator-Prey relationshipis the relationship between an animal that eats another and the animal that is eaten • Example: a lion hunts an antelope as a predator. The antelope is prey trying to stay alive • Competition is the head-to-head struggle between different species or organisms of the same species for resources from the habitat when two organisms of the same niche • Example: Gray vs Red squirrels cannot occupy the same habitat, because they occupy the same niche. They will compete for resources until only one species survives
Reviewing Evolution Concepts • Evolution is a theory of change in organisms in the environment over time as stated by Darwin as a four part theory Darwin studied organism in England and the Americas as he developed his theory on change Darwin’s most comprehensive evidence was studying Galopagos finches (birds) with different beaks adapted to different food sources on different islands.
Four Concepts of Evolution • Organism reproducing show genetic variation (example- people have different color skin, hair and eyes) • Organisms all overproduce, each pair trying to maximize its reproductive success. (example – frogs may lay 1000’s of eggs but only a few survive) 3. Organisms are stressed differently by environmental pressures – climate conditions, surplus or famine – and must compete for resources with other of the same species (example- individuals in a species that get more food survive) 4. A. Organisms have a different level of adaption for survival in the habitat as it changes over time (example- if climate gets colder, those with more hair survive) 4. B. Organism that have the best level of adaption and compete best over others are selected for survival over time. NOTE: This concept of competing best is called Natural Selection (example- a giraffe with a long neck is selected for over shorter necks
Applying Evolution Concepts to Compare Organisms – part 1 • Anatomical similarities: • Observing related organisms can demonstrate similar anatomical structures which can be explain by evolution from a common ancestor. (Example: many vertebrates – fish, lizards, birds, humans- show similar arm structures • The degree of similarity of structure can help to predict the degree of relationship (how closely one organisms is related to another) • Homologous structures: • Two similar structures from related species that came from a common ancestor (Example: vertebrate arm structures that came from a common ancestor are homologous structures)
Applying Evolution Concepts to Compare Organisms – part 2 • Classification: • Scientists use similar traits, including homologous structures, DNA similarities, etc., to name and organize the millions of known species on the planet using the categories of Kingdom, Phylum, Class, Order, Family, Genus, Species. • Binomial nomenclature: • Scientists use genus and species to name each organism uniquely