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Chap 4: BIODIVERSITY AND EVOLUTION, vecto mui ten xuong, lead to, vecto…
Chap 4: BIODIVERSITY AND EVOLUTION
Biodiversity and its important
Biodiversity is the variety in
The earth’s species
The number and variety of species in a biological community
Genetic Diversity
The variety of genes in a population or species
Ecological Diversity
The earth’s variety of deserts, grasslands, forests, mountains, oceans, lakes, rivers, and wetlands
Functional diversity
The variety of processes such as energy flow and matter cycling that occur within ecosystems
Biomes are major habitations/large ecosystems with distinct climates and species
Roles species play in ecosystems
4 major roles
nonnative species
deliberately/ accidentally introduced into an ecosystem (invasive, alien exotic species)
indicator species
provide early warnings of environmental change in a community or an ecosystem
native species
live and thrive in a particular ecosystem
keystone species
plays essential role to other species
sustain ecosystem
each species plays a role in its ecosystem
Ecological niche
way of life in a community and includes everything that affects its survival and reproduction (water, space, sunlight,..)
Generalist species
can tolerate a wide range of environmental
conditions
example: flies, cockroaches, rats, white-tailed deer, and humans
Specialist species
be able to live in only one type of habitat
use only one or a few types of food
tolerate a narrow range of environmental conditions
example: Giant Panda
Earth’s life change over time
Biological evolution
How life on the earth changes over time
due to changes in the genes of populations
Population evolution
Give individuals genetic traits →Enhance their
ability to survive and produce offspring
Occur through gene mutation
Fossil
Mineralized or petrified replicas of
skeletons
bones
teeth
shells
leaves
seeds
impressions of such items found in rocks
Factors affect biodiversity
New spices arise
Speciation
when one species splits
into two or more different species
Geographic isolation
when groups of the same population
become physically isolated from one another overtime
Artificial selection
select genetic variations of the same species
Genetic engineering
alter DNA, transfer genes between different species
Reproductive isolation
when mutation and natural selection operate independently of geographical isolated populations
All species eventually become extinct
a significant
rise in extinction rates above the background rate
species are vanishing at a slow rate compared to before the exponential rise of the human population.
species that are confined to a single location
the process by which a whole species vanishes
lead to
Human affect biodiversity
Extinction
Endemic species
Background extinction rate
Mass extinction
