4.1.1 Biodiversity. Biodiversity. The amount of biological diversity per unit area. It includes: genetic, habitat and species diversity. Genetic Diversity. Is the total number of genetic characteristics of a specific species. Habitat Diversity.
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The amount of biological diversity per unit area.
It includes: genetic, habitat and species diversity
Is the total number of genetic characteristics of a specific species.
Variety of forests, deserts, grasslands, lakes, oceans, coral reefs, wetlands, and other biological communities,
(niches per unit area).
Is the number of species or organisms per unit areafound in different habitats of the planet.
Tropic of Cancer
Tropic of Capricorn
Critical and endangered
Stable or intact
Projected Status of Biodiversity
usefulness to us.
because they exist,
Regardless of whether
they are useful to us or
Natural selection process by which individuals that are better suited to their environment survive and reproduce most successfully.
Adaptation is an inherited characteristic that increases an organism’s chance of survival.
fruit and seed eaters
insect and nectar eaters
Mutations & Sexual reproduction produces variations among offspring.
Overproduction of offspring
Limited resources leads to a struggle for survival between offspring.
Survivors reproduce more successfully.
Population changes over time.
Extinctions of many marsupials and early placental mammals
About 5 million years ago, during the Pliocene
Fig. 27.19d, p. 471
MONOTREMES, MARSUPIALS EVOLVE AND MIGRATE THROUGH PANGEA
About 150 million years ago, during the Jurassic
Fig. 27.19a, p. 471
Isolation of the early monotremes, marsupials on this land mass
Between 100 and 85 million years ago, during the Cretaceous
Fig. 27.19b, p. 471
Continued isolation of early monotremes and marsupials
Extinctions of mammals
About 20 million years ago, during the Miocene
Fig. 27.19c, p. 471
15-20 million years ago
40 million years ago
Fig. 20.10, p. 319
A group of potentially or actually interbreeding populations, with a common gene pool, which are reproductively isolated from other groups
The species concept is a human construct used to make sense of the natural world. While extraordinarily helpful in understanding life, it fails to capture the full complex reality of continually evolving populations of organisms.
Species that can’t interbreed, but have no significant differences in appearance.
= number of species becoming extinct per unit time.