APES - Chapter 4

Darwin’s Theory of Evolution by Natural Selection

Darwin’s Theory of Evolution by Natural Selection

• individuals produce an excess of offspring and not all survive

• individuals differ in their traits

• differences in traits can be passed on

• differences in traits are associated with differences in ability to survive and reproduce

Reducing competition and species food consumption

Speciation

Formation of 2 species form one because of divergent natural selection in response to changes in the environmental conditions

• faster with species with short life cycles + high reproductive rates

Reasons for speciation

• geographic isolation

• reproductive isolation

Reproductive isolation

two populations can no longer interbreed and produce viable offspring

Prokaryotic organisms

cells have NO double membrane-bound organelles

Eukaryotic organisms

cells have double membrane-bound organelles such as a nucleus and ER

Species

a group of individuals with similar characteristics

• can reproduce

• produce fertile offspring

Types of biodiversity

• ecosystem

• species

• general

• functional

Ecosystem diversity

variety of ecosystems in a given region

Species diversity

Variety of species in a given ecosystem

General diversity

Variety of genes in a given ecosystem

Functional diversity

energy flow and matter recycling needed for survival

Species richness

number of species in a given area

Species evenness

if an ecosystem is dominated by one species or more even

Ecological niche

way of life/role of a species in an ecosystem

• its job

Habitat

the place a species lives

• its address

Generalist species

• broad niches

• live in many places

• variety of food

• wide range of environmental conditions

Ex: bears, raccoons, mice

Specialist species

• narrow niche

• limited type of habitat

• limited food sources

Ex: Pandas, spotted owls

Nonnative species

alien/invasive/exotic

• may spread rapidly w/no predators

• compete with native species

Ex: African honeybees, green crabs, ice plant

Indicator species

provide early warnings of changes in environmental conditions

Ex: frogs, trout, birds

Keystone species

• have a large effect on the types and abundance of other species

Pollinators: butterflies, hummingbirds

Apex predator: help regulate populations

Foundation species

create or enhance their habitats

Evolution

change in the genetic composition of a population over time

• depends on genetic diversity

• occurs in 3 ways

  • artificial selection

  • natural selection

  • random processes

Microevolution

evolution below the species level

Macroevolution

evolution which gives rise to a new species or genera, family, class, or phylla

Levels of organization

Dear King Phillip came over for great soup

• domain

• kingdom

• phylum

• class

• order

• family

• genus

• species

Mutation

random changes in DNA

Recombination

• occurs as chromosomes are duplicated during cell division

• sexual reproduction

Charles Darwin

• marine biologist

• worked on natural selection

• wrote “On the Origin of Species”

• Galapagos turtles, finches, mockingjays

Alfred Wallace

• proposed concept of natural selection

• father of biogeography

Types of fossils

• original remains/true form

• petrified fossils

• carbon films and impressions

• trace fossils

• molds and casts

Fitness

An individual’s ability to survive and reproduce

Phylogenics

branching patterns of evolutionary relationships

What do 1/0 mean in cladograms?

1 - YES

0 - NO